DORMANCY BREAKING, GERMINATION, AND PRODUCTION OF MIMOSA BIMUCRONATA (DC.) KUNTZE SEEDLINGS

Abstract

ABSTRACT Mimosa bimucronata is a pioneer, easily adapted, fast-growing species used in restoration programs. The objectives of this study were to experimentally compare (1) methods for dormancy breaking; (2) suitable temperature and substrate for germination; and (3) suitable light intensity and substrate volume for seedling production of M. bimucronata. In the first two experiments, the variables percentage of germination, speed of germination and germination mean time were analyzed. In dormancy test, seeds were submitted to ten methods divided into three groups: hot water, sulfuric acid, and control. In the second experiment, effects of five different temperatures and four substrates were evaluated. In the third experiment, morphometric and biomass variables of seedlings were evaluated in two substrate volumes and two light intensities. The most effective method for breaking dormancy was hot water at 80 °C for one minute with post-treatment immersion in water at room temperature for 24 hours. This finding contrasted with the recommended method for dormancy breaking in the Brazilian Rules for Seed Analysis. The most suitable substrates and temperatures for germination were germitest paper at alternating temperatures of 25-35 °C and sand at constant temperature of 30 °C. The most adequate volume of substrate for seedling production was 280 cm3 in both shaded and full sunlight conditions.