NUCLEAR-DNA AMOUNTS IN PALMS (ARECACEAE)

Nuclear DNA amounts are reported for 83 species and 53 genera of palms , covering all of the six subfamilies. 4C DNA contents range between 3 .89 and 55.62 pg in diploids, showing an approximate 14.3-fold variati on in genome size. Polyploids have DNA contents of up to 156.40 pg/4c which demonstrates a 40.2-fold variation. Diploids with high DNA conte nts occur in three subfamilies of palms (Coryphoideae, Calamoideae, Ar ecoideae), and seem to be further restricted to particular tribes or s ubtribes (Thrinacinae, Borasseae, Lepidocaryeae, Caryoteae, some subtr ibes of Areceae). Palms from the subfamilies Nypoideae and Phytelephan toideae have the lowest DNA amounts, followed by the Phoeniceae and th e Corypheae: Livistoninae from the subfamily Coryphoideae. Although DN A amounts in some genera and subtribes are usually constant, e.g., in Phoenix, Phytelephas, the Livistoninae, Dypsidinae, diploid Butiinae), considerable variation occurs at the diploid level in some large and apparently actively evolving genera such as Chamaedorea, Pinango, Geno me and possibly Bactris. Formaldehyde fixation is recommended for palm s, as conventional ethanol-acetic acid fixation has proved to be unsui table for DNA estimation of Feulgen-stained nuclei by microdensitometr y, since it can lead to errors up to 2.5-fold in extent. Chromosome co unts are reported for 72 of the species studied, of which 42 are new.