紫露草表皮细胞膨压、叶片水势及气体交换的原位测量
In Situ Measurement of Epidermal Cell Turgor, Leaf Water Potential, and Gas Exchange in Tradescantia virginiana L.
作者信息
Shackel K A, Brinckmann E
机构信息
Universität Bayreuth, Lehrstuhl für Pflanzenökologie, Postfach 3008, 8580 Bayreuth, West Germany.
出版信息
Plant Physiol. 1985 May;78(1):66-70. doi: 10.1104/pp.78.1.66.
A combined system has been developed in which epidermal cell turgor, leaf water potential, and gas exchange were determined for transpiring leaves of Tradescantia virginiana L. Uniform and stable values of turgor were observed in epidermal cells (stomatal complex cells were not studied) under stable environmental conditions for both upper and lower epidermises. The changes in epidermal cell turgor that were associated with changes in leaf transpiration were larger than the changes in leaf water potential, indicating the presence of transpirationally induced within-leaf water potential gradients. Estimates of 3 to 5 millimoles per square meter per second per megapascal were obtained for the value of within-leaf hydraulic conductivity. Step changes in atmospheric humidity caused rapid changes in epidermal cell turgor with little or no initial change in stomatal conductance, indicating little direct relation between stomatal humidity response and epidermal water status. The significance of within-leaf water potential gradients to measurements of plant water potential and to current hypotheses regarding stomatal response to humidity is discussed.
已经开发出一种组合系统，用于测定弗吉尼亚紫露草（Tradescantia virginiana L.）蒸腾叶片的表皮细胞膨压、叶片水势和气体交换。在稳定的环境条件下，上下表皮的表皮细胞（未研究气孔复合体细胞）均观察到了均匀且稳定的膨压值。与叶片蒸腾变化相关的表皮细胞膨压变化大于叶片水势变化，这表明存在蒸腾诱导的叶内水势梯度。叶内水力传导率的值估计为每平方米每秒每兆帕3至5毫摩尔。大气湿度的阶跃变化导致表皮细胞膨压迅速变化，而气孔导度几乎没有初始变化，这表明气孔湿度响应与表皮水分状况之间几乎没有直接关系。本文讨论了叶内水势梯度对植物水势测量以及当前关于气孔对湿度响应的假设的意义。
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