披针叶黄华试管苗适应盐胁迫的渗透调节机制

以披针叶黄华(Thermopsis lanceolata)试管苗为材料,通过组培方法研究其在0、0.2%、0.4%、0.6%、0.8%和1.0%NaCl和Na2SO4胁迫30d后的生长、有机渗透调节物质和无机渗透调节物质(Na+、K+和Ca2+)含量的变化,以探讨其耐盐性机制。结果显示:(1)随NaCl和Na2SO4胁迫浓度的增加,披针叶黄华试管苗叶片脯氨酸和可溶性糖含量均显著持续增加,且NaCl胁迫下脯氨酸上升的幅度均大于相同浓度Na2SO4胁迫下的增幅,而可溶性糖上升的幅度却小于相同浓度Na2SO4胁迫下的幅度;可溶性蛋白含量随NaCl浓度的增大呈先升高后降低的趋势,但随Na2SO4浓度的增加呈持续上升的趋势。(2)随NaCl和Na2SO4浓度的增加,披针叶黄华试管苗Na+含量呈增加趋势且各处理均显著高于对照,Ca2+含量和叶片K+含量却呈逐渐减少趋势且各处理均显著低于对照,而根系K+含量呈先降后升的趋势;Na2SO4胁迫下披针叶黄华试管苗叶片Na+含量上升幅度以及K+和Ca2+含量下降幅度均明显低于相同浓度NaCl胁迫组;而Na+/K+和Na+/Ca2+比值随NaCl和Na2SO4浓度增加而升高;NaCl胁迫下,叶片Na+/K+和Na+/Ca2+高于相同浓度Na2SO4胁迫下的比值,而根系Na+/K+和Na+/Ca2+却低于相同浓度Na2SO4胁迫下的比值。研究表明,盐胁迫下,披针叶黄华试管苗通过抑制叶片中Na+积累并增加可溶性糖和可溶性蛋白含量,在根系中维持较高K+和Ca2+含量以及较低水平Na+/K+和Na+/Ca2+比,以降低披针叶黄华细胞渗透势来适应盐渍环境;披针叶黄华对NaCl胁迫的调节能力弱于Na2SO4。

Mechanisms of Osmotic Adjustment of Themopsis lanceolata Test-tuble Plantlets in Adapting to Salt Stress

To study the salt-tolerance mechanism of Thermopsis lanceolata,we determined the growth parameters,organic osmotic adjustment substance contents and inorganic ions such as Na⁺,K⁺ and Ca²⁺ cation contents of T.lanceolata test-tube plantlets which have been growing for 30 d under 0,0.2%,0.4%,0.6%,0.8%,1.0% NaCl and Na₂SO₄ Stress.The results showed:(1)With NaCl and Na₂SO₄ concentration increasing,the contents of free proline and soluble sugar in leaves of T.lanceolata test-tube plantlets increased significantly,but the increasing extent of free proline under NaCl stress was greater than that under the same Na₂SO₄ concentration stress,while the increasing extent of soluble sugar content under NaCl stress was smaller than that under the same Na₂SO₄ concentration stress;the soluble protein content increased first then decreased with the increasing of NaCl concentration while went up continuously with the increasing of Na₂SO₄ concentration.(2)Na⁺ content of T.lanceolata test-tube plantlets went up continuously with the increased of the NaCl and Na₂SO₄ concentrations and the Na⁺ contents of all treatments were significantly higher than those in the control.Ca²⁺ and K⁺ content in leaves presented a decreasing trend,which were significantly lower than that of the control,respectively.In roots,K⁺ content first increased and then declined.Compared with NaCl,Na₂SO₄ stress caused a lower increase of Na⁺ content and lower reduction of K⁺ and Ca²⁺ contents in leaves;Na⁺/K⁺and Na⁺/Ca²⁺ ratios increased with the increase of salt content;In leaves,Na⁺/K⁺and Na⁺/Ca²⁺ ratios under NaCl stress were higher than that under Na₂SO₄ stress,while Na⁺/K⁺and Na⁺/Ca²⁺ ratios in roots were lower than that under Na₂SO₄ stress.T.lanceolata test-tube plantlets under salt stress may adapt to salt environment depressing Na⁺ contents,increasing soluble sugar and soluble protein contents in leaves,higher K⁺ and Ca²⁺ contents and decreased Na⁺/K⁺and Na⁺/Ca²⁺ ratios in roots.In words,the adaptation of T.lanceolata to NaCl stress was smaller than that to Na₂SO₄ stress.