Salicylic acid and soaking times on the emergence, gas exchange and early growth of umbu

Abstract

ABSTRACT Umbu is a fruit species to the Brazilian Caatinga, showing a significant potential for various purposes and serving as a source of job and income for small producers in northeastern Brazil. This species has seed coat dormancy, which limits the production of uniform planting areas. In this scenario, this study aimed to evaluate the overcoming of dormancy, gas exchange and initial growth of S. tuberosa subjected to different soaking times and concentrations of salicylic acid. The experiment was conducted in a randomized block design with a 5 × 5 factorial arrangement referring to five concentrations of salicylic acid (0, 40, 80, 120, and 160 mg L-1) and five soaking times (0, 8, 16, 24, and 32 hours). Seed conditioning for 32 hours at the concentration of 120 mg L-1 promoted the highest germination percentage and germination speed index of S. tuberosa seedlings. Soaking at 40 and 80 mg L-1 of salicylic acid improves the gas exchange and growth of S. tuberosa seedlings. The concentration of 160 mg L-1 for 32 hours increased root, stem, and total dry matter. Leaf dry matter was higher in plants subjected to the concentration of 80 mg L-1 and the time of 14 hours. Conditioning the seeds for 32 hours at a concentration of 120 mg L-1 was effective in overcoming seed dormancy and could be a alternative for producing S. tuberosa seedlings.