Karyomorphological and biochemical studies in Glebionis coronaria (L.) Spach and Glebionis segetum (L.) Fourreau from Italy

Abstract

The karyotype structures and the composition and distribution of the heterochromatin in Glebionis coronaria and Glebionis segetum using Giemsa and fluorescent banding techniques were analysed. The species studied are diploids with 2n = 2x = 18 chromosomes. G. coronaria possesses the most symmetrical karyotype, comprising mainly metacentric chromosomes. G. segetum, with formula 12 m + 6 sm, showed a slightly less symmetrical karyotype. Giemsa C‐banding revealed little constitutive heterochromatin in both species. The presence of telomeric bands was restricted to two chromosome pairs. After staining with chromomycin A₃, the chromosomes of G. coronaria and G. segetum revealed bright fluorescence at the telomeric regions of two chromosomes. No 4‐6‐diamidino‐2‐phenyl‐indole bright blocks were observed. To estimate genetic variability in the species under consideration, genotypic expression was also determined through isozyme electrophoresis of cytosolic ascorbate peroxidase, considered a genetic marker in the study of plant phylogenetics. The relationships between G. coronaria and G. segetum are discussed.

Abbreviations: ASC, ascorbate; BSA, bovine serum albumin; cAPX, cytosolic ascorbate peroxidase; CMA, chromomycin A₃; DAPI, 4‐6‐diamidino‐2‐phenyl‐indole; EDTA, ethylenediaminetetraacetic acid; PAGE, polyacrylamide gel electrophoresis

Keywords:

• Electrophoresis
• Giemsa C‐banding
• Glebionis coronaria
• Glebionis segetum
• heterochromatin content
• isozymes