MORPHO-ANATOMIC OF ADVENTITIOUS RHIZOGENESIS IN MINI-CUTTINGS OF Eucalyptus grandis x Eucalyptus urophylla

O presente estudo teve como objetivo principal a caracteriza\ue7\ue3o morfoanat\uf4mica da rizog\ueanese advent\uedcia de miniestacas de quatro clones de Eucalyptus grandis x Eucalyptus urophylla . As miniestacas foram coletadas de minicepas estabelecidas em minijardim clonal, conduzido em sistema semi-hidrop\uf4nico em canaletas com fertirriga\ue7\ue3o. Para a caracteriza\ue7\ue3o histol\uf3gica do processo de rizog\ueanese das miniestacas foram coletadas amostras teciduais aos 0, 1, 2, 4, 6, 8, 10 e 12 dias ap\uf3s o estaqueamento em casa de vegeta\ue7\ue3o climatizada, para enraizamento. As amostras foram fixadas em FAA70%, desidratadas em s\ue9rie et\uedlica e inclu\ueddas em metacrilato. Os resultados revelaram a origem end\uf3gena de prim\uf3rdios radiculares a partir do c\ue2mbio vascular e, em alguns casos, a prolifera\ue7\ue3o e a forma\ue7\ue3o de uma massa de c\ue9lulas desorganizadas (calos) em miniestacas dos clones avaliados, entre 8 e 12 dias de idade.The present work aimed to accomplish the histological analysis of the events involved in the adventitious rooting pattern of four Eucalyptus grandis x Eucalyptus urophylla clones. The mini-cuttings were collected from a mini-stump and the rooting experiments were set up under mini-hedge indoor semi-hydroponics by means of intermittent flooding fertirrigation. For histological analyses, the proximal ends of the minicuttings were collected after 0, 1, 2, 4, 6, 8, 10, and 12 days after planting them at greenhouse. After fixation with FAA70%, the samples were dehydrated in a graded ethanol series and infiltrated overnight in metracrilate resin, and finally embedded in resin. It was verified the endogenous origin of adventitious root primordia from vascular cambium, and in some cases, the formation and proliferation of calli at the proximal end of the mini-cuttings within 8 to 12 days