Question

In some tissue culture mediums, coconut milk is used because it is rich in?
A) Sucrose
B) Vitamins
C) Cytokinins
D) Minerals

Answer 1

Hint: Coconut milk or the coconut water from tender coconut is nothing but a free-nuclear endosperm (made up of thousands of nuclei) and the surrounding white kernel is the cellular endosperm. Endosperm can either be consumed by an embryo before seed maturation or may persist in the mature seed and be used up during seed germination.

Complete step-by-step answer:
Coconut milk is rich in cytokinins so it is used in tissue culture medium. As cytokinins are a group of hormones that enhance cell division in plant roots and shoots and also for the growth of buds.
Tissue culture medium has main principal components like inorganic nutrients ( macronutrients like nitrogen, phosphorus, potassium, calcium, magnesium, and Sulphur and micronutrients like iron, manganese, zinc, boron, copper, and molybdenum). Growth and morphogenesis can be improved by small amounts of vitamins, amino acids, and certain undefined supplements. In early work, the requirements of tissue culture for trace amounts of certain organic substances were satisfied by ‘undefined’ supplements such as fruit juices, coconut milk, yeast or malt extracts, and hydrolyzed casein.
Hence the correct answer is option C i.e., Cytokinins.

Note: Cytokinins induce cell division with auxin. From autoclaved herring sperm, the first cytokinin was isolated in 1955 by Miller and his associates. And it was called kinetin due to its ability to enhance cytokinesis. The first naturally occurring cytokinin was isolated from corn by Miller and Letham independently and was called Zeatin.