InduÃÃo de tetraplÃides e alongamento de plantas de Dendrobium nobile Lindl. (Orchidaceae. / Tetraploids induction and elongation of Dendrobium nobile Lindl. plants (Orchidaceae).

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The present study was developed at the campus of the Universidade Federal de Lavras, Minas Gerais, over period from January of 2003 to February of 2005, aiming at, for Dendrobium nobile Lindl., the induction and polyploidys identification, the stomatal analysis in diploid (2n=2x=38) and tetraploids (2n=4x=76) leaves, as well as the plant elongation with gibberellic acid application. In the first experiment, intact plants of D. nobile were completely submerged in 0,05% or 0,1% colchicine solution during 24, 48, 72 or 96 hours. For the polyploids plants identification by cytogenetics analysis, tips roots were pre-treatment in cold water for 24 hours, fixed in solution of acetic acid: chloroform: ethanol 95% (1:3:6) to 4oC for 24 hours and submitted to the conventional crushing technique The staining was done with solution of Giemsa 3% with phosphate buffer pH 6,8. In the second experiment, for the stomatal analysis in light microscopy, completely expanded leaves of the 3o knot were fastened in FAA50, submitted to the usual procedures in vegetable and staining with safranine 1%. For the stomatal analysis in scanning electron microscopy, the leaves in the same conditions described for the light microscopy, were cut in 2 x 2 cm segments. The materia was fixed in karnovisk solution, pH 7.2 for 24 hours, pos- fixed with aqueuos solution of tetroxid of osmio 1%, in cacodilato buffer 0,1 M, for and dehydrated with growing series of acetone. Later, the material was dried until the critical point and, soon after, it

ASSUNTO(S)

orchid planta ornamental orquidea dendrobium ornamental plant fitotecnia dendrobium

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