Efeitos de fatores ambientais induzidos na germina？？o de sementes de Chaptalia nutans (L.) Polack

chaptalia nutans is species whose medicinal value has been studied thoroughly, and aspects regarding seed germination are important to define better propagation practices. the objective of the present study was to evaluate the germination response of c. nutans seeds to conditions of light and temperature, as well as osmotic and saline stresses and potassium nitrate. four experiments were conducted: a) combination of four temperatures (20oc, 25oc, 30oc and laboratory atmosphere) with two light conditions (presence or absence); b) ten levels of osmotic stress induced with manitol (0.0; -0.05; -0.1; -0.2; -0.3; -0.4; -0.5; -0.6; -0.7 and -0.8 mpa); c) eight levels of saline stress induced with nacl (0.0; -0.1; -0.2; -0.3; -0.4; -0.5; -0.6 and -0.7 mpa) and d) combination of two levels of potassium nitrate (presence or absence) with two temperatures (20 and 25 oc) and two levels of light (presence or absence). germination of c. nutans seeds was maximized under light, at constant temperatures of 25 , 30 oc, or room temperature between 19 and 31 oc. there was no germination reduction with osmotic stress of up to -0.6 mpa and saline stress of up to -0.5 mpa. the addition of potassium nitrate did not promote any increase in the germination.