In photosynthesis research, non-invasive in vivo spectroscopic analyses have been used as a practical tool for studying photosynthetic electron transport. Klas-NIR spectrophotometer has been recently developed by Klughammer and Schreiber (Photosynth Res 128:195–214, 2016) for in vivo measurements of redox changes of P700, plastocyanin (Pcy) and ferredoxin (Fd). Here we show examples using the Klas-NIR spectrophotometer for the evaluation of the redox states and quantities of these components in plant leaves and cyanobacterial suspensions. The redox poise under light of the electron transport components is different in leaves from higher plants compared with cyanobacteria. During a short illumination with an actinic light, P700, Pcy, and Fd are kept reduced in barley leaves but are oxidized in cyanobacteria. During far-red light illumination, P700 and Pcy are mostly oxidized in the leaves but are partially kept reduced in cyanobacteria. In the cyanobacterium, Thermosynechococcus elongatus, which has no Pcy but uses cytochrome c₆ (cyt c₆) as the electron donor to photosystem I, a cyt c₆ signal was detected in vivo. To show the potential of Klas-NIR spectrophotometer for studying different developmental stages of a leaf, we performed measurements on fully mature and early senescing barley leaves. Pcy content in leaves decreased during senescence at an early stage. The Pcy loss was quantitatively analyzed using Klas-NIR spectrophotometer, giving absolute ratios of Pcy to PSI of 2.5 and 1.6 in younger and older leaves, respectively. For quantification of the signals in vivo, in vitro data (Sétif et al. in Photosynth Res142:307–319, 2019) obtained with Klas-NIR spectrophotometer were used.

在光合作用研究中，无创体内光谱分析已被用作研究光合作用电子传输的实用工具。Klas-NIR分光光度计最近由Klughammer和Schreiber开发（Photosynth Res 128：195–214，2016），用于体内测量P700，质体蓝蛋白（Pcy）和铁氧还蛋白（Fd）的氧化还原变化。在这里，我们显示了使用Klas-NIR分光光度计评估植物叶片和蓝细菌悬浮液中氧化还原状态和这些成分的数量的示例。与蓝细菌相比，高等植物叶片中电子传递成分的氧化还原平衡不同。在短短的光化光照下，大麦叶片中的P700，Pcy和Fd保持还原状态，但在蓝细菌中被氧化。在远红光照明下，P700和Pcy在叶子中大部分被氧化，但在蓝细菌中部分被还原。在蓝藻中嗜热嗜热球菌，没有Pcy，但使用细胞色素c ₆（cyt c ₆）作为光系统I cyt c ₆的电子供体在体内检测到信号。为了显示Klas-NIR分光光度计在研究叶片不同发育阶段的潜力，我们对完全成熟和早衰的大麦叶片进行了测量。叶片中的Pcy含量在衰老的早期阶段下降。使用Klas-NIR分光光度计对Pcy损失进行定量分析，在年轻和较老叶片中，Pcy与PSI的绝对比分别为2.5和1.6。为了量化体内信号，使用了通过Klas-NIR分光光度计获得的体外数据（Sétif等人，Photosynth Res142：307-319，2019年）。