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    NaCl胁迫对2种鹅耳枥幼苗生长及离子吸收、分配与运输的影响

    Effects of NaCl stress on seedling growth and mineral ions uptake, distribution and transportation of two varieties of Carpinus L.

    • 摘要: 以2种鹅耳枥属植物(欧洲鹅耳枥和鹅耳枥)2年生幼苗为试验材料,采用不同浓度NaCl溶液进行胁迫处理,对其生长和Na+、K+、Ca2+、Mg2+等矿质离子在不同器官的分配、吸收与运输情况进行研究,探讨2种鹅耳枥的耐盐性差异。结果表明:盐胁迫下,2种鹅耳枥生长受到显著抑制,高浓度盐胁迫下(0.3%~0.5%)死亡率逐渐增加,且欧洲鹅耳枥死亡率高于鹅耳枥。各部分干质量随着NaCl浓度的增加而降低,0.3%~0.5%盐处理下,欧洲鹅耳枥总干质量下降比率高于鹅耳枥。随着盐胁迫的加重,2种鹅耳枥对Na+的吸收均增大,高浓度盐胁迫下,欧洲鹅耳枥体内Na+含量高于鹅耳枥,且欧洲鹅耳枥Na+主要集中在茎部,而鹅耳枥Na+主要集中在根部;K+在叶片中均维持较高的水平,Ca2+和 Mg2+含量变化不大;2种鹅耳枥不同器官中的K+/ Na+、Ca2+/ Na+和 Mg2+/ Na+随盐浓度的增加呈下降趋势,且显著低于对照,盐处理组中,鹅耳枥幼苗茎和叶片的离子比值均高于欧洲鹅耳枥。随着NaCl浓度的增加,欧洲鹅耳枥幼苗从根到茎的离子选择性运输能力下降,从茎到叶片的离子选择性运输能力先降低后增加,鹅耳枥从根部到叶片整体的离子选择性运输能力均显著高于欧洲鹅耳枥。综合分析表明,高浓度的盐胁迫对2种鹅耳枥均产生不利影响,造成植物体内盐离子积累,但鹅耳枥幼苗保持体内离子平衡能力高于欧洲鹅耳枥,其耐盐性高于欧洲鹅耳枥。

       

      Abstract: We studied the seedling growth and the absorption, distribution and translocation of mineral nutrients including Na+, K+, Ca2+ and Mg2+ in different organs of seedlings of two Carpinus L. varieties (C. betulus and C. turczaninowii) at different levels of NaCl stress. The results showed that under salt stress, the growth of seedlings of the two varieties was significantly inhibited. As the salt concentration increased from 0.3% to 0.5%, the mortality of seedlings increased, with that of C. betulus higher than that of C. turczaninowii; the dry weight of different parts decreased with the increasing NaCl concentration, and the rate of reduction of total dry weight of C. betulus was higher than C. turczaninowii. As salt stress increased, the absorption of Na+ was increased for the two seedlings at high concentrations of salt from 0.3% to 0.5%, with the content of Na+ in C. betulus higher than that in C. turczaninowii, and Na+ in C. betulus was concentrated in the stem while that in C. turczaninowii mainly in the roots. K+ in the leaves remained a higher level, but Ca2+ and Mg2+ contents changed little. K+/Na+, Ca2+/Na+ and Mg2+/Na+ ratios in different organs decreased with increasing salt stress, and were significantly lower than the control. In salt-treated groups, ion ratios in the stem and leaves of C. turczaninowii seedlings were higher than in C. betulus. The ion-selective transport capacity from root to stem of C. betulus seedlings decreased, and that from stem to leaves dropped first and then increased with the increasing NaCl stress; however, the ion-selective transport capacity from root to leaves of C. turczaninowii seedlings was significantly higher than that of C. betulus. Comprehensive analysis showed that the seedlings of two Carpinus varieties were adversely affected by severe salt stress, resulting in the accumulation of salt ions in plants, but the ability of C. turczaninowii to keep balance of ion in the plant was higher than that of C. betulus, and the former also had stronger ability than the latter in salt tolerance.

       

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