Adverse factors affect the physiological performance of soybean seeds during field establishment. This study evaluates the physiological potential of Intacta soybean seeds under hypoxia and salinity stress, by submersion in water using different osmotic potentials. In both situations, three intact soybean cultivars (TMG 7062 IPRO, 63i64 RSF IPRO, 7166 RSF IPRO) were tested in the laboratory. To test the effect of hypoxia, the seeds subjected to the tests were previously immersed in water for periods of 0, 6, 12, 24, and 48 hours. In the evaluation of salinity stress, towel papers were moistened with different solutions of potassium chloride (KCl) (0.0;-0.4;-0.8; and-1.2 MPa). Seed germination and vigor (first germination count, shoot length, primary root length, and seedling dry biomass) were evaluated. Seed germination was negatively affected by the 12-hour period of hypoxia. Cultivars 763i64 and 7166 were more tolerant to hypoxia conditions. Cultivar 7062 was more tolerant to salinity stress. Osmotic potential of-0.4 MPa affected the vigor of soybean seeds. Soybean cultivars showed adaptive differences under hypoxia and salinity stress.

Seed performance is one of the key points for high productivity in crop development. The objective of this study was to evaluate the physiological potential of popcorn cultivar seeds (IAC 125 and BRS-Ângela) treated with Stimulate ® bioregulator under water stress. Popcorn seeds were submitted to different osmotic potential levels 0; -0.1; -0.3; -0.6 and -0.9 MPa and induced by mannitol, after being treated with bioregulator at the dose of 1.5 L 100 kg -1 of seeds. The experiment was conducted in a completely randomized design, in a 5 × 2 × 2 factorial design (osmotic potential levels x cultivars x absence and presence of bioregulator). The variables evaluated were: first count and final count of germination standard, shoot length, primary root length, and dry biomass of seedlings. Treating popcorn seeds with bioregulator is inefficient in improving the physiological potential under normal conditions and little water restriction, but under conditions in which water may be limited, the use of bioregulator positively influences germination, growth, and initial performance of seedlings.