Definition of Seed Dormancy:
Non – germination of seeds due to absence of suitable conditions is termed as dormancy.
The seed dormancy is divided in to three groups
1. Endogenous
2. Exogenous
3. Combined
Various methods have been used by seed scientist and technologists to break the dormancy of seed.
Simple and widely used methods are
A. Scarification:
Any treatment i.e. physical or chemical that weakness the seed coat, is known as scarification.
Scarification method is applied, when dormancy is imposed by hard seen coat e. g. in legumes- cajanus cajan, (tur), gram etc.
B. Temperature Treatments:
When the dormancy is due to embryo factor i.e. the seed is incubating at low temp. (0- 5o C) over a substratum for 3 to 10 days placing it at optimum temp. Required for germination. E.g. mustard. – (Brassica campestrits)
C. Light Treatments:
Same seeds do not germinate in dark thus it provides continuous or periodic exposure of light is essential e. g. Lettuce (Lactuca Sativa) required red light (660nm) or white light is essential for germination to occur.
D. Treatments with growth regulators & other Chemicals:
Endogenous dormancy may be due to presence of germination inhibitors. Application of low level of growth regulators (i.e. Gibberellins, Cytokinins and Ethylene etc) may break the seed dormancy.
Note:
Article contributed by the authors from agriinfo.in for publication in biologyonline.com
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