Cytokinins are a group of hormones that promote cell division in plant roots and shoots and the growth of buds. Coconut milk is at times used in some tissue culture medium as it is rich in cytokinins.So option B is correct.

Coconut milk (coconut water) is widely used in tissue culture because it contains cytokinin.

Coconut milk, also known as coconut water, is the liquid found inside a coconut. It is widely used in tissue culture due to its high content of cytokinins.

What are cytokinins?
Cytokinins are a class of plant hormones that play a crucial role in cell division, growth, and differentiation. They promote cell division and prevent cell death, which is important in tissue culture where cells are being cultured and grown in a controlled environment. Cytokinins also regulate various physiological processes in plants such as leaf senescence, nutrient mobilization, and flowering.

Why is cytokinin important in tissue culture?
In tissue culture, plant cells or tissues are grown in vitro under controlled conditions. The addition of cytokinins to the culture medium promotes the growth of shoot buds, callus formation, and the development of multiple shoots from a single explant. Cytokinins stimulate the production of new cells and promote the formation of new shoots, which is essential for the propagation and multiplication of plants in tissue culture.

Why is coconut milk used as a source of cytokinins?
Coconut milk is a rich source of cytokinins, specifically zeatin and zeatin riboside. These cytokinins are naturally present in high concentrations in coconut water, making it an effective and readily available source for tissue culture. The cytokinins present in coconut milk stimulate the growth and development of plant cells, leading to enhanced shoot regeneration and multiplication.

Other benefits of coconut milk in tissue culture:
In addition to cytokinins, coconut milk also contains other essential nutrients and growth factors that are beneficial for tissue culture. These include sugars, vitamins, amino acids, and minerals. These nutrients provide the necessary energy and building blocks for cell growth and development.

Conclusion:
Coconut milk is widely used in tissue culture due to its high content of cytokinins, specifically zeatin and zeatin riboside. These cytokinins promote cell division, shoot regeneration, and multiplication in plant cells, making coconut milk an effective and convenient source for tissue culture. Additionally, coconut milk also provides other essential nutrients that support cell growth and development.