title: Evolutionary tradeoffs for nitrogen allocation to photosynthesis versus cell walls in an invasive plant.
abstract: Many studies have shown that individuals from invasive populations of many different plant species grow larger than individuals from native populations and that this difference has a genetic basis. This increased vigor in invasive populations is thought to be due to life history tradeoffs, in which selection favors the loss of costly defense traits, thereby freeing resources that can be devoted to increased growth or fecundity. Despite the theoretical importance of such allocation shifts for invasions, there have been no efforts to understand apparent evolutionary shifts in defense-growth allocation mechanistically. Reallocation of nitrogen (N) to photosynthesis is likely to play a crucial role in any growth increase; however, no study has been conducted to explore potential evolutionary changes in N allocation of introduced plants. Here, we show that introduced Ageratina adenophora, a noxious invasive plant throughout the subtropics, appears to have evolved increased N allocation to photosynthesis (growth) and reduced allocation to cell walls, resulting in poorer structural defenses. Our results provide a potential mechanism behind the commonly observed and genetically based increase in plant growth and vigor when they are introduced to new ranges.
authors.affiliation: Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, Yunnan Province, China. fyl@xtbg.ac.cn
authors.forename: Yu-Long
authors.initials: YL
authors.lastname: Feng
authors.forename: Yan-Bao
authors.initials: YB
authors.lastname: Lei
authors.forename: Rui-Fang
authors.initials: RF
authors.lastname: Wang
authors.forename: Ragan M
authors.initials: RM
authors.lastname: Callaway
authors.forename: Alfonso
authors.initials: A
authors.lastname: Valiente-Banuet
authors.lastname: Inderjit
authors.forename: Yang-Ping
authors.initials: YP
authors.lastname: Li
authors.forename: Yu-Long
authors.initials: YL
authors.lastname: Zheng
mesh_terms: D036603:Ageratina / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D005075:Biological Evolution; D002473:Cell Wall / Q000737:chemistry*; D017753:Ecosystem; D009584:Nitrogen / Q000378:metabolism*; D010788:Photosynthesis; D063245:Plant Development; D010944:Plants / Q000235:genetics / Q000378:metabolism
chemical_list: D009584:Nitrogen