EFFECT OF WATER AND SALT STRESS ON SEEDS GERMINATION AND VIGOR OF DIFFERENT EUCALYPTUS SPECIES

Seed plays a key role in the propagation of Eucalyptus, allowing greater distribution and adaptation of the material under different soil and weather conditions. Since water and salt stress are the main factors that affect plant development, studying their effect on germination and initial growth of seedlings of these species is relevant. In order to determine the species with the most contrasting behavior, to tolerate water and salt stress, germination tests at different osmotic potentials, obtained by aqueous solutions of polyethylene glycol and NaCl, were performed to simulate water and salt stress. Radicle protrusion was counted daily while normal seedlings were counted at the end of the tests (45 days). Generalised linear model analysis was used and the data were analysed by the LSD test at 5% probability. It was verified that the maximum limit of tolerance to water stress ranged from -0.6 to -0.8 MPa for the six studied species. Eucalyptus urophylla and E. tereticornis were more tolerant to drought while E. camaldulensis and E. tereticornis were the most tolerant to salt stress during germination.