Ans. Conditions for Seed Germination
Seed germination depends on both internal and external conditions,
i) The internal conditions include a live embryo and sufficient food storage.
ii)The most important external conditions include water, oxygen and favourable temperatures.
1.Water (moisture): Seed of most plants have low water content, and germination cannot occur until seed coat or other tissues have imbibed (taken in) water. The absorbed water is used in the digestion of the stored food and it also helps in the elongation of hypocotyl and epicotyl.
2- Oxygen: Oxygen is essential for the respiration in the cells of embryo.
3- Temperature: Seeds differ greatly in their temperature requirements for germination. The optimum temperature for the germination of the seeds of most plants ranges from 25-30 °C.
4- Light: Germination of seeds of many plants is also favoured by light. In others, germination is retarded by light.