Department of Agricultural Chemistry, Oregon State University, Corvallis, Oregon 97331.
Plant Physiol. 1978 Feb;61(2):231-5. doi: 10.1104/pp.61.2.231.
For studies into the uptake of mercury vapor by wheat (Triticum aestivum), a simple theory and plant chamber were employed to estimate total leaf resistance of whole plants to water vapor exchange. The estimates were independent of leaf temperature, for which mean values were indirectly determined. The approach involved the measurement, at steady-state conditions, of the net change in water vapor flux per unit of leaf surface (Deltaq(v)) in response to a small induced change in absolute humidity (DeltaC(a)). Assuming that total leaf resistance (r(l)) was constant and that change in leaf temperature (T(l)) was negligible, total leaf resistance was calculated from the equation, [Formula: see text]While the assumptions concerning r(l) and T(l) may or may not be correct, evidence is presented which indicates that such assumptions did not significantly alter estimates of r(l) from their true values for changes in ambient relative humidity ranging from 0.011 to 0.074. Total leaf resistance of groups of whole plants estimated in this manner did not differ for ambient temperatures of 17, 25, and 33 C. Mean values of r(l) ranged from 83 sec cm(-1) in darkness to 2.4 sec cm(-1) at an illumination of 12.8 klux.
对于研究小麦（Triticum aestivum）对汞蒸气的吸收，采用了简单的理论和植物室来估算整株植物对水蒸气交换的总叶阻力。这些估计与叶片温度无关，因为叶片温度是间接确定的。该方法涉及在稳态条件下测量单位叶面积的水蒸气净通量变化（Δq（v））对绝对湿度（ΔC（a））的微小诱导变化的响应。假设总叶阻力（r（l））保持不变，并且叶片温度（T（l））的变化可以忽略不计，则从方程中计算出总叶阻力[公式：见文本]。尽管关于 r（l）和 T（l）的假设可能正确也可能不正确，但有证据表明，对于环境相对湿度从 0.011 到 0.074 的变化，这些假设并没有显著改变 r（l）的估计值与其真实值之间的差异。以这种方式估算的整株植物的总叶阻力在环境温度为 17、25 和 33°C 时没有差异。r（l）的平均值范围从黑暗中的 83 sec cm（-1）到 12.8 klux 光照下的 2.4 sec cm（-1）。
