Question

An enzyme that stimulates germination of barley seed is?
A. Invertase
B. $\alpha$- amylase
C. Lipase
D. Protease

Answer 1

The plant growth regulators (PGR) are small, simple molecules that have different chemical composition. They are produced naturally by the plants that influence the growth of the plants. It is also called plant hormones or phytohormones. Gibberellin is one of the PGR which is released by the process of imbibition. Gibberellin stimulates the synthesis of the enzyme that breaks down the starch into glucose.

Complete step by step answer: Germination is the process by which a dormant embryo starts showing active growth and forms seedling. In the initial germination, it uptake the water and seed tissues rehydrated by the process of imbibition. The process imbibition releases the gibberellin. The gibberellin helps in stimulating the amylase enzyme. This enzyme is found in germinating seed. The food for the embryo is present in cotyledon in the form of starch. This starch is hydrolysed by the enzyme called amylase and converted into the glucose. The glucose provides the energy for plants to grow and develop.
Barley seed is rich in starch. The starch is hydrolysed by the amylase and provides energy for growth.
Invertase is the enzyme that converts the one form of sugar into another form that is sucrose into glucose and fructose.
-Lipase enzymes work on the fat. They break down the fat.
-Protease enzymes break down the protein structure.
Therefore the correct answer is option B, i.e. $\alpha$-amylase.

Note: PGR is divided into two groups – the first group helps in the plant growth activities such as cell enlargement, cell division, flowering, fruiting, seed formation, etc. The plant’s hormones involved in growth include auxins, cytokinins, and gibberellin. While other groups involved in the inhibiting activities like abscission and dormancy. Ethylene and abscisic acid belong to this group. They also respond to stresses and wounds of biotic and abiotic origin.