title: The reproductive strategy of a pollinator-limited Himalayan plant, Incarvillea mairei (Bignoniaceae).
abstract: BACKGROUND
  Plants may adapt to alpine habitats by specialization in the reproductive strategy and functional aspects of their flowers and pollination systems. Alpine habitats reduce the opportunities for cross-pollination in a relatively high proportion of alpine plant species, and self-pollination may be favored in these adverse conditions. Here, we investigated the mating system and pollination of Incarvillea mairei, a perennial Himalayan herb typically found at altitudes between 3000 and 4500 m.
  
  
  RESULTS
  Analyses of floral morphology, observation of plant-pollinator interactions, and hand pollination experiments were conducted in three natural populations. Outcrossing rates and effective numbers of pollen donors were assessed in 45 open-pollinated families by using progeny analysis based on seven microsatellite markers. Incarvillea mairei displayed a set of apparently specialized floral traits, the stigma is sensitive to touch and close immediately and its reopening allows a second opportunity for the receipt of pollen. The species is fully self-compatible but employs a predominantly outcrossing mating system according to parentage analysis (tm > 0.9). Fruit set was low (26.3%), whereas seed set was high (67.2%), indicating that this species suffers pollinator limitation. Its main effective pollinator was Halictus sp., and visitation frequency was low.
  
  
  CONCLUSIONS
  Floral features such as having a sensitive stigma and anther-prongs, in conjunction with pollinator behavior, function together contributing to a set of unique reproductive adaptations that enhance outcrossing success. The increased floral longevity and high pollination efficiency operated as compensatory mechanisms to counteract low pollinator visitation frequency.
authors.affiliation: Key Laboratory for Plant Biodiversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China. wanghong@mail.kib.ac.cn.
authors.forename: Honglian
authors.initials: H
authors.lastname: Ai
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.forename: Kun
authors.initials: K
authors.lastname: Xu
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Dezhu
authors.initials: D
authors.lastname: Li
mesh_terms: D029402:Bignoniaceae / Q000378:metabolism / Q000502:physiology*; D017753:Ecosystem; D005638:Fruit / Q000378:metabolism / Q000502:physiology; D054817:Pollination / Q000502:physiology