DNA contents inPaspalum spp. determined by flow cytometry

Abstract

DNA contents in nuclei isolated from 81 accessions ofPaspalum, representing 35 species, was determined by laser flow cytometry. Nuclei were isolated by chopping leaf base tissue in Tris/HCl buffer containing 1 % Triton X-100 and fixed in EtOH. Fixation, or no fixation, of nuclei in 70% or 95% EtOH did not affect estimates of DNA contents in DAPI-stained nuclei. DNA contents, among the species examined, varied approximately four-fold (1.02 – 3.86 pg/2C nucleus). Coefficients of variation ranged from less than 1% to approximately 5% and did not increase following fixation. Variation in DNA contents between plants within accessions was less than 0.1%. Significant differences in DNA contents estimates within and between species were detected. Data presented suggested that DNA content is a useful descriptor for characterization of plant genetic resources. The occurrence of significant levels of variation within and betweenPaspalum species indicates that estimates of DNA contents may be useful for characterization and identification ofPaspalum cytotypes. In addition, the identification and maintenance of variability for DNA contents withinPaspalum spp. might be useful as a means to capture genomic adaptations to ecological variation.