در ارقام برنج a اثر زمان‌ نشاکاری بر صفات مرتبط با فلورسانس کلروفیل

To evaluate the effect of environmental conditions on chlorophyll a fluorescence-related traits in rice cultivars, a field research was conducted as a split plot experiment in randomized complete block design with three replications at Research Farm of University of Guilan in 2013. To deal with different environmental conditions, rice transplanting time with interval of 15 days was used. Main plots and subplots were allocated to transplanting time and rice cultivars (Hashemi, Dorfak, Sange jo, Ali kazemi, Khazar and Gouhar), respectively. The results showed that the maximum quantum efficiency, zero fluorescence, maximum fluorescence, variable fluorescence and electron transfer rate were affected by the main effects of transplanting time and cultivars. Gouhar was highest in amount of 0.77 and 1086 in maximum quantum efficiency and variable fluorescence, respectively. The lowest rate of zero fluorescence was obtained in Gouhar with amount of 315.4. The fluorescence maximum had the highest value in Ali kazemi, Gouhar and Hashemi. The maximum rate of electron transport was observed in Sange jo and Khazar with amount of 145 and 134.4, respectively. The results of this research showed that Gouhar cultivar had higher average of maximum quantum efficiency and variable fluorescence parameters than other cultivars. Hence, it can be recognized as cultivar tolerant to stressful condition such as high temperature. Delaying of transplanting time caused facing of rice cultivars with incompatible environmental conditions like higher temperatures. This conditions had a negative impact on traits such as maximum quantum efficiency and caused a failure in proper functioning of the photosynthetic apparatus. Therefore, it seems that delaying in transplanting time is not suitable particularly in grain filling period of rice due to facing of cultivars with unfavorable environmental conditions.