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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Control of transpiration by radiation
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Control of transpiration by radiation

机译：通过辐射控制蒸腾作用

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摘要

The terrestrial hydrological cycle is strongly influenced by transpiration-water loss through the stomatal pores of leaves. In this report we present studies showing that the energy content of radiation absorbed by the leaf influences stomatal control of transpiration. This observation is at odds with current concepts of how stomata sense and control transpiration, and we suggest an alternative model. Specifically, we argue that the steady-state water potential of the epidermis in the intact leaf is controlled by the difference between the radiation-controlled rate of water vapor production in the leaf interior and the rate of transpiration. Any difference between these two potentially large fluxes is made up by evaporation from (or condensation on) the epidermis, causing its water potential to pivot around this balance point. Previous work established that stomata in isolated epidermal strips respond by opening with increasing (and closing with decreasing) water potential. Thus, stomatal conductance and transpiration rate should increase when there is condensation on (and decrease when there is evaporation from) the epidermis, thus tending to maintain homeo-stasis of epidermal water potential. We use a model to show that such a mechanism would have control properties similar to those observed with leaves. This hypothesis provides a plausible explanation for the regulation of leaf and canopy transpiration by the radiation load and provides a unique framework for studies of the regulation of stomatal conductance by CO_2 and other factors.
机译：陆地水文循环受蒸腾-水分通过叶片气孔的损失的强烈影响。在这份报告中，我们目前的研究表明，叶片吸收的辐射能量影响气孔蒸腾控制。该观察结果与当前关于气孔如何感测和控制蒸腾的概念相矛盾，我们建议使用替代模型。具体来说，我们认为完整叶片中表皮的稳态水势受叶片内部水蒸气的辐射控制速率与蒸腾速率之间的差异控制。这两个潜在的大流量之间的任何差异都是由表皮的蒸发（或凝结在表皮上）造成的，从而导致其水势围绕该平衡点旋转。先前的工作建立了孤立的表皮条中的气孔通过打开（增加和关闭）减少水势来响应。因此，当表皮上有凝结时气孔导度和蒸腾速率应增加（表皮上有蒸发时应降低），从而趋于保持表皮水势的稳态。我们使用模型来证明这种机制将具有类似于叶片观察到的控制特性。该假设为辐射负荷对叶片和冠层蒸腾作用的调节提供了合理的解释，并为研究CO_2和其他因素对气孔导度的调节提供了独特的框架。

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  • 作者

    Roland Pieruschka; Gregor Huber; Joseph A. Berry;

  • 作者单位

    Forschungszentrum Julich GmbH, Institut fuer Chemie und Dynamik der Geosphare, 52425 Juelich, Germany Carnegie Institution of Washington, Department of Global Ecology, Stanford, CA 94305;

    rnForschungszentrum Julich GmbH, Institut fuer Chemie und Dynamik der Geosphare, 52425 Juelich, Germany;

    rnCarnegie Institution of Washington, Department of Global Ecology, Stanford, CA 94305;

  • 收录信息 美国《科学引文索引》(SCI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    plant physiology; stomata; micrometeorology;

    机译：植物生理学气孔微气象学;

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