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In mature and young leaves of sunflower (Helianthus annuus L
The C3 and C4 refer to how these classes of plants assimilate carbon dioxide into their systems. During the first steps in CO2 assimilation, C3 plants form a pair of three carbon-atom molecules. C4 plants, on the other hand, initially form four carbon-atom molecules. In C3 plants CO2 enters the leaf through the stomata, which are microscopic pores found on the under-surface of leaves and on stems. They occur in the epidermal tissue. The CO2 then diffuses into the mesophyll cells where a bifunctional enzyme called Rubisco fixes carbon dioxide or molecular oxygen, which leads to photosynthesis or photorespiration. The Rubisco catalyzes the CO2 of and forms two Phosphoglycerate (PGA) molecules, which is a three carbon compound. This PGA is converted to sugars and transported to the growing leaves, roots and reproductive structures. This form of photosynthesis is found in all major plant families or in about 300,000 species and make up 95% of all plants. Typical C3 plants include: barley, sunflower, rice, tomatoes, wheat, peanuts, cotton, sugar beet, oats, and most trees and are found in typically cooler and wetter environments. C4 plants on the other hand the CO2 enters through the stomata again, but goes into the mesophyll tissue, where it is fixed by PepCarboxylase to form , which unlike Rubisco does not have the ability to fix oxygen, which contributes to lower photorespiratory carbon losses in C4 plants. This Oxaloacetate is then converted to malate, which is a four carbon molecule and transported to the bundle sheath cells. From this CO2 is released and forms sucrose and starch. These plants have a special mechanism within their leaves by which they are able to increase CO2 concentration several times higher than ambient levels. These plants tend to be found in warmer and water-limited environments. Typical examples include many tropical grasses and agricultural crops such as maize (corn), sugarcane, and sorghum. Characteristically, C4-plants have higher rates of photosynthesis than C3-plants. Photosynthesis in C4 plants does not saturate but increases at high light intensities and can continue at very low CO2 concentrations. Subsequently, these plants have rapid growth rates and higher biomass and economic yields than C3-plants.
In mature and young leaves of sunflower (Helianthus annuus L. cv. Catissol-01) plants grown in the greenhouse, photosynthetic rate, stomatal conductance, and transpiration rate declined during water stress independently of leaf age and recovered after 24-h rehydration. The intercellular CO2 concentration, chlorophyll (Chl) content, and photochemical activity were not affected by water stress. However, non-photochemical quenching increased in mature stressed leaves. Rehydration recovered the levels of non-photochemical quenching and increased the Fv/Fm in young leaves. Drought did not alter the total Chl content. However, the accumulation of proline under drought was dependent on leaf age: higher content of proline was found in young leaves. After 24 h of rehydration the content of proline returned to the same contents as in control plants.
Inhibition of Corn and Sunflower Photosynthesis by Lead
Sunflowers were treated with mixing proportions of NaCl, Na2SO4, NaHCO3, and Na2CO3. Effects of salt and saltalkaline mixed stress on growth, photosynthesis, chlorophyll fluorescence, and contents of inorganic ions and organic acids of sunflower were compared. The growth of sunflower decreased with increasing salinity. The contents of photosynthetic pigments did not decrease under salt stress, but their contents decreased sharply under salt-alkaline mixed stress. Net photosynthetic rates, stomatal conductance and intercellular CO2 concentration decreased obviously, with greater reductions under salt-alkaline mixed stress than under salt one. Fluorescence parameters showed no significant differences under salt stress. However, maximal efficiency of PSII photochemistry, photochemical quenching coefficient, electron transport rate, and actual PSII efficiency significantly decreased but non-photochemical quenching increased substantially under salt-alkaline mixed stress. Under salt-alkaline mixed stress, sunflower leaves maintained a low Na+- and high K+ status; this may be an important feature of sunflower tolerance to salinity. Analysis of the mechanism of ion balance showed that K+ but not Na+ was the main inorganic cation in sunflower leaves. Our results indicated that the change in organic acid content was opposite to the change of Cl−, and the contribution of organic acid to total charge in sunflower leaves under both stresses decreased with increasing salinity. This may be a special adaptive response to stresses for sunflower. Sunflower under stress conditions mainly accumulated inorganic ions instead of synthesizing organic compounds to decrease cell water potential in order to save energy consumption.
If placed in a suitable nutrient environment, cells and tissues of many organisms are ableto reproduce and form new plants or animals. Now, we will deal with vegetable tissues,whose culture is simpler than that of animal cellules and tissues. It is necessary toprepare a nutritive and sterilized culture medium for the piece of plant tissue. Keep theculture in the suitable conditions of light and temperature and which vary from plant toplant. Over many days, you will observe the growth of a callus or roots or shoots. In thisway you can obtain even whole plants (cloning). These experiments show that special cellskeep all the information necessary to generate the whole plant.
As we have mentioned, it is necessary avoid bacteria and moulds in the cultures. For thisyou will need sterilize tools, vials, tubes, and nutrient medium. Place each in anautoclave for a ten minutes or, lacking an autoclave, a pressure cooker. The tissues aswell have to be free from microorganisms and they have to be sterilized with bleach (40%solution for 15 min) or with alcohol.
The transfer of the tissues into the test tubes has to be made in aseptic conditions,using a sterile box. Lacking that, make your first trials in a quiet place, as devoid ofwind and dust as possible. The culture medium should contain water, vitamins (particularlythose of the B-complex. For this, use yeast extract), sugars, mineral salts. To enrich thewater with mineral salts, boil some water with a handful of soil, then let settle andfilter it. Usually, people also insert 0.5-0.8% of agar-agar to "solidify" themedium. As culture medium, coconut milk has been used. It contains mineral salts, sugars,vitamins and growth hormones.
1 - For yours first tests of micropropagation, use strawberries tissues.
2 - If this simple experiment interests you, you can continue on the way of the invitro culture of vegetable tissues. In fact you can propagate a lot of plants in thisway. Plants easy to culture are the following: tomato, potato, strawberry, chrysanthemum,geranium, sunflower, tobacco, carrot and onion. You can use tissues obtained from seeds,such as the embryo, but you can use also tissues taken from adult plants, such as tissuesof roots, stems, apical buds, shoots, leaves, even single cells. Each plant and tissue hasits own needs. They are different from each other. You can try the influence of thevegetable hormones, special nutrients, etc.
This field is very broad and complex so, if you are interested in continuing with theseexperiments, you can buy special books and you should build a sterile box.
Plant Tissue Culture for the Gardener
Basic Principle in Plant Tissue Culture Technique
Plant Tissue Culture Kit Manual
Plant Micropropagation Using African Violet Leaves
Plant Tissue Culture (links)
Internet keywords: in vitro culture plant tissue micropropagation.
T he sunflower is adapted to a ..
Also, for the bacterias and virus’ that are also in the fallout, we need to make sure we are eating a healthy processed food-free, mucus-less diet as organic as possible [preferably non gmo, organic, food grown inside greenhouses and not from shallow gardening] to make our immune system strong adding great herbs such as sunflower seeds, and other seeds and nuts, sprouts, red raspberry, nettle, morianga, cilantro, magnesium spray, progesterone.
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