Department of Plant Sciences, University of Western Ontario, N6A 5B7, London, Ontario, Canada.
Photosynth Res. 1994 Nov;42(2):145-55. doi: 10.1007/BF02187125.
The size of the Photosystem II light harvesting antenna and the absorption cross-sections of PS I (σPSI) and PS II (σPSII) were examined in relation to photosynthetic performance fluorescence. Wild-type (WT) rye (Secale cereale) and barley (Hordeurn vulgare) as well as the barley chlorophyllb-less chlorina F2 mutant were grown under control and intermittent light (IML) conditions. (σPSII) in control barley F2 was similar to IML grown WT rye and barley, which, in turn was 2.5 to 3.5 times smaller than for control WT plants. In contrast, σPSI was similar for all control plants. This was 2.5 to 4 times larger than for IML-grown WT plants. IML-grown barley mutant plants had the smallest absorption cross-sections. Photosynthetic light response curves revealed that the barley chlorina F2-mutant had rates of oxygen evolution on a per leaf area basis that were only slightly lower than control WT rye and barley while IML-grown plants had strongly reduced photosynthetic performance. Convexity (Θ) for control barley chlorina F2-mutants was equal to the WT controls (0.6-0.7), while all IML-grown plants had a Θ of 0. This indicates that, in contrast to control barley mutants, IML-plants were limited by PS II turn-over rates at all irradiances. However, on a per leaf Chl-basis the IML-grown plants exhibited the highest photosynthetic rates. Thus, the comparatively poor photosynthetic rates for IML-grown plants on a per leaf area basis were not due to less efficient photosynthetic reaction centers, but may rather be due to an increased limitation from PS II turn-over and a reduction in the number of reaction centers per leaf area.
研究了光系统 II （PS II）的捕光天线大小以及 PS I（σPSI）和 PS II（σPSII）的吸收截面与荧光的光合性能的关系。以野生型（WT）黑麦（Secale cereale）和大麦（Hordeurn vulgare）以及大麦叶绿素 b 缺失的叶绿素 F2 突变体为材料，在对照和间歇光照（IML）条件下进行培养。在对照大麦 F2 中，σPSII 与 IML 培养的 WT 黑麦和大麦相似，而后者又比对照 WT 植物小 2.5 至 3.5 倍。相比之下，σPSI 对于所有对照植物均相似。它比 IML 培养的 WT 植物大 2.5 至 4 倍。IML 培养的大麦突变体植物具有最小的吸收截面。光合光响应曲线表明，大麦叶绿素 F2 突变体的单位叶面积产氧量仅略低于对照 WT 黑麦和大麦，而 IML 培养的植物光合作用性能大大降低。对照大麦叶绿素 F2 突变体的凸度（Θ）与 WT 对照相等（0.6-0.7），而所有 IML 培养的植物的Θ均为 0。这表明，与对照大麦突变体不同，在所有辐照度下，IML 植物均受到 PS II 周转率的限制。但是，以每叶 Chl-b 为基础，IML 培养的植物表现出最高的光合速率。因此，在单位叶面积基础上，IML 培养的植物相对较差的光合速率不是由于光合反应中心效率较低，而是可能由于 PS II 周转率增加和每叶面积反应中心数量减少所致。
