盐碱胁迫下枸杞和柽柳的水力学特性和碳代谢

Hydraulic characteristics and carbon metabolism of Lycium chinense Miller and Tamarix chinensis Lour. under saline-alkali stress

盐碱胁迫是全球范围内重要的非生物胁迫形式之一,但目前对植物水力学特性和碳代谢应对盐碱胁迫响应的研究还不多。本研究以耐盐碱植物枸杞(Lycium chinense Miller)和柽柳(Tamarix chinensis Lour.)为对象,测定不同盐碱程度下两种植物的枝条水势和导水损失率(PLC)、叶片光合作用和气孔导度、不同部位的非结构性碳(NSC)浓度以及植株生长情况。结果显示,重度盐碱胁迫显著降低了两种植物凌晨和正午水势、光合速率和枝条PLC,重度胁迫下柽柳的光合速率、气孔导度和枝条PLC下降程度均大于枸杞,重度盐碱胁迫下枸杞不同部位的NSC浓度均显著降低,但柽柳的地上部分NSC浓度显著增加,根部NSC浓度显著减低。两种植物有不同的应对盐碱胁迫策略,枸杞有较强的气孔调节能力,对水力结构的维持有利,但会限制碳摄取,柽柳气孔调节能力弱,水力结构易受影响,但对碳平衡维持有利。

Saline-alkali stress is a significant abiotic stress affecting plant growth worldwide.However,the hydraulic characteristics and carbon metabolism features of plants responding to saline-alkali stress remain poorly understood. Two saline-alkali tolerant plants, wolfberry（ Lycium chinense Miller） and Chinese tamarisk（ Tamarix chinensis Lour.）,were examined to explore their water-carbon responses to saline-alkali stress under different salinity-alkalinity levels. Branch water potential,percentage loss of conductivity（ PLC）,stomatal conductance,net photosynthetic rate,nonstructural carbohydrate（ NSC） concentration,and growth status of the plants were measured. Results showed that severe saline-alkali stress significantly reduced the predawn and midday water potential,photosynthetic rate,and PLC of both species,with T. chinensis exhibiting a more severe reduction in photosynthetic rate,stomatal conductance,and branch PLC than L. chinense. Strong saline-alkali stress also significantly reduced NSC concentration of all tissues in L. chinense; however,the NSC concentration inthe aerial parts in T. chinensis was significantly increased,whereas the root NSC concentration was significantly decreased. Both species coped with saline-alkali stress using different strategies. Strong stomatal regulation of L. chinense was beneficial for the maintenance of hydraulic architecture, but constrained carbon uptake. Weak stomatal regulation of T.chinensis affected hydraulic architecture,but was advantageous for the maintenance of the carbon balance.