GERMINA\uc7\uc3O E VIGOR DE SEMENTES DE Apeiba tibourbou SUBMETIDAS AO ESTRESSE H\ucdDRICO E DIFERENTES TEMPERATURAS

The Apeiba tibourbou is a forest species belonging to the family Tiliaceae, popularly known as 'pau-dejangada', which is widely used as ornamental, in medicine and your timber used in the manufacture of small boats. Seeds of this species were submitted to different osmotic potentials induced by polyethyleneglycol (PEG-6000) in order to verify their resistance to drought conditions. Seeds were previously scarified with sandpaper for 5 minutes and incubated at 25 and 30 \ub0C, at osmotic potentials of 0.0; 120.2; 120.4; 120.6; 120.8 and 121.0 MPa. The following parameters were analyzed: germination percentage, index germination speed, first count germination, length and dry matter of seedlings. A significant reduction in germination velocity and final percentage of germination from 120.2 MPa in relation to control was observed. It was found that water stress resistance limits ranged from 120.4 to 120.6 MPa.A Apeiba tibourbou \ue9 uma esp\ue9cie florestal pertencente \ue0 fam\uedlia Tiliaceae, conhecida popularmente como pau-de-jangada, que \ue9 bastante utilizada como planta ornamental, na medicina popular e sua madeira usada na fabrica\ue7\ue3o de pequenas embarca\ue7\uf5es. Sementes dessa esp\ue9cie foram escarificadas com lixa d'\ue1gua n\ub080, por 5 minutos e submetidas a diferentes potenciais osm\uf3ticos, induzidos por polietilenoglicol (PEG 126000), com o objetivo de avaliar a sua resist\ueancia a condi\ue7\uf5es de defici\ueancia h\ueddrica. As sementes foram colocadas para germinar a 25 e 30\ub0C, nos potenciais osm\uf3ticos de 0,0; 120,2; 120,4; 120,6; 120,8 e 121,0 MPa. Avaliou-se a porcentagem, o \uedndice de velocidade e a primeira contagem de germina\ue7\ue3o, bem como o comprimento e massa seca de pl\ue2ntulas. Pelos resultados obtidos observou-se que a velocidade e a porcentagem final de germina\ue7\ue3o foram significativamente reduzidas a partir de 120,2 MPa, em rela\ue7\ue3o \ue0s sementes n\ue3o submetidas ao estresse h\ueddrico. O limite de resist\ueancia da esp\ue9cie ao estresse h\ueddrico situa-se entre 120,4 e 120,6 MPa