Pollination Ecology of Impatiens rufescens (Balsamineae) - An Endemic Annual Herb From Nilgiri Mountains, Western Ghats, India

摘要

I examined the breeding and pollination systems of Impatiens rufescens (Balsamineae), a rare annual balsam restricted to the Western Ghats of India. The experiments were conducted in the Korakundah (KR) and Upper Bhavani (UB) montane swamps of the Nilgiri Mountains (2200 m altitude). In each treatment, 46-50 flowers were emasculated from 15-22 plants at each swamp site. Manipulation experiments demonstrated that the geitonogamyproduced, on average, lower fruit set (43%) and seed number (3.73 +-0.18%) than the xenogamy treatment (fruit set (92%) and seed number (7.94 +- 0.06%). Fruit set (87%) and mean seed number (7.26 +- 0.14%) in the control set were not significantly different between two sites and no fruit set was recorded from the autogamy. The results suggest that I. rufescens is an obligate out-crosser and is partially self-incompatible. The self-incompatibility index (ISI) was calculated as 43/92 = 0.47% (between 0.2 and 1), the ratio of fruit set between the two sites. Each pollinator visit differed significantly from the total number of visits; however diverse insect visit was significantly higher between two sites. It is concluded that outcrossing rate may increase the I. rufescens population by greater pollen deposition through manipulation and aid by foraging pollinators.