Developing Inflorescences of Male and Female Rumex acetosa L. Show Differences in Gibberellin Content

Rumex acetosa L. (common sorrel) is a dioecious perennial in the family Polygonaceae. Gibberellins (GAs) of the early 13-hydroxylation pathway and the putative early 3, 13-hydroxylation pathway were previously identified in young R. acetosa inflorescences by GC-MS. In this investigation to examine the GA content of individual inflorescences ELISAs were used for quantitative analysis. Significant differences were revealed between the sexes in the GA content of young inflorescences, and GC-SRM was used to validate the observed trends. Males had higher levels of the 3, 13-hydroxylated C20-GA GA18 and the 2, 13-hydroxylated C19-GA GA29, whereas females had higher levels of the 13-hydroxylated C20-GAs GA53 and GA19. It is suggested that the conversion from C20-GAs to C19-GAs is under tighter control in the inflorescences of females compared to male plants and therefore there is accumulation of the C20-GAs in the females. Results from flowering bioassays using authentic GAs indicate that differences in GA content between the sexes are unlikely to be a consequence of sex determination.