Varietal Difference in Resistance of Rice Plant to Submersion under Water

Abstract

In the previous paper it was made clear that resistance of rice plants to submersion is determined by amount of available car-bohydrates contained in the plants and their rate of respiration. The present paper concerns whether the varietal difference in the resistance is also determined by the same mechanism. Thirty six varieties and twenty five varieties were used in 1953 and 1954, respectively. A high correlation was found between the resistance and starch or total carbohydrate content, but no significant correlation was found between the resistance and sugar content or soluble and insoluble nitrogen fractions content. Moreover the ratio total carbohydrate/respiratory rate showed higher correlation with the resistance than that between the resistance and the amount of carbohydrate itself. From these results it can be concluded that the authors, theory on the mechanism of resistance to submersion is proved to be true with varietal difference.