GERMINAÇÃO E VIGOR DE SEMENTES DE Caesalpinia echinata Lam. EM FUNÇÃO DO ESTRESSE HÍDRICO EM DIFERENTES TEMPERATURAS

Abstract

The species Caesalpinia echinata Lam., From the Fabaceae family, popularly known as Brazil-wood, is a large tree with pod-like fruit, occurring from Rio Grande do Norte to Rio de Janeiro, which has a very important historical and economic value To Brazil. Thus the objective was to evaluate the effect of water stress at different temperatures on the germination and vigor of its seeds. The work was developed in the Laboratory of Seed Analysis, belonging to the Center of Agricultural Sciences of the Federal University of Paraíba, Areia - PB. For the simulation of the water stress condition, solutions of polyethylene glycol 6000 (PEG 6000) were used in the different osmotic potentials of -0.2; -0.4; -0.6 MPa and control 0.0 (control), at constant temperatures of 25, 30 and 35 ° C, in a completely randomized design. To determine the effect of the treatments, the percentage of germination, first count and germination speed index, as well as seedling length and dry mass were evaluated. The temperatures of 25 and 30 ° C favor the germination and vigor of the seeds of C. echinata that were not submitted to water stress. The reduction of the osmotic potentials from -0.4 MPa negatively affects the germination and the vigor of the seeds, mainly in the temperature of 35 ° C.