ANALYSIS OF INTRASPECIFIC NUCLEAR-DNA CONTENT VARIATION IN GLEDITSIA-TRIACANTHOS BY FLOW-CYTOMETRY

Honeylocust trees (Gleditsia triacanthos L.) are distributed across a wide range of climatic and edaphic conditions, demonstrating considera ble variation in cold, drought, and salinity tolerances. In many angio sperm species, an evolutionary change in nuclear DNA content accompani es colonization into more stressful environments. Fresh leaf nuclei we re isolated from 22 honeylocust sources from across the species' nativ e range, mixed with trout red blood cells, stained with propidium iodi de, 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 am ong the sources was not significant (p < 0.05), suggesting that adapti ve evolutionary changes in honeylocust are not evident in increasing o r decreasing amounts of leaf nuclear DNA content.