Germinção de sementes emergência de plântulas de Pueraria phaseoloides (ROXB.) Benth e de Urena lobata L.

Abstract

The objectives of this work were to determine the effects of continuous (20;25; 30; 35 and 40 ºC) and alternate temperatures (20-40; 25-40; 20-35 and 25-35 ºC), light time (0; 6; 12; 18 and 24 hours), osmotic potential (0,0; -0,3; -0,6; -0,9 and -1,2 MPa), saline stress (0; 25; 75; 150 and 300 mM) and depth of sowing depth (0; 2; 4; 6; 8 and 10 cm) on germination of seeds, speed germination index and emergency of Pueraria phaseoloides and Urena lobata seedlings. The P. phaseoloides secds germinated satisfactorily under continuous and alternate temperatures. However, the continuous temperature of 40 ºC was restrictive to the germination of U. lobata seeds and the germination was always higher than 85% under alternated temperatures. Duration of light did not affect P. phaseoloides and U. lobata seed germination or seedling emergency. Seed of U. lobata had higher germination in conditions of osmotic stress. Seeds of this specie were also more tolerant to the salinity. The P. phaseoloides seeds showed higher capacity to emerge in depths from Oto 10 cm.