赤水河上游水源涵养树种的水分生理特征

Water Physiological Characteristics of Water Conservation Plant Species in Upper Reaches of Chishui River

以赤水河上游32个水源涵养树种为试验材料,研究其水分、光合等生理特征差异。结果表明:(1)叶片δ13 C值变幅为(-26.97‰)^(-31.72)‰,均值为(-29.44±1.19)‰,低于中国总体水平,与最大持水率、最大持水速率呈显著的指数函数关系(P<0.05),但与自然含水率无显著的相关关系;(2)叶片含水量为54.44%~80.46%,束缚水/自由水为0.02~10.07,蒸腾速率为0.06~1.30g/(cm2·h),水势为(-2.43)^(-14.74)MPa,相对水分亏缺为34.74%~69.03%,比叶面积为230.15~585.39cm2/g,干物质量为8.39~31.83;(3)光合特征表现为高光合低蒸腾高水分利用效率、低光合低蒸腾高水分利用效率、低光合高蒸腾低水分利用效率、低光合低蒸腾低水分利用效率和高光合高蒸腾低水分利用效率5种类型;(4)可将植物适应水分特征划分为高水分亏缺低自由水、高水势高束缚水、高干物质量低水分亏缺、高自由水低水势和高光合高蒸腾低水势5组适应功能群。

32water conservation plant species in upper reaches of Chishui River were selected as research materials to study their differences in physiological characteristics,such as foliarδ13 C values,and photosynthetic and water physiological traits.The results showed that（1）foliarδ13C values of different plant species ranged from-26.97‰to-31.72‰,with an average of（-29.44±1.19）‰,which was lower than the general level of foliarδ13C values in China and had significant exponential function relationships with maximum water holding rate and ratio（P〈0.05）,but did not correlate with leaf water content.（2）The leaf water content range was 54.44%to 80.46%,and the bound water/free water,transpiration rate,water potential,relative water deficit,specific leaf area and the dry matter content were 0.02 to 10.07,0.06g/（cm2·h）to 1.30g/（cm2·h）,-2.43 MPa to-14.74 MPa,34.74%to 69.03%,230.15cm2/g to 585.39cm2/g,and 8.39 to 31.83,respectively.（3）Photosynthetic characteristics of32 water conservation plant species could be divided into 5types：high photosynthetic rate（Pn）-low transpiration rate（Tr）-high water use efficiency（WUE）,low Pn-low Tr-high WUE,low Pn-high Tr-low WUE,low Pn-low Tr-low WUE,and high Pn-high Tr-low WUE.（4）The 32 plant species could be divided into 5functional groups according to their adaptabilities to water environment,including high relative water deficit-low free water,high water potential-high bound water,high dry matter content-low relative water deficit,high free water-low water potential,and high Pn-high Tr-low water potential.