High-Temperature Tolerance of Photosynthesis Can Be Linked to Local Electrical Responses in Leaves of Pea

Abstract

It is known that numerous stimuli induce electrical signals which can increase a plant's tolerance to stressors, including high temperature. However, the physiological role of local electrical responses (LERs), i.e., responses in the zone of stimulus action, in the plant's tolerance has not been sufficiently investigated. The aim of a current work is to analyze the connection between parameters of LERs with the thermal tolerance of photosynthetic processes in pea. Electrical activity and photosynthetic parameters in pea leaves were registered during transitions of air temperature in a measurement head (from 23 to 30°C, from 30 to 40°C, from 40 to 45°C, and from 45 to 23°C). This stepped heating decreased a photosynthetic assimilation of CO2 and induced generation of LERs in the heated leaf. Amplitudes of LERs, quantity of responses during the heating and the number of temperature transition, which induced the first generation of LERs, varied among different pea plants. Parameters of LERs were weakly connected with the photosynthetic assimilation of CO2 during the heating; however, a residual photosynthetic activity after a treatment by high temperatures increased with the growth of amplitudes and quantity of LERs and with lowering of the number of the heating transition, inducing the first electrical response. The effect was not connected with a photosynthetic activity before heating; similar dependences were also observed for effective and maximal quantum yields of photosystem II after heating. We believe that the observed effect can reflect a positive influence of LERs on the thermal tolerance of photosynthesis. It is possible that the process can participate in a plant's adaptation to stressors.

Exogenous Abscisic Acid Can Influence Photosynthetic Processes in Peas through a Decrease in Activity of H+-ATP-ase in the Plasma Membrane

“…It is interesting that the changes in photosynthesis, its heat tolerance, and transpiration are similar to responses induced by electrical signals, including a decrease in the CO 2 assimilation and activation of the cyclic electron flow around photosystem I [ 42 , 50 , 53 , 59 , 60 , 64 , 65 , 66 , 67 ], increase in the plant heat tolerance [ 55 , 68 , 69 , 70 ], and decrease in the stomata conductance [ 67 , 68 ]. This similarity can be explained considering the important role of H + -ATP-ase inactivation in the generation of electrical signals (especially, VP [ 37 , 40 ]), in the induction of changes in photosynthesis and its heat tolerance [ 38 ], and in the decrease in transpiration [ 68 ].…”

“…Third, inactivation of the H + -ATP-ase participates in the generation of electrical signals (especially variation potentials, VPs) [ 37 , 39 , 59 , 60 ] and, probably, in the formation of various fast physiological responses, induced by these signals [ 38 , 40 ]. In particular, it is known that electrical signals interact with hormonal signaling [ 61 , 62 ] (including the ABA signal [ 8 , 9 , 63 ]), strongly influence photosynthetic processes [ 42 , 50 , 53 , 59 , 60 , 64 , 65 , 66 , 67 ], change transpiration [ 41 , 64 ], increase the plant tolerance to stressors [ 55 , 68 , 69 , 70 , 71 , 72 ], and induce many other responses (e.g., stimulation of the expression of defense genes [ 66 , 73 ], activation of respiration [ 74 ], and suppression of phloem mass flow [ 75 , 76 ]). Many of these responses are similar to responses induced by ABA treatment; as a result, it can be expected that the exogenous ABA can modify electrical signals and physiological responses caused by these signals.…”

High humidity alleviates photosynthetic inhibition and oxidative damage of tomato seedlings under heat stress

“…In addition to growth and biomass reduction, HT stress also induces the decline in photosynthesis of tomato plants before other physiological symptoms appear (Murkowski 2001). It is well known that HT stress causes the local electrical responses (LERs) (Sukhov et al 2017) and the propagation of electrical signals (Fromm andLautner 2007, Sukhov 2016), which, in turn, can affect photosynthesis (Sukhova et al 2018 ), transpiration (Sukhov et al 2015), respiration (Lautner et al 2014), and ATP content (Surova et al 2016) in leaves. Additionally, important photosynthetic processes, such as Chl synthesis, electron transport, and carbon dioxide assimilation process have been found very susceptible to HT stress in tomato plants (Camejo et al 2005, Wu andKubota 2008).…”

The Role of Potassium Channels in Arabidopsis thaliana Long Distance Electrical Signalling: AKT2 Modulates Tissue Excitability While GORK Shapes Action Potentials

“…Plants also show electrical responses, occurring after stimuli such as abrupt changes in temperature and light intensity, the action of depolarising agents (potassium, glutamate etc. ), wounding and the application of electrical currents [ 1 , 2 ]. The stimulation of a plant tissue is thought to modify the activities of plasma membrane ion channels/transporters, which in turn, affects the membrane voltage.…”