Caracterização citogenética de espécies e variedades de bambu com potencial econômico no Nordeste brasileiro

Abstract

Bambusa vulgaris is cultivated in Pernambuco, Paraíba and Maranhão states, aiming at to the production of cellulose with longer staple fibres for manufacture of high quality paper for packings. The improvement program of this and the too much species of bamboo in the region depends on the study of the cytogenetic variability to inform of its potentials for genetic manipulation. The present paper characterized cytogenetically six species, with two varieties of bamboo with economic potential for the Northeast of Brazil using conventional technique,banding with fluorochromes (CMA3 and DAPI) and Nitrate of Silver (AgNO3). The results had not shown differences in the chromosomic number of the species Dendrocalamus giganteus (2n=64), D. strictus (2n=64), D. asper (2n=64) and Bambusa tuldoides (2n=64), as well as B. textilis (2n=72) and B. vulgaris var. vittata (2n=72), however the last specie had distinct number of its another variety B. vulgaris var. vulgaris (2n=54). The basic numbers ranges from x=8 to x=12 and the level ploidy varied from hexaploid to octaploid. In general, the species had presented high chromosomic number and had not presented karyotype symmetrical. The structure of the interphase nucleus had been semireticulated with presence of some chromocenteres. The morphology of the chromosomes for all the analyzed species consist of metacentric and submetacentric. The double coloration with fluorochromes CMA3 and DAPI evidenced blocks CMA3+/DAPI- in the terminal region in chromosomes of all the analyzed species. In this coloration, in metaphase, had revealed secondary constrictions and had evidenced satellites in B. tuldoides, B. textilis, D. asper and D. giganteus. The others species had evidenced NOR`s (Nucleolar Organization Regions). The coloration with AgNO3 showed the occurrence of only one great nucleolar that occupies almost all part of the interphase nucleus in all the species.