Question

Dwarfness can be controlled by treating the plant with

• A. cytokinin
• B. gibberellic acid
• C. auxin
• D. antigibberellin.

Answer 1

The Correct Option is B

Viable seeds of some plants are unable to germinate even after getting all the necessary conditions. This inability of viable seeds to germinate even under favorable conditions, is called dormancy of seeds. This is considered to be due to some barriers or blocks inside the seeds. Some common causes of seed dormancy are : (i) Mechanically hard seed coat, which does not allow proper growth of embryo inside it, e.g., Brassica campestris. (ii) Presence of impermeable (impervious) seed coat j to H2O, e.g. many seeds of legumes. (iii) Presence of impermeable seed coat to oxygen, e.g. Xanthium (cocklebur). (iv) Presence of germination inhibitors like ABA (abscisic acid) and phenolics, etc., in seed coat or fruit pulp, e.g., in tomoto, inhibitor is present in fruit pulp. Seed coats may contain relatively high concentrations of growth inhibitors that can suppress germination of the embryo. Abscisic acid (ABA) is a common germination inhibitor present in the seed coats. Repeated washing and heavy rainfall removes such substances from the seed coat.