田间盐渍土壤条件下碱茅与赖草离子关系的比较研究

A COMPARASION OF ION RELATION IN PUCCINELLIA TENUIFLORA AND LEYMUS DASYSTACHS IN THE FIELD SALINE SOIL OF HEXI CORRIDOR

在河西走廊盐渍化草地的３个群落中设置样点，分别取土样及植物样，分析离子含量，以比较研究碱茅与赖草的离子关系及对盐分的适应性。结果表明，碱茅与赖草地上部Ｋ含量随土壤盐分的变化较小，而根系Ｋ含量随土壤盐分上升呈增加的趋势。赖草对Ｋ的选择性高于碱茅，且随土壤含盐量变化不大，碱茅对Ｋ的选择性随土壤总盐含量的增大而增加；赖草地上部Ｎａ含量及Ｋ／Ｎａ比在较低土壤含盐量（０．３％）下与碱茅接近，当土壤含盐量较高时，Ｎａ是碱茅的１／３～２／３，而Ｋ／Ｎａ是碱茅的１．９～３．５倍；土壤含盐量为０．３％及１．２９％时碱茅地上部Ｃｌ含量高于赖草，土壤含盐量为２．０３％时则低于赖草。对Ｋ较高的选择性与对Ｃｌ的富集是碱茅与赖草耐盐性较强的原因，也是两个种的共性。碱茅与赖草的Ｋ、Ｎａ与Ｃｌ含量（或比值）均从侧面反映了两种植物耐盐性的差异。对Ｋ较高的选择性。

Samples of soil and plants were taken from three plant communities in the sulphate-dominant saline soil of Hexi Corridor, China. The ion(K,Na and Cl) contents of the samples were analysed to investigate ion relation and adaptation of P. tenuiflora and L.dasystachs to saline soil. The result showed that as total soluble salt content(TSSC) increased, K content kept little changed or a tendency of increase respectively in the aboveground parts and in the root of the both plants. L. dasystachs had a higher selectivity ot K than P.tenuiflora, and selectivity to K kept unchanged in L.dasystachs and increased in P.tenuiflora with increased TSSC. When TSSC was 0.3%, Na contents and K/Na ratios of the aboveground parts were approximately equal in the two plants, while TSSC was higher, Na contents and K/Na ratios in L. dasystachs were 1/3～ 2/3 and 1.9～3.5 times that in P.tenuiflora. Cl contents were higher when TSSC was 0.3% and 1.29%, or lower when TSSC was 2.03% in P.tenuiflora than in L.dasystachs. Selectivity to K and abundant accumulation of Cl in plants were probably the cause of high salt-tolerance of the both plants, while K, Na and Cl contents and their ratios in the plants reflected the difference of salt-tolerance of the two plants from indirect sources , and a higher salt- tolerance of L.dasystachs was associated with its higher selectivity to K,K/Na ratio, Cl content( when TSSC was higher), and lower Na content as compared with lower that of P.tenuiflora.