Plants - Groups : Embryophyte part 3

Other groups, which first appeared towards the end of the Palaeozoic, reproduce using desiccation-resistant capsules called seeds. They are accordingly are called spermatophytes or seed plants. In these forms the gametophyte is completely reduced, taking the form of single-celled pollen and ova, and the sporophyte begins its life enclosed within the seed. Some seed plants may survive in extremely arid conditions. They include the following extant groups:

    * Cycadophyta (Cycads)
    * Ginkgophyta (Ginkgo)
    * Pinophyta (Conifers)
    * Gnetophyta (Gnetae)
    * Magnoliophyta (Flowering plants)

The first four groups are referred to as gymnosperms, since the embryonic sporophyte is not enclosed until after pollination. In contrast, the flowering plants or angiosperms the pollen has to grow a tube to penetrate the seed coat. They were the last major group of plants to appear, developing from gymnosperms during the Jurassic and spreading rapidly during the Cretaceous. They are the predominant group of plants in most terrestrial biomes today.

Note the higher-level classification of plants varies considerably. Some authors have restricted the kingdom Plantae to include only embryophytes, others have given them various names and ranks. The groups listed here are often considered divisions or phyla, but have also been treated as classes, and they are occasionally compressed into as few as two divisions.

On a microscopic level, embryophyte cells remain very similar to those of green algae. They are eukaryotic, with a cell wall composed of cellulose and plastids surrounded by two membranes. These usually take the form of chloroplasts, which conduct photosynthesis and store food in the form of starch, and characteristically are pigmented with chlorophylls a and b, generally giving them a bright green color. Embryophytes also generally have an enlarged central vacuole or tonoplast, which maintains cell turgor and keeps the plant rigid. They lack flagella and centrioles except in certain gametes.

 
 

source : hydroponicsearch

Plants - Groups : Embryophyte part 2

All bryophytes are relatively small and are usually confined to moist environments, relying on water to disperse their spores. Other plants better adapted to terrestrial conditions appeared during the Silurian, and during the Devonian they diversified and spread to many different land environments. These are called vascular plants or tracheophytes. They have vascular tissues or tracheids, which transport water throughout the body, and an outer layer or cuticle that resists desiccation. In most the sporophyte is the dominant individual, and develops true leaves, stems, and roots, while the gametophyte remains very small.

Many vascular plants still reproduce using spores, including the following extant groups:

    * Lycopodiophyta (clubmosses)
    * Equisetophyta (horsetails)
    * Psilotophyta (whisk ferns)
    * Ophioglossophyta (adders'-tongues and grape-ferns)
    * Pteridophyta (ferns)

Other groups, which first appeared towards the end of the Palaeozoic, reproduce using desiccation-resistant capsules called seeds. They are accordingly are called spermatophytes or seed plants. In these forms the gametophyte is completely reduced, taking the form of single-celled pollen and ova, and the sporophyte begins its life enclosed within the seed. Some seed plants may survive in extremely arid conditions. They include the following extant groups:

    * Cycadophyta (Cycads)
    * Ginkgophyta (Ginkgo)
    * Pinophyta (Conifers)
    * Gnetophyta (Gnetae)
    * Magnoliophyta (Flowering plants)

The first four groups are referred to as gymnosperms, since the embryonic sporophyte is not enclosed until after pollination. In contrast, the flowering plants or angiosperms the pollen has to grow a tube to penetrate the seed coat. They were the last major group of plants to appear, developing from gymnosperms during the Jurassic and spreading rapidly during the Cretaceous. They are the predominant group of plants in most terrestrial biomes today.

 

source : hydroponicsearch

Plants - Groups : Embryophyte

The embryophytes are the most familiar group of plants, including trees, flowers, ferns, mosses, and various others. All are complex multicellular organisms with specialized reproductive organs and, with very few exceptions, they obtain their energy through photosynthesis, i.e. by absorbing light, and synthesize food from carbon dioxide. They may be distinguished from multicellular algae by having sterile tissue within the reproductive organs. Further, embryophytes are primarily adapted for life on land, although some are secondarily aquatic. Accordingly they are often called land plants.

Embryophytes developed from complex green algae during the Palaeozoic era. Their closest living relatives are the Charales or stoneworts. These algae undergo an alternation between haploid and diploid generations, respectively called gametophytes and sporophytes. In the first embryophytes, however, the sporophytes became very different in structure and function, remaining small and dependent on the parent for their entire brief life. Such plants are called bryophytes; they include three surviving groups:

    * Bryophyta (mosses)
    * Anthocerotophyta (hornworts)
    * Marchantiophyta (liverworts)

All bryophytes are relatively small and are usually confined to moist environments, relying on water to disperse their spores. Other plants better adapted to terrestrial conditions appeared during the Silurian, and during the Devonian they diversified and spread to many different land environments. These are called vascular plants or tracheophytes. They have vascular tissues or tracheids, which transport water throughout the body, and an outer layer or cuticle that resists desiccation. In most the sporophyte is the dominant individual, and develops true leaves, stems, and roots, while the gametophyte remains very small.

Many vascular plants still reproduce using spores, including the following extant groups:

    * Lycopodiophyta (clubmosses)
    * Equisetophyta (horsetails)
    * Psilotophyta (whisk ferns)
    * Ophioglossophyta (adders'-tongues and grape-ferns)
    * Pteridophyta (ferns)



 

source : hydroponicsearch

Plants - Dandelion : Introduction Antioxidant properties

Dandelion contains Luteolin , an antioxidant, and has demonstrated antioxidant properties without cytotoxicity .

Chun Hu and David D. Kitts. Food, Nutrition and Health, Faculty of Agricultural Sciences, University of British Columbia, Vancouver, BC, Canada. October 2004. Luteolin and luteolin-7-O-glucoside from dandelion flower suppress iNOS and COX-2 in RAW264.7 cells. Springer Netherlands. 245:1-2(107-113). [1]

Caffeic acid and carcinogenicity

 
The dandelion's taproot, shown in this drawing, makes this plant very difficult to uproot; the top of the plant breaks away, but the root stays in the ground and can sprout again.
Caffeic acid is a secondary plant metabolite produced in dandelion, yarrow , horsetail and whitethorn . Despite its name, it is totally unrelated to caffeine. Recent studies have revealed this acid may be carcinogenic. Caffeic acid was tested for carcinogenicity by oral administration in mice, it produced rena l cell adenomas in females, and a high incidence of renal tubular cell hyperplasia in animals of each sex.[4] However, more recent research shows that bacteria present in the rats' guts may alter the formation of metabolites of Caffeic acid. [2] and [3] Also, there have been no known ill-effects of Caffeic acid in humans.

 

False dandelions

Dandelions are so similar to cat's-ears (Hypochoeris ) that cat's-ears are also known as "false dandelions". Both plants carry similar flowers which form into windborne seeds. However, catsear flowering stems are forked and solid, whereas dandelions possess unforked stems that are hollow. Both plants have a rosette of leaves and a central taproot. However, the leaves of dandelions are jagged in appearance, whereas those of catsear are more lobe-shaped and hairy.

Other plants with similar flowers include hawkweeds (Hieracium) and hawksbeards (Crepis). These are both readily distinguished by their branched flowering stems.

References:

 

    * Richards, A. J. 1972. The Taraxacum flora of the British Isles. Watsonia 9 (supplement): 1-141.
    * Gail, Peter. The Dandelion Celebration: A Guide to Unexpected Cuisine. Cleveland, Ohio: Goosefoot Acres Press, 1994. ISBN 1-879863-51-0.
    * How to cook dandelions ~ at Wikibooks
    * Dandelion Poetry, Folklore, Literature, and Pictures
    * Dandelion at Plants For A Future
    * a university of Wisconsin article on dandelions
    * SpringerLink. Chun Hu and David D. Kitts. Food, Nutrition and Health, Faculty of Agricultural Sciences, University of British Columbia, Vancouver, BC, Canada. October 2004. Luteolin and luteolin-7-O-glucoside from dandelion flower suppress iNOS and COX-2 in RAW264.7 cells. Springer Netherlands. 245:1-2(107-113).





 

source : hydroponicsearch

Plants - Dandelion : Introduction Uses

 
A patch of dandelions in Canada.
While the dandelion is considered a weed by many gardeners, the plant does have several culinary and medicinal uses. Dandelions are grown commercially at a small scale as a leaf vegetable. The plant can be eaten cooked or raw in various forms, such as in soup or salad. They are probably closest in character to mustard greens . Usually the young leaves and unopened buds are eaten raw in salads, while older leaves are cooked. Raw leaves have a slightly bitter taste. Dandelion salad is often accompanied with hard boiled eggs. The leaves are high in vitamin A , vitamin C and iron, carrying more iron and calcium than spinach.[3]

 

Dandelion flowers can be used to make dandelion wine. The recipe usually contains citrus fruit. Another recipe using the plant is dandelion flower jam. Ground roasted dandelion root can be used as a coffee substitute. Drunk before meals, it is believed to stimulate digestive functions. Sold in most health food stores, often in a mixture, it is considered an excellent cleansing tonic for the liver.

