Indução e identificação de poliploidia em Musa acuminata, Colla

Abstract

The aimed study to induct and to identify polyploidys identification through stomatal analysis, chromosome counting and flow cytometry, as well polyploidys and mixoploids effects on the structural and ultrastructural characteristics in banana varieties: Malbut, Ouro, Lidi e Thong Dok Mak. In polyploidys induction, explants were treated with concentrations of colchicine (0, 2.5; 7.5 and 12,5mM) for 24 and 48 hours and with oryzalin (0, 10, 30 and 50μM) for 4 and 7 days. Toward polyploidys identification through stomatal analysis, samples of young leaves from every plant were evaluated by scanning electron microscopy size (polar diameter x equatorial diameter) and stomatal density were evaluated. Toward analysis in flow cytometry, quantity of leave tissue from each plant was cuted and after, triturated (aiming a nucleus liberate) and redden with propidium iodide. A number of 10,000 events was evaluated. Toward cytogenetics analysis, types roots were previous treated with 8-HQ 500 mg L-1 solution for 3 hours and fixed in Carnoy solution for 24 hours and submitted to the conventional crushing techniques. Staining was done with solution of Giemsa (10%). Towards second experiment, analysis of structural and ultrastructural characteristics of diploids plants, mixoploids and tetraploids in 3 banana cultivars: Lidi, Ouro e TDM were carried out. Fragments from young leaves were submitted to the conventional techniques for analysis in transmition electron microscopy. Thick (>100nm) and thin (<100nm) sections were evaluated in light and transmition electron microscopy, respectively. Length and breadth of cells from palyçadic and spongy parenchyma, adaxial and abaxial epidermis, leave thickness were measured and chloroplasts numbers were estimated. While to thin sections ultrastructural characteristics of chloroplasts were examined. It was concluded that 4 plants were identified as tetraploids and 6 as mixoploids through three identification techniques. No differences between tetraploids and mixoploids was produced, only structural and ultrastructural characteristics of diploids.