NaCl胁迫对酸枣幼苗离子吸收与分配的影响

Effects of NaCl Stress on Ion Absorption and Distribution in Sour Jujube Seedlings

以酸枣水培幼苗为试验材料,研究了不同浓度NaCl胁迫对其活性氧、细胞膜透性、根系活力、不同器官Na+、K+、Ca2+和Mg2+离子含量的影响。结果表明:NaCl处理6 d,50、100 mmol·L-1处理酸枣叶片无萎蔫症状,150、200 mmol·L-1处理叶片萎蔫。在150、200 mmol·L-1 NaCl处理下叶片H2O2积累增加,50、100、150、200 mmol·L-1 NaCl处理下均有积累。随着NaCl处理浓度的升高,根、茎、叶中Na+含量均显著增加,叶片中K+、Ca2+和Mg2+含量显著下降,根和茎的K+和Mg2+含量变化不显著,Ca2+在200 mmol·L-1NaCl处理下显著下降。根、茎、叶中K+/Na+、Ca2+/Na+、Mg2+/Na+均显著下降,但是根的K+/Na+值始终大于1。总之,NaCl胁迫下,维持根和茎中相对稳定的K+、Mg2+水平、保持根部K+/Na+比值>1,是酸枣幼苗对盐胁迫的一种适应。

A hydroponic experiment was conducted to study the effects of NaCl concentration on reactive oxygen species,cell membrane permeability,root activity,and the concentrations of Na+,K+,Ca2+,and Mg2+ in different organs of sour jujube seedlings. The results showed no leaf wilting after six days in either 50 or 100 mmol · L-1 NaCl treatments. In contrast,leaf wilting was observed in both the 150 and 200 mmol · L-1 NaCl treatments. Leaf H2O2 concentrations were significantly greater in both the 150 and 200 mmol · L-1 NaCl treatments than in the 0 mmol · L-1 NaCl(control)treatment. Leaf concentrations were significantly greater in the NaCl treatments(i.e.,50,100,150,200 mmol · L-1 NaCl)than in the control treatment. The NaCl treatments significantly increased Na+ concentrations in roots,stems,and leaves. In contrast,the NaCl treatments significantly reduced K+,Ca2+,Mg2+ concentrations in leaves. The NaCl treatments had no significant effect on K+ and Mg2+ concentrations,regardless of the plant organ. Compared with the control,the 200 mmol · L-1 NaCl treatment significantly reduced Ca2+ concentrations in roots and stems. The NaCl treatments significantly reduced the K+/Na+,Ca2+/Na+,and Mg2+/Na+ ratios of roots,stems and leaves;However,the K+/Na+ ratio of roots was always greater than 1. In conclusion,in order to adapt to salt stress,sour jujube seedlings not only maintained relative stable K+and Mg2+ concentrations in roots and stems,but also maintained a K+/Na+ ratio > 1 in roots.