Studies on the Floating Rice : III. Effects of raising water level on the growth and carbohydrate contents of the tops

[摘要] Some varieties of floating and non-floating rice plants were grown under submerged condition by raising water level at a slow rate of 3 cm per day for 23 days followed by a rapid rate of 11 cm for 12 days. Growth and carbohydrate of the floating and non-floating rice were compared to those in ordinary condition. The results obtained were as follows: 1. Total internode length, leaf number and plant height tended to increase under submerged condition and the response was more striking in the floating rice. 2. Dry matter of the non-floating rice decreased associated with growth under submerged condition when the rate of raising water level was rapid, but that of the floating rice increased even at the rapid rate. 3. Under ordinary condition, the contents and concentrations of reducing and non-reducing sugars (especially of the former) were larger, but the concentration of crude starch was lower in the floating rice than in the non-floating rice respectively. In the floating rice, the content of reducing sugar become larger under submerged condition when the rate of raising water level was slow, and remained the similar value when the rate was rapid as compared to that in ordinary condition. In the non-floating rice the content of reducing sugar was markedly reduced under submerged condition when the rate was rapid. 4. The contents and concentrations of non-reducing sugar and crude starch decreased under submerged condition, but the rate of decrease was lower in the floating rice than in the non-floating rice. These results may suggest that the larger increase in total internode length of the floating rice under submerged condition is closely related to the increase in reducing sugar content within plant.

[学科分类] 农业科学（综合）