 
Eye level view of dandelions
Dandelion root is a registered drug in Canada, sold as a diuretic. A leaf decoction can be drunk to "purify the blood", for the treatment of anemia , jaundice , and also for nervousness . The milky latex has been used as a mosquito repellent; the milk is also applied to warts, helping get rid of them without damaging the surrounding skin. A dye can also be obtained from the roots of the plant. A new mixture of roasted roots is sold as a product called DandyBlend which tastes like coffee after the inulin in the dandelion is roasted.

 

"Dandelion and Burdock" is a soft drink that has long been popular in the United Kingdom with authentic recipes sold by health food shops. It is unclear whether cheaper supermarket versions actually contain either plant.

This plant also is useful in farming, because its deep, strong roots break up hardpan.


 

source : hydroponicsearch

Plants - Dandelion : Introduction Selected species

    * Taraxacum officinale (syn. T. officinale subsp. vulgare), Common Dandelion. Found in many forms, but differs at least from the following species:
    * Taraxacum albidum, a white-flowering Japanese dandelion.
    * Taraxacum japonicum, Japanese dandelion. No ring of smallish, downward-turned leaves under the flowerhead.
    * Taraxacum laevigatum (syn. T. erythrospermum), Red-seeded Dandelion; achenes reddish brown and leaves deeply cut throughout length. Inner bracts' tips are hooded.


Seed development and genetics

 
Macro photo of dandelion seed dispersal.
As aforementioned, the taxonomical situation of the genus is quite complex, mainly because many dandelions are genetically triploid. An odd number of chromosomes usually is associated with sterility , but dandelions with this karyotype can reproduce without fertilization, a process called apomixis [2]. In these individuals flowers are useless vestigial structures, although they may still produce a small percentage of fertile pollen, keeping some genetic contact with sexual individuals. Diploid dandelions develop seeds after cross-pollination and are self-incompatible. In most zones of southern Europe and Asia, dandelion populations are sexual or mixed sexual-apomictic , while in northern countries only triploid and tetraploid apomicts are present, as is in the zones where it is not native. This seems to be linked to higher temperatures, survival of pre-glacial populations and human impact, but the subject is still being studied.

 

There are usually 54 to 172 seeds produced per head, but a single plant can produce more than 2000 seeds a year. It has been estimated that more than 97 000 000 seeds/hectare could be produced every year by a dense stand of dandelions.

 

source : hydroponicsearch

Plants - Dandelion : Introduction Dandelion clock

 
A flowering dandelion.
The flower matures into a globe of fine filaments that are usually distributed by wind, carrying away the seed-containing achenes . This globe (receptacle ) is called the "dandelion clock", and blowing it apart is a popular pastime for children. In German it's called a Pusteblume, translated as "blow flower". The number of blows required to completely rid the clock of its seeds is deemed to be the time of day.

 

Seeds

 
A dandelion clock.
The flower head is surrounded by bracts (sometimes mistakenly called sepals ) in two series. The inner bracts are erect until the seeds mature, then flex down to allow the seeds to disperse; the outer bracts are always reflexed downward. Some species drop the "parachute" (called a pappus , modified sepals) from the achenes. Between the pappus and the achene, there is a stalk called beak , which elongates as the fruit matures. The beak breaks off from the achene quite easily.

 

Name

 
Macro photo of dandelion clock
The name dandelion is derived from the Old French, dent-de-lion, which is literally "lion's tooth", referring to the sharply-lobed leaves of the plant. The English spelling reflects the French pronunciation at the time this French word was absorbed into English. The first written usage of the word occurs in an "herbal " dated 1373, but there is a 1363 document in which the word "dandelion" was used as a proper name (Willelmus Dawndelyon).

 

In German, the dandelion is called Löwenzahn, which is also translated as "lion's tooth." In modern French the plant is called pissenlit, which means "urinate in bed", apparently referring to its diuretic properties. Likewise, "pissabeds " is an English folkname for this plant, and "piscialletto" is one of its folknames in Italian (with "dente di leone", meaning "lion's tooth"). Similarly in Spanish, it is known as the "meacamas", but also commonly "diente de león".


 

source : hydroponicsearch

Plants - Dandelion : Introduction

A dandelion is a short plant, usually with a yellow flower head and notched leaves. A dandelion flower head consists of many tiny flowers. The dandelion is native to Europe and Asia, and has spread to many other places. The dandelion is also known by its generic name Taraxacum. In Northern areas and places where the dandelion is not native, it reproduces asexually .
Description

Dandelion (Taraxacum ) is a large genus of flowering plants in the family Asteraceae . They are tap-rooted biennial or perennial herbaceous plants, native to temperate areas of the Northern Hemisphere of the Old World .

 
Image
The genus is taxonomically very complex, with numerous macrospecies, and polyploidy is also common; over 250 species have been recorded in the British Isles alone (Richards 1972). Some botanists take a much narrower viewpoint, and only accept a total of about 60 species.

 

The leaves are 5-25 cm long, simple and basal , entire or lobed , forming a rosette above the central taproot . As the leaves grow outward they push down the surrounding vegetation, such as grass in a lawn, killing the vegetation by cutting off the sunlight. A bright yellow flower head (which is open in the daytime but closes at night) is borne singly on a hollow stem (scape) which rises 4-30 cm above the leaves and exudes a milky sap (latex ) when broken. A rosette may produce several flowering stems at a time. The flower head is 2-5 cm in diameter and consists entirely of ray florets .

Dandelions are used as food plants by the larvae of some species of Lepidoptera . [1]

Away from their native regions, they have become established in the Americas, Australia and New Zealand as weeds. They are now common plants throughout all temperate regions.
 
 

source : hydroponicsearch

Genetic modification

Genetic modification of plants is achieved by adding a specific gene or genes to a plant, or by knocking out a gene with RNAi, to produce a desirable phenotype. The plants resulting from adding a gene are often referred to as transgenic plants. Plants in which RNAi is used to silence genes are now starting to be called Cisgenic plants. Genetic modification can produce a plant with the desired trait or traits faster than classical breeding because the majority of the plant's genome is not altered.

To genetically modify a plant, a genetic construct must be designed so that the gene to be added or knocked-out will be expressed by the plant. To do this, a promoter to drive transcription and a termination sequence to stop transcription of the new gene, and the gene of genes of interest must be introduced to the plant. A marker for the selection of transformed plants is also included. In the laboratory, antibiotic resistance is a commonly used marker: plants that have been successfully transformed will grow on media containing antibiotics; plants that have not been transformed will die. In some instances markers for selection are removed by backcrossing with the parent plant prior to commercial release.

The construct can be inserted in the plant genome by genetic recombination using the bacteria Agrobacterium tumefaciens or A. rhizogenes, or by direct methods like the gene gun or microinjection. Using plant viruses to insert genetic constructs into plants is also a possibility, but the technique is limited by the host range of the virus. For example, Cauliflower mosaic virus (CaMV) only infects cauliflower and related species. Another limitation of viral vectors is that the virus is not usually passed on the progeny, so every plant has to be inoculated.

The majority of commercially released transgenic plants, are currently limited to plants that have introduced resistance to insect pests and herbicides. Insect resistance is achieved through incorporation of a gene from Bacillus thuringiensis (Bt) that encodes a protein that is toxic to some insects. For example, the cotton bollworm, a common cotton pest, feeds on Bt cotton it will ingest the toxin and die. Herbicides usually work by binding to certain plant enzymes and inhibiting their action. The enzymes that the herbicide inhibits are known as the herbicides target site. Herbicide resistance can be engineered into crops by expressing a version of target site protein that is not inhibited by the herbicide. This is the method used to produce glyphosate resistant crop plants (See Glyphosate)

Genetic modification of plants that can produce pharmaceuticals (and industrial chemicals), sometimes called pharmacrops, is a rather radical new area of plant breeding.

 

source : hydroponicsearch

Plant breeding - Introduction part 4

After World War II

Following World War II a number of techniques were developed that allowed plant breeders to hybridize distantly related species, and artificially induce genetic diversity.

When distantly related species are crossed, plant breeders make use of a number of plant tissue culture techniques to produce progeny from other wise fruitless mating. Interspecific and intergeneric hybrids are produced from a cross of related species or genera that do not normally sexually reproduce with each other. These crosses are referred to as Wide crosses. The cereal triticale is a wheat and rye hybrid. The first generation created from the cross was sterile, so the cell division inhibitor colchicine was used to double the number of chromosomes in the cell. Cells with an uneven number of chromosomes are sterile.

Failure to produce a hybrid may be due to pre- or post-fertilization incompatibility. If fertilization is possible between two species or genera, the hybrid embryo may abort before maturation. If this does occur the embryo resulting from an interspecific or intergeneric cross can sometimes be rescued and cultured to produce a whole plant. Such a method is referred to as Embryo Rescue. This technique has been used to produce new rice for Africa, an interspecific cross of Asian rice (Oryza sativa) and African rice (Oryza glaberrima).

Hybrids may also be produced by a technique called protoplast fusion. In this case protoplasts are fused, usually in an electric field. Viable recombinants can be regenerated in culture.

