Salicylic acid relieves the effect of saline stress on soursop morphysiology

Abstract

The cultivation of soursop has increased in recent years due to the advance of agribusiness and due to its use by the pharmaceutical industry. As a source of vitamin C, calcium, carbohydrates and antioxidant substances, soursop helps to protect the human body against oxidative stress, acting in the prevention of a series of chronic degenerative disorders. In this context, the objective of present study was to evaluate the effects of foliar sprays with salicylic acid to mitigate the effects of salt stress on the morphophysiology of soursop. The study was conducted in a greenhouse, in a randomized block design and a 5 × 4 factorial arrangement, with five levels of electrical conductivity of irrigation water - ECw (0.8-control; 1.6; 2.4; 3.2 and 4.0 dS m-1) and four concentrations of salicylic acid - SA (0; 1.2; 2.4 and 3.6 mM), with three replicates. Foliar application of SA at concentrations between 1.2 and 1.6 mM mitigated the effects of salt stress on stomatal conductance, CO2 assimilation rate, transpiration and instantaneous carboxylation efficiency of soursop at 480 days after transplanting. Spraying with SA at concentrations between 1.3 and 1.6 mM induced acclimatization to salt stress in soursop plants, since the percentage of intercellular electrolyte leakage was reduced and the growth was favored by the application of SA, even when exposed to salinity. Irrigation with ECw above 0.8 dS m-1 reduced the relative water content in the leaves of soursop cv. Morada Nova.

Hydrogen peroxide in attenuation of salt stress effects on physiological indicators and growth of soursop

“…Similar results were obtained in a study conducted by Silva et al (2021a), who evaluated the effect of salt stress caused by irrigation water (0.8 to 4.0 dS m -1 ) on soursop morphophysiology at 480 days after transplanting and found that irrigation with ECw above 1.7 dS m -1 reduced soursop growth, with the lowest values of SD (30.09 mm) and VVI (2.42) obtained in plants subjected to ECw of 4.0 dS m -1 .…”

“…The increase in the percentage of electrolyte leakage and water saturation deficit in plants subjected to higher H 2 O 2 concentration (30 μM) may occur because, at high concentration, hydrogen peroxide can intensify the deleterious effects of salt stress, causing changes in plant metabolism due to the restriction of photosynthetic processes. Under salt stress conditions, photosynthetic processes can be affected directly, by stomatal restriction, reduced transpiration, and consequently, low CO 2 availability, or indirectly, by the imbalance between the production and removal of reactive oxygen species (ROS) produced during the photosynthetic process, causing oxidative stress (Carvalho et al, 2011;Silva et al, 2021a).…”

Salinização secundária no semiárido e seus impactos no solo, na agricultura e cultivo das plantas – uma revisão

“…Em outra pesquisa, Silva et al (2021b) ratificaram os efeitos do ácido salicílico (AS) na mitigação do estresse salino na morfofisiologia da gravioleira, ao confirmarem a atenuação dos efeitos da água de irrigação com CE de1,6; 2,4; 3,2 e 4,0 dS m -1 sobre a condutância estomática, a taxa de assimilação de CO2, a transpiração e a eficiência instantânea da carboxilação da gravioleira após a aplicação foliar de AS entre as concentrações de 1,2 e 1,6 mM. Veloso et al (2019) avaliaram os efeitos da aplicação exógena de quatro concentrações de peróxido de hidrogênio -H2O2 (0, 25, 50 e 75 µM) sobre o crescimento da gravioleira 'Morada Nova' irrigada com água de condutividade elétrica 0,7; 1,7; 2,7 e 3,7 dS m -1 .…”