盐胁迫下柚实生苗生长、矿质营养及离子吸收特性研究

以坪山柚为材料,对盐胁迫下实生苗生长、矿质营养及离子吸收特性进行了研究。结果表明,沙培30d,80～200mmol/L盐胁迫,随盐浓度提高,坪山柚实生苗株高、叶面积、地上部干重和根部干重明显降低。溶液培养8d,坪山柚实生苗地上部及根Na+、Cl-含量随盐浓度的增加而增加,根及地上部K+、Ca2+、Mg2+以及P和Mn含量下降,Fe、Zn、Cu含量的变化因器官而异。其中,地上部Fe含量对盐胁迫敏感,可作为柚耐盐性鉴定指标。40mmol/L盐胁迫,坪山柚地上部K+/Na+、Ca2+/Na+、Mg2+/Na+值均显著下降,且Mg2+/Na+值+/Na+值>1;浓度≥160mmol/L盐胁迫,K+/Na+值+吸收、运转效率比Cl-高。

Study on the growth and characteristics of mineral nutrition and ion absorption of pomelo seedlings under salt stress

The growth and characteristics of mineral nutrition and ion absorption of pomelo (Citrus grandis Osbeck cv. Pingshanyou) seedlings were studied under various salinity levels. The results showed that the plant height, leaf area, shoot and root dry weight decreased drastically with the increase in the concentration of 80～200(mmol/L) NaCl salinity after sand culture for 30days. Solution culture for 8 days, the contents of Na⁺ and Cl^- in root and shoot of pingshanyou seedlings increased with the salt concentration increased, but the contents of K²⁺,Ca²⁺,Mg⁺ and P, Mn decreased, the contents of Fe,Zn and Cu depended on organ. The Fe content in shoot was sensitive to salt stress, it could be used as an important index for evaluating the salt tolerance of pomelo seedlings. The value of K⁺/Na⁺,Ca²⁺/Na⁺ and Mg²⁺/Na⁺ in shoot of seedlings decreased obviously when the salt concentration was 40(mmol/L), the value of Mg²⁺/Na⁺<1. It was an adaptability for the seedlings to have better salt tolerance that the value of K⁺/Na⁺>1 when salt concentration lower than 120(mmol/L) and K⁺/Na⁺<1 when salt concentration higher than 160(mmol/L). The efficiency of absorption and transport of Na⁺ was higher than that of Cl^- under various salinity levels.