Micropropagação e analise da anatomia foliar de Handroanthus chrysotrichus (Mart. ex DC.) J. Mattos

Abstract

Handroanthus chrysotrichus is a Brazilian native forest species which presents several important aspects both under the economic and ecological points of view, because its ability to provide timber products as well as for being indicated for degraded and permanent preservation areas recovery. Its seeds present problems concerning loss of viability when subjected to storage. This way, micropropagation emerges as an alternative for the species propagation. However, some characteristics inherent in in vitro grown plants may promote physiological and anatomic changes in tissues under that condition. Thus, the aim of this study was to evaluate aspects related to micropropagation and leaf anatomy of H. chrysotrichus. Firstly, health and germination tests were applied to seeds from different lots of that species. As for in vitro multiplication of H. chrysotrichus explants, different sources and concentrations of cytokines combined or not with auxin were tested, as well as the influence of successive subculture execution on multiplication rates. Aspects concerning leaf senescence of sprouts maintained in vitro in Woody Plant Medium (WPM) were also assessed. Concerning rooting in vitro, different concentrations of 3-Indolebutyric acid (IBA) combined with the presence or absence of vermiculite in ½ WPM were tested and, later, the ex vitro acclimatization of plants micropropagated was assessed. Finally, the test was conducted in order to compare the leaf anatomy of H. chrysotrichus plants grown in vivo, in vitro and acclimatized. The seed lots of H. chrysotrichus showed differences in health quality and geminal capacity of the seeds. As for in vitro multiplication of H. chrysotrichus, the use of cytokinins was not considered necessary. High rates of in vitro multiplication were obtained, when considered in vitro formation of buds. As for leaf senescence, the species showed great potential, remaining long periods in the same nutrient medium. There was rooting in vitro in more than 50% of the shoots cultivated in the presence of vermiculite, regardless IBA concentration. It was not possible to satisfactorily promote the acclimatization of micropropagated plants, as only 7.12% of the seedlings survived. Differences in leaf anatomy of plants grown in vivo, in vitro or acclimatized were verified. The results can contribute with information about H. chrysotrichus, concerning aspects related to its in vitro culture and leaf anatomy of the tissues grown in different environments.