The achene pappi and elaisomes of Centaurea L.: Dispersal and germination in some Italian species

Abstract

The presence/absence of pappi and elaiosomes, types of elaiosome reserves, and germination were studied in 38 Italian taxa belonging to different sections of the genus Centaurea L. Achenes with pappus, with elaiosome, with pappus and elaiosome, and without pappus and elaiosome were found. Many species had elaiosomes containing lipids, which were sometimes associated with proteins and/or starch; in sporadic cases, only proteins were found. Subspecies of the same genus and specimens of the same species from different localities were sometimes diversified with regard to pappus and elaiosome.

Germination experiments were carried out in 16 taxa using intact achenes and achenes with elaiosomes removed. In eight taxa, no statistically significant difference was found between germination of achenes with and without elaiosomes. Seeds of C. aeolica, C. aplolepa subsp. ligustica, C. leucophaea, and C. veneris without elaiosome germinated, sometimes in a low percentage, but better than seeds with elaiosome intact.