Plant reproduction in the high-Andean Puna: Kentrothamnus weddellianus (Rhamnaceae: Colletieae)

Abstract

The global picture of plant reproduction at high altitudes is still diffuse due to conflicting reports (e.g., about which are the prevalent breeding systems) and incomplete geographical and taxonomic coverage of high-altitude ecosystems. This paper reports on the reproductive biology of Kentrothamnus wedellianus, a shrub inhabiting the Puna semidesert in Argentina and Bolivia at ca. 3,600 m a.s.l. A set of four traits, including a high pollen/low nectar floral reward strategy, homogamy, a dry stigma, and partial self-compatibility, appear to be central for K. weddellianus to accomplish sexual reproduction in the high-altitude Puna. The existence of an entirely different set of characteristics in the related species Ochetophila nana suggests that adaptation to reproduction at high altitudes can be achieved through different pathways. Hence, the final results may strongly diverge from the patterns found in lowland species of each lineage, or not. More case studies still seem to be necessary before specific patterns can be discerned within the panorama of high-altitude plant reproduction.