Effect of the seed coat on dormancy and germination in Stylosanthes humilis seeds

Izabel de Souza Chaves, Nilo Cesar Queiroga Silva, Dimas Mendes Ribeiro


Seed of Townsville stylo (Stylosanthes humilis H.B.K.) is know to exhibit a hard seed coat and when freshly harvested also show a physiological dormancy, however, the nature of the co-actions between seed coat and embryo growth that determine dormancy is poorly understood. In this study, physical dormancy of Townsville stylo seeds was not reduced during natural ageing at room temperature, in contrast to the physiological dormancy, which is gradually overcome during post-harvest ageing. Furthermore, the permeability of seed coat was affected by scarification treatments as well as by low-pH solutions. However, freshly harvested seeds exhibited a reduced germination compared with non-dormant seeds. Together, these data indicate that seed coat weakening is prerequisite for radicle protrusion and physiological dormancy of Townsville stylo seeds contribute to its timing


physical dormancy, physiological dormancy, Townsville stylo

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