Restrição hídrica e ponto de priming em sementes de Psidium cauliflorum Landrum & Sobral

Abstract

The objective of this study was to evaluate the germination response to water deficit and define the priming point for the osmopriming of P. cauliflorum seeds, a forest species endemic to Brazil. Two germination experiments were carried out, in which the seeds were exposed to different osmotic potentials between 0.0 and -2.0MPa simulated with distilled water or PEG 6000 solutions. At the end of each experiment, the seeds from treatments without germination were transferred to distilled water and germination was evaluated. The highest germination percentages (~65%) and the shortest average germination times (~41 days) occurred at the potential 0.0 MPa (water). At potentials -0.4, 0.5 and -0.6 MPa these variables were negatively influenced and from -0.7 MPa, germination was inhibited. Seeds rehydrated after exposure to -0.7 and -0.8 MPa potentials showed 58 to 70% germination, and 45 to 70% normal seedlings, a reduction in average time (~15 days) and an increase in germination synchronization. From the results it is concluded that water deficit reduces the germination performance of P. cauliflorum and that the potential of - 0.7 MPa is the priming point for the osmopriming of seeds of the species.