Alleviation of Salt-Induced Adverse Effects on Gas Exchange, Photosynthetic Pigments Content and Chloroplast Ultrastructure in Gerbera Jamesonii L. by Exogenous Salicylic Acid Application

Abstract

Aims: The effects of exogenously applied salicylic acid (SA) on gas exchange characteristics, photosynthetic pigments and chloroplast ultrastructure were investigated in gerbera at their reproductive stage under salt-stressed conditions.
 Methodology: A pot experiment was conducted under glasshouse conditions at the Zhejiang University, Hangzhou, China, (30° N/120° E) between February 2008 and March 2009.Plants, pretreated with foliar applications of 0, 0.5, and 1.0 mmoldm-3 SA at the onset of flower initiation were irrigated with 100 mmoldm-3NaCl(aq) for two weeks, starting after three days from the SA pretreatment. Control did not receive either NaCl or SA.Photosynthetic rate, gas exchange, photosynthetic pigments content and chloroplast ultrastructure were investigated against treatments. All data were subjected to analysis of variance (ANOVA) and Generalized Linear Model (GLM) using SAS statistical software. Pearson’s correlation test was carried out to study the relationships among the parameters. The means were compared using Duncan’s multiple range test (DMRT). For all the tests, P< .05 was considered statistically significant.
 Results: Salt stress adversely affected the gas exchange characteristics, photosynthetic pigment contents and chloroplast ultrastructure. SA application significantly increased the net photosynthesis, stomatal conductivity, intra-cellular CO2 content and transpiration rate but decreased the stomatal limitation, compared to those of untreated salt-stressed plants. Further, the enhanced photosynthetic pigment contents and notably undamaged chloroplast ultrastructure were evident of the ameliorative effects of SA on photosynthetic system under salt stress. Of the two concentrations tested, 0.5 mmoldm-3 SA concentration seemed to have greater effect throughout the experiment showing no significant variation from control in some attributes (chlorophyll contents and chloroplast ultrastructure).
 Conclusion: Responses of plants pretreated with SA spraying and significant correlation among them plausibly suggest SA-induced enhancement of photosynthetic system as another target for conferring salt tolerance in crop plants.

Salicylic acid concentrations and forms of application mitigate water stress in sour passion fruit seedlings

“…The initially greater stomatal opening is related to the action of SA in forming secondary metabolites, such as proline and glycine betaine, that act by reducing the root osmotic potential, favoring water and nutrient uptake from the soil (Silva et al, 2020;Ali, 2021). As a result, transpiration is also increased, corroborating the results obtained by Saheri et al (2020), who evaluated the gas exchange of common purslane (Portulaca oleracea L.) and observed that the transpiration flux increased with the On the other hand, the increase in the CO 2 assimilation rate caused by SA application highlights the role of the studied phytohormone in maintaining the photosynthetic apparatus, probably due to the plant's photochemical activity and the CO 2 entry induced by stomatal opening (Kumara et al, 2021;Zafar et al, 2021). These findings were also observed by Lobato et al (2021), who evaluated tomato plants under water deficit and found a positive correlation between the increase in photosynthesis and the increase in the antioxidant defense of plants after SA application, especially superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase.…”

Calcium Regulates Growth and Nutrient Absorption in Poplar Seedlings

“…Photosynthesis is affected by interactions with various environmental factors, such as light, temperature, water, and minerals (Ke, 2001 ; Feller and Vaseva, 2014 ; Rubenovna and Ramazanovich, 2018 ). Chlorophyll is an important photosynthetic pigment that absorbs and transforms light energy (Kumara et al, 2021 ). Its content is closely related to thephotosynthetic capacity of plants (Mohsenpour and Willoughby, 2013 ).…”