干旱胁迫对白木通光合生理特性的影响

Effects of drought stress on photosynthetic physiological characteristics of Akebia trifoliate

采用盆栽试验,研究干旱胁迫对白木通光合生理指标及叶绿素荧光参数的影响,揭示干旱胁迫对白木通光合作用及生理指标之间的关系,为白木通水肥管理及栽培提供参考依据。结果表明:轻度干旱(LS)提高了白木通幼苗的水分利用效率(P<0.05),对其它光合生理指标无明显影响(P>0.05);中度干旱(MS)使白木通叶片叶绿素含量、净光合速率(Pn)、蒸腾速率(Tr)、胞间CO2浓度(Ci)、电子传递速率(ETR)、最大光化学效率(Fv/Fm)、PSII的潜在活性(Fv/Fo)及光化学猝灭系数(qP)显著下降(P<0.05),而对Ru BP羧化酶活性、气孔导度(Gs)、实际光化学量子效率(ΦPSII)及暗下最大荧光(Fm)影响不显著(P>0.05);重度干旱(SS)导致白木通叶绿素含量、Ru BP羧化酶活性、净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、电子传递速率(ETR)、最大光化学效率(Fv/Fm)、实际光化学量子效率(ΦPSII)、PSII的潜在活性(Fv/Fo)、暗下最大荧光(Fm)及光化学猝灭系数(qP)显著下降(P<0.05),胞间CO2浓度(Ci)、水分利用效率(WUE)、初始荧光(Fo)、非光化学猝灭系数(CNPQ)显著升高(P<0.05);在中度干旱胁迫下白木通幼苗光合作用的降低主要是由气孔关闭引起的,而重度干旱胁迫下光合作用的下降主要是由光合机构活性降低的非气孔因素引起的。

In order to provide theoretical basis for different water and fertilizer managements and drought resistance cultivation, potted culture experiments were conducted to study the physiological and biochemical responses and chlorophyll fluorescence parameters to reveal the effect of drought stress on photosynthesis and associated physiological characters ofAkebia trifoliate. The results show that there was no signiifcant effect onA.trifoliate besides that the water use efifciency（RWUE） was increased under light drought stress; When under modest drought stress, the chlorophyll content, net photosynthetic rate（Pn）, transpiration rate（Tr）, intercellular CO2 concentration（Ci）, electron transfer rate（RETR）, the maximum photochemical efficiency（Fv/Fm）,Fv/Fo andqP decreased significantly （P〈0.05） while RuBP carboxylase activity, stomatal conductance（Gs）,ΦPSI and Fm had no significant changes; When under severe drought stress, the chlorophyll content, RuBP carboxylase activity, net photosynthetic rate（Pn）, transpiration rate（Tr）, stomatal conductance（Gs）, electron transfer rate（RETR）, the maximum photochemical efficiency（Fv/Fm）,ΦPSI,Fv/Fo,Fm, andqP decreased signiifcantly （P〈0.05）, while intercellular CO2 concentration（Ci）, water use efifciency（RWUE）,Fo andCNPQ increased signiifcantly（P〈0.05）. Under moderate drought stress, the photosynthesis reduce ofA.trifoliate seedlings was primarily caused by stomatal closure while the decrease of net photosynthetic rate was considered as a result of non-stomatal factors under severe drought stress condition.