Chemical mutagens like EMS and DMSO, radiation and transposons are used to generate mutants with desirable traits to be bred with other cultivars. Classical plant breeders also generate genetic diversity within a species by exploiting a process called somaclonal variation, which occurs in plants produced from tissue culture, particularly plants derived from callus. Induced polyploidy, and the addition or removal of chromosomes using a technique called chromosome engineering may also be used.

When a desirable trait has been bred into a species, a number of crosses to the favoured parent are made to make the new plant as similar as the parent as possible. Returning to the example of the mildew resistant pea being crossed with a high-yielding but susceptible pea, to make the mildew resistant progeny of the cross most like the high-yielding parent, the progeny will be crossed back to that parent for several generations (See backcrossing ). This process removes most of the genetic contribution of the mildew resistant parent. Classical breeding is therefore a cyclical process.

It should be noted that with classical breeding techniques, the breeder does not know exactly what genes have been introduced to the new cultivars. Some scientists therefore argue that plants produced by classical breeding methods should undergo the same safety testing regime as genetically modified plants. There have been instances where plants bred using classical techniques have been unsuitable for human consumption, for example the poison solanine was accidentally re-introduced into varieties of potato though plant breeding.

 
source : hydroponicarticle

Plant breeding - Introduction part 3

Before World War II

Intraspecific hybridization within a plant species was demonstrated by Charles Darwin and Gregor Mendel, and was further developed by geneticists and plant breeders. In the early 20th century, plant breeders realized that Mendel's findings on the non-random nature of inheritance could be applied to seedling populations produced through deliberate pollinations to predict the frequencies of different types.

In 1908, George Harrison Shull described heterosis, also known as hybrid vigor. Heterosis describes the tendency of the progeny of a specific cross to outperform both parents. The detection of the usefulness of heterosis for plant breeding has lead to the development of inbred lines that reveal a heterotic yield advantage when they are crossed. Maize was the first species where heterosis was widely used to produce hybrids.

By the 1920s, statistical methods were developed to analyze gene action and distinguish heritable variation from variation caused by environment. In 1933, another important breeding technique, cytoplasmic male sterility (CMS), developed in maize, was described by Marcus Morton Rhoades. CMS is a maternally inherited trait that makes the plant produce sterile pollen, enabling the production of hybrids and removing the need for detasseling maize plants.

These early breeding techniques resulted in large yield increase in the United States in the early 20th century. Similar yield increases were not produced elsewhere until after World War II, the Green Revolution increased crop production in the developing world in the 1960s.

 
After World War II

Following World War II a number of techniques were developed that allowed plant breeders to hybridize distantly related species, and artificially induce genetic diversity.

When distantly related species are crossed, plant breeders make use of a number of plant tissue culture techniques to produce progeny from other wise fruitless mating. Interspecific and intergeneric hybrids are produced from a cross of related species or genera that do not normally sexually reproduce with each other. These crosses are referred to as Wide crosses. The cereal triticale is a wheat and rye hybrid. The first generation created from the cross was sterile, so the cell division inhibitor colchicine was used to double the number of chromosomes in the cell. Cells with an uneven number of chromosomes are sterile.

source : hydroponicarticle

Plant breeding - Introduction part 2

Classical plant breeding
The Yecoro wheat (right) cultivar is sensitive to salinity, plants resulting from a hybrid cross with cultivar W4910 (left) show greater tolerance to high salinity
Classical plant breeding uses deliberate interbreeding (crossing) of closely or distantly related species to produce new crops with desirable properties. Plants are crossed to introduce traits/genes from one species into a new genetic background. For example, a mildew resistant pea may be crossed with a high-yielding but susceptible pea, the goal of the cross being to introduce mildew resistance without losing the high-yield characteristics. Progeny from the cross would then be crossed with the high-yielding parent to ensure that the progeny were most like the high-yielding parent, (backcrossing), the progeny from that cross would be tested for yield and mildew resistance and high-yielding resistant plants would be further developed. Plants may also be crossed with themselves to produce inbred varieties for breeding.

 

Classical breeding relies on homologous recombination of two genomes to generate genetic diversity. The Classical plant breeder may also makes use of a number of in vitro techniques such as protoplast fusion, embryo rescue or mutagenisis (see below) to generate diversity and produce plants that would not exist in nature.


The Yecoro wheat (right) cultivar is sensitive to salinity, plants resulting from a hybrid cross with cultivar W4910 (left) show greater tolerance to high salinity

Traits that breeders' have tried to incorporate into crop plants in the last 100 years include:

   1. Increased quality and yield of the crop
   2. Increased tolerance of environmental pressures (salinity, extreme temperature, drought)
   3. Resistance to viruses, fungi and bacteria
   4. Increased tolerance to insect pests
   5. Increased tolerance of herbicides


source : hydroponicarticle

Plant breeding - Introduction part 1

Plant breeding is the purposeful manipulation of plant species in order to create desired genotypes and phenotypes for specific purposes. This manipulation involves either controlled pollination, genetic engineering, or both, followed by artificial selection of progeny. Plant breeding often, but not always, leads to plant domestication.

Plant breeding has been practiced for thousands of years, since near the beginning of human civilization. It is now practiced worldwide by government institutions and commercial enterprises. International development agencies believe that breeding new crops is important for ensuring food security and developing practices of sustainable agriculture through the development of crops suitable for their environment 1 2.

Domestication

Domestication of plants is an artificial selection process conducted by humans to produce plants that have fewer undesirable traits of wild plants, and which renders them dependent on artificial (usually enhanced) environments for their continued existence. The practice is estimated to date back 9,000-11,000 years. Many crops in present day cultivation are the result of domestication in ancient times, about 5,000 years ago in the Old World and 3,000 years ago in the New World. In the Neolithic period, domestication took a minimum of 1,000 years and a maximum of 7,000 years. Today, all of our principal food crops come from domesticated varieties.

A cultivated crop species that has evolved from wild populations due to selective pressures from traditional farmers is called a landrace. Landraces, which can be the result of natural forces or domestication, are plants (or animals) that are ideally suited to a particular region or environment. An example are the landraces of rice, Oryza sativa subspecies indica, which was developed in South Asia, and Oryza sativa subspecies japonica, which was developed in China.

 


source : hydroponicarticle

Phytoextraction - Using Plants to Clean Soils

Phytoextraction (or phytoaccumulation) uses plants to remove contaminants from soils, sediments or water into harvestable plant biomass. Phytoextraction is growing rapidly in popularity world-wide. Generally this process has been more effective for extracting heavy metals than organics. It is clean, efficient, inexpensive and less environmentally desruptive than processes that require excavation of soil. At the time of disposal contaminants are typically concentrated in a much smaller volume of plant matter than an inital contaminated soil or sediment.

After the plant absorbs contaminants through the root system it will either store them in the root biomass or transport them up into the stems and leaves. A living plant may continue to absorb contaminants until it is harvested. After harvest a lower level of the contaminant will remain in the soil, so the growth/harvest cycle must be repeated through several crops to achieve a significant cleanup. After the process, the soil usually is fertile and can support other vegetation.

There are two versions of phytoextraction:

    * natural hyper-accumulation, where plants naturally take up the contaminants in soil unassisted, and
    * induced or assisted hyper-accumulation, in which a conditioning fluid containing a chelator or another agent is added to soil to increase metal solubility or mobilization so that the plants can absorb them much easily.

Examples of Phytoextraction from Soils:

    * Lead, using Indian Mustard, Ragweed or Hemp Dogbane.
    * Arsenic, using the Sunflower (Helianthus annuus), or the bracken fern, a hyperaccumulator. Bracken can store arsenic in its leaves, as much as 200 times that present in the soil.
    * Cadmium and zinc, using alpine pennycress (Brassicaceae), a hyperaccumulator of these metals at levels that would be toxic to many plants.
    * Uranium, using Sunflowers, as used after the Chernobyl accident.


Cite: Wikipedia


source : hydroponicarticle

Photosynthesis - Molecular production part 2

Oxygen and photosynthesis

With respect to oxygen and photosynthesis, there are two important concepts.

    *
      Plant and algal cells also use oxygen for cellular respiration, although they have a net output of oxygen since much more is produced during photosynthesis.

    *
      Oxygen is a product of the photolysis reaction not the fixation of carbon dioxide, during the light-independent reactions. Consequently, the source of oxygen during photosynthesis is water, not carbon dioxide.


Bacterial variations

The concept that oxygen production is not directly associated with the fixation of carbon dioxide was first proposed by Cornelis Bernadus van Neil in the 1930s, who studied photosynthetic bacteria. Aside from the cyanobacteria, bacteria only have one photosystem and use reducing agents other than water. They get electrons from a variety of different inorganic chemicals including sulfide or hydrogen, so for most of these bacteria oxygen is not produced.

The 'Z-scheme' of electron flow in light-dependent reactions.
The 'Z-scheme' of electron flow in light-dependent reactions.
 

Others, such as the halophiles (an Archeae) produced so called purple membranes where the bacteriorhodopsin could harvest light and produce energy. The purple membranes was one of the first to be used to demonstrate the chemiosmotic theory: light hit the membranes and the pH of the solution that contained the purple membranes dropped as protons were pumping out of the membrane.


