Traits of the pollination process in Gladiolus imbricatus and Iris sibirica (Iridaceae)

Abstract

Results of a study of self-pollination in two of Ukrainian flora's threatened species, Gladiolus imbricatus and Iris sibirica (Iridaceae), are presented. To confirm or refute the occurrence of self-pollination in G. imbricatus and I. sibirica, an experiment was conducted on pollen germination on their stigmas. It has been found that in G. imbricatus pollination with autogenous pollen grains on the last day of flowering leads to the growth of pollen tubes in the cases of both hand and natural pollination. However, pollen grains on the stigma of an isolated I. sibirica flower were not detected on the first or last day of flowering, which means the absence of a mechanism of autonomous pollen transfer within the meranthium. Ungerminated pollen grains were also found on the stigma after autogenous hand pollination. It has been experimentally confirmed that in the absence of pollinators at the end of the flowering phase in G. imbricatus, as well as in some other members of the genus, self-pollination and self-fertilization are possible, which contribute to the wellbeing of populations and species. With regard to I. sibirica, it has been found that the autogamous self-incompatibility inherent in this species prevents inbreeding, maintaining heterozygosity in plant populations, allowing plants' better adaptation to different environmental conditions.