Inhibitory effects of oxygen on seed germination as a specific trait of Japonica rice, Oryza sativa L.

Abstract

Dormancy in cereal seeds of oat, barley and rice is usually broken by a higher oxygen tension. In this experiment, however, the inhibitory effect of high oxygen tension on seed germination was observed in the seeds of japonica rice, unlike in those of indica and wild type rices. Standard dehusking, which increases the supply of oxygen to the embryo of a seed and the increment of the oxygen tension in the atmosphere surrounding an intact seed strongly inhibited germination of rice for a certain period of time after harvest. This inhibition was not observed under anaerobic conditions, such as in water and at a low oxygen tension. The inhibitory effect was especially recognizable in japonica rice seeds with a high water content irrespective of whether they were dormant or non-dormant cultivars, but not in indica or in wild rice (O. perennis MOENCH and O.sativa f.spontanea ROSCHEY).