Aspects of the pollination biology of a rare alpine calciphile, Saussurea weberi Hulten (Asteraceae).

摘要

The biology of most rare alpine plants is little known. Pollination biology of the rare Colorado alpine calciphile Saussurea weberi Hulten was investigated, including mating system, insect pollinators/associates, and physiological/morphological characters. Plants are obligately outcrossing. Fruit development onset might not require presence of viable seeds. Principal pollinators are bumblebees; other insect associates utilize S. weberi to obtain food. Inflorescences undergo general cymose development adaptive for the alpine. Other characters are adaptive for attracting bumblebees: inflorescences flower at least eight days; skunky-sweet inflorescence odor varies in diurnal/nocturnal intensity; UV-reflective floret corollas, anthers and pollen contrast with absorptive pappuses, while stem leaves possessing UV-reflective hairs surround inflorescences. Even before exsertion, adaxial/distal stigma surfaces seem most receptive to pollination. Pollen is monomorphic and similar to that of other Saussurea species. Results contribute to academic study and conservation of S. weberi and other rare alpine plants.