盐胁迫对沙拐枣光合生理特性的影响

以采自甘肃民勤一年生的沙拐枣幼苗为试材,对不同NaCl浓度(0、50、100、200、300mmol·L~(-1))处理下沙拐枣光合生理特性进行分析,并对各生理指标与地上生物量进行灰色关联度分析,以探讨荒漠植物沙拐枣的抗盐机理,为沙拐枣的保护及其恢复荒漠生态系统稳定提供理论依据。结果显示:随着NaCl浓度的升高,沙拐枣同化枝内脯氨酸含量逐渐增大,而其可溶性糖含量逐渐减小;在低浓度NaCl(50mmol·L~(-1) NaCl)处理下,同化枝光合参数均增加,且净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)均达到最大值,比对照分别显著增加了33.3%、68.0%、60.8%;与50mmol·L~(-1) NaCl相比,处理浓度超过50mmol·L~(-1) NaCl时,Pn、Gs、Tr均降低;同化枝叶绿素b含量随着NaCl浓度的增加而降低,而叶绿素a和总叶绿素含量均呈先增加后降低的趋势。灰色关联度分析发现,同化枝的Tr、Gs、Ci以及叶绿素b与地上生物量的关联度较大。研究表明,低盐浓度NaCl激活了沙拐枣的某些生理机制,有利于植株的光合作用和生长,而植物在高盐浓度胁迫时能通过调节脯氨酸和可溶性糖的含量,减少叶绿素含量、Pn和Tr等维持自身的生长。

Photosynthetic Characteristics of Calligonum arborescens in Salt Stress

One year seedlings of Calligonum arborescens from Minqin in Gansu province were treated with different concentrations of NaCl (0,50,100,200,300 mmol·L^-1). We analyzed the photosynthetic characteristics and made the gray correlation analysis between physiological indexes and aboveground biomass, to explore the salt tolerance mechanism of desert plants, provide a theoretical basis for C. arborescens to better adapt to the virtual environment and to protect and restore the stability and sustainability of desert ecosystems. The results showed that, with the increasing of NaCl concentration, proline content gradually increased, in opposition to the change in soluble sugar. the photosynthetic parameters increased obviously under 50 mmol·L^-1 NaCl, and the net photosynthetic rate, stomatal conductance and transpiration rate reached the maximum, and significantly increased by 33.3%,68.0% and 60.8% compared with the control, the net photosynthetic rate, stomatal conductance and transpiration rate decreased when the concentration was more than 50 mmol·L^-1 compared with 50 mmol·L^-1 NaCl. The content of chlorophyll b decreased with the increasing of NaCl concentration while chlorophyll a and chlorophyll increased first and then decreased. Gray correlation analysis showed that transpiration rate, stomatal conductance, intercellular CO₂ concentration and chlorophyll b were significantly correlated with aboveground biomass. The research showed, low NaCl concentrations improving the growth of plants by activating certain mechanisms of plants. Through the adjustment of proline and soluble sugar contents, reducing chlorophyll content, net photosynthetic rate and transpiration rate, plants could maintain growth under high salt concentration.