不同程度盐胁迫对碱茅离子吸收与分配的影响

Effects of Salt Stress on the Characteristics of Ion Absorption and Distribution in Puccinellia tenuiflora

用不同盐分浓度的硫酸盐混合盐对盆栽碱茅进行胁迫，探讨盐胁迫下碱茅根系对土壤中Na+、K+选择性吸收（SA）及植株各部位间Na+、K+选择性运输（ST）能力的变化，并对盐胁迫下植株各部位中Na+、K+、Ca2+、Cl-分布特性的变化进行研究。结果表明，当土壤有效性Na+含量小于22mmol／100g干土时，盐胁迫对碱茅根系的选择性吸收能力无显著影响，且选择性运输能力尚有所增强，但当土壤有效性Na+含量达31mmol／100g干土时，碱茅根系的选择性吸收能力约为对照的1／2，其选择性运输能力极弱；随着土壤中盐分含量的增加，碱茅叶鞘控制Na+、促进K+向叶片运输的能力则不断增强。

The plants of potted Puccinellia tenuoflora were stressed by treating with various gradient solutions of mixed salts. The main ingredient is sulphate. Changes in the selective ab sorption (SA)capacity of Na+, K+ from the soil by root system and in the selective transportation (ST) capacity of Na, K in different parts of the plant under saline conditions were studied, and changes in the distribution characteristics of Na+, K +, Ca2 + and Cl- in different parts of the plant under saline conditions were also studied. The results showed that SA value of the plant in treat-ment - 1 and treatment - 2 conditions is slightly lower than that of the plant in CK, and that ST1 (root system; stem)value of the plant in the former two conditions is higher than that of the plant in CK; SA value of the plant in treatment - 3 is almost half of that of the plant in CK, ST1 value of the plant in treatment - 3 is also lower than that of the plant in treatment - 1 and treatment 2. This suggests that within a certain extent of salintiy, effects of salt stress on the selective ab sorption capacity of the root system are weak, and the selective transportation capacity of the root system somewhat increases; but in higher salinity, the selective absorption capacity of the root system decreases greatly, and the selective trarisportation capacity of the root system somewhat decreases. The fact that ST2 (stem: leaf sheath)values are lowest in all the salinity conditions indi cates that stem has a very weak selective transportation capacity. With the increase in salt content of the soil, ST3 (leaf sheath: blade) value of the plant increases correspondingly, this shows that under salt stress the capacity of the leaf sheath limiting Na+ and promoting K+ transported ion to the blade increases gradually.