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三种植被恢复树种的冠层气孔导度特征及其对环境因子的敏感性

胡彦婷,赵平**,牛俊峰,孙振伟,朱丽薇    

  1. (中国科学院华南植物园中国科学院退化生态系统植被恢复与管理重点实验室, 广州 510650)
  • 出版日期:2015-09-18 发布日期:2015-09-18

Characteristics of canopy stomatal conductance in plantations of three revegetation tree species and its sensitivity to environmental factors.

HU Yan-ting, ZHAO Ping, NIU Jun-feng, SUN Zhen-wei, ZHU Li-wei   

  1. (Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China)
  • Online:2015-09-18 Published:2015-09-18

摘要:

应用Granier热消散探针,长期监测华南地区荷木、大叶相思和柠檬桉林不同径级样树的树干液流,结合同步观测的气象数据,求算冠层气孔导度(gc),并分析其对环境因子的响应方式及敏感性.结果表明: 不同季节荷木林日间平均gc显著高于大叶相思和柠檬桉(P<0.05)(除3月外).在干季和湿季,gc与光合有效辐射(PAR)呈现对数正相关关系(P<0.001),湿季gc对PAR响应比干季更敏感.gc与水汽压亏缺(VPD)在干湿季均呈现对数负相关关系(P<0.001),同样在湿季表现出更高的敏感性.湿季gc与VPD的偏相关系数高于干季,VPD对气孔行为的调控作用在湿季更为明显.随着土壤含水量的降低,gc对VPD的敏感性下降,荷木和柠檬桉林下降的幅度大于大叶相思林,荷木和柠檬桉林下降的幅度相当.通过综合分析gc对环境因子(PAR和VPD)的敏感性及其对土壤含水量变化的响应规律,发现乡土树种荷木作为植被恢复树种比外来引种的大叶相思和柠檬桉更为适宜.
 

Abstract:

In plantations of three different re-vegetation tree species (Schima superba, Acacia auriculaeformis and Eucalyptus citriodora) in southern China, the stem sap flow of individuals at different DBH classes were monitored using Granier’s thermal dissipation probes. With synchronouslymeasured meteorological data, the canopy stomatal conductance (gc) was determined and the responses of gc to environmental variables were analyzed. We found that daytime mean gc in S. superba forest on average was significantly higher than those of A. auriculaeformis and E. citriodora plantations during a year (except in March). In the three plantations, gc was positively logarithmically correlated with photosynthetically active radiation (PAR) (P<0.001), with a higher sensitivity of gc to PAR during wet season than that of dry season. By contrast, a negative logarithmical correlation between gc and vapor pressure deficit (VPD) was observed, with a higher sensitivity of gc to VPD during the wet season. Additionally, a higher partial correlation coefficient between gc and VPD was observed during wet season, indicating that VPD played a more important role in regulating the behavior of stomata during wet season. In general, the sensitivity of gc to VPD decreased with the decreases of soil water content, but more manifest decreases were found in S. superba and E. citriodora forests than in A. auriculaeformis plantation, while the descend degree in S. superba and E. citriodora forests were equal. Overall, our results demonstrated that the native species S. superba is more suitable for revegetation in southern China than the exotic species A. auriculaeformis and E. citriodora.