摘要
在低盐介质中，含有垛叠类囊体（基粒）与不垛叠类囊体（间质片层）结构的叶绿体进行的光系统Ｉ电子传递与磷酸化反应（ＰＳＰ）都为低浓度的尼日利亚菌素所促进，低浓度的氯化铵对基粒结构叶绿体的系统Ｉ与包括两个系统的电子传递以及与之相偶联的磷酸化反应有促进效应，而对间质片层膜上进行的ＰＳＰ反应无影响。尼日利亚菌素或氯化铵对ＰＳＰ的促进效应在高盐介质中消失，且它们对高能态（Ｚ）形成的抑制效应在低盐介质中较高盐介质中大。当存在吡啶时，在低盐介质中它们对Ｚ形成的影响是抑制作用，在高盐介质中则是促进效应。这都表明不同结构的膜上均存在区域化质子。
Nigericin or NH4Cl at low concentrations stimulated both electrontransport and photophosphorylation.These phenomena cannot be explainedby the chemiosmotic hypothesis. In order to explain these phenomena, weused the stacked and unstacked thylakoids from the chloroplast of mesophyll cells or bundle sheath cells inSorghum to study these phenomena, andwe also studied these phenomena underdifferent KCl concentrations. The results obtained were as follows:(1 ) The photophosphorylation activity and electron transport activity ofPS I in both stucked and unstuckedthylakoids of chloroplast were stimulated by low concentrations of nigericin ina low salt medium (Tables 1, 3; Figs.1 ￣ 3).(2 ) Only in the stacked thylakoids had low concentration of NH4Cla stimulative effect on the activity ofcyclic or noncyclic PSP and that ofelectron transport through PS I orthrough both PS Ⅱ and PS I in low saltmedium (Tables 2, 4; Figs. 1￣ 3).(3 ) The stimulative effect ofnigericin or NH4Cl on PSP was not observed in high salt medium (Table 5).(4 ) The inhibitory effect ofnigericin or NH4Cl on the formation ofthe high energy state was greater inlow salt medium than in high saltmedium (Table 6).(5) In low salt medium pyridinedecreased the inhibitory effect ofnigericin or NH4Cl on the formation ofhigh energy state while in high saltmedium, pyridine caused nigericin orNH4Cl to stimulate the formation ofhigh energy state (Table 6).These results show that localizedprotons exist in the stacked and unstacked thylakods, it may be transformed into the delocalized form.
基金
国家自然科学基金
