EFEITOS DOS ESTRESSES HÍDRICO E SALINO NA GERMINAÇÃO DE SEMENTES DE GLIRICIDIA [Gliricidia sepium (JACQ.) STEUD.]

Abstract

Seed hydration is considered the most important external factor interfering on germination. This study evaluated the tolerance of Gliricidia sepium (Jacq.) Steud seeds to water and salt stresses during germination. Seed germination was observed in four 100-seed replications, in polyethylene glycol (PEG-6000) or sodium chloride (NaCl) solutions with four osmotic potentials levels (0; -0.5; -1.0 and -2.0 MPa), arranged according to a completely random design, simulating water and salt stresses, respectively, using four replications of 100 seeds. The germination percentage and germination velocity index were estimated. Percentage germination of the control seeds averaged 94%, and reduced to 77.6% and 44.3% in -1.0 MPa NaCl and PEG solutions, respectively. No germination was observed in -2.0 MPa. Germination velocity index showed the same trend. Gliricidia sepium seeds showed less tolerance to water than to salt stress, and in this condition they are not tolerate to osmotic stress up to -0,5 MPa.