The effects of loss of sex in clonal populations of an endangered perennial Coptis teeta (Ranunculaceae)

Abstract

The reproductive biology of two subspecies of Coptis teeta was studied. The species is an endangered, herbaceous perennial, endemic to the Mishmi Hills in Eastern Himalaya. We investigated reproductive strategies of the subspecies, their breeding systems and reproductive output. They had contrasting reproductive strategies; ssp. teeta reproduces sexually and produces fewer ramets, while ssp. lohitensis propagates mostly vegetatively through a higher number of ramets. There is a resource adjustment between vegetative and sexual functions with a greater allocation to the former, particularly in ssp. lohitensis. Manual crosses showed that the species is self-and cross-compatible, but is essentially an autogamous selfer. Seed set in the species is generally low, with higher output in ssp. teeta and lower in ssp. lohitensis. The low fecundity is ascribed to a number of pre- and postfertilization events, including unsuitability of floral features for attracting pollinators, high pollen sterility and high rates of fruit and seed abortion. Sexual reproduction does not contribute significantly towards population increase in this species. This could be an important factor contributing to its rarity.