Abstract
In order to make clear the factors affecting to the accumulation of dry matter in flue-cured tobacco leaves in maturing stage, the effects of night temperature and nitrogen concentration of leaves upon the loss of dry matter from leaves due to the respiration and translocation at night were studied by means of punching method. The results obtained were as follows: (1) High temperature at night and high concentration of total nitrogen of leaves markedly affected the loss of dry matter from leaves dy respiration. At 30°C, close correlation was recognized between the loss of dry matter by respiration and total nitrogen concentration of leaves. This correlation was lowered with decrease in temperature, and at 15°C, no correlation was recognized between them. (2) When much nitrogen was supplied, increment of dry matter by translocation in upper leaves was observed. Under the low nitrogen supply, however, upper leaves lost dry matter by translocation. On the other hand, the lower leaves lost dry matter by translocation under both condition; especially this tendency was remarkable under the low nitrogen supply. (3) Negative correlation was recognized between the amounts of dry matter increment by translocation and the ratio of total carbohydrate to total nitrogen in leaves. (4) It was not able to make clear the effect of night temperature upon the loss of dry matter from leaves by translocation.
