不同浓度NaCl胁迫下甘草幼苗光合特性与离子代谢特征的研究

Photosynthetic Characteristics and Ion Metabolic Properties of Glycyrrhiza uralensis Seedlings under Different Concentrations of NaCl

本研究以甘草幼苗为试材,采用浇灌培养方式进行盐胁迫处理,分别设置50 mmol·L^(-1)、100 mmol·L^(-1)、150 mmol·L^(-1)、200 mmol·L^(-1)等4个NaCl处理浓度,以不含NaCl为对照,于胁迫后15 d、30 d测定甘草叶片光合相关指标和K^(+)、Na^(+)含量。结果显示:50 mmol·L^(-1)NaCl处理15 d,甘草叶片净光合速率与对照相当;100 mmol·L^(-1)NaCl处理15 d,50~100 mmol·L^(-1)NaCl处理30 d,甘草叶片净光合速率、气孔导度、蒸腾速率下降,叶绿素含量维持较高水平,气孔因素是此期间净光合速率下降的主要原因。150~200 mmol·L^(-1)NaCl处理15 d、30 d,胞间CO_(2)浓度上升,叶绿素降解,非气孔因素是此期间净光合速率下降的主要原因。不同浓度NaCl胁迫下,甘草叶片均表现为Na^(+)含量升高,K^(+)含量降低,K^(+)/Na^(+)降低,且随处理浓度升高,处理时间延长,上述变化幅度加大。本研究认为甘草幼苗对一定浓度(50~100 mmol·L^(-1))NaCl胁迫具有耐受性。

This study used Glycyrrhiza uralensis seedlings as the test materials.Four different NaCl concentrations of 50 mmol·L^(-1),100 mmol·L^(-1),150 mmol·L^(-1),and 200 mmol·L^(-1)were set.The contrast group without NaCl was also constructed.The index of photosynthesis and the content of K^(+)and Na^(+)were determined after 15 and 30 days with the stresses.The results showed that,the net photosynthetic rate of Glycyrrhiza uralensis leaves after processing with 15 days under 50 mmol·L^(-1)NaCl stress was as the same as that of the contrast group.After processing 15 days with 100 mmol·L^(-1)NaCl and 30 days with 50-100 mmol·L^(-1)NaCl,the concentration of net photosynthetic rate,stomatal conductance,and transpiration rate were all decreased,the content of chlorophyll maintained in a high level.The stomatal factor was the main reason causing the concentration of net photosynthetic rate decrease.After processing 15 and 30 days with 150-200 mmol·L^(-1)NaCl,the concentration of intercellular CO_(2)increased,and the content of chlorophyll degraded.The non-stomatal factor was the main reason resulting in the concentration of net photosynthetic rate decrease.Under the stresses of different concentrations of NaCl,the contents of Na^(+),K^(+),K^(+)/Na^(+)in Glycyrrhiza uralensis leaves increased,decreased,and decreased,respectively.Above changes all increased with the concentration and processing time increasing.It could be concluded that the Glycyrrhiza uralensis seedlings were tolerant to the NaCl stress with the concentration of 50-100 mmol·L^(-1).