الفهرس 
acknowledgmentOnly 14 pages are availabe for public view
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Abstract
Seed germination is one of the basic processes in the life cycle of a plant. The term germination is used to designate those processes begining with the imbibition of water by a dry seed and ending when a portion of the embryo pentrates the seed coat (Noggle and Fritz, 1976). However, Mayer and Shain, (1974) regarded seed germination as that series of steps normally occurring prior to the emergence of the radicle from the seed coat. The emergence phase of growth begins when the embryo pentrates the seed coat and ends when the shoot system is able to sustain the growth of the plant by photosynthesis.
During germination the following kinds of processes have been observed: imbibition of water, hydration of subcellular organelles, changes in the subcellular organization of the embryo and endosperm or cotyledon, changes in phytochrome activity, activation of enzyme, de nove synthesis of enzymes, digestion of food reserves, translocation of soluble organic molecules to the embryo, synthesis of proteins and other cellular constituents, increase in oxygen uptake and in respira- tory activity, cell enlargement, cell division, synthesis or activation of growth substances, cellular differentiation, redistribution of metabolites within the embryonic axis and changes in oxygen and carbon dioxide levels.
The sudden change, from the dry state of the seed to the high concentration of water in the seedling, initiates complex series of.