Carbon fixation

The fixation of carbon dioxide is a light-independent process in which carbon dioxide combines with a five-carbon sugar, ribulose bisphosphate (RuBP), to give two molecules of a three-carbon compound, glycerate 3-phosphate (GP). This compound is also sometimes known as 3-phosphoglycerate (PGA). GP, in the presence of ATP and NADPH from the light-dependent stages, is reduced to glyceraldehyde 3-phosphate (G3P). This product is also referred to as 3-phosphoglyceraldehyde (PGAL) or even as triose phosphate (a three-carbon sugar). This is the point at which carbohydrates are produced during photosynthesis. Some of the triose phosphates condense to form hexose phosphates, sucrose, starch and cellulose or are converted to acetylcoenzyme A to make amino acids and lipids. Others go on to regenerate RuBP so the process can continue (see Calvin cycle).



source : hydroponicarticle

Photosynthesis - Molecular production part 1

Light to chemical energy

The light energy is converted to chemical energy using the light-dependent reactions. The products of the light dependent reactions are ATP from photophosphorylation and NADPH from photoreduction. Both are then utilized as an energy source for the light-independent reactions.


Z scheme

In plants, the light-dependent reactions occur in the thylakoid membranes of the chloroplasts and use light energy to synthesize ATP and NADPH. The photons are captured in the antenna complexes of photosystem I and II by chlorophyll and accessory pigments (see diagram at right). When a chorophyll a molecule at a photosystem's reaction center absorbs energy, an electron is excited and transferred to an electron-acceptor molecule through a process called Photoinduced charge separation. These electrons are shuttled through an electron transport chain that initially functions to generate a chemiosmotic potential across the membrane, the so called Z-scheme shown in the diagram. An ATP synthase enzyme uses the chemiosmotic potential to make ATP during photophosphorylation while NADPH is a product of the terminal redox reaction in the Z-scheme.

A photosystem: a light-harvesting cluster of photosynthetic pigments in a chloroplast thylakoid membrane.
A photosystem: a light-harvesting cluster of photosynthetic pigments in a chloroplast thylakoid membrane.
 


Water photolysis

The NADPH is the main reducing agent in chloroplasts, providing a source of energetic electrons to other reactions. Its production leaves chlorophyll with a deficit of electrons (oxidized), which must be obtained from some other reducing agent. The excited electrons lost from chlorophyll in photosystem I are replaced from the electron transport chain by plastocyanin. However, since photosystem II includes the first steps of the Z-scheme, an external source of electrons is required to reduce its oxidized chlorophyll a molecules. This role is played by water during a reaction known as photolysis and results in water being split to give electrons, oxygen and hydrogen ions. Photosystem II is the only known biological enzyme that carries out this oxidation of water. Initially, the hydrogen ions from photolysis contribute to the chemiosmotic potential but eventually they combine with the hydrogen carrier molecule NADP+ to form NADPH. Oxygen is a waste product of light-independent reactions, but the majority of organisms on Earth use oxygen for cellular respiration, including photosynthetic organisms.

source : hydroponicsearch

Photosynthesis - Introduction part 2

Where n is defined according to the structure of the resulting carbohydrate. However, hexose sugars and starch are the primary products, so the following generalised equation is often used to represent photosynthesis:

    6 CO2 + 12 H2O + light energy → C6H12O6 + 6 O2 + 6 H2O

More specifically, photosynthetic reactions usually produces an intermediate product, which is then converted to the final hexose carbohydrate products. These carbohydrate products are then variously used to form other organic compounds, such as the building material cellulose, as precursors for lipid and amino acid biosynthesis or as a fuel in cellular respiration. The latter not only occurs in plants, but also in animals when the energy from plants get passed through a food chain. In general outline, cellular respiration is the opposite of photosynthesis: glucose and other compounds are oxidised to produce carbon dioxide, water, and chemical energy. However, both processes actually take place through a different sequence of reactions and in different cellular compartments.

Plants capture light primarily using the pigment chlorophyll, which is the reason that most plants have a green color. The function of chlorophyll is often supported by other accessory pigments such as carotenoids and xanthophylls. Both chlorophyll and accessory pigments are contained in organelles (compartments within the cell) called chloroplasts. Although all cells in the green parts of a plant have chloroplasts, most of the energy is captured in the leaves. The cells in the interior tissues of a leaf, called the mesophyll, contain about half a million chloroplasts for every square millimeter of leaf. The surface of the leaf is uniformly coated with a water-resistant, waxy cuticle, that protects the leaf from excessive evaporation of water as well as decreasing the absorption of ultraviolet or blue light to reduce heating. The transparent, colourless epidermis layer allows light to pass through to the palisade mesophyll cells where most of the photosynthesis takes place.


Cite: Wikipedia    n CO2 + 2n H2O + light energy → (CH2O)n + n O2 + n H2O


source : hydroponicsearch

Photosynthesis - Introduction part 1

Photosynthesis is an important biochemical process in which plants, algae, protistans, and some bacteria convert the energy of sunlight to chemical energy and store it in the bonds of sugar, glucose. Ultimately, nearly all living things depend on energy produced from photosynthesis for their nourishment, making it vital to life on Earth. It is also responsible for producing the oxygen that makes up a large portion of the Earth's atmosphere. Organisms that produce energy through photosynthesis are called photoautotrophs. Plants are the most visible representatives of photoautotrophs, but it should be emphasized that bacteria and algae as well contribute to the conversion of free energy into usable energy.

Plant photosynthesis

Most plants are photoautotrophs (exceptions include the famous venus fly trap), which means that they are able to synthesize food directly from inorganic compounds using light energy -for example the sun, instead of eating other organisms or relying on nutrients derived from them. This is distinct from chemoautotrophs that do not depend on light energy, but use energy from inorganic compounds - like flies and other insects.



The energy for photosynthesis ultimately comes from absorbed photons and involves a reducing agent, which is water in the case of plants, releasing oxygen as a waste product. The light energy is converted to chemical energy, in the form of ATP and NADPH, using the light-dependent reactions and is then available for carbon fixation. Most notably plants use the chemical energy to fix carbon dioxide into carbohydrates and other organic compounds through light-independent reactions. The overall equation for photosynthesis in green plants is:

    n CO2 + 2n H2O + light energy → (CH2O)n + n O2 + n H2O


source : hydroponicsearch

Photosynthesis - Discovery

    
Although some of the steps in photosynthesis are still not completely understood, the overall photosynthetic equation has been known since the 1800s.

Jan van Helmont began the research of the process in the mid-1600s when he carefully measured the mass of the soil used by a plant and the mass of the plant as it grew. After noticing that the soil mass changed very little, he hypothesized that the mass of the growing plant must come from the water, the only substance he added to the potted plant. This was a partially accurate hypothesis - much of the gained mass also comes from carbon dioxide as well as water. However, this was a signalling point to the idea that the bulk of a plant's biomass comes from the inputs of photosynthesis, not the soil itself.

Joseph Priestley, a chemist and minister, discovered that when he isolated a volume of air under an inverted jar, and burned a candle in it, the candle would burn out very quickly, much before it ran out of wax. He further discovered that a mouse could similarly "injure" air. He then showed that the air that had been "injured" by the candle and the mouse could be restored by a plant.

In 1778, Jan Ingenhousz, court physician to the Austrian Empress, repeated Priestley's experiments. He discovered that it was the influence of sun and light on the plant that could cause it to rescue a mouse in a matter of hours.

In 1796, Jean Senebier, a French pastor, showed that CO2 was the "fixed" or "injured" air and that it was taken up by plants in photosynthesis. Soon afterwards, Nicolas-Théodore de Saussure showed that the increase in mass of the plant as it grows could not be due only to uptake of CO2, but also to the incorporation of water. Thus the basic reaction by which photosynthesis is used to produce food (such as glucose) was outlined.

Modern scientists built on the foundation of knowledge from those scientists centuries ago and were able to discover many things.

Cornelius Van Niel made key discoveries explaining the chemistry of photosynthesis. By studying purple sulfur bacteria and green bacteria he was the first scientist to demonstrate that photosynthesis is a light-dependent redox reaction, in which hydrogen reduces carbon dioxide.

Further experiments to prove that the oxygen developed during the photosynthesis of green plants came from water, were performed by Robert Hill in 1937 and 1939. He showed that isolated chloroplasts give off oxygen in the presence of unnatural reducing agents like iron oxalate, ferricyanide or benzoquinone after exposure to light. The Hill reaction is as follows:

    2 H2O + 2 A + (light, chloroplasts) → 2 AH2 + O2

where A is the electron acceptor. Therefore, in light the electron acceptor is reduced and oxygen is evolved.

Samuel Ruben and Martin Camen used radioactive isotopes to determine that the oxygen liberated in photosynthesis came from the water.

Melvin Calvin and his partner Benson were able to puzzle out each stage in the dark or light-independent phase of photosynthesis, known as the Calvin cycle.

