Efeito da salinidade na germina？？o de sementes e no crescimento inicial de mudas de pinh？o-manso

the physic nut (jatropha curcas l.) shrub is found in almost all the intertropical regions, and is adaptable to climatic conditions from the brazilian northeast to s？o paulo and paraná. we evaluated the effects of salt stress on j. curcas seeds and seedlings grown under laboratory and field conditions. in the laboratory experiments, two lots of physic nut seeds were submitted to different concentrations of sodium chloride dissolved in distilled water to produce electrical conductivities (ds m-1) of 2, 4, 6, 8, 10 and 12. for the field experiments, plants were grown in pots watered with sodium chloride dissolved in distilled water to produce electrical conductivities of 2 ds m-1, 4 ds m-1 and 6 ds m-1. a distilled water control was used for both sets of experiments. our results indicate that j. curcas seeds suffer a delay in germination under saline conditions and that reduced seedling growth and development occur when they are subjected to sodium chloride solution with an electrical conductivity of 6 ds m-1. it thus appears that salt stress interferes with the physiological processes occurring in jatropha seeds.