Reproductive biology of Trillium govanianum, an endangered plant species endemic to the Himalaya: implications for conservation

ABSTRACT In this study, we investigated the reproductive biology of Trillium govanianum — a medicinally important endangered plant species endemic to the Himalaya. We specifically aimed to unravel the key floral traits that aid and/or limit the species’ reproduction, including the breeding strategies and modes of pollination. We studied qualitative and quantitative floral traits, and conducted different breeding experiments to understand reproductive biology of this plant species for its conservation and sustainable utilization. Our results show no temporal separation between anther dehiscence and stigma receptivity in the species, though essential organs are spatially separated. The absence of nectar secretion in the flowers and lack of pollenkitt in the pollen wall indicates anemophily is operative in the species; nevertheless, some flies and beetles were observed to occasionally visit the plants. The pollen/ovule ratio indicates a value between facultative-xenogamy to xenogamy. Our pollination experiment results reveal that the species undertakes both self- and cross-pollination. We observed a significant difference in fruit set between the supplemented and open-pollinated controls, indicating that the species might be pollen-limited. Although both self- and cross-pollinations are operating in the species, yet the fruit set was low, which may be due to the inefficient pollination system and meiotic abnormality found in the species. Overall, our results suggest that the reproduction in T. govanianum is limited by some inherent biological traits in combination with environmental conditions. Looking ahead, we highlight how our findings can help in guiding conservation of this endangered species in the Himalaya.