Nishimura M, Akazawa T
Research Institute for Biochemical Regulation, School of Agriculture, Nagoya University, Chikusa, Nagoya, 464, Japan.
Plant Physiol. 1975 Apr;55(4):712-6. doi: 10.1104/pp.55.4.712.
Photosynthetic activities of protoplasts isolated from spinach leaf (Spinacia oleracea L.) were investigated. The protoplasts were stable up to 9 hr, without loss of the original activity of CO(2) fixation (33-75 mumoles CO(2)/mg Chl.hr) and light-dependent O(2) evolution (33-40 mumoles O(2)/mg Chl.hr), when stored in 0.8 m mannitol-0.05 m N-tris (hydroxymethyl)-methylglycine-NaOH buffer, pH 7, at 4 C in dark. The optimum pH of 8.5 for CO(2) fixation reaction carried out in the present experimental condition employed is about the same as that reported for intact spinach chloroplasts. The CO(2) concentration for half-maximal rate of CO(2) fixation by protoplasts. "Km (CO(2))," were determined to be 19.8 mum (pH 7) and 42 mum (pH 8.5) and are similar to those observed for intact spinach chloroplasts. Protoplasts showed postillumination CO(2) fixation. Over-all results indicate that spinach protoplasts are as active as the intact plant leaf tissues in their photosynthetic activities.
对从菠菜叶（菠菜）中分离出的原生质体的光合活性进行了研究。当原生质体储存在0.8 m甘露醇-0.05 m N-三（羟甲基）-甲基甘氨酸-NaOH缓冲液（pH 7）中，于4℃黑暗条件下保存时，其稳定性可达9小时，且不会丧失最初的二氧化碳固定活性（33 - 75微摩尔二氧化碳/毫克叶绿素·小时）和光依赖的氧气释放活性（33 - 40微摩尔氧气/毫克叶绿素·小时）。在本实验条件下进行的二氧化碳固定反应的最适pH为8.5，这与报道的完整菠菜叶绿体的最适pH大致相同。原生质体二氧化碳固定半最大速率时的二氧化碳浓度“Km（二氧化碳）”，在pH 7时测定为19.8微摩尔，在pH 8.5时测定为42微摩尔，与完整菠菜叶绿体观察到的结果相似。原生质体表现出光照后二氧化碳固定现象。总体结果表明，菠菜原生质体在光合活性方面与完整的植物叶片组织一样活跃。
