title: Differentiation in drought tolerance mirrors the geographic distributions of alpine plants on the Qinghai-Tibet Plateau and adjacent highlands.
abstract: Climatic tolerance, especially drought tolerance, is one of the major factors shaping the geographic distributions of plant species. Thus, the general decline in rainfall from the Himalaya-Hengduan Mountains (HHM) to the inner Qinghai-Tibet Plateau (QTP) might account for the significant differences in species distributions and richness between the two regions. To test this hypothesis, we conducted a water stress experiment using four Anisodus species (A. tanguticus, A. luridus, A. carniolicoides and A. acutangulus), which were treated with different levels of water stress in a glasshouse, and examined their differences in physiological responses. The results suggest that A. tanguticus, which inhabits the inner QTP, generally has higher fitness under severe water stress than the other species based on its high root:shoot ratio, long-term water use efficiency and photosynthetic rate, indicating that it possesses a genetically based drought tolerance mechanism. Our results suggest that plant species inhabiting the inner QTP may be more drought tolerant than those inhabiting the HHM regions. This provides a new example supporting the hypothesis that climatic tolerance plays a major role in shaping plant distributions on the QTP and its adjacent highlands and presents new insights into the patterns of geographic distribution and diversity of the plants inhabiting these areas.
authors.affiliation: School of Life Sciences, Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan Normal University, Kunming 650092, P. R. China.
authors.forename: Li-Hua
authors.initials: LH
authors.lastname: Meng
authors.affiliation: School of Life Sciences, Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan Normal University, Kunming 650092, P. R. China.
authors.forename: Jie
authors.initials: J
authors.lastname: Yang
authors.affiliation: Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, P. R. China.
authors.forename: Wen
authors.initials: W
authors.lastname: Guo
authors.affiliation: Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, P. R. China.
authors.forename: Bin
authors.initials: B
authors.lastname: Tian
authors.affiliation: Key Laboratory of Plateau Lake Ecology and Global Change, School of Tourism and Geography, Yunnan Normal University, Kunming 650500, P. R. China.
authors.forename: Guang-Jie
authors.initials: GJ
authors.lastname: Chen
authors.affiliation: Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, P. R. China.
authors.forename: Yong-Ping
authors.initials: YP
authors.lastname: Yang
authors.affiliation: Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, P. R. China.
authors.forename: Yuan-Wen
authors.initials: YW
authors.lastname: Duan
mesh_terms: D000220:Adaptation, Biological; D018533:Biomass; D002734:Chlorophyll / Q000378:metabolism; D055864:Droughts; D004777:Environment; D009584:Nitrogen / Q000378:metabolism; D019655:Quantitative Trait, Heritable; D012987:Soil / Q000737:chemistry; D019657:Solanaceae / Q000502:physiology*; D013312:Stress, Physiological; D018609:Tibet; D014867:Water
chemical_list: D012987:Soil; D014867:Water; D002734:Chlorophyll; D009584:Nitrogen