Aplicação foliar de ácido salicílico como atenuante do estresse salino no algodoeiro naturalmente colorido.

Abstract

The Brazilian Northeast is characterized by low rainfall and high evaporation rates, making agricultural production in this region difficult. However, salicylic acid can minimize the deleterious effects of salts on plants. In this sense, the objective was to evaluate the growth, gas exchange and phytomass accumulation of naturally colored cotton 'BRS Jade' irrigated with saline water and foliar application with salicylic acid in semi-arid conditions. The research was carried out from March to June 2021 in pots adapted for drainage lysimeters, under open sky conditions at the Centro de Ciências e Tecnologia Agroalimentar - CCTA of the Federal University of Campina Grande - UFCG, located in the municipality of Pombal, Paraíba. A randomized block design in a 5 × 5 factorial scheme was adopted, the treatments resulting from the combination of two factors: five levels of electrical conductivity of the irrigation water (ECa 0.3; 1.8; 3.3; 4.8 and 6.3 dS m-1) associated with five concentrations of salicylic acid (0; 1.5; 3.0, 4.5 and 6.0 mM) with three replications and one plant per plot, totaling 75 experimental units. Irrigation with water from 0.3 dS m-1 reduced gas exchange, growth and cv. BRS Jade. The foliar application of salicylic acid at a concentration of 6.0 mM mitigated the effects of saline stress on stomatal conductance and transpiration of cotton. Irrigation with salinity-increasing water associated with foliar applications of salicylic acid intensified the deleterious effects of salt stress on cotton leaf dry biomass and stem dry biomass.