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应用生态学报 ›› 2020, Vol. 31 ›› Issue (12): 4017-4026.doi: 10.13287/j.1001-9332.202012.010

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控水条件下侧柏冠层气孔导度对土壤水的响应

颜成正1, 郑文革2, 贾剑波3*, 闫文德1, 王忠诚3, 贾国栋4   

  1. 1中南林业科技大学生命科学与技术学院, 长沙 410004;
    2北京市水土保持工作总站, 北京 100036;
    3中南林业科技大学林学院, 长沙410004;
    4北京林业大学水土保持学院, 北京 100083
  • 收稿日期:2020-06-22 接受日期:2020-09-24 发布日期:2021-06-15
  • 通讯作者: *E-mail: jotham880303@163.com
  • 作者简介:颜成正,男,1994年生,硕士研究生。主要从事森林生态学研究。E-mail:ycz1548472260@163.com
  • 基金资助:
    湖南省自然科学基金项目(2019JJ50994,2017JJ2405)和湖南省教育科学研究重点项目(16A224)资助

Responses of canopy stomatal conductance of Platycladus orientalis to soil water under water control.

YAN Cheng-zheng1, ZHENG Wen-ge2, JIA Jian-bo3*, YAN Wen-de1, WANG Zhong-cheng3, JIA Guo-dong4   

  1. 1College of Life Science and Technology, Central South University of Forestry and Technology, Changsha 410004, China;
    2Beijing General Station of Soil and Water Conservation, Beijing 100036, China;
    3College of Forestry, Central South University of Forestry and Technology, Changsha 410004, China;
    4College of Water and Soil Conservation, Beijing Forestry University, Beijing 100083, China
  • Received:2020-06-22 Accepted:2020-09-24 Published:2021-06-15
  • Contact: *E-mail: jotham880303@163.com
  • Supported by:
    Natural Science Foundation of Hunan Province (2019JJ50994, 2017JJ2405), and the Key Program by the Education Science Research of Hunan Pro-vince (16A224).

摘要: 建立了不同控水条件下(无降水、一半降水、自然降水和二倍降水)的侧柏样地,于2016年8月—2017年8月监测了样地土壤含水量(SWC)、降水量、液流密度(Js)、叶面积指数(LAI)和水汽压亏缺(VPD)等因子,分析SWC对侧柏冠层气孔导度(gs)的影响。结果表明: 一半、自然和二倍降水样地的SWC与降水量呈正相关,SWC变化范围分别为4.9%~16.0%、7.2%~22.9%、7.4%~29.6%,无降水样地的SWC在8—10月下降50%;7月的日gs在14:00达到峰值(166.64 mmol·m-2·s-1),显著高于其他月份,且出现双峰现象, 1月的日gs在12:00达到峰值(54.1 mmol·m-2·s-1);3个降水条件下,侧柏gs与SWC呈负二次相关关系,且gs达到峰值,对应的SWC分别为8.5%、12.5%和18.5%,均趋近于年平均SWC。不同控水样地内侧柏gs对VPD的敏感性(δ)/参比冠层气孔导度(gsref)均≥0.6,表明不同控水条件下土壤水分状况较适合侧柏蒸腾用水的需求。当SWC在3.7%~7.5%时,δgsref值迅速增大,说明气孔调节能力更好,植物气孔对VPD的响应更敏感;当SWC上升到11%时,SWC变化对gsrefgs对VPD响应敏感性的影响不显著。可能存在侧柏产生适应状态的SWC阈值,植物体在自身的生命活动中关闭或减小气孔开度,降低叶片水势以适应过高的VPD,保护植物不会引起过度蒸腾,从而对蒸腾的调控更加有效。

关键词: 冠层气孔导度, 土壤含水量, 液流密度, 水汽压亏缺

Abstract: A water-controlled experiment with four treatments (no rain, half raining, natural raining and double raining) was carried out in a Platycladus orientalis forest. The factors including soil water content (SWC), precipitation, sap flow density (Js), leaf area index (LAI), vapor pressure deficit (VPD) were monitored during August 2016 to August 2017. We further analyzed the response of canopy stomatal conductance (gs) to changes of SWC. The results showed that the SWC of plots (half, natural and double raining) showed a positive correlation with precipitation, and the range of SWC was 4.9%-16.0%, 7.2%-22.9%, 7.4%-29.6%, respectively. The SWC in the plot with no rain decreased by 50% from August to October. The daily gs reached a peak of 166.64 mmol·m-2·s-1 at 14:00 in July, which was significantly higher than other months. A bimodal phenomenon occurred. The daily gs reached a peak of 54.1 mmol·m-2·s-1 at 12:00 in January. Under the three rain plots, diurnal variation of gs and SWC showed a negative quadratic correlation. The SWC corresponding to the peak of gs was 8.5%, 12.5% and 18.5%, respectively, close to the annual average SWC. Sensitivity (δ) of gs to VPD /reference canopy stomatal conductance (gsref) was more than or equal to 0.6 in different water-controlled plots, indicating that soil water condition was more suitable for water demand of P. orientalis. When SWC was between 3.7% and 7.5%, the δ and gsref increased rapidly, indicating that stomata had better regulation ability, and that plant stomata was more sensitive to VPD. When SWC increased to 11%, SWC alteration did not affect the response sensitivity of gsrefand gs to VPD. There might be a SWC threshold value for the adaptation of P. orientalis. By closing or reducing stomatal aperture, leaf water potential decreased, P. orientalis could adapt to excessive VPD and avoid excessive transpiration, which was more effective in regulating transpiration.

Key words: canopy stomatal conductance, soil water content, sap flow density, vapor pressure deficit.