Assessment of the effects of selenium application on leaves or substrate on the growth of sunflower plants

Avaliação dos efeitos da aplicação de selênio nas folhas ou no substrato sobre o crescimento de plantas de girassol

Resumo

Though Selenium (Se) is a nonessential micronutrient to plants, its presence under appropriate concentrations helps in the plant antioxidant system, thus benefiting crop growth and productivity. Considering the need for acclimatization of crops due to climate changes and the need for diversification of the energy matrix, this study aimed to assess the different concentrations and forms of application of selenium (sodium selenite and sodium selenate) suitable for the cultivation of sunflower plants through growth analysis (height, diameter and number of leaves) and relative chlorophyll contents. The experimental design was completely randomized, and consisted of 18 treatments with 5 replications each, with applications of selenium in the substrate or by leaf spraying. All 18 treatments were independently assessed. Analysis of variance was performed and means were independently compared using the Tukey test (P ≤ 0.05) in the AgroEstat program. Sunflower plants supplemented with 0.8 mg L^-1 of sodium selenite in the substrate presented values higher than those of the other treatments for plant height variable. For relative contents of chlorophyll, concentrations of 0.8 mg L^-1 and 1.7 mg L^-1 of selenate in the substrate and 3.3 mg L^-1 of selenite in the substrate stood out. For the other variables, treatments containing selenium were equivalent to the control. It was concluded that the treatments whose application was directly made on the substrate showed higher values than those that received foliar application.