A Theoretical Analysis of Relations between Pressure Changes along Xylem Vessels and Propagation of Variation Potential in Higher Plants

Sukhov

2021

Plants

Self Cite

In environmental conditions, plants are affected by abiotic and biotic stressors which can be heterogenous. This means that the systemic plant adaptive responses on their actions require long-distance stress signals including electrical signals (ESs). ESs are based on transient changes in the activities of ion channels and H+-ATP-ase in the plasma membrane. They influence numerous physiological processes, including gene expression, phytohormone synthesis, photosynthesis, respiration, phloem mass flow, ATP content, and many others. It is considered that these changes increase plant tolerance to the action of stressors; the effect can be related to stimulation of damages of specific molecular structures. In this review, we hypothesize that programmed cell death (PCD) in plant cells can be interconnected with ESs. There are the following points supporting this hypothesis. (i) Propagation of ESs can be related to ROS waves; these waves are a probable mechanism of PCD initiation. (ii) ESs induce the inactivation of photosynthetic dark reactions and activation of respiration. Both responses can also produce ROS and, probably, induce PCD. (iii) ESs stimulate the synthesis of stress phytohormones (e.g., jasmonic acid, salicylic acid, and ethylene) which are known to contribute to the induction of PCD. (iv) Generation of ESs accompanies K+ efflux from the cytoplasm that is also a mechanism of induction of PCD. Our review argues for the possibility of PCD induction by electrical signals and shows some directions of future investigations in the field.

Section: Electrical Signals In Plants: Types and Mechanismsmentioning

confidence: 99%

Section: Electrical Signals In Plants: Types and Mechanismsmentioning

confidence: 99%

Section: Electrical Signals and Plant Tolerance To Action Of Stressors: Potential Role Of Pcdmentioning

confidence: 99%

See 1 more Smart Citation

Electrical Signals, Plant Tolerance to Actions of Stressors, and Programmed Cell Death: Is Interaction Possible?

Sukhov

2021

Plants

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“…H + -ATP-ases play an important role in the forming of plant electrical responses, which are local or propagating changes in electrical potential in the plasma membrane and induced by actions of stressors [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. It should be noted that there are several types of electrical responses in higher plants including (i) local electrical responses, which are generated in the irritated zone [ 15 , 16 , 17 ]; (ii) action potentials, which are induced by weak or moderate irritations (e.g., cooling or touch) and actively propagate through the plant body [ 6 , 7 , 8 ]; (iii) variations potentials, which are probably local electrical responses on the propagation of hydraulic and/or chemical signals after action of local damages (e.g., burning, heating, and crush) [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]; and (iv) system potentials, which are weakly investigated hyperpolarization signals [ 10 , 11 , 12 , 13 , 25 , 26 ]. The electrical responses influence numerous physiological processes (expression of defense genes, synthesis of stress phytohormones, photosynthesis, respiration, phloem mass flow, ATP production, etc.)…”

Section: Introductionmentioning

confidence: 99%

Stochastic Spatial Heterogeneity in Activities of H+-ATP-Ases in Electrically Connected Plant Cells Decreases Threshold for Cooling-Induced Electrical Responses

Ratnitsyna

Sukhov

2021

IJMS

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H+-ATP-ases, which support proton efflux through the plasma membrane, are key molecular transporters for electrogenesis in cells of higher plants. Initial activities of the transporters can influence the thresholds of generation of electrical responses induced by stressors and modify other parameters of these responses. Previously, it was theoretically shown that the stochastic heterogeneity of individual cell thresholds for electrical responses in a system of electrically connected neuronal cells can decrease the total threshold of the system (“diversity-induced resonance”, DIR). In the current work, we tested a hypothesis about decreasing the thresholds of generation of cooling-induced electrical responses in a system of electrically connected plant cells with increasing stochastic spatial heterogeny in the initial activities of H+-ATP-ases in these cells. A two-dimensional model of the system of electrically connected excitable cells (simple imitation of plant leaf), which was based on a model previously developed in our works, was used for the present investigation. Simulation showed that increasing dispersion in the distribution of initial activities of H+-ATP-ases between cells decreased the thresholds of generation of cooling-induced electrical responses. In addition, the increasing weakly influenced the amplitudes of electrical responses. Additional analysis showed two different mechanisms of the revealed effect. The increasing spatial heterogeneity in activities of H+-ATP-ases induced a weak positive shift of the membrane potential at rest. The shift decreased the threshold of electrical response generation. However, the decreased threshold induced by increasing the H+-ATP-ase activity heterogeneity was also observed after the elimination of the positive shift. The result showed that the “DIR-like” mechanism also participated in the revealed effect. Finally, we showed that the standard deviation of the membrane potentials before the induction of action potentials could be used for the estimation of thresholds of cooling-induced plant electrical responses. Thus, spatial heterogeneity in the initial activities of H+-ATP-ases can be a new regulatory mechanism influencing the generation of electrical responses in plants under actions of stressors.

“…The mechanisms of VP propagation are still being discussed. The first hypothesis [ 13 , 14 , 15 , 16 ] supposes that a VP is a local electrical response induced by a hydraulic wave, which propagates through a plant from the damaged zone and activates mechanosensitive Ca 2+ channels. The second hypothesis [ 4 , 17 ] supposes that the VP is the local electrical response induced by the propagation of a specific “wound substance” from the damaged zone and the activation of ligand-dependent Ca 2+ channels.…”

Section: Introductionmentioning

confidence: 99%

Influence of Local Burning on Difference Reflectance Indices Based on 400–700 nm Wavelengths in Leaves of Pea Seedlings

Yudina

Gromova

et al. 2021

Plants

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Local damage (e.g., burning) induces a variation potential (VP), which is an important electrical signal in higher plants. A VP propagates into undamaged parts of the plant and influences numerous physiological processes, including photosynthesis. Rapidly increasing plant tolerance to stressors is likely to be a result of the physiological changes. Thus, developing methods of revealing VP-induced physiological changes can be used for the remote sensing of plant systemic responses to local damage. Previously, we showed that burning-induced VP influenced a photochemical reflectance index in pea leaves, but the influence of the electrical signals on other reflectance indices was not investigated. In this study, we performed a complex analysis of the influence of VP induction by local burning on difference reflectance indices based on 400–700 nm wavelengths in leaves of pea seedlings. Heat maps of the significance of local burning-induced changes in the reflectance indices and their correlations with photosynthetic parameters were constructed. Large spectral regions with significant changes in these indices after VP induction were revealed. Most changes were strongly correlated to photosynthetic parameters. Some indices, which can be potentially effective for revealing local burning-induced photosynthetic changes, are separately shown. Our results show that difference reflectance indices based on 400–700 nm wavelengths can potentially be used for the remote sensing of plant systemic responses induced by local damages and subsequent propagation of VPs.