不同生境种源盐地碱蓬幼苗生长发育对盐分胁迫的响应和适应

为探讨盐地碱蓬适应不同生境的生理机制,研究了不同盐分处理(0,200和400 mmol/L的NaCl;0,200和400 mmol/L的KCl)对盐碱地和潮间带两种种源盐地碱蓬的生长发育、植株离子积累、叶片光合荧光指标和植株抗氧化系统的影响。结果表明,与对照相比,200 mmol/L的NaCl处理使盐地碱蓬的地上部鲜重、干重、肉质化程度显著增加,400 mmol/L的NaCl处理和两种浓度的KCl处理使盐地碱蓬的鲜重、干重、肉质化程度显著降低。不同浓度的NaCl处理使盐地碱蓬地上部Na⁺和Cl^-含量显著增加,K⁺含量显著降低;不同浓度的KCl处理使盐地碱蓬地上部K⁺和Cl^-含量显著增加,Na⁺含量显著降低。200 mmol/L的NaCl处理对碱蓬叶片的净光合速率、光合放氧速率、F_v/F_m值和φPSⅡ值无明显影响,而KCl处理则使碱蓬叶片各光合荧光参数显著降低。低浓度(200 mmol/L)NaCl处理使碱蓬SOD活性显著增加,但高浓度(400 mmol/L)NaCl处理和两种浓度的KCl处理均使碱蓬SOD活性显著降低。两种离子的不同浓度处理均使碱蓬POD活性显著增加。潮间带种源盐地碱蓬的地上部鲜重、干重、肉质化程度、光合荧光参数、地上部离子含量(Na⁺和Cl^-)均显著低于盐碱地生境。钾盐对盐地碱蓬的胁迫效应显著大于钠盐。盐碱地生境种源盐地碱蓬对盐分胁迫的响应显著高于潮间带。

Growth of Suaeda salsa tin response to salt stress in different habitats

The influence of salt (0,200 and 400 mmol/L NaCl;0,200 and 400 mmol/L KCl)on growth,ion accumulation,chlorophyll fluorescence and gas exchange in leaves and antioxidant levels was assessed in Suae-da salsa plants from different habitats;intertidal and inland saline.200 mmol/L NaCl significantly increased shoot fresh weight and dry weight and succulence of S .salsa plants,while 400 mmol/L NaCl and all KCl treat-ments resulted in reduced growth.The concentrations of Na+ and Cl- were increased by NaCl treatments while the concentration of K+ significantly decreased.Similarly KCl treatments resulted in increasing K+ and Cl-concentrations accompanied by a marked reduction in Na+ concentration.The 200 mmol/L NaCl treatment had no effect on net photosynthesis,photosynthetic oxygen evolution rate,F v/F m and φPSⅡin S .salsa,but KCl treatments resulted in a significant decrease in these traits.In addition,200 mmol/L NaCl resulted in a signifi-cant increase in the SOD activity whereas 400 mmol/L NaCl and all KCl treatments markedly decreased SOD activity.Interestingly,the POD activity in S .salsa was significantly increased by all NaCl and KCl treat-ments.Shoot fresh weight and dry weight,succulence,net photosynthesis,photosynthetic oxygen evolution rate and ion concentration (Na+ and Cl- )of S .salsa plants from the intertidal zone were lower than that those from an inland saline areas.The salt stress effect of KCl was greater than that of NaCl.Saline stress in S .sal-sa plants from saline inland habitats was significantly greater than plants from an intertidal zone.