Cytometric determination of genome size and base composition of tree species of three genera of Casuarinaceae

• Published in: Plant cell reports 1998-12, Vol.18 (3/4), p.346-349
• Main Authors: Schwencke, J, Bureau, J.M, Crosnier, M.T, Brown, S
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Allocasuarina; Allocasuarina verticillata; Bark; Biological and medical sciences; Casuarina glauca; Casuarinaceae; chromosome number; Cytogenetics; diploidy; fluorescence; Frankia; Fundamental and applied biological sciences. Psychology; Generalities. Genetics. Plant material; Genetics and breeding of economic plants; Genomes; genomics; gymnostoma deplacheana; Gymnostoma deplancheana; leaves; measurement; Plant species; roots; size
• ISSN: 0721-7714; 1432-203X
• DOI: 10.1007/s002990050584

The genome size and base composition of diploid plant species from three genera of the Casuarinaceae family were determined by flow cytometry. Casuarina glauca Sieb. ex Spring. and Gymnostoma deplancheana (Miq.) L. Johnson showed a small genome with 2C = 0.70 pg, 58.6% AT, 40.5% GC for the first species and 2C = 0.75 pg, 58.7% AT, 40.5% GC for the second. Allocasuarina verticillata (Lam.) L. Johnson had a larger genome: 2C = 1.90 pg, 59.3% AT, 41.1% GC. One haploid genome of C. glauca is therefore about 340x 10(6) base pairs. In leaves, roots or bark of these three species, polysomaty was virtually absent: a maximum frequency of 4C nuclei of only 0.08 was found in bark of C. glauca. The genome sizes of C. glauca and G. deplancheana are among the smallest described for higher plants. Small genome size, diploidy and the absence of polysomaty are advantageous traits for facilitating molecular approaches to improvement of these actinorhizal plants and developing the study of their symbiotic interactions with Frankia.