Jeschke W D, Simonis W
Botanisches Institut der Universität Würzburg, Würzburg, Deutschland.
Planta. 1969 Jun;88(2):157-71. doi: 10.1007/BF01391122.
The light curve of Cl(-)-uptake (uptake vs. light intensity) byElodea densa in pure N2 shows that saturation is reached at a very low light intensity. In N2+3% CO2, on the other hand, there is considerably less Cl(-) uptake. Under these conditions, the saturation attained at low light intensity is only temporary, and the Cl(-)-uptake increases steadily with a further rise in light intensity. It is suggested that the reason for the low intensity of light saturation may be the necessity for an intracellular transport of ATP from the site of its formation to the site of Cl(-)-uptake.CO2 exerts a strong inhibitory influence on the Cl(-)-uptake, especially at low light intensities. At higher intensities the inhibition diminishes and it is nearly absent at high intensities of white light.The inhibition by CO2 is also a function of the wavelength of the light; it is greatest in the region below 683 nm, where photosynthesis occurs with high efficiency, but it is still present at wavelengths beyond 700 nm.CO2 also inhibits the Cl(-)-uptake at high light intensities of white light when small concentration of DCMU (5×10(-7) M) is present at the same time.The inhibitory action of CO2 is partly interpreted as a consequence of a competition for ATP between CO2-assimilation (espectially below 683 nm) and the light-dependent Cl(-)-uptake. In addition, however, it is suggested that at low light intensities the presence of CO2 effects a regulation between noncyclic and cyclic electron transports and photophosphorylation which is supposed to be a consequence of a change in the redox potential of ferredoxin or another cofactor acting in noncyclic and cyclic electron transports. Especially the inhibition of the Cl(-)-uptake by CO2 in far-red light (λ>700 nm) and in the presence of DCMU is taken to be an indication of this intracellular regulation.
在纯氮气中，伊乐藻对氯离子的吸收光曲线（吸收量与光强的关系）表明，在很低的光强下就达到了饱和。另一方面，在氮气 + 3%二氧化碳的环境中，氯离子的吸收量要少得多。在这些条件下，低光强下达到的饱和只是暂时的，随着光强进一步升高，氯离子的吸收量会持续增加。有人认为，光饱和强度较低的原因可能是需要将ATP从其形成部位转运到氯离子吸收部位。二氧化碳对氯离子的吸收有很强的抑制作用，尤其是在低光强时。在较高光强下，这种抑制作用减弱，在白光的高光强下几乎不存在。二氧化碳的抑制作用也是光波长的函数；在683纳米以下的区域抑制作用最强，在该区域光合作用效率很高，但在700纳米以上的波长处仍然存在。当同时存在低浓度的二氯苯基二甲基脲（5×10⁻⁷ M）时，二氧化碳在白光的高光强下也会抑制氯离子的吸收。二氧化碳的抑制作用部分被解释为二氧化碳同化作用（特别是在683纳米以下）和光依赖的氯离子吸收之间对ATP竞争的结果。然而，此外还表明，在低光强下，二氧化碳的存在会影响非循环和循环电子传递以及光合磷酸化之间的调节，这被认为是铁氧化还原蛋白或参与非循环和循环电子传递的另一种辅助因子的氧化还原电位变化的结果。特别是二氧化碳在远红光（λ>700纳米）和存在二氯苯基二甲基脲的情况下对氯离子吸收的抑制作用被认为是这种细胞内调节的一个迹象。
