Abstract: Seed hydration memory is the ability of seeds to retain biochemical and physiological changes caused by discontinuous hydration. This study aimed to determine if Senna spectabilis (DC.) H.S. Irwin & Barneby var. excelsa (Schrad.) H.S.Irwin & Barneby (Fabaceae) present seed memory and evaluate the effects of hydration and dehydration cycles (HD) on the seed germination of this species when submitted to conditions of water stress. Seeds underwent HD cycles (0, 1, 2 and 3 cycles) corresponding to the hydration times X (6 hours), Y (16 hours) and Z (24 hours), determined from the imbibition curve, with 5 hours of dehydration and submitted to water stress conditions. Germination was evaluated at 0.0, -0.1, -0.3, -0.6 and -0.9 MPa, obtained with polyethylene glycol 6000 solution. Germinability (%), mean germination time (days) and hydrotime (MPa d-1) were calculated. The seeds of S. spectabilis var. excelsa are sensitive to the low osmotic potentials tested in this study, however, when submitted to the HD cycles of 16 hours hydration (time Y), the tolerance to water stress conditions is increased. In addition, the observed benefits on the evaluated germination parameters show that S. spectabilis var. excelsa present seed hydation memory.
Seed germination response to high temperature and water stress in three invasive Asteraceae weeds from Xishuangbanna, SW China