Dormancy occurs in seeds. Seed dormancy involves multiple, complicated biological mechanisms, all of which are designed to protect the seed from germinating when conditions are not optimal for plant survival. Seed dormancy may include a combination of physical, physiological, and/or morphological factors.
Physical dormancy may include water impermeability of the seed coat. Physiological factors involve chemical inhibitors, such as abscisic acid, that require breaking down prior to germination. Morphological dormancy prevents a seed from germinating because this means it requires additional maturation.
Each dormant seed contains food stores, that are broken down and made available for growth when the environmental clues activate it. For example, there must be adequate moisture, sunlight, and temperature for the seed to germinate into a seedling.
Seeds are living, and are respiring (breathing) and over time, the food stores can be broken down just keeping the seed alive. This is why seeds are refrigerated during storage.This slows down the respiration process and lengthens the lifetime of the seed.
Seeds can be dormant for months, or years, even without refrigeration. Some have an extremely long viability period. Radiocarbon dating has shown some to survive up to 2000 years!!
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