| 摘要: |
| 【目的】研究不同土壤盐分和水分含量条件下，盐渍生境中盐穗木(Halostachys caspica)体内水分、无机离子和有机渗透调节物质含量的变化特征。【方法】按土壤盐含量（土壤电导率）的不同，在新疆阜康荒漠生态站附近盐渍化荒漠区设置了样地1(土壤电导率为3.56 mS/cm，土壤含水率为3.39%)、样地2(土壤电导率为7.39 mS/cm，土壤含水率为11.34%)和样地3(土壤电导率为7.71 mS/cm，土壤含水率为6.49%)，对不同样地的土壤(0～60 cm土层)及所生长的盐穗木进行采集，分析土壤的基本理化性质，同时测定植物样品中的含水率、无机盐离子及有机渗透调节物质含量等指标。【结果】3个样地中，土壤Na+、Cl-含量均较高，K+、Ca2+、Mg2+含量均较低，土壤均呈碱性，有机质含量较低。在同一样地中，盐穗木根、茎、叶中的Na+、Cl-含量较高，且均表现为叶>茎>根。而在同一部位，不同采样点Na+、Cl-含量总体表现为样地3>样地2>样地1。盐穗木地上和地下部分含水率与3个样地土壤含水率变化一致，即样地2显著高于样地3和样地1。样地3盐穗木地上和地下部分肉质化程度均最高，显著高于样地1和样地2。样地1和样地2盐穗木叶片可溶性糖含量显著高于样地3，脯氨酸含量的变化则与可溶性糖含量相反。【结论】在盐渍生境中，盐穗木受到水分与盐分的双重胁迫时会抑制其对盐分的吸收。盐穗木进行渗透调节时，在盐含量较低及水分含量充足的土壤中以合成可溶性糖为主，而随着盐胁迫的增加，土壤中盐含量较高且水分含量较低时，则以合成脯氨酸为主。在不同土壤盐含量和水分含量条件下，盐穗木抵抗盐胁迫的机制有明显差异。 |
| 关键词: 盐穗木 无机离子 有机渗透调节物质 盐渍荒漠区 |
| DOI： |
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| 基金项目:国家科技支撑计划项目(2009BAC54B04) |
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| Adaptation of Halostachys caspica to different soil salt and water contents in salted desert |
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HAN Zhang-xiong,LI Li,XU Xin-wen,et al
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| Abstract: |
| 【Objective】In this paper,the effects of salt and water contents in soil on water content,inorganic ions,and soluble organic osmotica of Halostachys caspica were studied.【Method】3 plots were set up based on soil conductivity in the salinized desert near Fukang Station of Desert Ecology.The plots were named plot 1 (soil conductivity is 3.56 mS/cm,and soil moisture is 3.39%),plot 2 (soil conductivity is 7.39 mS/cm,and soil moisture is 11.34%),and plot 3 (soil conductivity is 7.71 mS/cm,and soil moisture is 6.49%).The physical and chemical properties of soil samples (0-60 cm) were measured in the laboratory of Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences.The moisture content,inorganic ions,organic osmolytes content and other indicators of Halostachys caspica were determined as well.【Result】The contents of Na+ and Cl- in soil were higher than K+,Ca2+,and Mg2+ in all 3 plots.Soils in the 3 plots were alkaline.The organic matter content in the soil was low.At the same sampling point,the contents of Na+ and Cl- were higher in the roots,stems and leaves of H.caspica than other ions.The contents of Na+ and Cl- in deferent parts of H.caspica were in a decreasing order of leaf>stem>root.While at the same part of H.caspica,the contents of Na+ and Cl- among the 3 plots were in a decreasing order of plot 3 >plot 2>plot 1.The moisture contents in both ground and underground parts of H.caspica were consistent with soil moistures i.e.plot 2 was significantly higher than plot 3 and plot 1.Succulence degrees of ground and underground parts of H.caspica in plot 3 were significantly higher than that of plot 1 and plot 2.Soluble sugar contents in the leaves of H.caspica in plot 1 and plot 2 were significantly higher than that of plot 3,while proline contents were opposite.【Conclusion】Absorption of salt was inhibited when H.caspica suffered high salt and high water content stress.Soluble sugar was the main product in soil with low salt and high moisture,while proline was the main product in soil with high salt and low moisture.Adaptation mechanisms of H.caspica to different stresses were significantly different. |
| Key words: Halostachys caspica inorganic ions soluble organic osmotica salted desert |
