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SST 608 / PP 608 PHYSIOLOGY OF SEEDS                                                                               (2L +1P) III

Objective
To apprise students regarding seed germination, dormancy, physiological processes involved in regulation of seed development and physiological processes governing seed quality and its survival.

Theory

UNIT I
Introduction, importance of seeds, seed structure and function, chemical composition of seed, seed development and maturation – physiological and molecular aspects; hormonal regulation of seed development, desiccation tolerance and sensitivity in relation to seed longevity, LEA protein.

UNIT II
Physiological and biochemical changes during seed maturation assimilate movement to seeds, storage of carbohydrate, protein and fats in seeds and biosynthesis.

UNIT III
Seed germination, factors inf luencing, breakdown and mobilization of  stored products, carbohydrate, fat, protein, respiration and pathways of interconversion, control process in the mobilization of food reserve, hormonal control of germination. Seed dormancy, different types, environmental influences, mechanism and control including phytochrome, methods of breaking seed dormancy.

UNIT IV
Factors influencing loss of seed viability during storage, physiological and biochemical changes associated with seed ageing,, theories of seed ageing, seed viability and its evaluation, seed storage, protection from water, temperature and contaminants, desiccation tolerance and sensitivity in relation to seed longevity.

UNIT V
Seed vigour, concept, importance, measurement; seed invigoration, methods, physiological and molecular basis of seed invigoration, effect of vigour on field emergence and yield, seed hardening.

Practicals
Chemical composition of seed, testing seed vigour and viability, breaking of seed dormancy, germination, seed invigoration and priming treatments, accelerated ageing treatments, seed imbibition and leakage, enzyme activities during germination, sink ability of ovules, seed respiration.

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