Unique arrangement and temporal separation of essential organs promotes cross pollination in Impatiens edgeworthii Hook. f.: an endemic species of Western Himalaya

Abstract

Impatiens edgeworthii is an important plant species endemic to Western Himalaya. In this species male reproductive organs conceal the stigma – seat of pollen reception during male phase therefore acts as barrier for self-pollination. In addition the stigma become receptive only after the androecium of the same flower is shed and then receptive stigma become exposed. This unique type of dichogamy and arrangement of essential organs are contrivance for cross-pollination in the species. The large showy flowers, production of large quantities of nectar, protandry, presence of nectar guides, ornamented exine sculpturing, high pollen to ovule ratio points towards cross-pollinated mode of reproduction is operative in this species. This was also established by breeding experiments. Our study may prove useful in conservation of this Himalayan endemic plant species and also useful in understanding the evolution of breeding system in the genus.