盐胁迫下柚和橘幼苗体内矿质元素变化的比较研究

Changes in Mineral Element Contents in Pomelo and Citrus Seedlings under Salt Stress

摘要:

采用沙培法，对盐胁迫下坪山柚和福橘幼苗体内矿质元素的变化进行了研究。结果表明，随着NaCl浓度的增加，坪山柚和福橘幼苗根部及地上部Na⁺、Cl^-含量增加，且相同浓度下，福橘比坪山柚高。40mmol／L NaCI胁迫下，坪山柚和福橘幼苗地上部的K⁺、Fe含量，根部的Ca²⁺、Mg²⁺、Zn含量显著下降，而根部Fe含量及地上部Zn含量显著增加。随NaCl浓度增大，坪山柚根部K^＋含量，地上部Ca²⁺、Mg²⁺含量变化不明显，而福橘根部、地上部上述离子含量在NaCl浓度≥160mmol／L时均显著下降。因此，根部K⁺含量，地上部Ca²⁺、Mg²⁺含量存在品种问差异，或许可作为耐盐性鉴定指标。NaCl胁迫降低坪山柚和福橘幼苗根部及地上部P、Mn含量，而Cu含量在较高浓度NaCl胁迫下显著增加。NaCl胁迫明显降低坪山柚和福橘幼苗地上部K⁺／Na⁺、Ca²⁺／Na⁺和Mg²⁺／Na⁺值，其中K⁺／Na⁺值的变化可考虑作为柑橘耐盐性鉴定的指标。

Abstract:

Changes in mineral element contents in young seedlings of Citrus maxima cv. Pingshanyou and C. reticulata cv. Fuju cultured in plastic pots and treated with various salt concentrations were studied. Na⁺ and CIcontents in roots and shoots of Pingshanyou and Fuju seedlings increased with the increase of NaCl concentration. The contents of Na⁺ and Cl in roots and shoots of Fuju seedlings were higher than those of Pingshanyou under the same salinity. 40 mmol/L of NaCl significantly decreased Ca²⁺, Mg⁺ and Zn contents in roots and K⁺ and Fe contents in shoots of Pingshanyou and Fuju seedlings, whereas markedly increased the contents of Fe in roots and Zn in shoots. As salt concentration increased, K⁺ in roots and Ca²⁺, Mg²⁺ in shoots of Pingshanyou seedlings exhibited little change, but the above-mentioned mineral ions in Fuju seedlings significantly decreased when the salinity was higher than 160 mmol/L. It was shown that the contents of K⁺ in roots and Ca²⁺, Mg²⁺ in shoots were related to citrus varieties, which might be used as indices for evaluating the salt tolerance. Under salt stress, P, Mn in roots and shoots of Pingshanyou and Fuju seedlings decreased, but Cu increased obviously at high salt concentration. The value of K⁺/Na⁺, Ca²⁺/Na⁺ and Mg²⁺/Na⁺ decreased significantly in shoots of Pingshanyou and Fuju seedlings under NaC1 stress, of which the value of K⁺/Na⁺ could be considered as an index for evaluating the salt tolerance of citrus seedlings.