Question

1. With respect to efficiency, what is the best size of an explant for shoot proliferation – one or two nodes? Support your answer.

2. What is callus tissue? Why is it important to look for callus production during shoot proliferation techniques?

Answer 1

Answer 1: With respect to efficiency bset size of explant. Probably, the larger explants contain more nutrient reserves and endogenous plant growth regulators to sustain the culture.

Answer 2: Callus is defined as a group of cells derived from competent source tissue that is cultured under in vitro conditions to form an undifferentiated mass of cells. It is also defined as an unorganized tissue mass growing on solid substrate. Callus forms naturally on plants in response to wounding, infestations, or at graft unions

It is imporatant to look for callus production durng shoot proliferation because Callus can be multiplied and later used to clone numerous whole plants. During callus formation, there is some degree of dedifferentiation (i.e. the changes that occur during development and specialization are, to some extent, reversed), both in morphology (a callus is usually composed of unspecialized parenchyma cells) and metabolism.