NaCl和Na2CO3对盐地碱蓬胁迫效应的比较

在相同的Na 浓度(如100 mmol/L)下,NaCl处理促进碱蓬植株干重增加,提高根系活力,而Na2CO3处理导致植株干重减少,根系活力降低;与NaCl胁迫相比,Na2CO3胁迫下叶片内Na 含量上升和K 含量下降幅度更大,叶肉细胞质Na 含量和叶内脯氨酸含量增加幅度更大,而V-H -ATPase(液泡膜H -ATPase)和V-H -PPase (液泡膜H -PPase)增加幅度较少;与NaCl胁迫不同,Na2CO3胁迫下SOD(超氧化物歧化酶)活性不是增加,而是降低,与此相一致,MDA(丙二醛)含量大幅度增加.上述结果表明,碱蓬对Na2CO3胁迫的抗性低于对NaCl的抗性,这可能与Na2CO3胁迫引起的Na 、K 离子严重失衡、活性氧清除能力降低有关.

Comparison of the Stress Effects of NaCl and Na2 CO3 on Suaeda salsa L.

Seedlings of Suaeda salsa L. grown in Hoagland nutrient solutions were treated with different concentrations of NaCl (50,100, 200, 300 mmol/L) and Na 2CO 3 (12.5, 25, 37.5, 50, 62.5 mmol/L). The results showed that the NaCl stress made the dry weight increase(Fig.1a) but the root vitality not change much (Fig.1b). On the contrary, the Na 2CO 3 stress which was of the similar Na + concentration to the corresponding NaCl stress made the dry weight (Fig.1a) and the root vitality (Fig.1b) all decrease. Compared with NaCl treatment, under Na 2CO 3 stress, the Na + content in leaves increased greater and the K + content decreased greater (Fig.2); the Na + content in cytoplasm of mesophyll cell (Fig.3) and the proline content in leaves rised greater (Fig.5b), the activities of V H + ATPase and V H + PPase rised less (Fig.6). Different from NaCl stress, under Na 2CO 3 stress, the SOD activity in leaves did not increase but decreased (Fig.7a). The MDA content in leaves increased greatly (Fig.7b) that correspond to the change of SOD activity. All above results showed that the Na 2CO 3 resistance of Suaeda salsa is less than NaCl resistance. The reason of this may be concerned with the serious imbalance of Na + and K + and with the decline of the ability of scavenging reactive oxygen species(ROS).