Tolerância de plantas de pinhão manso à salinidade em resposta a adubação silicatada

Abstract

The long periods of drought and the irregularity of precipitation make practical irrigation more and more indispensable to ensure agricultural production. However, the intense anthropic activities have compromised the water resources, making the use of water of inferior quality, in general saline, become a reality. Salinity is one of the abiotic stresses that most limits plant growth and productivity. Thus, silicate fertilization is a viable and beneficial alternative to plants under abiotic stresses. The objective of this work was to evaluate the effect of silicate fertilization on the growth of jatropha plants under saline stress. The work was carried out under a greenhouse at the State University of Goiás, Ipameri Campus, Brazil. The experiment was set up in a completely randomized design in a 2x5 factorial arrangement (plants irrigated with saline water with electrical conductivities equal to 0 dS m-1 ; 2 dS m-1 ; 4 dS m-1 ; 6 dS m-1 and 8 dS m-1 and absence or presence of silicate fertilizer (1 g L-1 of Bugram Protect RSO 380), five replicates and one experimental unit. The electrical conductivity levels of the irrigation water were obtained with the use of a benchtop conductivity meter through the calibration of the chloride solution (NaCl) applied to the irrigation from 80 days after emergence (DAE). The amount of water applied to the vessels was determined following the recommendations of Padilha et al. (2016). Silica fertilizations were performed at 80 and 95 DAE and each plant received 30 mL of the solution with the aid of a manual sprayer. 130 DAE with the respective analyzes: plant height, stem diameter, number of leaves, leaf area, transpiration, relative water content, photosynthetic pigments, total soluble sugar, total biomass, biochemical and nutritional analyzes. The data were evaluated by the NewmanKeuls test and regression analysis. The use of silicon did not minimize the deleterious effects of salinity on jatropha plants. The vegetative growth of the jatropha plants was significantly affected by the salinity of the irrigation water. The increase in Ca2+ concentrations reduced ionic toxicity and promoted an increase in the activity of antioxidant enzymes in jatropha plants in tolerance to salt stress