A Nobel Prize winning scientist, Rudolph A. Marcus, was able to discover the function and significance of the electron transport chain.




Cite: Wikipedia


source : hydroponicsearch

Palms : Washingtonia

Washingtonia is a genus of palms, native to the southwestern United States (in southern California, southwest Arizona) and northwest Mexico (in northern Baja California and Sonora).

They are fan palms (Arecaceae tribe Corypheae), with the leaves with a bare petiole terminating in a rounded fan of numerous leaflets. The flowers are in a dense inflorescence, with the fruits maturing into a small blackish-brown drupe 6-10 mm diameter with a thin layer of sweet flesh over the single seed.

 

There are two species:

    * Washingtonia filifera (Lindl. ex André) H. A. Wendl. California Washingtonia, Northern Washingtonia, or California Fan Palm. Tree to 23 m tall; leaves large, with petiole up to 2 m long, and leaflets up to 2 m long. Inflorescence to 5 m long; flowers white; fruit oval. Southwestern USA, just into extreme northwest Mexico.
    * Washingtonia robusta H. A. Wendl. Mexican Washingtonia or Southern Washingtonia. Tree to 25 m tall; leaves smaller, with petiole up to 1 m long, and leaflets up to 1 m long. Inflorescence to 3 m long; flowers pale orange-pink; fruit spherical. Northwest Mexico.

This image is licensed under the Creative Commons
Washingtonia Palms near Twentynine Palms, California, USA. Taken February 7, 2004 by Jim Harper.

The fruit is edible, and was used by Native American people as a minor food source. They are also eaten by birds, which disperse the seeds in their droppings after digesting the fruit pulp. Washingtonia species are also used as food plants by the larvae of some Lepidoptera species including Paysandisia archon.

 

Both species are cultivated as ornamental trees, widely planted in California in particular, but also in the Mediterranean region in southern Europe, and parts of Australia.

The genus is named after George Washington.


Cite: Wikipedia

Palms - Phoenix

Phoenix is a genus of about 15-20 species of palms, native from the Canary Islands east across northern and central Africa, the extreme southeast of Europe (Crete), and southern Asia from Turkey east to southern China and Malaysia.

The stems are single, or suckering and clumped, and vary from 1-30 m tall. The leaves are pinnate, 1-6 m long. The plants are dioecious, with male and female flowers on separate plants; pollination is by wind. The flowers are inconspicuous yellowish-brown and about 1 cm wide, but grouped on conspicuous large multi-branched panicles 30-90 cm long. The fruit is a drupe, 1-7 cm long, yellow to red-brown or dark purple when mature, with one seed.

Selected species

    *
      Phoenix abyssinica
    *
      Phoenix acaulis
    *
      Phoenix canariensis (Canary Island Date Palm)
    *
      Phoenix dactylifera (Date Palm)
    *
      Phoenix lourierii
    *
      Phoenix paludosa
    *
      Phoenix pusilla
    *
      Phoenix reclinata (Senegal Date Palm)
    *
      Phoenix roebelinii (Pygmy Date Palm)
    *
      Phoenix rupicola (Cliff Date Palm)
    *
      Phoenix sylvestris (Indian Date Palm)
    *
      Phoenix theophrastii (Cretan Date Palm)

Date Palm (Phoenix dactylifera)
Date Palm (Phoenix dactylifera)

The fruit of P. dactylifera, the Date Palm of commerce, is large with a thick layer of fruit pulp, edible, very sweet and rich in sugar; the other species have only a thin layer of fruit pulp.

While P. dactylifera is grown for its dates, P. canariensis the Canary Island Date Palm is widely grown as an ornamental plant. It differs from the former in having a stouter trunk, more leaves to the crown, more closely spaced leaflets and deep green rather than grey-green leaves. The fruit of P. canariensis are edible, but rarely eaten by humans because of their small size and thin flesh.

The different species of the genus frequently hybridise where they grow in proximity. This can be a problem when planting P. canariensis as an ornamental plant, as the hybrid palms are aesthetically inferior and do not match the pure-bred plants when planted in avenues, etc.

Phoenix species are used as food plants by the larvae of some Lepidoptera species including Paysandisia archon.


Cite: Wikipedia




www.etraderportal.com

Palms - Coconut : The fruit

Botanically, a coconut is a simple dry fruit known as a fibrous drupe (not a true nut). The husk (mesocarp) is composed of fibres called coir and there is an inner "stone" (the endocarp). This hard endocarp (the coconut as sold in the shops of non-tropical countries) has three germination pores that are clearly visible on the outside surface once the husk is removed. It is through one of these that the radicle emerges when the embryo germinates. Adhering inside wall of endocarp is the testa with a thick albuminous endosperm, the coconut meat, the white and fleshy edible part of the seed.

When viewed on end, the endocarp and germination pores resemble the face of a monkey, the Portuguese word for which is macaco, sometimes abbreviated to coco, whence the name of the fruit. The specific name nucifera is Latin for nut bearing.

Maturing Coconuts on the tree
Maturing Coconuts on the tree

When the coconut is still green, the endosperm inside is thin and tender, a favourite snack. But the main reason to pick the nut at that stage is to drink its juice; a big nut contains up to one litre of refreshing drink. When the nut has ripened and the outer husk has turned brown, a couple of months later, it will fall from the tree of its own accord. At that time the endosperm has thickened and hardened, while the juice has become somewhat bitter. Drinking more than a sip then is a sure recipe for diarrhoea within 15 minutes.

A man climbing a tree to harvest coconuts
A man climbing a tree to harvest coconuts

To open a coconut, remove the outer husk (if not purchased already removed) and pierce two of the three eyes of the fruit (one for the juice to come out of, one to enable air to go in); drain the juice from the fruit. Since coconuts have a naturally-forming fracture point, they can be opened by taking a heavy knife, such as a meat cleaver, and striking the coconut with the flat edge of the knife. Or you can use a flat-bladed screwdriver and a hammer (which is easier, and may be safer than using a cleaver). After inserting the screwdriver slightly, twist it to crack the shell. The coconut should then be turned, and this process repeated until there is a contiguous crack in the shell around the entire fruit. Afterwards, the fruit can be separated at this fracture point.

When the nut is still green the husk is very hard, but green nuts rarely fall, only when they have been attacked by moulds, etc. By the time the nut naturally falls, the husk has become brown, the coir has become dryer and softer, and the nut is less likely to cause damage when it drops. Still there have been instances of coconuts falling from trees and injuring people, and claims of some fatalities. This was the subject of a paper published in 1984 that won the Ig Nobel Prize in 2001. Falling coconut deaths are often used as a comparison to shark attacks, making the claim that it is more likely to be killed by a falling coconut than by a shark. There is no evidence of people being killed in this manner (column from The Straight Dope). However William Wyatt Gill, an early LMS missionary on Mangaia recorded a story in which Kaiara, the concubine of king Tetui, was killed by a falling, green nut. The offending tree was immediately cut down. This was around 1777, the time of captain Cook's visit.

In some parts of the world, trained monkeys are used to harvest coconuts. Training schools for monkeys still exist in southern Thailand. Competitions are held each year to discover the fastest harvester.


Cite: Wikipedia

source : hydroponicsearch

http://www.etraderportal.com

Palms - Coconut

The Coconut Palm (Cocos nucifera), is a member of the Family Arecaceae (palm family). It is the only species in the Genus Cocos, and is a large palm, growing to 30 m tall, with pinnate leaves 4-6 m long, pinnae 60-90 cm long; old leaves break away cleanly leaving the trunk smooth. The term coconut refers to the fruit of the coconut palm.

 

The coconut palm thrives on sandy soils and is highly tolerant of salinity and prefers areas with abundant sunlight and regular rainfall (750 to 2,000 mm annually), which makes colonising shorelines of the tropics relatively straightforward. Coconuts also need high humidity (70–80%+) for optimum growth, which is why they are rarely seen in areas with low humidity (e.g. the Mediterranean), even where temperatures are high enough. They are very hard to establish and grow in dry climates.
Coconut Palm (Cocos nucifera)
Coconut Palm (Cocos nucifera)

The flowers of the coconut palm are polygamomonoecious, with both male and female flowers in the same inflorescence. Flowering occurs continuously, with female flowers producing seeds. Coconut palms are believed to be largely cross-pollinated, although some dwarf varieties are self-pollinating.


Cite: Wikipedia


source : hydroponicsearch

Oca (Oka) - Introduction

The oca or oka is the Quechuan word for a perennial plant grown in the central and southern Andes for its starchy edible tuber, used as a root vegetable. Its leaves and young shoots can be eaten as a green vegetable as well. Introduced to Europe in 1830 as a competitor to the potato and to New Zealand as early as 1860, it has become popular in that country under the name New Zealand yam and is now a common table vegetable.

The oca is one of the important staple crops of the Andean highlands, second only to the potato due to its ability to its easy propogation, and tolerance for poor soil, high altitude and harsh climates.

The flavor is slightly tangy, and texture ranges from crunchy (like a carrot) when undercooked, to starchy or mealy when fully cooked. Though the original Andean varieties are widely variable in color from purple to yellow, the standard NZ variety is a fleshy pink.

