Citrullus lanatus morphophysiological responses to the combination of salicylic acid and salinity stress

Abstract

The salinity of irrigation water is one of modern agriculture's major obstacles, as it can damage the plants metabolism and, consequently, its development. Currently there is a great demand for substances that may mitigate such effects, such as salicylic acid. Thus, this study aimed to evaluate the effects of salicylic acid application on watermelon plants (Citrullus lanatus L.) under salinity stress. The experimental design was a randomized block design, in an incomplete factorial scheme, with four replications and two plants per replicate. The treatments resulted from the combination of five concentrations of salicylic acid (0.00, 0.15, 0.50, 0.85 and 1.00 mM) and five electrical conductivities of the irrigation water (0.50, 1.01, 2.25, 3.49 and 4.00 dS m-1). The development, gas exchange, chlorophyll index and fluorescence were evaluated 30 days after transplanting. This data was submitted to analysis of variance and then confidence bands (confbands) and Pearson correlation were produced. The application of salicylic acid (up to 0.85 mM) promotes beneficial effects for the watermelon plants morphophysiology, while the increase in electrical conductivity of the irrigation water is harmful.

Gas Exchange and Hydroponic Production of Zucchini Under Salt Stress and H2o2 Application

“…In a study with watermelon cv. Crimson Sweet using a mixture of soil and organic compost, in a 1:1 ratio, Ribeiro et al (2020) observed that the increase in irrigation water salinity reduced the internal CO 2 concentration, leading to the lowest value under water with electrical conductivity of 4.0 dS m -1 .…”

Evaluation of Salicylic Acid Effects on Growth, Biochemical, Yield, and Anatomical Characteristics of Eggplant (Solanum melongena L.) Plants under Salt Stress Conditions

“…However, this effect varies depending on the species, application methods, SA concentration, and growing environments. Ribeiro et al [30] evaluated watermelon characteristics in relation to water S and SA exogenous treatment and observed that the SA did not alleviate the detrimental impact of salinity but rather that it positively enhanced the plant morphophysiology up to the concentration of 0.85 mM. In light of the aforementioned discussions, the SA foliar spray produced thicker leaflets in bean plants due to the increment in the lamina's thickness at midvein.…”

Exogenous application of salicylic acid induces salinity tolerance in eggplant seedlings

“…However, there is variation of this effect in species, forms of application and concentration of SA and cultivation conditions. In the study by Ribeiro et al (2020), when evaluating morphophysiological aspects of watermelon as a function of salinity in water and exogenous application of SA, found that the acid did not mitigate the deleterious effect of salinity, however, it beneficially increased the morphophysiology of plants up to a dosage of 0.85 mM. However, Rafique et al (2011), in the cultivation of pumpkin seedlings, when soaking the seed with SA, observed that the protein content and activities of the protease and nitrate reductase enzymes were significantly influenced with concentrations of 30 mg L -1 of SA and that the soaking of the seed mitigates the adverse effects of salt stress on the initial growth of pumpkin.…”

“…The minimum (−α) and maximum (α) values ranged, respectively, from 0.5 to 4.5 dS m −1 and 0.0 to 1.5 mM, totaling 9 treatments (Table 1), with four replicates, making up 36 experimental plots, each plot consisting of three plants. Salicylic acid concentrations were based on previous experiments with other vegetables (Silva et al, 2019;Ribeiro et al, 2020). The electrical conductivities in the irrigation water were based on the threshold salinity of the crop (Dias et al, 2016).…”