Nuclear DNA Amounts in Angiosperms

Abstract

Bennett and Smith (Philosophical Transactions of the Royal Society of LondonB274:227-274; B334: 309-345) and Bennett, Smith and Heslop-Harrison (Proceedings of the Royal Society of London, B216: 179-199) published lists of nuclear DNA amounts estimated for 1612 angiosperm species collected from 163 sources dated between 1951 and 1986. Subsequently, interest in genome size in angiosperms and its significance has continued, and many new DNA estimates were published during 1986-1994. Their inaccessibility, and the flow of enquiries for such information, shows that a further compilation is needed. This paper presents a supplementary list of nuclear DNA C-values for 105 sources for 899 angiosperm species not listed in the above-mentioned compilations, plus 284 additional estimates for 208 species already listed by them. The data are assembled primarily for reference purposes, with species listed in alphabetical order, rather than by any taxonomic scheme. Some advantages and limitations of flow cytometry, now increasingly used to quantify DNA C-values in plants, are reviewed. Recent reports regarding the occurrence and extent of intraspecific variation in genome size are also discussed. While some examples are real, others reflect technical shortcomings. Work has begun to combine the genome size data compiled in this and the above-mentioned papers into a unified data base, and to present the information in separate lists, with species in alphabetical and systematic orders, respectively. DNA C-values are now known for 1% of the world's angiosperm flora, but improved representation of taxonomic groups, geographical regions and plant life forms is urgently needed.