Department of Biology, University of Essex, CO4 3SQ, Colchester, Essex, UK.
Photosynth Res. 1993 Oct;38(1):15-26. doi: 10.1007/BF00015057.
Wheat leaves were exposed to light treatments that excite preferentially Photosystem I (PS I) or Photosystem II (PS II) and induce State 1 or State 2, respectively. Simultaneous measurements of CO2 assimilation, chlorophyll fluorescence and absorbance at 820 nm were used to estimate the quantum efficiencies of CO2 assimilation and PS II and PS I photochemistry during State transitions. State transitions were found to be associated with changes in the efficiency with which an absorbed photon is transferred to an open PS II reaction centre, but did not correlate with changes in the quantum efficiencies of PS II photochemistry or CO2 assimilation. Studies of the phosphorylation status of the light harvesting chlorophyll protein complex associated with PS II (LHC II) in wheat leaves and using chlorina mutants of barley which are deficient in this complex demonstrate that the changes in the effective antennae size of Photosystem II occurring during State transitions require LHC II and correlate with the phosphorylation status of LHC II. However, such correlations were not found in maize leaves. It is concluded that State transitions in C3 leaves are associated with phosphorylation-induced modifications of the PS II antennae, but these changes do not serve to optimise the use of light absorbed by the leaf for CO2 assimilation.
小麦叶片分别暴露在优先激发光系统 I（PS I）或光系统 II（PS II）的光处理下，从而分别诱导形成状态 1 或状态 2。同时测量 CO2 同化、叶绿素荧光和 820nm 处的吸光度，用于估计状态转变过程中 CO2 同化和 PS II 和 PS I 光化学的量子效率。发现状态转变与被吸收的光子向开放 PS II 反应中心转移的效率变化有关，但与 PS II 光化学或 CO2 同化的量子效率变化无关。对小麦叶片中与 PS II（LHC II）相关的光捕获叶绿素蛋白复合物的磷酸化状态的研究，以及使用该复合物缺乏的大麦叶绿素突变体的研究表明，在状态转变过程中 PS II 有效天线大小的变化需要 LHC II，并与 LHC II 的磷酸化状态相关。然而，在玉米叶片中未发现这种相关性。结论是，C3 叶片中的状态转变与磷酸化诱导的 PS II 天线的修饰有关，但这些变化并不能优化叶片吸收的光用于 CO2 同化。
