NaCl胁迫对骆驼蓬幼苗液泡膜H+-ATPase和H+-PPase活性的影响

 研究了不同浓度NaCl胁迫对骆驼蓬幼苗Na⁺、K⁺含量及液胞膜H⁺-ATP酶(H⁺-ATPase)和H⁺-焦磷酸酶(H⁺-PPase)活性的影响。结果表明,NaCl胁迫浓度的增加使骆驼蓬幼苗根、叶中的K⁺含量下降,Na+含量和Na+/K⁺比及K⁺对Na⁺的吸收和运输选择性增高;根、叶液胞膜H⁺-ATPase和H⁺-PPase活性升高,H⁺-ATP酶耦联比率无显著变化;根液胞膜依赖ATP和PPi的质子泵活性及Na⁺/H⁺逆向转运活性先升后降,叶依赖ATP的质子泵活性及Na⁺/H⁺逆向转运活性升高,依赖PPi的质子泵活性先升后降。说明液泡膜H⁺-ATPase和H⁺-PPase驱动的质子泵和Na⁺/H⁺逆向转运活性对Na+在液泡内的积累及其骆驼蓬的耐盐性起重要作用。

Effects of NaCl Stress on Tonoplast H+-ATPase and H+-PPase Activities in Peganum harmala Seedlings

Effects of the different concentration of NaCl stress on Na⁺ and K⁺ contents, tonoplast H⁺-ATPase and H⁺-PPase activities in peganum harmala seedling leaves were studied. The results showed that with NaCl stress concentration increased, K⁺ content in roots and leaves was decreased, but Na⁺ content, Na⁺/K⁺ ratio, K⁺/Na⁺ selectivity, as well as tonoplast H⁺-ATPase and H⁺-PPase activities were all increased, the H⁺/substrate stoichiometry was significantly unchanged, the activities of the ATP-dependent proton pump and the Na⁺/H⁺ antiport in leaves were increased, the activities of PPi-dependent proton pump in leaves and ATP and PPi-dependent proton pump and Na⁺/H⁺ antiport of the tonolast vesicles in roots were all increased and then decreased with the increase of NaCl concentration. These results indicated that the activity of Na⁺/H⁺ antiport and proton pump driven by H⁺-ATPase and H⁺-PPase in tonoplast of P. harmala plays an important role in Na+ accumulation in vacuoles and salt tolerance.