Bravdo B
Department of Pomology and Viticulture, The Faculty of Agriculture, Rehovot, The Hebrew University of Jerusalem, Israel.
Plant Physiol. 1971 Nov;48(5):607-12. doi: 10.1104/pp.48.5.607.
The interactions between CO(2) and H(2)O vapor exchange of the leaf and respirant organs like stems were studied in tobacco plants. The results were analyzed according to a suggested model. Good agreement between open and closed system measurements supported the validity of the model.The measured over-all resistance to CO(2) of a leaf and a stem enclosed in a measuring cuvette was the same as the measured resistance of the leaf when measured alone provided the resistance of the stem to CO(2) is relatively high. The combined CO(2) compensation concentration of a leaf and stem having high resistance to CO(2) was higher than the CO(2) compensation point of the leaf alone, by the magnitude of rate of CO(2) evolution from the stem multiplied by the overall resistance of the leaf.CO(2) evolution into CO(2)-free air was found to be higher in light than in dark in leaves, while the reverse was true for stems. It was concluded that normally the CO(2) compensation point of a leaf is unaffected by stomata and boundary layer resistance while the combined CO(2) compensation point of a leaf and a stem differs in its nature since it represents a steady state of photosynthesis in which stem contribution, I(a), is equal to net photosynthesis, I(s). Interpretation of the experimental data shows tht respiration in the light is unaffected by external CO(2) concentration (at the range of 0-300 mul liter) and by intensity of photosynthesis.
在烟草植株中研究了叶片与茎等呼吸器官之间二氧化碳（CO₂）与水汽交换的相互作用。根据一个提出的模型对结果进行了分析。开放系统和封闭系统测量结果之间的良好一致性支持了该模型的有效性。当测量比色皿中封闭的叶片和茎对CO₂的总体阻力时，如果茎对CO₂的阻力相对较高，那么其测量值与单独测量叶片时的阻力相同。对CO₂具有高阻力的叶片和茎的组合CO₂补偿浓度高于单独叶片的CO₂补偿点，高出的幅度为茎中CO₂释放速率乘以叶片的总阻力。发现在光照下叶片向无CO₂空气中释放的CO₂比黑暗中更高，而茎的情况则相反。得出的结论是，通常叶片的CO₂补偿点不受气孔和边界层阻力的影响，而叶片和茎的组合CO₂补偿点在性质上有所不同，因为它代表了一种光合作用的稳定状态，其中茎的贡献I(a)等于净光合作用I(s)。对实验数据的解释表明，光照下的呼吸作用不受外部CO₂浓度（在0 - 300微升/升范围内）和光合作用强度的影响。
