P, Q, R and S are four major types of phytohormones. P is a phytohormone which functions mainly as a growth inhibitor. It promotes the wilting and falling of leaves. Q, R and S are phytohormones which all promote growth of plants in various ways. Q is responsible for the phenomenon of phototropism in plants. R is involved mainly in shoot extensions. The phytohormone S helps in breaking the dormancy of seeds and buds. What are P, Q, R and S? Give one reason each for your choice.
P is abscisic acid (a plant growth inhibitor hormone) and is responsible for the wilting and falling of leaves. Q is auxin which is responsible for the phenomenon of phototropism in plants as it is present at shoot tip. R is gibberellin which is responsible for enlargement of shoot. S is cytokinin which is responsible for breaking the dormancy of seeds and buds.