Superação de dormência e metodologias para testes de germinação em sementes de Trifolium riograndense Burkart e Desmanthus depressus Humb.

Abstract

The objective of this study was to investigate methods for overcoming seed dormancy and the germination test in Trifolium riograndense Burkart and Desmanthus depressus Humb, seeds, native legumes not yet included in the current Seed Analysis Rules. The experiment consisted of two parts: the first one was designed to overcome seed dormancy and the treatments were: immersion in hot water (60°C, 5min); chemical scarification with concentrated sulphuric acid for 5 minutes and manual scarification with number 180 sandpaper. For determination of the optimal conditions for the seed germination test, the variables evaluated were: the effects of light (presence and absence), substrate (paper and sand), seed position on the substrate (over and inside) and different constant temperatures (5, 10, 15, 20, 25 and 30°C). A completely randomized design with four replications (25 seeds each) was employed. The immersion in hot water and manual scarification with sandpaper were the more effective methods in breaking seed dormancy, of D. depressus and T. riograndense, respectively. Germination of D. depressus seeds was higher with presence of light, on paper substrate and at 25°C. T. riograndense seeds germinated better with light absence, on paper substrate and under 30°C. Alternates temperatures of 20-30°C was adequate for the germination tests for both species.