Exogenous salicylic acid alleviates the negative impacts on production components, biomass and gas exchange in tomato plants under water deficit improving redox status and anatomical responses

Abstract

Salicylic acid (SA) is an interesting messenger in plant metabolism that modulates multiple pathways, including the antioxidant defence pathway, and stimulates anatomical structures essential to carbon dioxide fixation during the photosynthetic process. The aim of this research was to determine whether pre-treatment with exogenous SA can alleviate the deleterious effects induced by water deficit on production components, biomass and gas exchange, measuring reactive oxygen species, antioxidant enzymes, variables connected to photosynthetic machinery, anatomical

Effectiveness of Seed Priming and Soil Drench with Salicylic Acid on Tomato Growth, Physiological and Biochemical Responses to Severe Water Deficit

“…Water reductions at the levels of 40, 30, and 20% of the WHC induced the reduction of vegetative growth of tomato plants, lower shoot heights (SL), leaf area (LA), as well as less biomass accumulation in shoot and roots can be observed. Such changes are expected in tomato plants exposed to drought (Lobato et al 2021;Moles et al 2018;Zhou et al 2017) and can be attributable to lowers photosynthetic rates induced by drought stress (Liang et al 2020), confirmed by reductions in CO 2 assimilation rate (A), stomatal conductance (gs), and leaf transpiration (E) observed in this study and linked positively to growth variables (Fig. 4).…”

“…However, 20% WHC reduced this variable. Effects of soil drench with SA (+SA-root) on A, gs, and E were observed in well-watered conditions but not with water-restriction, differing from reports that relate gains in photosynthesis induced by SA under drought (Hayat et al 2008;Lobato et al 2021). Alternatively, results of this work agree with Gharbi et al (2018) who observed that SA positively impacted net photosynthesis, but in unstressed plants only.…”

“…So, +SA-seed can induce characteristics that are beneficial during water restriction conditions allowing the maintenance of a larger photosynthetic area and allocation of resources to the roots that assist in the absorption of water and nutrients (Jangid and Dwivedi 2017). A large number of works have indicated that SA enhances growth attributes -leaf area and dry matter production -in tomato when exposed to water stress (El-Hady et al 2021;Galviz-Fajardo et al 2020;Gharbi et al 2018;Lobato et al 2021). Effects on root growth must be carefully considered, Abbasi et al (2020) highlight that SA improved and kept the root system of cucumber plants, improving the absorption of nutrients, increasing the carbohydrate content of flowers and fruits, all this resulting in the increased number and size of fruits.…”

“…Although many studies report that SA has the ability to induce drought tolerance by increasing antioxidant activity (El-Hady et al 2021;Hayat et al 2008;Lobato et al 2021), many others also point out that it is not a general response (Bortolin et al 2020;El-Esawi et al 2017). Furthermore, Saruhan et al (2012) reported that this is a SA-induced mechanism of water stress tolerance, consequence of the ability of SA molecule to bind to CAT and to inhibit its activity while intensifying SOD activity (Razmi et al 2017;Galviz-Fajardo et al 2020) and finally results in enhanced H 2 O 2 levels as the ones observed in leaves and roots with +SA-seed.…”

“…In this sense, the need for dose-optimization studies for each crop under specific stress conditions has been underlined (Srivastava et al 2021). Chakma et al (2021) and Lobato et al (2021) verified the capacity of SA in reducing the damage of a moderate water deficit at reproductive stages on number and size of fruits. Nevertheless, yields similar to the control were not achieved.…”