Diversity in nighttime transpiration behavior of woody species of the Atlantic Rain Forest, Brazil
Diversity in nighttime transpiration behavior of woody species of the Atlantic Rain Forest, Brazil
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DOI：
10.1016/j.agrformet.2012.02.002
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发表时间：
2012-06
影响因子：
6.2
通讯作者：
Bruno H. P. Rosado;R. Oliveira;C. Joly;M. Aidar;S. S. Burgess-S.
中科院分区：
文献类型：
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作者：
Bruno H. P. Rosado;R. Oliveira;C. Joly;M. Aidar;S. S. Burgess-S.
夜间蒸腾作用(NT)在许多植物物种中都有记载，但我们还没有完全了解这种现象的非生物和生物控制。在这项研究中，我们研究了在巴西大西洋热带雨林低地(100米)和山地森林(1000米)发生的不同树冠暴露(CE)植物的NT行为的种间差异，以回答以下问题：在不同条件下，植物是否有不同的NT行为与CE的程度和/或海拔相关？由于较高的水汽压差(VPD)，山地森林中NT的速率相对于日最大值是否较高？考虑到低VPD通常会产生较低的相对NT通量，我们是否应该预期，由于冠层内小气候的缓冲性质，两个高度的林下物种与地上物种相比，具有相当一致的较低的NT相对速率？NT确实表现出海拔和物种之间的差异。最重要的是在山烷点观察到的NT和VPD之间的显著的非线性关系。这种非线性与以前发表的大多数NT动力学相反，表明NT受气孔和/或叶片能量平衡控制。我们的发现为热力学对非线性NT动力学的贡献提出了一个新的视角，并讨论了一些可能的原因。
Nighttime transpiration (NT) has been documented in many plant species but we do not yet have a thorough understanding of the abiotic and biotic controls of this phenomenon. In this study we examined interspecific variation in NT behaviors in plants with distinct crown exposures (CE) and occurring at lowland (100m) and montane forests (1000m) in the Brazilian Atlantic rainforest to answer the following questions: are there different NT behaviors in plants subjected to distinct conditions associated with degree of CE and/or altitude? Are there higher rates of NT relative to daily maximum values at the montane forest due to higher vapor pressure deficit (VPD)? Taking into account that low VPD should generally produce low relative NT fluxes, should we expect that understory species in both altitudes will have quite uniform low relative rates of NT in comparison to overstory species owing to the buffered nature of within-canopy microclimate? NT did show differences between altitude and species. Of most significance was a prominent non-linear relationship between the NT and VPD, observed at the montane site. This non-linearity is in contrast to most previously published NT kinetics and suggests stomatal and/or leaf energy balance controls on NT. Our findings raise a new perspective concerning thermodynamic contributions to non-linear NT kinetics and some possible reasons for this interesting behavior are discussed.