分根区盐胁迫下绒毛白蜡盐离子分配和渗透调节物质积累特征

局部盐胁迫条件下植物不同器官中离子的分配和渗透调节物质的积累对耐盐性有重要影响,为揭示根区盐分异质性分布条件下植物对盐离子的积累和分配特征,通过分根的方式控制不同根区盐分的浓度,对绒毛白蜡(Fraxinus velutina)幼苗根、茎和叶中的Na^+、K^+、Ca^2+、Mg^2+和Cl^-的分配以及叶中可溶性糖和脯氨酸积累进行研究。结果表明,绒毛白蜡在局部盐胁迫时,盐胁迫根系中的Na^+和Cl^-含量略高于无盐胁迫的根系;叶中的Na^+和Cl^-含量显著低于均匀盐胁迫处理,但是显著高于对照;局部盐胁迫处理提高了盐胁迫根系中的K^+、Ca^2+和Mg^2+含量,提高了叶片K^+/Na^+,而对叶中Ca^2+和Mg^2+的影响不明显。局部盐胁迫显著降低了叶中的脯氨酸的含量,而对可溶性糖的影响不明显。因此在局部盐胁迫条件下,绒毛白蜡能够显著降低叶片中Na+和Cl-的积累,提高了叶片K^+/Na^+,降低脯氨酸的积累,有助于缓解局部盐胁迫。

Distribution of Salt Ions and the Accumulation of Osmatic Adjustment Substances in Velvet Ash under Heterogeneous Salt Stress

The distribution of salt ions and the accumulation of osmotic substances in the woody plant under partial salt stress are key prosperities for plant salt resistance.To better understand these features,in this study,taking the seedlings of velvet ash ( Fraxinus velutina ) as materials,the distribution of salt ions (such as Na^+,K^+,Ca^2+,Mg^2+ and Cl^-) in the roots,stems and leaves,and the accumulation of soluble sugar and proline in the leaves were examined by root-splitting method from which the salt concentrations in different root-zones was regulated.The results showed that the contents of Na^+ and Cl^- in the partial salt stressed roots were slightly higher than those without salt stress,and the contents of Na^+ and Cl^- contents in the partial salt stressed leaves were significantly lower than those of the uniform salt stress,and significantly higher than those of the control.Partial salt stress increased the contents of K^+,Ca^2+,Mg^2+ in the roots and the ratio of K^+/Na^+ in the leaves,and exhibited no significant differences for the contents of Ca^2+ and Mg^2+ contents in the leaves.Also,the partial salt stress significantly decreased the proline content in the leaves,while showed no significant impacts on soluble sugar.It was concluded that under partial salt stress,the accumulation of Na^+ and Cl^- in the leaves decreased,the ratio of K^+/Na^+ increased,and the accumulation of proline decreased to alleviate the salt stress.