WATER DEFICIT ON GERMINATION AND VIGOUR IN SEEDS OF THE JAMBU

Water availability influences plant metabolism during the various stages of development, especially in the period between germination and seedling emergence. The aim of this study was to evaluate the effect of water deficit during the germination process on seeds of A. oleracea. The experiment was carried out in a completely randomised design, with four replications of 50 seeds. The treatments were arranged in a 5 x 2 factorial scheme, with the first factor consisting of the osmotic potentials (-0.2, -0.4, -0.6, 0.8 and distilled water for the potential 0.0 MPa) and the second factor consisting of two lots of seed. The germination test was carried out on substrates moistened with solutions of mannitol and polyethylene glycol (PEG 6000) at the various potentials, in a Biochemical Oxygen Demand (BOD) germinator at a temperature of 30 degrees C and under constant light. The test was evaluated daily for 14 days, considering the seeds that had a root length equal to or greater than two millimetres as having germinated. The variables under analysis were germination, germination speed index, seedling length and seedling dry weight. The germination process of A. oleracea is compromised at water potentials of -0.2 MPa and -0.4 MPa when submitted to PEG and mannitol respectively. Seeds from Lot 1 were more tolerant to the water deficit than were those from Lot 2.