Alterações metabólicas induzidas pelo silício em plantas de pimentão cultivadas sob estresse salino

Abstract

The objective of this research was to investigate alternatives to mitigate the effects of soil salinity on sweet pepper (Capsicum annuum L.), by evaluating production factors and gas exchange. Two experiments were conducted in the Olericulture and Experimentation sector of the Department of Agronomy of the University of José do Rosario Vellano (Unifenas), Alfenas, MG. Magali R pepper cultivar was used, whose seedlings were produced in trays and transplanted after 35 days, where each pot (19 dm3) received a plant. The experiments were arranged in a randomized block design in a factorial scheme with five replications each, the first 2 × 5 (two corrective sources: limestone and calcium silicate) and five increasing doses of KCl (150, 300, 450, 600 and 700 kg ha-1 of K2O), where were evaluated the electrical conductivity (EC), silicon content (Si) in the soil and plant (leaf), liquid photosynthesis, stomatal conductance, intercellular concentration of CO2, transpiration, efficiency water use and instantaneous carboxylation, besides fruit production, fruit mass, length and diameter and plant height. The second experiment 2 x 2 (two sources of concealer: limestone and calcium silicate) and two doses of KCl (control: equivalent to 150 kg ha-1 and salt stress 700 kg ha-1 K2O) where the EC were evaluated, Si translocation in the plant, water use efficiency and instantaneous carboxylation and stress index. The results found in the different evaluations were submitted to variance analysis. To evaluate the means, the Scott-Knott (first experiment) and Tukey (second experiment) tests were applied. Standard deviations were calculated and correlation estimators (Pearson) were applied using SISVAR software. It was concluded that the 300 kg ha-1 K2O dose, in the presence of calcium silicate, provided the highest Si translocation, the best results for the electrical conductivity of 2,76 dS m-1, Si content in the soil. of 5,70 mg kg-1, 14% Si leaf content, improving photosynthetic rates and transpiration, increasing water use efficiency, instantaneous carboxylation efficiency and fruit yield, reducing stress index. Increasing salinity reduced fruit yield in the presence and absence of Si.