【摘要】 以3个玉米品种为试材,研究低温胁迫下光合指标的变化。结果表明,随着低温胁迫处理时间的延长和程度的加强,3个品种表现出一致的规律。光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、PSⅡ最大光能转换效率(Fv/Fm)和光系统PSⅡ的潜在活性(Fv/Fo)呈下降趋势,胞间CO2浓度(Ci)在18℃/9℃、16℃/7℃低温处理下逐渐降低,14℃/5℃低温处理下呈先降低后升高的趋势。水分利用率(WUE)呈先升高之后趋于稳定。由此可知,低温胁迫使叶绿素所吸收的光能被用于光合作用的减少,叶光系统Ⅱ(PSⅡ)活性中心受损,植株通过调节气孔导度(Gs)、蒸腾速率(Tr)、胞间CO2浓度(Ci)、水分利用率(WUE)来进行自我调控。。更多还原

【Abstract】 Three varieties were employed as materials.The experiment studied changes of photosynthetic characteristics under low-temperature stress.The results showed that Pn,Gs,Tr,Fv/Fm,Fv/Fo were decreased with low temperature treatment time and the increasement of level.Ci was decreased in 18 ℃/9 ℃,16 ℃/7 ℃,and decreased in earlier stage after increased in 14 ℃/5 ℃ with treatment time.WUE was increased in earlier stage and after stabilizing.This experiment showed that light absorbed by chlorophyll for photosynthesis could be reduced.The PSⅡ active centers of maize leaves were injured under low temperature stress.The plant is proceeding the self-regulation through adjust Gs,Tr,Ci,WUE.更多还原