Submergence tolerance of transplanted rice seedlings with several plantages in leaf number - The duration of submergence and the role ofendosperm reserves [Japanese]

摘要

Rice seedlings (Oryza sativa L. cv. Sasanishiki) with plant ages of 2.0, 2.3, 2.5, 2.7, and 3.4 in leaf number were transplanted and completely submerged for 0, 5, and 10 days. Plant length and total root length were measured 10 days after transplanting (DAT), and the percent survival and total dry weight of the survived plants were recorded at 25 DAT to evaluate the difference in submergence tolerance among the seedlings. When the seedlings were submerged for 5 days, all survived. When they were submerged for 10 days, however, the elongation of plant length was promoted and growth of the roots was conversely suppressed. The percent survival of the seedlings with a plant age of 2.0-2.7 ranged from 53% to 81%, and it was higher than the 22% of seedlings with a plant age of 3.4. In particular, the: percent survival of seedlings with a plant age of 2.5 was highest among seedlings. When endosperm reserves were removed from the seedlings just prior to transplantation, the reduction of elongation growth and the percent survival was hardly observed in the seedlings, except for those with a plant age of 2.0. The results indicate that the difference in percent survival among the seedlings was not caused by the amount of the residual endosperm reserves at the start of submergence.