叶尔羌河流域胡杨叶片生理特性和对土壤水盐及pH值的响应

Physiological characteristics of of Populus euphratica leaves and their response to soil water,salt and pH value in Yarkant River Basin

以叶尔羌河流域为研究区,研究了胡杨林下土壤水分、盐分和pH值的空间分布及其对胡杨叶片生理特性的影响.结果表明:叶尔羌河流域胡杨林下0~100 cm的土壤平均含水率以上游最高,下游最低,其中上游土壤含水量随着土壤深度的增加而增加.胡杨林下0~100 cm的土壤盐分以上游最高,中游最低,土壤盐分随着土壤深度的增加均呈递减趋势.0~100 cm的土壤平均pH值以上游最高,下游最低,垂直规律变化不显著.上游胡杨林下各层土壤含水率变异不显著;各层土壤盐分的变异明显;在中游土壤含水率随深度的增加其变异程度加大,随深度的增大,土壤盐分变异程度降低;在下游土壤含水率及盐分变异程度中等.上、中、下游的土壤各层pH值的变异程度均极小.胡杨叶片丙二醛含量及变异系数以下游最高,上游最低,变异程度均较弱;叶片可溶性糖含量以上游最高,下游最低;叶片可溶性糖的变异系数以下游最高,上游最低;叶片脯氨酸含量以中游最高,下游最低;叶片叶绿素含量及变异系数以中游最高,下游最低,变异程度均属于中低水平.胡杨叶片各生理指标与不同深度的土壤水分、盐分及pH值存在一定的相关性,脯氨酸与20~40 cm土壤含盐量之间有显著的负相关关系(P<0.05),脯氨酸与40~60 cm土壤含盐量之间有极显著的负相关关系(P<0.01);丙二醛与0~20 cm土壤含水率之间有极显著的负相关关系(P<0.01);脯氨酸与0~80 cm土壤pH值之间有显著的负相关关系(P<0.05),叶绿素与60~80 cm土壤pH值之间有显著的正相关关系(P<0.05).

The spatial distribution of soil moisture,salinity and pH in Populus euphratica forest and their effects on the physiological characteristics of Populus euphratica leaves were studied in the Yarkant River Basin.The results indicated that the average moisture content of the soil 0‒100 cm under the Populus euphratica forest in the upstream of Yarkant River Basin was the highest,while that in the downstream was the lowest.The soil moisture content in the upstream increased with the increase of soil depth.The salinity of the soil 0‒100 cm under Populus euphratica forest in the upstream was the highest,while that in the midstream was the lowest.The soil salinity decreased with the increase of soil depth.The average pH value of 0‒100 cm soil in the upstream was the highest,while that in the downstream was the lowest,and the vertical variation was not significant.The variation of soil moisture content in each layer of Populus euphratica forest in the upstream was insignificant;while the variation of soil salinity in each layer was substantial.The variation degree of soil moisture content in the midstream increased with the increase of depth.With the increase of depth,the degree of soil salt variation decreased.The soil moisture content and salt content in the downstream showed moderate variation.The variation of pH value of soil layers in the upstream,midstream and downstream was negligible.The malondialdehyde content and coefficient of variation of Populus euphratica leaves in the downstream were the highest and those in the upstream were the lowest,while both the degree of variation was trivial.The soluble sugar content of leaves in the upstream was the highest and that in the downstream was the lowest.The coefficient of variation of soluble sugar in the leaves in the downstream was the highest and that in the upstream was the lowest.The proline content of leaves in the midstream was the highest and that in the downstream was the lowest.The chlorophyll content and coefficient of variation of leaves in the midstream were the highest and those in the downstream was the lowest,while both the degree of variation was in the middle and low level.There were some correlations between the physiological indexes of Populus euphratica leaves and soil moisture,salinity and pH value at different depths.There were a significant negative correlation between proline and salt content in 20‒40 cm soil(P<0.05),a highly significant negative correlation between proline and salt content in 40‒60 cm soil(P<0.01),a highly significant negative correlation between malondialdehyde and soil water content in 0‒20 cm(P<0.01),a significant negative correlation between proline and 0‒80 cm soil pH(P<0.05),and a significant positive correlation between chlorophyll and 60‒80 cm soil pH(P<0.05).