Question

At the time of seed germination, digestive enzymes are induced to be formed under the influence of
A. Cytokinin
B. Gibberellin
C. Ethylene
D. Auxin

Answer 1

Hint: Before germination, the seed is in need of nourishment. The photosynthetic parts have not developed yet, hence, the starch stored in the embryo needs to provide nourishment to the seedling. $\alpha $-Amylase hydrolyzes the starch into glucose, this glucose is used by the seed to meet its energy requirements. A plant hormone (phytohormone), helps in synthesizing the $\alpha $-Amylase which in turn will help in breaking the seed dormancy.

Complete answer:
• Gibberellins (GAs) are a type of plant hormones that help to regulate various developmental processes in plants such as stem elongation, germination, dormancy, development of flowers and fruits, and also fruit senescence.
• Gibberellins help in the process of breaking dormancy and help in the germination of seeds.
• Generally during germination the breakdown of starch to glucose occurs as soon seeds are exposed to water, gibberellins present in the seed embryo are believed to initiate starch hydrolysis by helping in the process of synthesis of the enzyme $\alpha $-amylase in the aleurone cells.
• In the process of gibberellin-induced production of $\alpha $-amylase, it is observed that gibberellins produced in the scutellum diffuse into the aleurone cells, where they initiate the secretion of $\alpha $-amylase.
• The $\alpha $-Amylase synthesized hydrolyses starch, which in turn is converted into glucose. Glucose can be used in cellular respiration to produce energy for the seed embryo.
• Further studies of this process have shown that gibberellins can cause higher levels of transcription of the gene coding for the $\alpha $-amylase enzyme in order to stimulate the synthesis of $\alpha $-amylase.

Hence, the correct answer is option (B).

Note: Ethylene, auxin, and cytokinin are plant hormones. Ethylene hastens plant development. It helps the fruits mature and detach from the parent plant. Auxin helps in the growth of plant cells, the formation of buds, etc. In seeds, auxin helps in the synthesis of certain proteins. Cytokinins are plant hormones that partake in cell division. Apart from these three, there are other plant hormones that help in plant growth.