Slatyer R O
Department of Environmental Biology, Research School of Biological Sciences, Australian National University, P. O. Box 475, Canberra, A.C.T. 2601, Australia.
Plant Physiol. 1971 Feb;47(2):269-74. doi: 10.1104/pp.47.2.269.
Errors as small as 1 C in the measurement of leaf temperature (T(leaf)) are shown to cause significant changes in the estimated value of the stomatal resistance (expressed in terms of total resistance to water vapor transfer, summation operatorrH(2)O). The effect increases as T(leaf) increases and as ambient relative humidity increases, if other conditions are maintained constant. The effect on the key CO(2) exchange parameter, the intracellular (or mesophyll) resistance, r(int), tends to be small under open stomata conditions but increases rapidly as stomatal closure occurs, particularly if the true value of r(int) is relatively small.Errors in the determination of the ambient water vapor and CO(2) concentrations can also significantly affect the calculated value of summation operatorrH(2)O and r(int). The effect on summation operatorrH(2)O and summation operatorrCO(2) increases as the ratio of the inlet/outlet concentration departs from unity and also increases as the assumed leaf-air concentration difference decreases. The combined effect on r(int) tends to be less than the individual effects on summation operatorrH(2)O and summation operatorrCO(2) since both are in the same direction.
研究表明，叶片温度（T(leaf)）测量中低至1摄氏度的误差会导致气孔阻力估计值（以水汽传输总阻力表示，求和运算符rH(2)O）发生显著变化。如果其他条件保持不变，这种影响会随着T(leaf)升高以及环境相对湿度升高而增大。对关键的二氧化碳交换参数——细胞内（或叶肉）阻力r(int)的影响，在气孔开放条件下往往较小，但随着气孔关闭会迅速增大，特别是当r(int)的真实值相对较小时。环境水汽和二氧化碳浓度测定中的误差也会显著影响求和运算符rH(2)O和r(int)的计算值。对求和运算符rH(2)O和求和运算符rCO(2)的影响会随着进出口浓度比偏离1而增大，并且随着假定的叶 - 气浓度差减小而增大。对r(int)的综合影响往往小于对求和运算符rH(2)O和求和运算符rCO(2)的单独影响，因为二者方向相同。
