Sinclair J
Department of Biology, Carleton University, Ottawa, Ontario.
Plant Physiol. 1972 Dec;50(6):778-83. doi: 10.1104/pp.50.6.778.
The photosynthetic evolution of oxygen by isolated chloroplasts of Spinacia oleracea L. was studied using a modulated oxygen electrode. The enhancement effect, measured as the increase in the relative quantum yield of 650-nanometer light due to the presence of 710-nanometer light, was profoundly influenced by the concentration of inorganic cations in the bathing medium. Chloroplast fragments immersed in a solution containing a very low concentration of MgCl(2) or KCl, did not display enhancement but could be made to do so by raising the concentration of MgCl(2) to 3 mm, or that of KCl to 35 mm. This change in the enhancement properties was completely reversible. The maximum value of enhancement in a MgCl(2) solution appeared to occur at a concentration between 15 and 30 mm, while in KCl, the enhancement effect increased almost linearly up to a concentration of 100 mm.The appearance of the initial oxygen transient, the burst, was also controlled by the concentration of inorganic cations. Increasing concentrations of MgCl(2) or KCl caused the burst to grow in size in a way which was linearly related to the corresponding increase in enhancement.
利用调制氧电极研究了菠菜（Spinacia oleracea L.）离体叶绿体的光合放氧过程。以710纳米光的存在导致650纳米光的相对量子产率增加来衡量的增强效应，受到浴液中无机阳离子浓度的深刻影响。浸入含有极低浓度MgCl₂或KCl溶液中的叶绿体片段不显示增强效应，但通过将MgCl₂浓度提高到3毫米或KCl浓度提高到35毫米可使其显示增强效应。这种增强特性的变化是完全可逆的。在MgCl₂溶液中，增强效应的最大值似乎出现在15至30毫米的浓度之间，而在KCl中，增强效应几乎呈线性增加，直至浓度达到100毫米。初始氧瞬变（即爆发）的出现也受无机阳离子浓度的控制。MgCl₂或KCl浓度的增加导致爆发的规模以与增强效应相应增加呈线性相关的方式增大。
