Institute of Plant Breeding and Genetic Resources, Hellenic Agricultural Organisation-Demeter (ELGO-Dimitra), 57001 Thermi, Thessaloniki, Greece.
Department of Botany, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
Molecules. 2021 May 18;26(10):2984. doi: 10.3390/molecules26102984.
We evaluated photosystem II (PSII) functionality in potato plants ( L.) before and after a 15 min feeding by the leaf miner using chlorophyll fluorescence imaging analysis combined with reactive oxygen species (ROS) detection. Fifteen minutes after feeding, we observed at the feeding zone and at the whole leaf a decrease in the effective quantum yield of photosystem II (PSII) photochemistry (Φ). While at the feeding zone the quantum yield of regulated non-photochemical energy loss in PSII (Φ) did not change, at the whole leaf level there was a significant increase. As a result, at the feeding zone a significant increase in the quantum yield of non-regulated energy loss in PSII (Φ) occurred, but there was no change at the whole leaf level compared to that before feeding, indicating no change in singlet oxygen (O) formation. The decreased Φ after feeding was due to a decreased fraction of open reaction centers (q), since the efficiency of open PSII reaction centers to utilize the light energy (F'/F') did not differ before and after feeding. The decreased fraction of open reaction centers resulted in increased excess excitation energy (EXC) at the feeding zone and at the whole leaf level, while hydrogen peroxide (HO) production was detected only at the feeding zone. Although the whole leaf PSII efficiency decreased compared to that before feeding, the maximum efficiency of PSII photochemistry (F/F), and the efficiency of the water-splitting complex on the donor side of PSII (F/F), did not differ to that before feeding, thus they cannot be considered as sensitive parameters to monitor biotic stress effects. Chlorophyll fluorescence imaging analysis proved to be a good indicator to monitor even short-term impacts of insect herbivory on photosynthetic function, and among the studied parameters, the reduction status of the plastoquinone pool (q) was the most sensitive and suitable indicator to probe photosynthetic function under biotic stress.
我们使用叶绿素荧光成像分析结合活性氧（ROS）检测，在马铃薯植株（ Solanum tuberosum ）被叶甲取食 15 分钟前后，评估了光系统 II（PSII）的功能。取食 15 分钟后，我们在取食区和整片叶子上观察到 PSII 光化学有效量子产量（Φ）下降。虽然在取食区 PSII 调节非光化学能量耗散的量子产量（Φ）没有变化，但在整片叶子水平上却显著增加。因此，在取食区 PSII 非调节能量耗散的量子产量（Φ）显著增加，但与取食前相比，整片叶子水平上没有变化，表明单线态氧（O）的形成没有变化。取食后Φ 的降低是由于开放反应中心（q）的分数减少所致，因为取食前后 PSII 开放反应中心利用光能的效率（F'/F'）没有差异。开放反应中心分数的减少导致在取食区和整片叶子水平上的过剩激发能（EXC）增加，而仅在取食区检测到过氧化氢（HO）的产生。虽然与取食前相比，整片叶子的 PSII 效率降低，但 PSII 光化学的最大效率（F/F）和 PSII 供体侧水分解复合物的效率（F/F）没有差异，因此它们不能被认为是监测生物胁迫影响的敏感参数。叶绿素荧光成像分析被证明是监测昆虫取食对光合作用功能的短期影响的良好指标，在研究的参数中，质体醌池（q）的还原状态是最敏感和适合的生物胁迫下探测光合作用功能的指标。
