title: Pollen sensitivity to ultraviolet-B (UV-B) suggests floral structure evolution in alpine plants.
abstract: Various biotic and abiotic factors are known to exert selection pressures on floral traits, but the influence of ultraviolet-B (UV-B) light on the evolution of flower structure remains relatively unexplored. We have examined the effectiveness of flower structure in blocking radiation and the effects of UV-B on pollen viability in 42 species of alpine plants in the Hengduan Mountains, China. Floral forms were categorized as either protecting or exposing pollen grains to UV-B. The floral materials of plants with exposed and protected pollen grains were able to block UV-B at similar levels. Exposure to UV-B radiation in vitro resulted in a significantly greater loss of viability in pollen from plant species with protective floral structures. The pronounced sensitivity of protected pollen to UV-B radiation was associated with the type of flower structure. These findings demonstrate that UV-B plays an important role in the evolution of protective floral forms in alpine plants.
authors.affiliation: 1] Key Laboratory for Plant Biodiversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, P. R. China [2] Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, P. R. China [3] Graduate University of the Chinese Academy of Sciences, Beijing 100049, P. R. China.
authors.forename: Chan
authors.initials: C
authors.lastname: Zhang
authors.affiliation: 1] Key Laboratory for Plant Biodiversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, P. R. China [2] Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, P. R. China [3] Plant Germplasm and Genomics Center, the Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, P. R. China.
authors.forename: Yong-Ping
authors.initials: YP
authors.lastname: Yang
authors.affiliation: 1] Key Laboratory for Plant Biodiversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, P. R. China [2] Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, P. R. China [3] Plant Germplasm and Genomics Center, the Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, P. R. China.
authors.forename: Yuan-Wen
authors.initials: YW
authors.lastname: Duan
mesh_terms: D005075:Biological Evolution; D002681:China; D035264:Flowers / Q000502:physiology*; D018525:Germination / Q000502:physiology; D010641:Phenotype; D010944:Plants; D011058:Pollen / Q000502:physiology*; D054817:Pollination / Q000502:physiology*; D014466:Ultraviolet Rays