اثر تنش سرما و نور بر رنگیزه‌های فتوسنتزی گیاه سویا (Glycine max L.)

This research aimed to investigate the effect of chilling stress in different light conditions on chlorophyll content and electrolyte leakage in soybean leaves using a greenhouse experiment in 2013. Two soybean cultivars (032 and BP) after 20 days of growth at 28 ° C for 12 days exposed to two temperature (5 and 28 ° C) and light (2000 and 8000 lux) treatments. Chilling stress significantly reduced the chlorophyll a and a+b contents, about 17 and 14% respectively, and increased the electrolyte leakage up to 42 percent. Chlorophyll content in the cultivar 032 was higher than BP, about 11%. High light intensity markedly increased chlorophyll content about 23% in the control treatment, while the plant was grown under chilling stress had no significant response to increasing light level. Amount of chlorophyll b in the cultivar BP declined nearly 25% by chilling. High light intensity (8000 lux) increased rate of electrolyte leakage in cultivar 032 (approximately 65%) while BP cultivar did not show significant response to light intensity. In conclusion, the results showed that chilling stress could damage chlorophyll and plant cell membranes and its harmful effects increased as light intensity increased.