 
Raw oca tubers
Ocas need a long growing season, and are day length dependent, forming tubers when the day length shortens in the fall. In areas with harsh winter climates, the cold weather that accompanies shorter days may kill the plant before tubers have a chance to form. Likewise in tropical areas where the days are uniformly longer, the oca will not set a crop successfully, since the days are never short enough.

 

Ocas are fairly high in oxalates, concentrated in the skin, and traditional Andean preparation methods were geared towards reducing the oxalate level of the harvested vegetable. This is done by exposure to sunlight which increases the glucose content and sweet tase of the oca. Recent oca cultivars have a lower oxalate content, and have also been selected for more flexibility in day lengths.

The oca can be prepared like most root vegetables by being boiled, baked or fried. In the Andes it is part of stews and soups; served like potatoes or can be as served as a sweet. Oca is eaten raw in Mexico with salt, lemon and hot pepper.


Cite: Wikipedia


source : hydroponicsearch

www

Mushroom - Introduction Apical germ pore

Apical germ pore is a term applied to mushroom spores which have a pore at one end. Some spores have a hole in the cell wall where the first strand of germinating mycelium emerges. If the cell wall is divided from one end to the other, this is called a germ slit. Commonly the germ pore is at one end of the mushroom spore and is called an apical pore.



Mushroom genera with apical germ pores include Agrocybe, Panaeolus, Psilocybe, and Pholiota.

Of central interest with respect to chemical properties of mushrooms is the fact that many species produce secondary metabolites that render them toxic, mind-altering, or even bioluminescent.
These emerging mushrooms are too immature to accurately identify the species.

Toxicity likely plays a role in protecting the function of the basidiocarp: the mycelium has expended considerable energy and protoplasmic material to develop a structure to efficiently distribute its spores. One defence against consumption and premature destruction is the evolution of chemicals that render the mushroom inedible, either causing the consumer to regurgitate (see emetics) the meal or avoid consumption altogether (see Mushroom poisoning).
the relative sizes of the cap and the pileus vary widely.

Psilocybin mushrooms possess psychedelic properties. They are commonly known as "magic mushrooms" or "shrooms", and are available in smart shops in many parts of the world (see Psychedelic mushroom). A number of other mushrooms are eaten for their psychoactive effects, such as fly agaric, which is used for shamanic purposes by tribes in northeast Siberia.

Currently, many species of mushrooms and fungi utilized as folk medicines for thousands of years are under intense study by ethnobotanists and medical researchers. Maitake, shiitake, and reishi are prominent among those being researched for their potential anti-cancer, anti-viral, and/or immunity-enhancement properties.
Ganoderma sp.

Psilocybin, originally an extract of certain psychedelic mushrooms, is being studied for its ability to help people suffering from mental disease, such as obsessive-compulsive disorder. Minute amounts have been reported to stop cluster and migraine headaches. It has also been used in the West to potentiate religious experience. See entheogen.
Laetiporus sulphureus

Because of their psychoactive properties, some mushrooms have played a role in native medicine, where they have been used to effect mental and physical healing, and to facilitate visionary states. One such ritual is the Velada ceremony. A representative figure of traditional mushroom use is the shaman, curandera (priest-healer), Maria Sabina.

Some mushrooms have been used as fire starters (known as tinder fungi). Ötzi the Iceman was found carrying such mushrooms.


Cite: Wikipedia
source : hydroponicsearch

Mushroom - Introduction Mushroom structure

Mushroom in the Lacandon Jungle.

Identifying mushrooms requires a basic understanding of their macroscopic structure. A "typical" mushroom consists of a cap or pileus supported on a stem or stipe. Both can have a variety of shapes and be ornamented in various ways. The underside of the cap (in agarics) is fitted with gills or lamellae where the actual spores are produced. How the gills are attached is another important characteristic used in identification. In the boletes, the gills are replaced by small openings called pores. Bracket fungi essentially lack a stipe, and the cap is attached like a bracket to the substratum, usually a log or tree trunk. Some bracket fungi have gills, others have pores.
A mushroom from the Western Ghats
In general, identification to genus can be accomplished in the field using a local mushroom guide. Identification to species, however, requires more effort; one must remember that a mushroom develops from a young bud into a mature structure and only the latter can provide certain identification of the species. Examination of mature spores, or at least knowing their colour, is often essential. To this end, a common method used to assist in identification is the spore print.


Apical germ pore

Apical germ pore is a term applied to mushroom spores which have a pore at one end. Some spores have a hole in the cell wall where the first strand of germinating mycelium emerges. If the cell wall is divided from one end to the other, this is called a germ slit. Commonly the germ pore is at one end of the mushroom spore and is called an apical pore.

Mushroom genera with apical germ pores include Agrocybe, Panaeolus, Psilocybe, and Pholiota.

Of central interest with respect to chemical properties of mushrooms is the fact that many species produce secondary metabolites that render them toxic, mind-altering, or even bioluminescent.
These emerging mushrooms are too immature to accurately identify the species.

Toxicity likely plays a role in protecting the function of the basidiocarp: the mycelium has expended considerable energy and protoplasmic material to develop a structure to efficiently distribute its spores. One defence against consumption and premature destruction is the evolution of chemicals that render the mushroom inedible, either causing the consumer to regurgitate (see emetics) the meal or avoid consumption altogether (see Mushroom poisoning).


source : hydroponicsearch

Mushroom - Introduction

A mushroom (Old English muscheron, from the Old French mouscheron, French mousseron —same name in English as a common kind of mushroom— itself perhaps a diminutive of mousse, meaning moss) is an above-ground fruiting body (that is, a spore-producing structure) of a fungus, having a shaft and a cap. By extension, it designates the entire fungus producing the fruiting body of such appearance, the former consisting of a network (called the mycelium) of filaments or hyphae.

In a much broader sense, mushroom is applied to any visible fungus, or especially the fruiting body of any fungus, with the mycelium usually being hidden under bark, ground, rotten wood, leaves, etc. Mushrooms obtain food through decomposition. The technical term for the spore-producing structure of "true" mushrooms is the basidiocarp. The term "toadstool" is used typically to designate a basidiocarp that is poisonous to eat.
 

Types of Mushrooms
Basidiocarps (mushrooms) of the fungus Leucocoprinus sp.

The main types of mushrooms are agarics (including the button mushroom, the most common mushroom eaten in the U.S.), boletes, chanterelles, tooth fungi, polypores, puffballs, jelly fungi, coral fungi, bracket fungi, stinkhorns, and cup fungi. Mushrooms and other fungi are studied by mycologists. The "true" mushrooms are classified as Basidiomycota (also known as "club fungi"). A few mushrooms are classified by mycologists as Ascomycota (or "sac fungi"), the morel and truffle being good examples. Thus, the term mushroom is more one of common application to macroscopic fungal fruiting bodies than one having precise taxonomic meaning.
Mushrooms

Edible mushrooms are used extensively in cooking, in many cuisines. Though commonly thought to contain little nutritional value, many varieties of mushrooms are high in fibre and protein, and provide vitamins such as thiamine (B1), riboflavin (B2), niacin (B3), biotin (B7), cobalamins (B12) and ascorbic acid (C), as well as minerals, including iron, selenium, potassium and phosphorus. However, a number of species of mushrooms are poisonous, and these may resemble edible varieties, although eating them could be fatal. Picking mushrooms in the wild is risky —riskier than gathering edible plants— and a practice not to be undertaken by amateurs. The problem is that separating edible from poisonous species depends upon the application of only a few easily recognizable traits. People who collect mushrooms for consumption are known as mushroom hunters, and the act of collecting them as such is called mushroom hunting.



source : hydroponicsearch

Lilium lancifolium (Tiger Lily) - Introduction

Lilium lancifolium (syn. L. tigrinum) is a species of lily native to eastern Asia, including China, Korea and Japan. It is one of several species of lily to which the common name Tiger lily is applied, and the species most widely so known.
Tiger Lily

Like other true lilies, the flowers are borne on an erect stem 80-200 cm tall, clothed with the more or less linear leaves 6-9 cm long and 1-2 cm broad. It is one of a very small number of species that produce tiny bulbils in the axil of the leaves. These can be used to propagate the plant.


Cultivation and uses

It is cultivated in Asia for its edible bulb. It is also grown as an ornamental plant for its bold flowers, and has become naturalised in parts of North America.


Mushroom - Introduction       
A mushroom (Old English muscheron, from the Old French mouscheron, French mousseron —same name in English as a common kind of mushroom— itself perhaps a diminutive of mousse, meaning moss) is an above-ground fruiting body (that is, a spore-producing structure) of a fungus, having a shaft and a cap. By extension, it designates the entire fungus producing the fruiting body of such appearance, the former consisting of a network (called the mycelium) of filaments or hyphae.

In a much broader sense, mushroom is applied to any visible fungus, or especially the fruiting body of any fungus, with the mycelium usually being hidden under bark, ground, rotten wood, leaves, etc. Mushrooms obtain food through decomposition. The technical term for the spore-producing structure of "true" mushrooms is the basidiocarp. The term "toadstool" is used typically to designate a basidiocarp that is poisonous to eat.

source : hydroponicsearch

Jackfruit - Introduction Commercial availability

The jackfruit bears fruit three years after planting and the fruit is the largest edible fruit in commerce.

