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采用盆栽沙培,研究了不同浓度NaCl处理下耐盐性不同的胡杨和新疆杨2种杨属物种幼苗体内K+、Na+和Cl-在器官间的区域化分布及其吸收运输特性,以揭示其耐盐性差异机制。结果表明:①NaCl胁迫下,2种植物体内K+含量下降,Na+和Cl-含量增加。不同器官中,K+含量叶中最高,茎中次之,根中最低;Na+含量由高到低依次为叶>根>茎;Cl-含量在2种植物间存在差异,胡杨叶中Cl-含量最高,根中次之,而新疆杨则是根中最高,叶中次之,但均是茎中最低。就各离子变化幅度而言,胡杨体内K+含量下降幅度及Na+增加幅度均低于新疆杨;胡杨根和茎中Cl-含量增加幅度小于新疆杨,而在叶中的增加幅度大于新疆杨。②2种植物体内K+/Na+值均随着NaCl浓度的升高而降低;除了低盐胁迫的茎以外,胡杨各器官中的K+/Na+值均显著高于新疆杨。与耐盐性较弱的新疆杨相比,胡杨根-茎运输选择性SK,Na值较低,而茎-叶运输选择性SK,Na值较高,根系截留Na+的能力较强。③随着NaCl浓度的增加,胡杨根向茎运输的SCl,Na值呈降低趋势,而新疆杨呈先降低后增加的趋势。耐盐性强的胡杨根向茎运输的SCl,Na值显著高于新疆杨,而茎向叶运输的SCl,Na值均低于新疆杨(2.0%NaCl处理除外)。以上结果表明,NaCl胁迫下胡杨是将盐分离子优先积累在根系来抵抗盐害,而新疆杨则是将盐分离子优先积累在茎部抵抗盐害。胡杨细胞拒盐性及液泡对盐分离子区隔化能力、维持K+、Na+平衡的能力较新疆杨强是其耐盐性优于新疆杨的主要原因。
Potted sand culture was used to study the regional distribution of K +, Na + and Cl- in organs of Populus euphratica and Populus tomentosa seedlings with different salt tolerance under different NaCl concentrations to reveal their absorption and transport characteristics Salt tolerance mechanism. The results showed that: ①NaCl stress, K + content decreased, Na + and Cl- content increased. In different organs, the content of K + in leaves was the highest, in the stems was the second, and in the roots was the lowest. The contents of Na + in leaves were high in the order of leaves> roots> stems. Cl- content was different among the two plants. Cl- content Highest in the root followed by the Xinjiang Yang Ze is the highest root, followed by the leaves, but are the lowest stems. In terms of the amplitude of each ion, the K + content in Populus euphratica and the increase of Na + in Populus euphratica were lower than that in Xinjiang poplar. The increase of Cl- content in Populus euphratica roots and stems was less than that in Xinjiang poplar, while that in Populus euphratica was greater than that in Xinjiang poplar. ② The K + / Na + values of two plants decreased with the increase of NaCl concentration. Except for the stems under low salt stress, the K + / Na + values of all organs of Populus were significantly higher than that of Xinjiang. Compared with the Xinjiang salt-tolerant Xinjiang Poplar, the selective SK and Na values for root-stem transportation of Populus euphratica were lower, while the selective SK and Na values for stem-leaf transport were higher and the ability of root interception Na + was stronger. (3) With the increase of NaCl concentration, the SCl and Na values of Populus euphratica root to stem transport decreased, but that of Xinjiang Poplar decreased first and then increased. SCl and Na values of salinity-tolerant root tubers transported to the stem were significantly higher than those of Xinjiang poplar, while SCl and Na values of stem-leaf transport were lower than those of Xinjiang poplar (except 2.0% NaCl treatment). The above results show that Populus euphratica under salt stress preferentially accumulates salt ions in the roots to resist salt damage, whereas Xinjiang poplar salt preferentially accumulates salt ions in stems to resist salt damage. Populus euphratica cell salt rejection and vacuolar compartmentalization ability of salt ions to maintain the balance of K +, Na + than Xinjiang Yang Qiang Xinjiang Salt its salt tolerance is the main reason.