Study on the flowering traits and breeding systems of three Impatiens species

The flowering phenologies, floral traits, and breeding systems of three Impatiens species (I. blepharosepala Pritz. ex Diels, I. chlorosepala Hand.-Mazz., I. rhombifolia Y.Q. Lu et Y.L. Chen) grown in a greenhouse were explored by morphological observation, scanning electron microscopy, and manual control of pollination. Results showed that the flowering phenology of the three species could be divided into six periods according to changes in floral morphological. The various plant flowering periods showed partial overlap and certain differences were found in floral traits, breeding indicators, pollen grains, and ovary micromorphology. Overall, the trends in pollen viability and stigma receptivity in the three species were unimodal. The breeding systems were facultative outcrossing, with characteristics of self-compatibility and pollinator requirement. Nectar volume and sucrose met the pollination needs of small-sized insects. The setting percentage in the control treatments were lower than those in the three artificial pollination treatments, the absence of phenomenon of self-pollination and apomixis in six control pollination treatments for the three species, and the highest setting percentage in the manual xenogamy and the lowest in the manual geitonogamy.