Let’s expand our knowledge on plant tissue culture media and it’s composition.
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Media used in plant tissue culture are composed of several components; salts, vitamins, amino acids, growth regulators, sugars, agar or gelrite and water. Each of them fulfills one or more functions in-vitro. The minerals present in plant tissue culture media can be used by the plant cell as building blocks, for synthesis of organic molecules or as enzymes in catalyzed reactions.
The ions of the dissolved salts play an important role as couterion for the transport of oxidized molecules by the plant, in the osmotic regulation and in maintaining the electrochemical potentials of the plant.
Nitrogen, sulfur and phosphorus are components of proteins and nucleic acids, magnesium and many micro elements form essential parts of enzymes and cell organelles, and are therefore important in the cell catalyzation of various reactions.
Calcium and boric acid are mainly found in the cell wall and especially calcium has an important task in the stabilization of biomembranes. Potassium and chlorine on the contrary are important in osmotic regulation for the maintenance of the electrochemical potentials and for activation large number of enzymes.
Micro And Macro Elements
The salt component of the media can be grouped into micro and macro elements. Elements like iron (Fe), copper (Cu), manganese (Mn), cobalt (Co), molybedium (Mo), iodine (I), nickel (Ni), chlorine (Cl) and alluminium (Al) are the micro nutrients while magnesium (Mg), calcium (Ca), potassium (K), phosphorus (P), sulfur (S), and nitrogen (N) are the macro nutrients.
Micro elements are present in micro molar concentrations due to the low quest of them by the plant while macro elements are present in millimolar concentration in the media due to their high amount needed by the plants cultured. The necessity of micro elements in the media is not yet clear. Only the mineral parts of the micro elements are useful for the plant. The anions are mostly not essential.
Murashige and skoog (MS) media
MS medium is the most used tissue culture medium, of which many variations have been developed. This medium was derived from whites medium and made for the cultivation of Nicotiana tabacum calli.
It was developed by two scientist; Murashige and Skoog. It contains the micro and macro elements in combination with vitamins in a concentration that facilitates the growth of many plants. This medium is very rich and saline medium and can be too salty to some plants species.
It is a combination of four stock solutions (MS) namely: MS I, MS II, MS III and MS IV. The four stocks are processed and produced in powdered form, but the stocks can also be prepared and used instead of the powdered form.
Vitamins are added to the plants in several forms and concentrations. They are essential for many biochemical reactions. In almost all media for plant cell and tissue culture, thiamine (vitamin) is included.
Ascorbic acid is mostly used to prevent phenolic actions from the cuts given to explants before culturing. However, the vitamin is not all that essential for growth.
Concerning other vitamins, it is hard to judge their main importance. Hence, the effort of vitamin the development of the cell in-vitro differs from species to species or might be harmful.
They are also added to the medium to induce growth and development. Some of these hormones include Auxin, cytokinin gibberellic acid and others