Dormancy in Plants and Plant Cells

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Plant cells normally contain a large amount of water which is liable to freeze at low temperatures, with grave risk of damage to the protoplasm. Tropical plants are very easily killed by freezing, but it is evident that plants of temperate and arctic regions must have become adapted to survive the period of winter frost, meaning that they have developed cold resistance.
Dormancy can be defined as a state in which growth is temporarily suspended. In some species the decline/cessation of growth is directly due to unfavorable temperature and light conditions, thus many pasture grasses remain in continuous growth throughout a mild winter and cease growth only when temperatures fall to about zero to five degrees Celsius. However, certain annual weeds like groundsel (Senecio vulgaris), chickweed (Cerastium spp.), they stop growing only during the coldest part of the winter.
In such cases the dormancy of plants is evidently caused by the unfavorable external conditions and in that case it is called imposed or enforced dormancy. However, in many cases the unfavourable conditions are not directly the cause of dormancy. Thus, many trees form winter-resting buds during the summer and autumn, when the temperatures and light conditions are still favorable, and long in advance of the onset of winter.
In such woody plants the cause of dormancy appears to lie within the tissues of the buds themselves, which is termed innate or spontaneous dormancy. This form of dormancy also occurs in many

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