Seed Dormancy and Germination - Bradbeer, J. W.

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Sommaire:
1 The Seed.- The role of the seed.- Germination.- The germination test.- Dormancy.- 2 Seed Formation.- Morphological aspects of seed formation.- Gymnosperms.- Angiosperms.- Physiological and biochemical aspects of seed formation.- Experimental approaches to embryogenesis.- 3 Seed Structure and Composition.- Some seed types.- Dehiscent seeds.- Indehiscent seeds.- Seed size.- Seed reserve substances.- 4 Germination.- The physical requirements for germination.- The morphology of seed germination.- Comparative morphology of seedlings.- The physiology of germination.- Imbibition.- Growth and seedling establishment.- Etiolation.- Development of the photosynthetic machinery.- The biochemistry of germination.- Mobilization of reserves.- Protein synthesis.- 5 The Mechanisms of Seed Dormancy.- Dormancy caused by embryo coverings.- The restriction of gaseous exchange by embryo coverings.- The restriction of water uptake by embryo coverings.- Mechanical restriction of embryo growth.- Water-soluble inhibitors in the embryo coverings.- Dormancy from the failure to mobilize extra-embryonic food reserves.- Embryo dormancy.- Underdeveloped and undifferentiated embryos.- The mechanism of embryo dormancy.- Endogenous inhibitors in embryo dormancy.- The possession of more than one dormancy mechanism.- 6 The Breaking of Seed Dormancy.- Dormancy breaking by single factors.- Chilling.- The mechanism of dormancy breaking during chilling of hazel seeds.- Dry storage and/or exposure of dry seeds to elevated temperatures.- Light.- Leaching.- Scarification.- Treatment with chemicals.- Dormancy breaking by fluctuating temperature.- Dormancy breaking by two or more factors.- Molecular mechanisms of the breaking of seed dormancy.- 7 Seeds in the Natural Environment.- The seed bank of the soil.- The effect of light in dormancybreaking in seeds in the seed bank.- The effects of seasonal conditions on the germination of seeds in the seed bank.- Laboratory investigation of germination characteristics of the species in the British flora.- Seed production and dispersal.- 8 Seed Viability and Vigour.- Viability.- Vigour.- Factors affecting the maintenance of viability and vigour during storage.- Moisture content.- Temperature.- Oxygen concentration.- The mechanism of ageing.- Seed longevity.- 9 Seed Technology.- Seed quality and seed testing.- Seed and crop production.- Seed germination and establishment.- Seed production.- Harvest, postharvest treatments and storage.- Genotype preservation in seed banks.- Seed technology and plant breeding.- Vernalization.- Seed technology in the developing world.- 10 An Experimental Approach to Seed Biology.- The procedure for an investigation of the seed biology of the natural flora of a temperate zone.- Seed collection.- Seed treatments.- Germination tests.- Further ways for the investigation and breaking of seed dormancy.- Problems with infected seed samples.- The seed bank in the soil.- Seed biology as an open-ended research problem.- References.