Variation potential propagation decreases heat-related damage of pea photosystem I by 2 different pathways

Abstract

Local burning is known to generate and propagate variation potential (VP) in plants. VP affects different physiological processes, including reducing heat-related damage to photosystem I (PSI). We investigated mechanisms of the process. Photosynthesis parameters were measured with Dual-PAM-100 and GFS-3000. VP was induced by burning the first mature leaf and then waiting 5, 10, 15, or 20 min to initiate heating of the second mature leaf. Photosystems activities in the second leaf were investigated at 15 and 135 min after heating. In the absence of VP induction, when incubation in hot water (5 min) was used for heating the intact second leaf, PSI and PSII activities decreased after incubation at both exposure temperatures (45 C and 50 C). When local burning of the first leaf induced VP propagation into the second leaf, reduced photosynthesis (PSI) was observed. Arrival of VP in the second leaf prior to hot water incubation at 50 C decreased heating-induced suppression of PSI activity when measured 15 and 135 min later. Dependence of PSI activity on the time interval (5, 10, 15, or 20 min) between VP induction and heating of the second leaf was dissimilar at 15 and 135 min. Heat-induced suppression of PSII activity in the second leaf was stimulated after VP induction. In contrast, the effect of VP on PSI and PSII damage was weak when leaf 2 was heated at 45 C. VP-induced decrease of PSI activity suppression at 15 min after heating was correlated with stimulation of PSII activity suppression, but increase of PSI activity at 135 min after heating was not related to PSII activity. Thus, our results suggest the possibility of 2 different pathways of VPinduced decrease of heat-related PSI damage.Abbreviations: A CO2 , CO 2 assimilation rate; E, surface potential; PSI, photosystem I; PSII, hotosystem II; VP, variation potential; L PSI , photosystem I effective quantum yield; L PSII , photosystem II effective quantum yield; L PSI 0 , photosystem I quantum yield after 10-s illumination by far-red light; L PSII 0 , photosystem II maximum quantum yield.

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

“…There are two important questions in this problem. First, we previously showed that VP increased the thermotolerance of photosystem I and the whole plant (Sukhov et al, 2014b , 2015b ; Surova et al, 2016b ). However, VP was caused by the damaging thermal stimulus (burn), which is a standard stimulus for the induction of this electrical signal (Hlavácková et al, 2006 ; Grams et al, 2009 ; Katicheva et al, 2014 ; Vodeneev et al, 2015 ).…”

“…A number of studies (Retivin et al, 1997 , 1999 ; Sukhov et al, 2014b , 2015b ; Surova et al, 2016b ) show a positive influence of electrical signals, including VP, on plant tolerance to negative changes in temperature. Considering the similarity between mechanisms of LERs and mechanisms of the generation of VP (Vodeneev et al, 2015 , 2016 ), it can not be excluded that LERs can also influence the tolerance of plants to heating and chilling.…”

“…The important result of electrical signal propagation is an increase in a plant's tolerance to stressors (Retivin et al, 1997 ; Sukhov et al, 2015b ). In particular, electrical signals induce the increased tolerance of photosynthetic machinery and for the entire plant to cold and heat (Retivin et al, 1999 ; Sukhov et al, 2014b , 2015b ; Surova et al, 2016b ).…”

“…However, the possible connection with LERs was not investigated for another important stressor, namely heating. Taking into account the positive influence of VP [i.e., LER induced by chemical and (or) hydraulic signals] on the tolerance to heating of undamaged parts of the plant (Sukhov et al, 2014b , 2015b ; Surova et al, 2016b ), the connection between the thermotolerance and parameters of heating-induced LERs is probable. Analysis of the connection in peas was a task of the current investigation.…”

Automatic Determination of the Parameters of Electrical Signals and Functional Responses of Plants Using the Wavelet Transformation Method

“…A substantial consequence of distant signal propagation and induced functional changes is an increase in plant resistance to adverse factors [20][21][22][23][24][25]. The establishment of the correlation between the parameters of stress and induced changes of photosynthesis activity with the development of plant resistance to stress factors [26], in particular the resistance of the photosynthetic apparatus to heating [21,23,24], allows the creation of approaches and methods for selecting the most promising genetic lines in the early stages of plant breeding.…”