17. Hydrolysis of stored proteins produced free amino acids which can be used for glucose biosynthesis. Phytohormone responsible for conversion of stored protein into glucose by activating in germinating cereals

is-
(1) Cytokinin                       (2) Auxin
(3) Gibberellin                  (4) Abscissic Acid

Correct answer: (3) Gibberellin

Gibberellins in germinating cereal grains (like barley, wheat, and maize) stimulate the aleurone and scutellum to produce hydrolytic enzymes, including proteases and α‑amylase.​
These enzymes hydrolyse stored proteins to free amino acids, which then serve as substrates for gluconeogenesis, contributing to glucose supply for the growing embryo.​

Explanation of options

• (1) Cytokinin
  Cytokinins mainly promote cell division, delay senescence, and influence sink strength, but they are not the primary signal for reserve mobilization in cereal seeds.​

• (2) Auxin
  Auxin regulates cell elongation and patterning; it does not act as the key inducer of storage‑protein hydrolysis in germinating cereals.​

• (3) Gibberellin – Correct
  GA from the embryo diffuses to surrounding tissues and induces synthesis of proteases and α‑amylase, driving breakdown of stored proteins and starch into amino acids and sugars that can be converted to glucose and used in respiration and growth.​

• (4) Abscisic acid
  ABA generally maintains dormancy and inhibits germination, antagonizing GA‑induced hydrolytic enzyme production and reserve mobilization.​