Factors necessaryf for seed gamination
A number of factors are required for the process f germination . They are of two types-external and internal.
Seeds are generally highlly dehydrated with only 6-15% of water content in their cells.Therefore they have low physiological activity. Water provides sufficent hydration to the concentrated protoplasm of the transport gases, a cause hydrolysis of reserve food nd its trnansport and allow embryo cells to grow in size.
Oxygen is essential for aerobic respiration to release energy for the metabolic activities. Therefore, with the exception of the few plants. (eg. rice, Typha etc) seeds usually require oxygen or good aeration for their germination.
Seeds require a definite temperature range withinwhich they germinate. Commonly seeds germinate within temperature range of 50C to 400C. However, the optimum temperature or seed germination lies between 25-300C for most of the species.
Light is not an essential factor for the germination of most of the seeds. However some are light sensitive and their germination is influenced by the presence or absence of light.