RESEARCH ON IDENTIFICATION OF POLYPLOIDS BY FLOW CYTOMETRY IN LAGERSTROEMIA INDICA AND LAGERSTROEMIA SUBCOSTATA

Flow cytometry refers to the technique where the measurement of the physical and chemical characteristics of particles including chromosomes, nuclei and cells is made as the particles pass in a fluid stream through a measuring point surrounded by an array of detectors. Compared with chromosome counting using microscopy methods, it is a reliable method that is accurate, rapid and reproducible. To prepare nucleus suspensions, leaves were pretreated, and five different isolation buffers (Arumuganathan’s buffer, Otto buffers, Tris-MgCl₂ buffer, Galbraith’s buffer and Lysis buffer (Jin, 2007)) were used to prepare the nucleus suspensions. To reduce the impact that phenolic compounds had on the samples, PVP was added to the isolation buffer. The comparisons showed that pretreatment of the leaves enhanced the isolation efficiency, the sample prepared by Lysis buffer showed the best resolution in Lagerstroemia indica, with the smallest variation coefficient (CV) 4.73. The sample prepared by PVP-added-Otto buffers showed the best resolution in Lagerstroemia subcostata, with the smallest variation coefficient (CV) 4.66. Flow cytometry is an ideal method for the identification of polyploids in Lagerstroemia indica and Lagerstroemia subcostata, as the method readily distinguishes between chimeras and pure tetraploids.