Agricultural Research Service, US Department of Agriculture, in cooperation with the University of Idaho, College of Agriculture Research and Extension Center, 83341, Kimberly, ID, USA.
Photosynth Res. 1981 Sep;2(3):185-94. doi: 10.1007/BF00032357.
A new theory and experimental method was developed to measure the diffusion resistance to CO2 in the gas phase of mesophyll leaf tissue. Excised leaves were placed in a chamber and their net evaporation and CO2 assimilation rates measured at two different ambient pressures. These data were used to calculate CO2 gas phase diffusion resistances. A variety of field grown leaves were tested and the effects of various experimental errors considered. Increasing the gas phase diffusion resistance decreased transpiration more than it decreased CO2 assimilation. It was concluded that gas phase diffusion resistance associated with CO2 assimilation may sometimes be 100 or 200 s·m(-1) greater than the resistance implied by transpiration rates. This may be due to longer path lengths for the CO2 diffusion, constricted in places by the shape and arrangement of mesophyll cells.
开发了一种新的理论和实验方法来测量叶绿体组织气相中 CO2 的扩散阻力。将离体叶片置于腔室内，并在两种不同的环境压力下测量其净蒸发和 CO2 同化速率。这些数据用于计算 CO2 气相扩散阻力。测试了多种田间生长的叶片，并考虑了各种实验误差的影响。增加气相扩散阻力会使蒸腾作用比 CO2 同化作用减少更多。结论是，与 CO2 同化相关的气相扩散阻力有时可能比蒸腾速率所暗示的阻力大 100 或 200 s·m(-1)。这可能是由于 CO2 扩散的路径长度更长，在某些地方受到叶绿体细胞的形状和排列的限制。
