Yudina Lyubov, Sukhova Ekaterina, Popova Alyona, Zolin Yuriy, Abasheva Karina, Grebneva Kseniya, Sukhov Vladimir
Department of Biophysics, N.I. Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.
Front Plant Sci. 2023 Apr 5;14:1153731. doi: 10.3389/fpls.2023.1153731. eCollection 2023.
Local action of stressors induces fast changes in physiological processes in intact parts of plants including photosynthetic inactivation. This response is mediated by generation and propagation of depolarization electrical signals (action potentials and variation potentials) and participates in increasing plant tolerance to action of adverse factors. Earlier, we showed that a local action of physiological stimuli (moderate heating and blue light), which can be observed under environmental conditions, induces hyperpolarization electrical signals (system potentials) in wheat plants. It potentially means that these signals can play a key role in induction of fast physiological changes under the local action of environmental stressors. The current work was devoted to investigation of influence of hyperpolarization electrical signals induced by the local action of the moderate heating and blue light on parameters of photosynthetic light reactions. A quantum yield of photosystem II (Ф) and a non-photochemical quenching of chlorophyll fluorescence (NPQ) in wheat plants were investigated. It was shown that combination of the moderate heating (40°C) and blue light (540 µmol ms) decreased Ф and increased NPQ; these changes were observed in 3-5 cm from border of the irritated zone and dependent on intensity of actinic light. The moderate soil drought (7 days) increased magnitude of photosynthetic changes and shifted their localization which were observed on 5-7 cm from the irritated zone; in contrast, the strong soil drought (14 days) suppressed these changes. The local moderate heating decreased Ф and increased NPQ without action of the blue light; in contrast, the local blue light action without heating weakly influenced these parameters. It meant that just local heating was mechanism of induction of the photosynthetic changes. Finally, propagation of hyperpolarization electrical signals (system potentials) was necessary for decreasing Ф and increasing NPQ. Thus, our results show that hyperpolarization electrical signals induced by the local action of the moderate heating inactivates photosynthetic light reactions; this response is similar with photosynthetic changes induced by depolarization electrical signals. The soil drought and actinic light intensity can influence parameters of these photosynthetic changes.
应激源的局部作用会在植物的完整部位引起生理过程的快速变化，包括光合作用失活。这种反应是由去极化电信号（动作电位和变异电位）的产生和传播介导的，并参与提高植物对不利因素作用的耐受性。此前，我们发现，在环境条件下可以观察到的生理刺激（适度加热和蓝光）的局部作用会在小麦植株中诱导超极化电信号（系统电位）。这可能意味着这些信号在环境应激源的局部作用下诱导快速生理变化中起关键作用。当前的工作致力于研究由适度加热和蓝光的局部作用诱导的超极化电信号对光合光反应参数的影响。研究了小麦植株中光系统II的量子产率（Ф）和叶绿素荧光的非光化学猝灭（NPQ）。结果表明，适度加热（40°C）和蓝光（540 μmol·m⁻²·s⁻¹）的组合会降低Ф并增加NPQ；这些变化在受刺激区域边界3 - 5厘米处观察到，并且取决于光化光的强度。适度的土壤干旱（7天）会增加光合变化的幅度并改变其定位，在受刺激区域5 - 7厘米处观察到；相反，严重的土壤干旱（14天）会抑制这些变化。局部适度加热在没有蓝光作用的情况下会降低Ф并增加NPQ；相反，没有加热的局部蓝光作用对这些参数的影响较弱。这意味着局部加热正是诱导光合变化的机制。最后，超极化电信号（系统电位）的传播对于降低Ф和增加NPQ是必要的。因此，我们的结果表明，由适度加热的局部作用诱导的超极化电信号会使光合光反应失活；这种反应与去极化电信号诱导的光合变化相似。土壤干旱和光化光强度会影响这些光合变化的参数。
