植物夜间蒸腾及其生态水文效应研究进展

Research advances in nighttime transpiration and its eco-hydrological implications

  • 摘要: 传统理论认为植物在夜间由于气孔关闭而不会发生蒸腾现象,但是,越来越多的证据显示一些植物在夜间会开启气孔并且有蒸腾失水.夜间蒸腾通常为日间的5%~15%,在干旱和半干旱地区生态系统的夜间蒸腾能够占到日间蒸腾的30%以上.夜间蒸腾的控制具有相当的复杂性,涉及了不同层次的控制变量.除与植物固有的基因因素有关外,夜间蒸腾还受非生物因子的影响,如水汽压差、风速、土壤水分、大气CO2浓度和根区土壤温度等因素的影响,研究表明水汽压差是夜间蒸腾最重要的环境驱动因子.夜间蒸腾水分损失具有重要的生态水文意义,该过程可降低植物叶片水势,导致黎明前叶片水势和土壤水势不平衡,抑制水力再分配,影响生态水分平衡,增强植物的养分供应,影响植物生产力和生长状况.

     

    Abstract: It is generally assumed that transpiration does not occur at night because leaf stomata are opened during the day and closed at night. Nonetheless, there is increasing evidence that the stomata are opening in many species and in a range of habitats at night. Nighttime transpiration rates are typically 5%—15% of daytime rates. This proportion of nighttime transpiration is often highest (30%—60%) in arid desert systems. Control of nighttime transpiration may have considerable complexity, it relates to the different levels control variables. The magnitude of nighttime transpiration with plant genetic factors, it is also affected by abiotic factors, such as vapor pressure difference, wind speed, soil moisture, atmospheric CO2 concentration, soil temperature and so on. Study shows that water vapor pressure deficit is the most important environmental driving factors to nighttime transpiration. Nighttime transpiration has significant implications for water budgets as an inevitable process. It can reduce leaf water potential of plant, contribute to imbalance between predawn leaf water potential and soil water potential, reduce hydraulic redistribution, affect of ecological water balance, enhance nutrient availability, and affect the productivity and growth of plant.

     

/

返回文章
返回