In the United States and Europe, the fruit is available in shops that sell exotic products, usually sold canned with a sugar syrup. It is also obtained fresh from Asian food markets. Sweet jackfruit chips are also often available.

The wood is used for the production of musical instruments in Indonesia as part of the gamelan and in the Philippines, where its soft wood can be made into the hull of a kutiyapi, a type of Philippine boat lute. It is also used to make the body of the Indian drums mridangam and kanjira. It is also widely used for manufacture of furniture.

 
Dishes and preparations
A kutiyapi, made of jackfruit wood
Jackfruit is commonly used in South and Southeast Asian cuisines. It can be eaten unripe (young) or ripe, and cooked or uncooked. The seeds can also be used in certain recipes.

Unripe (young) jackfruits are also eaten whole, cooked as a vegetable. Young jackfruit has a mild flavour and distinctive texture. The cuisines of India, Bangladesh, Sri Lanka, Indonesia, and Vietnam use cooked young jackfruit. In many cultures, jackfruit is boiled and used in curries as a food staple.
Sweet Jackfruit chips

    * Chakka Pradaman: Jackfruit pudding from Kerala, India.
    * Chakka Varatti: Jackfruit Jam from Kerala, India.
    * Chakka Vattal: Jackfruit Chips from Kerala, India.
    * Panasa Koora: Traditional Jackfruit Curry from coastal Andhra, India.
    * Gudeg: traditional dish from Yogyakarta, Central Java, Indonesia.
    * Lodeh: traditional Indonesian vegetable dish with coconut milk.
    * An optional ingredient in Sayur asam (Indonesian clear soup; the name means tamarind vegetables)
    * Also ingredient in Indonesian traditional Padang cuisine.
    * Jackfruit salad: Vietnamese dish with boiled young jackfruit.
    * Rice and curry in Sri Lanka

The seeds can also be eaten cooked or baked like beans. They taste similar to chestnuts.

 
Other preparations:

    * Jackfruit chips
    * Asian ice desserts (including Indonesian & Filipino)
    * Turon, a Filipino dessert made of banana and jackfruit wrapped in an eggroll wrapper
    * Sometimes an added ingredient for cassava cake
    * An optional ingredient in kolak (an Indonesian mung bean and coconut based dessert).
    * It is thought that jackfruit is the basis for the flavour of Juicy Fruit chewing gum.
    * Jackfruit candy

 
Names
The fruit is called a variety of names around the world:

South Asian names

    * Bengali: কাঁঠাল Kãţhal (National fruit of Bangladesh)
    * Bhojpuri: Katahar
    * Kannada: Halasina hannu
    * Hindi: Katahal
    * Malayalam: Chakka
    * Marathi: फणस Phaṇas
    * Oriya: Panasa
    * Sinhala: Kos
    * Tamil: Palaa
    * Telugu: Panasa
    * Sanskrit: Panasam

Southeast Asian names

    * Cebuano: Nangka
    * Indonesian: Nangka
    * Lao: Mak mii
    * Malay: Nangka
    * Tagalog: Langka
    * Thai: ขนุน Kanoon
    * Vietnamese: Mít

East Asian names

    * Chinese: 波罗蜜 Bōluómì
    * Korean: 바라밀 Baramil

African names

    * Malagasy: Finésy
    * Swahili: Finesi

European names

    * Portuguese: Jaca
    * Spanish: Jaka; Fruta de Jack


Cite: Wikipedia

source : hydroponicsearch

Jackfruit - Introduction

The Jackfruit (Artocarpus heterophyllus) is a species of tree and its fruit, native to southwestern India, and possibly also east to the Malay Peninsula, though more likely an early human introduction there.
Jackfruits
It is a small evergreen tree growing to 10-15 m tall. The leaves are alternately arranged, elliptical, 5-25 cm long and 3-12 cm broad, often lobed on young trees but entire on mature trees. The flowers are produced in dense inflorescences 3-7 cm long and 1-2.5 cm broad; the male and female flowers produced on separate inflorescences, the female inflorescences commonly borne on thick branches or the trunk of the tree (cauliflory).

The fruit is huge, seldom less than about 25cm in diameter. Even a relatively thin tree (circa 10 cm) can have these huge fruits hanging on it. The fruits can reach 36kg in weight and up to 90cm long and 50 cm in diameter.

The sweet yellow sheaths around the seeds are about 3-5mm thick and have a taste similar to pineapple but milder and less juicy.

The English name jackfruit derives from Portuguese jaca, which is derived from Malayalam chakka. See below for other names of the fruit worldwide.
Cultivation and uses

Jackfruit is widely grown in South and Southeast Asia and Brazil. The jackfruit is in the mulberry family Moraceae. It is also grown in parts of central and eastern Africa, Brazil, and Suriname. It is the national fruit of Bangladesh.
Jackfruit hanging from tree
One of the earliest descriptions of the jackfruit is to be found in the 16th century memoirs of the Mughal Emperor Babar, who was not much enamoured of it:

    "The jackfruit is unbelievably ugly and bad tasting. It looks exactly like sheep intestines turned inside out like stuffed tripe. It has a cloyingly sweet taste. Inside it has seeds like hazelnuts that mostly resemble dates, but these seeds are round, not long. The flesh of these seeds, which is what is eaten, is softer than dates. It is sticky, and for that reason some people grease their hands and mouths before eating it. The fruit is said to grow on the branches, the trunk, and the roots of the tree and looks like stuffed tripe hung all over the tree". [1]

Like its cousin the durian, the jackfruit is something of an acquired taste, but it is very popular in many parts of the world. A unopened ripe fruit can have a unpleasant smell, like rotting onions. The lightbrown to black seeds with white innards are indeed about the size of dates. People often oil their hands with kerosene/parafin before preparing jackfruit, as the rest of the mass of the fruit is a loose white mass that bleeds a milky sticky sap, often used as glue.


source : hydroponicsearch

Herbs - Rosemary : Introduction part 2

Rosemary is a useful food preservative, according to research published in 1987 by Rutgers University, New Jersey. Researchers at Rutgers patented a chemical derived from rosemary that compares favourably with BHA and BHT in its preservative properties.

Rosemary can be added as an unusual extra flavouring in lemonade.

Medicinal uses
Image
Rosemary has been found to be a stimulant and mild analgesic, and has been used to treat headaches, poor circulation, and many ailments for which stimulants are prescribed.

Rosemary essential oil is a powerful convulsant; if applied to the skin, it may cause seizures in otherwise healthy adults or children [1].

It can be used as a disinfectant, as a mouth wash and to treat fever or rheumatism.

Externally it can be used in hair lotions; a few drops of Rosemary oil massaged into the scalp, then rinsed with an infusion of nettles can revitalise the hair. Used in this manner it supposed to prevent premature baldness. Rosemary is also reported to stop dandruff.
Image
Hungary water was first invented for a Queen of Hungary to 'renovate vitality of paralysed limbs'. It was used externally and is prepared by mixing 180g of fresh rosemary tops in full flower into a litre of spirits of wine. Leave to stand for four days then distill. It is also supposed to work as a remedy against gout if rubbed vigoursly on hands and feet.

For a tonic against headaches put some sprigs into a teapot, add hot water, strain, and serve.
Image
Rosemary has a very old reputation for improving memory, and has been used as a symbol for remembrance (as in worn during weddings, war commemorations and funerals) in Europe, probably as a result of this reputation. Students in ancient Greece are reported to have worn sprigs of rosemary in their hair while studying for exams to improve their memory, and mourners would throw it into graves as a symbol of remembrance for the dead. In Shakespeare's Hamlet, Ophelia says, "There's rosemary, that's for remembrance".
Image
Rosemary and its constituents carnosol and ursolic acid have been shown to inhibit the growth of skin tumors and to provide a natural anti-oxidant protection against skin cancer and photodamage.

Don Quixote (Chapter XVII, 1st volume) mixes it in its recipe of the miraculous balm of Fierabras with revolting results.

References

    * Calabrese, V., Scapagnini, G., Catalano, C., Dinotta, F., Geraci, D., & Morganti, P. (2000). Biochemical studies of a natural antioxidant isolated from rosemary and its application in cosmetic dermatology. International Journal of Tissue Reactions. 22 (1): 5-13.
    * Huang, M. T., Ho, C. T., Wang, Z. Y., Ferraro, T., Lou, Y. R., Stauber, K., Ma, W., Georgiadis, C., Laskin, J. D., & Conney, A. H. (1994). Inhibition of skin tumorigenesis by rosemary and its constituents carnosol and ursolic acid. Cancer Res. 54(3):701-8.



