223x Filetype PPTX File size 0.16 MB Source: ocd.lcwu.edu.pk
Setting Up a Tissue Culture Lab Any laboratory, in which tissue culture techniques are performed, regardless of the specific purpose, must contain a number of basic facilities. These usually include the following: • A general washing area • A media preparation, sterilization, and storage area • An aseptic transfer area • Environmentally controlled incubators or culture rooms • An observation/data collection area. Nutrient media: The type and composition of culture media very strongly govern the growth and morphogenesis of plant tissues. The choice of tissue culture medium largely depends upon the species to be cultured. For e.g. some species are sensitive to high salts or have different requirements for PGRs. Some tissues show better response on solid medium while others prefer a liquid medium. Therefore, development of culture medium formulations is result of systematic trial and experimentation considering specific requirements of a particular culture system. White’s medium is one of the earliest plant tissue culture media originally formulated for root culture. Murashige and Skoog (MS) medium is the most suitable and commonly used medium for plant regeneration from tissues and callus. This is a high salt medium due to its content of potassium and nitrogen salts. B5 medium works well 7 for protoplast culture. It has lesser amounts of nitrate and particularly ammonium salts than MS medium. Nitsch’s medium developed for anther culture contains salt concentration intermediate to MS and White. Components of Tissue Culture Medium: 1.In organic Nutrients: In vitro growth of plants also requires combination of macro and micronutrients like in vivo growth. Macronutrients are classified as those elements which are required in concentration greater than 0.5 mM/l. They include nitrogen, potassium, phosphorus, calcium, magnesium and sulphur in form of salts in media. Macro nutrients have structural and functional role in protein synthesis, cell wall synthesis enzyme Co-factors and membrane integrity. Nitrogen: Nitrogen is major component of all plant tissue culture media. Nitrogen helps to synthesis complex organic molecule. Nitrogen is usually supplied in form of ammonium (NH4 + ) and nitrate (NO3 - ) ions. Nitrate is superior to ammonium as the sole N source but use of NH4 + checks the increase of pH towards alkalinity. Potassium K ion is present in high concentration in the cytoplasm (100-200 mM) and in chloroplast(20-200 mM). K+ is essential for maintaining the ion balancing, activation of many enzymes. Maintaining osmotic pressure and osmotic regulation of cells. Culture media should contain atleast 25mM/l nitrogen and potassium. Other major elements are adequate in concentration range of 1-3mM/l. Calcium Calcium functions with different enzymes as Cofactor and bound to the cell wall and cell membrane. It gives strength to cell wall. It helps in the regulation of the the cell membrane structure. Deficiency causes disintegration of the membrane and shoot tip necrosis. Important in cell and root multiplication. Supplied as calcium chloride and calcium nitrate. Phosphorus Phosphorus Very important for energy metabolism. Essential element for DNA & RNA. Deficiency may cause delayed growth and dark green coloure of leaves. Supplied as sodium hydrogen phosphate or potassium hydrogen phosphate. Magnesium Essential for enzymatic reactions, energy metabolism(ATP synthesis). Supplied as magnesium sulphate. Sulphur Important substance. Deficiency of Sulphur inhibits protein synthesis and decreases Chlorophyll in leaves. Supplied as magnesium Sulphate and Potassium Sulphate. Micronutrients are those elements which are required at a concentration less than 0.05mM/l or 30ppm(mg/l). These include iron, manganese, zinc, boron, copper and molybdenum. Concentration is always in uM.These inorganic elements although required in small quantity are essential for plant growth, most critical of them being iron which is not available at low pH. Therefore, it is provided as iron EDTA complex to make it available at wide range of pH. Zinc: Zn plays an active role in protein synthesis and in the synthesis of tryptophan. Supplied as Zinc Sulphate. Manganese: Plays an important role in the Hill reaction of photasynthesis. Required in many enzymatic activities. Supplied as Manganese Sulphate. Copper: Copper plays important role in photosynthesis. Intermediate of the electron transport chain between photo system 1 & 2 Deficiency leads to decrease in photosynthesis. Supplied as Copper Sulphate. Molybdenum: Essential for conversation of Nitrate to Ammonium. Supplied as Sodium molybdate. Boron: Involves in different enzymatic activities. Supplied as Boric acid.
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