Traits of an invasive grass conferring an early growth advantage over native grasses

作     者：Lara G.Reichmann Susanne Schwinning H.Wayne Polley Philip A.Fay 

作者机构：Department of Integrative BiologyUniversity of Texas at AustinAustinTX 78712USA USDA-ARS GrasslandSoil and Water Research Laboratory808 E Blackland RoadTempleTX 76502USA Department of BiologyTexas State UniversitySan MarcosTX 78666USA 

出 版 物：《Journal of Plant Ecology》 (植物生态学报（英文版）)

年 卷 期：2016年第9卷第6期

页      面：672-681页

核心收录：

学科分类：0710[理学-生物学] 071001[理学-植物学] 07[理学] 

基　　金：funded by USDA-NIFA(2010-65615-20632) 

主　　题：biomass allocation invasive plants RGR Sorghum halepense trade-offs trait development 

摘      要：Aims Invasive species often have higher relative growth rates(RGR)than their native *** use efficiency,total leaf area and specific leaf area(SLA)are traits that may confer RGR differences between natives and invasives,but trait differences are less prominent when the invasive species belongs to the same plant functional type as the dominant native ***,we test if traits displayed soon after germination confer an early size ***,we predicted that invasive species seedlings grow faster than the natives because they lack trade-offs that more strongly constrain the growth of native *** We quantified plant morphological and physiological traits and RGR during early seedling growth at high and low nutrient levels in three dominant perennial native C_(4) grasses:Panicum virgatum L.(switchgrass),Schizachyrium scoparium(Michx.)Nash(little bluestem)and Andropogon gerardii Vitman(big bluestem);and a perennial C_(4) exotic invasive grass,Sorghum halepense(L.)Pers.(Johnsongrass).Important Findings After 2 weeks of growth,Johnsongrass seedlings had greater biomass,SLA and photosynthetic nitrogen use efficiency,but lower leaf N concentrations(%leaf N)and root:shoot ratio than *** growth continued,Johnsongrass more quickly produced larger and thicker leaves than the natives,which dampened the growth advantage past the first 2 to 3 weeks of *** in carbon gain appears to be the best explanation for the early growth advantage of *** natives,growth was constrained by an apparent trade-off between allocation to root biomass,which reduced SLA,and production of leaves with high N content,which increased carbon *** Johnsongrass,root:shoot ratio did not interact with other traits,and%leaf N was decoupled from RGR as a result of a trade-off between the positive indirect association of%leaf N with RGR and the negative direct association of%leaf N with RGR.