Cite: Wikipedia


source : hydroponicsearch

Herbs - Rosemary : Introduction

Rosemary (Rosmarinus officinalis) is a woody, perennial herb with fragrant evergreen needle-like leaves. It is native to the Mediterranean region. It is a member of the mint family Lamiaceae, which also includes many other herbs. Forms range from upright to trailing; the upright forms can reach 1.5 m tall, rarely 2 m. The leaves are evergreen, 2-4 cm long and 2-5 mm broad, green above, and white below with dense short woolly hairs. The flowers are variable in colour, being white, pink, purple, or blue.
Image
The name rosemary has nothing to do with the rose or the name Mary, but derives from the Latin name rosmarinus, which is presumed to mean "dew of the sea", though some think this too may be derived from an earlier name.

Rosemary is often commonly associated with memory and/or remembrance of the past.

Cultivation and uses
Image
The fresh and dried leaves are used frequently in traditional Mediterranean cuisine as a herb; a tisane can also be made from them. They are extensively used in cooking, and when burned gives off a distinct mustard smell.

Since it is attractive and tolerates some degree of drought, it is also used in landscaping, especially in areas having a Mediterranean climate. It can in fact die in over-watered soil, but is otherwise quite easy to grow for beginner gardeners. It is very pest-resistant.


Rosemary is easily pruned into shapes and has been used for topiary. When grown in pots, it is best kept trimmed to stop it getting too straggly and unsightly, though when grown in a garden, rosemary can grow quite large and still be attractive. It can be propagated from an existing plant by clipping a shoot 10-15 cm long, stripping a few leaves from the bottom, and planting it directly into soil.

Numerous cultivars have been selected for garden use. The following are frequently sold:

    * Albus: white flowers
    * Arp: leaves light green, lemon-scented
    * Aureus: leaves speckled yellow
    * Benenden Blue: leaves narrow, dark green
    * Blue Boy: dwarf, small leaves
    * Golden Rain: leaves green, with yellow streaks
    * Irene: lax, trailing
    * Lockwood de Forest: procumbent selection from 'Tuscan Blue'
    * Ken Taylor: shrubby
    * Majorica Pink: pink flowers
    * Miss Jessop's Upright: tall, erect
    * Pinkie: pink flowers
    * Prostratus
    * Pyramidalis (a.k.a 'Erectus'): pale blue flowers
    * Roseus: pink flowers
    * Severn Sea: spreading, with arching branches; flowers deep violet
    * Tuscan Blue: upright



source : hydroponicsearch

Herbs - Parsley : Introduction

Parsley (Petroselinum crispum) is a bright green, biennial herb that is very common in Middle Eastern, European, and American cooking. It is used for its leaf in much the same way as coriander (which is also known as Chinese parsley or cilantro), although it has a milder flavor.

Two forms of parsley are used as herbs: curly leaf and Italian or flat leaf. Curly leaf parsley is often used as a garnish. Many people think flat leaf parsley has a stronger flavor, and this opinion is backed by chemical analysis which finds much higher levels of essential oil in the flat-leaved cultivars. One of the compounds of the essential oil is apiol. Another type of parsley is grown as a root vegetable.

Parsley is used as a food plant by the larvae of some Lepidoptera species including the Mouse Moth and The Nutmeg.

In parts of Europe, and particularly in West Asia, many foods are served with chopped parsley sprinkled on top. The fresh flavor of parsley goes extremely well with fish. Parsley is essential to several West Asian salads, e.g., tabbouleh which is the national dish of Lebanon. In Southern and Central Europe, parsley is part of bouquet garni, a bundle of fresh herbs used to flavor stocks, soups and sauces. Additionally, parsley is often used as a garnish.

Parsley is valued as a breath-freshener, due to its high concentration of chlorophyll. Adam Blackman, a nutritionist, claims parsley enhances mental alertness, and affects the immune system.


Cultivation

Parsley grows well in a deep pot, which helps accommodate the long taproot. Parsley grown indoors requires at least five hours of sunlight.


Medicinal Uses

Parsley tea may be used as a diuretic. Chinese and German herbologists recommend parsley tea to help control high blood pressure, and Cherokee Indians use it as a tonic to strengthen the bladder. It is also often used as an emmenagogue.

Parsley appears to increase diuresis by inhibiting the Na+/K+-ATPase pump in the kidney, thereby enhancing sodium and water excretion while increasing potassium reabsorption (PMID 11849841).


Potential health concerns

Parsley is high in oxalic acid, a compound involved in the formation of kidney stones and nutrient deficiencies.


Cite: Wikipedia



source : hydroponicsearch

Herbs - Oregano : Introduction Mexican Dishes

The very similar, but stronger, taste of Mexican oregano (see below) is popular not only in its native country México, but also in the south of the U.S., where it is frequently used to flavour chili con carne (meat stewed with chiles and sometimes beans) or other México-inspired dishes. For this purpose, it is mostly combined with several varieties of chiles and paprika, dried garlic or onion and cumin).


Health benefits

Oregano is high in antioxidant activity, paticularly due to a high content of phenolic acids and flavonoids (PMID 16218659, PMID 12730411). Additionally, oregano has demonstrated antimicrobial activity against food-borne pathogens such as Listeria monocytogenes (PMID 16218659). Both of these characteristics may be useful in both health and food preservation.


Popular culture

In dried form, oregano bears a similar appearance to marijuana. A popular urban legend is the story of an inexperienced person unwittingly purchasing the spice from an unscrupulous dealer instead of the drug. A reference to this was made in passing in the movie A Few Good Men.

Lt. Kaffee: "My client bought and smoked a dime bag of oregano. What do you want me to charge him with, possession of a condiment?"


Other plants called Oregano

Mexican Oregano stems from the plant Lippia graveolens (Verbenaceae) and is closely related to lemon verbena. It is a highly studied herb that is said to be of some medical use and is common in curandera female shamanic practices in Mexico and the Southwestern United States. Although only loosely related to Oregano, Mexican Oregano has a very similar flavour, albeit stronger. It is increasingly traded, especially in the US. Its strong aroma makes it an acceptable substitute for epazote leaves if the latter are not available; this wouldn't work the other way round, though.

There is a significant taxonomic confusion about the term "oregano" in Mexican cooking. Several plants are named thus in different parts of México, and there is little clear information about those. Some plants that have been identified as "Mexican Oregano" are Poliomintha longiflora, Lippia berlandieri and Plectranthus amboinicus (syn. Coleus aromaticus), also called Cuban Oregano.


Cite: Wikipedia




source : hydroponicsearch

Herbs - Oregano : Introduction

 

Oregano (Origanum vulgare) (Catalan: orenga, Spanish: orégano, Portuguese: orégão, Italian: origano) is a spicy, Mediterranean, perennial herb, particularly common in Greek and Italian cuisines. It is the leaves that are used in cooking, and the dried herb is often more flavourful than the fresh.


Classification

Oregano (also called: Greek oregano (known as rigani), wild marjoram and mountain mint) is a member of the mint family, Lamiaceae. It means "Joy of the Mountains".


Sensoric quality

Aromatic, warm and slightly bitter. Oregano largely varies in intensity: good quality is so strong that it almost numbs the tongue, but the cultivars adapted to colder climates have often unsatisfactory flavour.


Origin

Several species of genus Origanum are native to the Mediterranean, all of which are traded as a spice. The influence of climate, season and soil on the composition of the essential oil is greater than the difference between the various species.

The most important species are O. vulgare (pan-European), O. onites (Greece, Asia Minor) and O. heracleoticum (Italy, Balkan peninsula, West Asia). A closely related plant is marjoram from Asia Minor, which, however, differs significantly in taste, because phenolic compounds are missing in its essential oil. Some breeds show a flavour intermediate between oregano and marjoram (gold marjoram = gold oregano)

Other Origanum species include:

    * Origanum syriacum is the Bible Hyssop or Syrian Oregano.
    * Origanum laevigatum is the Purple Oregano or Ornamental Oregano.
    * Origanum sativum is the Brazilian Orégano. 

Oregano in cooking

Oregano is a conditio sine qua non in Italian cuisine. It is used in tomato sauces, fried vegetables and grilled meat. Together with basil, it makes up for the character of Italian dishes; see parsley on Italian variants of bouquet garni.

Oregano combine nicely with pickled olives, capers and lovage leaves. Unlike most Italian herbs, oregano works with hot and spicy food, which is popular in Southern Italy. The plant is less popular in other Mediterranean cuisines, but still important in Spanish, French and Greek cooking.


Pizza

The dish most associated with oregano is pizza, an open pie of bread dough baked with a top of tasty ingredients. Its relatives have probably been eaten in Southern Italy for centuries. According to the legend, the first pizza was made in 1889 when King Umberto and his wife Margherita sojourned in Napoli (Naples). At this time, white bread flavoured with tomato paste was a popular food for the poor masses. To honour the Queen, a local baker devised a richer pie. In addition to the red tomato paste, white mozzarella cheese and green basil leaves were employed to reflect the colours of the Italian flag. This invention became known as pizza Margherita and spread all over Italy and now, over the rest of the world.

Today's pizza relies more on oregano than on basil, and use a multitude of further ingredients: Ham, sausage, fish, shellfish, mushrooms, artichokes, onion, garlic, olives, capers, anchovies and more make pizza a sophisticated delicacy, although it had once been the poor man's sandwich.

source : hydroponicsearch