Physiological Basis of Seed Dormancy in Woolly Cupgrass (Eriochloa villosa[Thunb.] Kunth.)

Abstract

Laboratory studies were conducted to determine the effect of seed coat on woolly cupgrass seed moisture and oxygen uptake, and to determine if water-soluble growth inhibitors are present in the seed. Intact dormant seeds did not respond to any temperature regime or to oxygen concentrations above atmospheric level. Dehulling increased germination of dormant seed to about 85%. Oxygen concentrations above atmospheric level increased germination of partially dehulled (1/4 distal end of the seed dehulled) seeds an additional 10%. Oxygen uptake by dehulled dormant and intact nondormant seeds was greater than intact dormant seeds. Leaching intact dormant seeds did not promote germination, nor did the leachate inhibit germination of nondormant seeds. Embryos excised from dormant seeds germinated under laboratory conditions. Results from this study suggest that the woolly cupgrass seed coat may inhibit germination by controlling oxygen availability to the embryo.