Hydropriming Treatment of Rice Seeds With Microbubble Water

In rice cultivation, seed emergence and seedling establishment tend to be unstable, and rice plants are likely to lodge during the ripening period in direct seeding, leading to an unsteady yield. Although the possibility of direct seeding in dry paddy fields is being re-examined from the viewpoint of reducing labor, unstable seed emergence and seedling establishment remain as challenges to be dealt with. Therefore, in order to improve unstable seed emergence and seedling establishment, we investigated the effects of hydropriming treatment of rice seeds with microbubble (MB)-water which have effect on promoting plant growth, on emergence and early growth of seedlings. In soil with 50% moisture content, the emergence rate, seedling height, longest root length, aboveground dry weight, underground dry weight, chlorophyll content, and a-amylase activity in seeds primed with MB-water were remarkably higher than those in seeds primed with dechlorinated-water and non-primed seeds. However, no significant differences were observed among the seeds primed the same way in soil with 25% moisture content. These results demonstrate that the hydropriming treatment of rice seeds with MB-water promotes their emergence in soil with 50% moisture content. In near future, we need to investigate seedling emergence of other cultivars hydropriming treatment with MB-water.