REPRODUCTIVE BIOLOGY OF IMPATIENS ELEGANS BEDD. (BALSAMINACEAE)- AN ENDANGERED BALSAM OF SOUTHERN WESTERN GHATS

摘要

A study on flowering phenology, floral biology, pollination and breeding system of Impatiens elegans Bedd., an endangered wild ornamental balsam of Western Ghats has been conducted. The flowering phase is extended up to 160 days and the pollen-ovule ratio calculated as 1050:1. Pollination is carried out by honey bees and butterflies. Impatiens elegans reproduced by means of cross pollination where the fruit production was only 22%. Artificial cross pollination through xenogamy enhanced fruit set to 48%. Percentage of fruit set in artificially cross pollinated flowers is higher than that resulting from natural pollination, which indicates that some external agents are required for successful pollination. The percentage of seed germination was limitedto 18% which may be one of the reasons for its restricted distribution. Its dependence on specialized habitats, fragmentation of populations, narrow environmental niche, delayed stigma receptivity, self in-compatibility, scarcity of pollinators, low insect visitation rate, poor fruit set and low percentage of seed germination could be the reasons for its limited distribution in the Western Ghats.