Mention the function of the following plant hormones:

(a) Abscisic acid — It acts as a growth inhibitor. It prevents or slows down seed germination, causes closure of stomata and promotes the abscission of leaves, flowers and fruits. It also increases the tolerence of plants to various kinds of stresses. Therefore it is also called the "stress harmone".

(b) Gibberellins — They bring about elongation of the internodes of the stem, overcome genetic dwarfism in plants and help in breaking the dormancy of seeds and buds.