Analysis of intraspecific nuclear DNA content variation in Gleditsiatriacanthos by flow cytometry

Abstract

Honeylocust trees (Gleditsiatriacanthos L.) are distributed across a wide range of climatic and edaphic conditions, demonstrating considerable variation in cold, drought, and salinity tolerances. In many angiosperm species, an evolutionary change in nuclear DNA content accompanies colonization into more stressful environments. Fresh leaf nuclei were isolated from 22 honeylocust sources from across the species' native range, mixed with trout red blood cells, stained with propidium iodide, and their DNA content was measured by flow cytometry. According to DNA stainability of the trout red blood cells, leaf nuclei had a DNA content of 1.72 ± 0.02 pg (mean ± SD). Variation in DNA content among the sources was not significant (p < 0.05), suggesting that adaptive evolutionary changes in honeylocust are not evident in increasing or decreasing amounts of leaf nuclear DNA content.