Explain any three factors causing dormancy of seeds.

Explanation

(i) Hard, tough seed coat causes barrier effect as impermeability of water,gas and restrication of the expansion of embryo prevents seed germination.
(ii) Many species of seeds produce imperfectly developed embryos called rudimentary embryos which promotes dormancy.
(iii) Lack of specific light required lead to seed dormancy.
(iv) A range of temperatures either higher or lower cause dormancy.
(v) The presence of inhibitors like phenolic compounds which inhibits seed germination cause dormancy.