Which of the following is used to break the seed dormancy?
Correct answer: (d)
Solution: ABA, abscisic acid was discovered for its role in regulating abscission and dormancy. It acts as a general plant growth inhibitor and an inhibitor of plant metabolism. It inhibits seed germination, stimulates the closure of stomata in the epidermis and increases the tolerance of the plant to various kind of stresses.
Gibberellins cause fruits like apple to elongate and improve its shape. They also delay senescence.
Auxins promote stem elongation, inhibit the growthof lateral buds (maintains apical dominance). They are produced in the stem, buds, and root tips. Ethylene is highly effective in fruit-ripening, it promotes senescence and abscission of plant organs especially leaves and flowers. Ethylene breaks the seed and bud dormancy and initiates seed germination.