The relationship between anther dehiscence and dehydration of the filament tip and the connective tissue were followed in Gasteria verrucosa (Mill.) H. Duval, Allium cepa L. and Lilium hybrida cv.‘Enchantment’using various microscopical techniques, including direct observations of living tissues in the SEM.
In G. verrucosa anther dehiscence immediately follows anthesis, with concomitant dehydration and shrivelling of the filament tip. In L. hybrida the filament tip dehydrates and shrivels before anthesis. The anthers start to dehisce immediately after anthesis. In A. cepa the filament tip dehydrates and shrivels slowly after anthesis and dehiscence, which may take up to several days, correlates with the rate of extension of the filament.
The attenuated period of dehiscence in A. cepa may be related to the absence of stomata on the anther. Experiments on xylem conductivity and transpiration reveal that the presence of continuously open stomata on the anthers sets the time of dehiscence after anthesis in G. verrucosa and L. hybrida.
The shrinking filament tip in all three species functions as a hinge which suspends the dangling anther after dehiscence. The uniformly thickened epidermal cell walls on the anthers opposite the filament prevent the outwardly bending locule walls from embracing the filament.