水分胁迫对枣叶片光合作用和保护酶活性的影响

以枣为试材,在大田滴灌条件下采取控水试验,研究不同水分处理对枣树光合作用和保护酶活性的影响。结果表明,各处理的蒸腾速率(Tr)、气孔导度(Gs)和胞间CO2浓度(Ci)日变化规律一致:Tr呈双峰曲线,Gs先上升后下降,Ci先下降后上升;对照(CK)和轻度水分胁迫(Ⅰ)的净光合速率(Pn)和Tr呈双峰曲线,重度水分胁迫(Ⅱ)下"双峰"和"午休"现象消失;随着水分胁迫的加剧,枣树叶片的Pn、Tr、Gs和Ci均下降,枣叶片中的过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活性及丙二醛(MDA)含量均升高,过氧化物酶(POD)活性在轻度水分胁迫下升高,在重度水分胁迫下,活性降低。综合各项指标测定,轻度胁迫处理的灌溉周期为不影响枣生长及生产的节水灌溉策略。

Effects of Water Stress on Photosynthetic Characteristics and Antioxidant Enzyme Activities of Jujube Leaves in Southern Xinjiang

The photosynthetic characteristics and antioxidant enzyme activities in jujube leaves were studied under different degrees of water stress in this paper. The results showed that the net photosynthetic rate（Pn）,transpiration rate（Tr）,stomata conductance（Gs） and intercellular CO2concentration（Ci） significantly decreased with increasing drought stress.Contrary to other treatments,the phenomenon of midday depression of photosynthesis disappeared under severe water stress.Meanwhile,the transpiration rate（Tr）,stomata conductance（Gs） and intercellular CO2concentration（Ci） significantly increased and then decreased under water stress.In addition,the activities of superoxide dismutase（SOD）,catalase（CAT） and malondialdehyde（MDA） contents increased continuously with the deepening of drought stress.The activities of superoxide dismutase（SOD）, peroxidase（POD） and catalase（CAT） increased and then decreased.