This work aimed to evaluate the effect of water potential as induced by polyetyleneglycol and of osmotic conditioning on the physiological quality of Cnidosculus juercifolius seeds. The water stress was carried out by germinating the seeds in substratum filter paper saturated with 0.2% nystaten solution without (control) or with polyethyleneglycol (PEG-6000) at the following osmotic potential values: 0.0, -0.1, -0.2, -0.3, -0.5, -0.7, -0.9, -1.1 and -1.3 MPa. For osmotic conditioning, the seeds were subjected to -0.7 MPa PEG-6000 solution, for 24, 48, 72 and 96 h, at 30 ºC. The seeds germinated well until the potential of -0.3 MPa. The germination percentage reduced from -0.5MPa while the speed of germination was reduced from -0.3 MPa. The limit of tolerance to water stress in PEG-6000 of Cnidosculus juercifolius seeds is between -0.7 and -0.9 MPa. The osmotic conditioning at-0.7 MPa for 48 h was beneficial for seeds with low vigor.
osmotic potential; forest seed; polyelthyleneglycol
