HORMONAL REGULATION OF DORMANCY IN PLANTS

Dormancy, a phenomenon commonly occurring in plants, may involve the whole plants belonging to different taxonomical groups, as well as their organs such as floral and leaf buds, tubers, bulbs, rhizomes and seeds. According to an old, classical definition dormancy is a temporal cessation of active growth. It is now evident that such a definition is too narrow. A more general one can be proposed based on the observations that formation of new bulbs from unchilled dormant mother bulbs of Helianthus tuberosus do occur /Courduroux and Margot, 1963/, or slow germination and abnormal seedling development from embryos isolated from nonstratified seeds of several species do appear /Nikolaeva, 1967; 1977; Côme, 1970; Wyzinska and Lewak, 1978/. Thus, it seems that dormancy can be regarded as a block preventing the normal course of growth and development. The nature of the block is complex, but a partial elimination of its compounds is possible, leading to impaired growth and various developmental abnormalities. Complete removal of the block restores normal growth and development of a plant.

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