Seed dormancy in two Medicago species typical of natural pastures of Ragusa plateau [Sicily]
1993
Patane, C. (Catania Univ. (Italy). Istituto di Agronomia Generale e Coltivazioni Erbacee) | Bradford, K.J. (California Univ., Davis (USA). Dept. of Vegetable Crops)
Pasture improvement of the Ragusa plateau requires establishment of desirable forage species from seeds. In particular, the germination and establishment of legume species can be limited by seed dormancy due to hard seeds, or impermeability of the seed coats to water. Experiments were conducted to identify the factors which determine this dormancy and the actions required to remove it. Seeds of the two annual leguminous species (Medicago ciliaris (L.) All. and Medicago rugosa Desr. were exposed to several mechanical (scarification by hand and within a scarifier), physical (high temperature in hot water or ultra-low temperature in liquid nitrogen) and chemical (sulfuric acid) treatments being the most effective in breaking dormancy. Scanning electron microscopy of the seed coats of the two species indicated that the differences in responsiveness to the treatments may be related to the Malpighian cell layer of the seed coat, which was thicker in M. ciliaris (82.3 micron)
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