Seed priming with salicylic acid potentiates water restriction-induced effects in tomato seed germination and early seedling growth

Abstract

Seed priming with salicylic acid (SA) has been described as a method with potential to improve seed germination under unfavorable conditions. The present study aimed to evaluate the ability of seed priming with SA to attenuate the impact of water restriction during germination and early seedling growth of tomato. Seeds were subjected to different concentrations of SA (0, 25 and 50 µM) and sowed on substrates at different percentages of the water holding capacity (20, 30, 40 and 100%). The following variables were evaluated: germination, first count of germination, germination speed index, shoots/root length and dry mass, superoxide dismutase, ascorbate peroxidase and catalase activities, contents of hydrogen peroxide and of malondialdehyde. Water restriction significantly decreased the variables related to germination and seedling performance. Despite increasing germination speed and seedling development when combined with well-irrigated conditions, priming with SA negatively impacted those characteristics under water deficit conditions. That was through increases in superoxide dismutase activity and H2O2 accumulation. Thus, it was concluded that seed priming with SA does not improve tomato seed germination and early seedling growth under water deficit.

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

“…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. Huang et al (2019) point out that SA inhibits the expression of ROS scavenging-related genes, which increases ROS levels and promotes root meristem activity, promoting root growth.…”

“…(1) −SA: control without SA application, (2) +SA-seed: seed priming with SA, and (3) +SA-root: soil drench of seedlings with a solution of SA prior to transplanting. The concentration of SA, 50 µM, was determined according to a previous study (Galviz-Fajardo et al 2020). For priming with SA, a group of seeds was soaked in the solution of 50 µM SA for 60 min.…”

“…Therefore, considering that drought events can have an indefinite duration and severity, the exogenous application of SA to mitigate the effects of a severe water-deficit stress during the vegetative growth of plants is an interesting gap to be studied. Galviz-Fajardo et al (2020) observed that the early growth of tomato seedlings was enhanced by seed priming with SA. Thus, given this context, it was hypothesized that application of SA could mitigate the harmful effects of drought, that is, a decrease in ROS through the activation of antioxidant enzyme activity, induction of the synthesis of osmopotrectors, increases in photosynthetic activity and plant growth.…”

Hongos causantes de la mancha gris de la hoja en <i>Lycopersicon esculentum</i> Mill., su variabilidad y el rol de la resistencia sistémica adquirida (RSA) en la reducción de su incidencia

“…Considerando que la RSA involucra un incremento del contenido endógeno en tejidos vegetales del AS, y puesto que ha sido evaluado la aplicación exógena para aplicar protección en contra de varios tipos de estreses bióticos (Fan et al 2009;Rangel Sánchez et al 2010;Sanchez Rojo 2010;Galviz-Fajardo et al 2020;Maia Junior et al 2020)y abióticos, tales como altas y bajas temperaturas, salinidad o metales pesados en una multiplicidad de patosistemas (Gunes et al, 2007;Chávez-Suarez et al, 2012;Bernardo 2016).…”