Tratamento de sementes de couve de bruxelas com ácido salicílico: efeitos na germinação de sementes e crescimento de plântulas em diferentes temperaturas

Abstract

Seed treatment is essential to protect against pathogens and improve the physical and physiological conditions of seeds. Salicylic acid (SA), a phenolic plant hormone, contributes to plant development by protecting it against biotic and abiotic stresses. Therefore, the objective of this research is to evaluate the effect of seed treatment with different doses of salicylic acid on Brussels sprout seed germination and seedling growth under ideal conditions and under heat stress conditions. Brussels sprout seeds (Brassica oleracea var. gemmifera) were used. The experimental design was completely randomized, with four doses of SA and five replications. The tested doses were: 0; 0.5; 1.0; and 2.0 mM/L of salicylic acid. The treated seeds were evaluated in the laboratory using the following tests: germination, root and shoot length, dry mass of roots and shoots, under temperature stress (30°C) and ideal temperature conditions (20°C). The results showed that seed treatment with salicylic acid (SA) at ideal temperature conditions did not improve the evaluated parameters, and higher doses caused damage to seedling development. Under heat stress conditions, the dose of 0.5 mM/L of SA increased shoot dry mass, while the dose of 1.0 mM/L of SA increased root dry mass. The temperature of 30°C did not reduce the germination capacity of Brussels sprout seeds, but it negatively affected seedling development, decreasing root and shoot length, as well as reducing biomass accumulation in the seedlings.