论文部分内容阅读
以玉米品种‘东单213’和‘恒宇709’为试验材料,研究低温对孕穗期玉米叶片气体交换、叶绿素荧光及碳代谢酶活性的影响。结果表明:低温条件下,叶片气体交换参数[光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)]、叶绿素荧光参数[最大光化学效率(Fv/Fm)、实际光化学效率(ΦPSII)和光化学猝灭系数(qP)]、碳代谢相关酶[(磷酸烯醇式丙酮酸(PEP)羧化酶、磷酸蔗糖合成酶(SPS)和蔗糖合成酶(SS)]活性均有不同程度的降低,温度越低,降幅越大;在相同温度和胁迫时间,各项指标以‘东单213’降幅最大。15℃下,‘恒宇709’的叶片蔗糖含量仅在第7天显著低于对照,‘东单213’则在第5和7天均显著低于对照。总的来说:低温胁迫下玉米光合速率的下降可能与光系统II反应中心伤害以及暗反应相关酶活性的降低有关。
The effects of low temperature on gas exchange, chlorophyll fluorescence and carbon metabolic enzyme activities of maize leaves at booting stage were studied with maize varieties ’Dongdan 213’ and ’Hengyu 709’. The results showed that under low temperature, the parameters of leaf gas exchange (Pn, Tr and Gs), chlorophyll fluorescence parameters [maximum photochemical efficiency (Fv / Fm), actual photochemical efficiency (ΦPSII ) And photochemical quenching (qP)]. The activities of carbon metabolism related enzymes [PEP carboxylase, SPS and sucrose synthase (SS)] were all different , And the lower the temperature, the greater the decline. At the same temperature and stress time, the indexes decreased most with Dongdan 213, and the content of sucrose in ’Hengyu 709’ was significantly lower than that at the 7th day only In contrast, ’Dongdan 213’ was significantly lower than the control on the 5th and 7th day.In general, the decrease of maize photosynthetic rate under low temperature stress may be related to the injury of the photoreaction center II and the decrease of enzymatic activity related to dark reaction.