增强UV-B辐射、NaCl胁迫及其复合处理对小麦幼苗光合作用及黄酮代谢的影响

依据增强UV-B辐射、NaCl胁迫及其复合处理不同天数，分别测定各处理小麦幼苗第一片真叶的净光合速率、气孔导度、叶肉细胞间隙二氧化碳浓度、叶绿素含量、黄酮含量和苯丙氨酸裂解酶活性.发现NaCl胁迫和增强UV-B辐射均明显降低小麦幼苗的净光合速率、气孔导度和叶肉细胞间隙CO2浓度;和NaCl胁迫相较， NaCl+UV-B辐射对小麦幼苗上述指标无进一步降低效应.增强UV-B辐射、NaCl胁迫及其复合处理均促进苯丙氨酸裂解酶活性和黄酮含量提高.说明了增强UV-B辐射降低小麦幼苗净光合速率的主要原因是气孔限制，而NaCl胁迫减轻了增强UV-B辐射对小麦幼苗光合作用的降低效应.

The Effects of Increased UV-B Radiation,NaCl Stress and Their Combined Treatment on the Photosynthesis and Flavone Metabolism in Wheat Seedlings

During increased UV-B radiation,NaCl strees and their combined treatment,measuring the net photosynthetic rate,stomatal conductance,intercellular CO_2 concentration,PAL activity,the contents of chlorophyll and flavone of first leave of wheat seedlings respectively.The net photosynthetic rate,stomatal conductance and intercellular CO_2 concentration of wheat seedlings were reduced by NaCl stress and increased UV-B radiation;In comparison with NaCl stress,NaCl + UV-B did not influence the net photosynthetic rate,stomatal conductance and intercellular CO_2 concentration of wheat seedlings; PAL activity and content of flavone of wheat seedlings were enhanced by increased UV-B radiation,NaCl stress and their combined treatment.The main reason of inhibition of photosynthesis by increased UV-B radiation was stomatal limitation;In NaCl + UV-B treatment,the reduction effect of increased UV-B radiation on photosynthesis of wheat seedlings could be weakened by NaCl stress.