An experiment was conducted to study the changes in contents of osmotic adjustment substances in one-year-old seedlings of three species of Salix, three species of Tamarix and two species of Nitraria subjected to different concentrations of NaCl (0, 100, 200, 300 and 400 mmol/L) after 30 days of salt stress. Results showed that the contents of proline and soluble sugar in the leaves of the eight species of trees increased, and the soluble protein contents of Salix and Nitraria seedlings also increased in response to salt stress. Soluble protein was not the main osmotic adjustment substance in Tamarix austromongolica and Tamarix hispida seedlings. Na+ and Cl- contents in the leaves, stems and roots of all the tree species increased obviously compared with those of the control. Na+ and Cl- contents of Nitraria were higher than those in Salix and Tamarix seedlings. K+ content of the three species of Salix seedlings decreased, and there was a great difference in K+ content in different parts of Tamarix and Nitraria. The contents of Na+ , Cl- and K+ were various in different parts of different tree species. Na+ : K+ ratios decreased with increasing salt concentration. The importance of osmotic adjustment substances in different tree species is various. The main osmotic adjustment substances and their contents in different parts are related to salt tolerance mechanism and interspecific difference.%研究了3种柳树(Salix)、3种柽柳(Tamarix)和2种白刺(Nitraria)的1年生苗在不同浓度(0、100、200、300、400 mmol/L) NaCl胁迫30 d后渗透调节物质含量的变化.结果表明:盐胁迫后8个树种叶片中积累脯氨酸和可溶性糖抵御盐胁迫,柳树和白刺中的可溶性蛋白增加,可溶性蛋白不是甘蒙柽柳和刚毛柽柳的主要有机渗透调节物质；各树种根茎叶中Na+和Cl-显著增加,白刺的Na+和Cl-的质量分数明显高于柳树和柽柳,3种柳树K+下降,柽柳和白刺各部位K+种间差别较大,各离子在不同植物的不同部位的分布存在差异,K+/Na+总体来说随着盐浓度增加而降低.可见,不同渗透调节物质在不同盐生植物中的重要性是不同的,植物的耐盐机理和种间差异对植物在盐胁迫下用于渗透调节的主要渗透调节物质及其含量变化以及在各器官组织中的分布有一定的影响.
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