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Current Category » Principles of Agronomy

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Seed and Sowing- Factors Affecting the Germination

External Factors:

1.Moisture: It enables the resumption of physiological activities, swelling of seed due to absorption of moisture & causes bursting of seed coat & softening the tissue due to which embryo awakes & resumes its growth.
2. Temperature: A suitable temperature is necessary for proper germination. Germination does not take place beyond certain minimum & maximum temperature i.e. 0⁰C & above 50⁰C. Optimum temperature range for satisfactory germination of seed is 25 to 30⁰C.
3. Oxygen: It is essential during germination for respiration & other physiological activities which are vigorous during the process.
4. Light: It is not considered as essential for germination & it takes place without light. The seedlings grow more vigorously during darkness rather in light. However, for survival of germinating seedling, light is quite essential.
5. Substratum: It is the medium used for germinating seeds. In the laboratory, it may be absorbent paper (blotting paper, towel or tissue paper), soil & sand. Substratum absorbs water & supplies to the germinating seeds. It should be free from toxic substances & should not act as medium for growth of micro-organisms.

Internal Factors:

1. Food & Auxins: An Embryo feed on the stored food material until young seedlings prepares its own food. Auxins are the growth promoters, hence quite essential during the germination.
2. Viability: All seeds remain viable for certain definite period of time and thereafter embryo becomes dead. It depends on maturity of seed, storage conditions & vigour of parents and type of species. Generally, it is for 3-5 years and they remain for more than 200 years also as in lotus.
3. Dormancy: It is the failure of mature viable seed to germinate under favorable condition of moisture. Many seeds do not germinate immediately after their harvest, they require rest period for certain physiological activities.

Current Category » Principles of Agronomy