Studies of the Effect of High Temperature on Growth and Developmental Response of Tobacco Plants : 3. Effect of the length of high temperature exposures in the day on the growth and developmental response of tobacco plants

[摘要] Seedlings of flue cured tobacco (var. Bright Yellow) were exposed to high temperature of 43°C for 1, 2 and 3 hours each in successive 14 days in daytime. The area of middle and lower leaves reduced with the durations of exposures, but the area of the upper of exposed plants was larger than that of untreated control. Dry matter of leaves and tops rose up to 2 hours exposure and then fell with the length of exposures. On the contrary, dry weight of stem increased with time of the exposures. The portion occupied by stem increased with time and the exposures in the day, whereas the portion of leaf, vice versa. Dry matter production of middle and lower leaves reduced with the exposure to high temperatures but that of the upper was larger than that of untreated control. Dry weight per unit leaf area of the middle and lower reduced with increasing the exposure except for 1 hour exposure of middle leaf. On the contrary, that of the upper was increased by the exposures to high temperature. Plant height of flowering stage increased with the duration of exposures to high temperature, and leaf area of the largest leaf at flowering stage was reduced by the exposures as compared with that of untreated control. Total number of leaves and days to flowering were increased by the durations of exposures to high temperatures. Rate of leaf emergence was reduced by the increasing exposures, and floral induction was retarded by the durations of exposure to high temperature.

[学科分类] 农业科学（综合）