Plant physiological changes along an encroachment gradient: an assessment of US Mid-Atlantic serpentine barrens

作     者：Nicole A.Havrilchak Jessica L.Schedlbauer 

作者机构：Department of BiologyWest Chester University750 S.Church StreetWest ChesterPA 19383USA 

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

年 卷 期：2018年第11卷第6期

页      面：853-865页

核心收录：

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

主　　题：encroachment photosynthesis serpentine barren Schizachyrium scoparium Smilax rotundifolia Sorghastrum nutans 

摘      要：Aims Serpentine barrens of the Mid-Atlantic United States are globally rare,grass-dominated ecosystems thought to exclude C3 spe-cies and characterized by unique soil ***,like many grassland ecosystems globally,these sites are presently facing encroachment by surrounding *** this ecosystem,the tendril climbing vine,Smilax rotundifolia,forms dense thickets around bar-rens that typically precede forest *** numerous factors speculatively initiate and promote encroachment in these systems,few studies have examined photosynthetic responses of serpentine grasses to changes in resource availability initiated by encroachers or physiological ability of encroaching *** to colonize high-light barren *** sought to under-stand both environmental and physiological dynamics of encroach-ment along an irradiance gradient in these *** At three serpentine barren sites in southeastern Pennsylvania,physiological responses of the native grasses Sorghastrum nutans and Schizachyrium scoparium to increased shading by ***-folia were ***,the physiological performance of *** in the forest understory was compared to that in sunlit barrens ***-saturated photosynthesis(A_(sat)),stomatal conductance(g_(s)),instantaneous transpiration efficiency(ITE),maximum efficiency of photosystem II(F_(v)/F_(m)),midday leaf water potential(ψ_(leaf))and specific leaf area(SLA)were measured for all species over the course of the 2014 growing ***-way analyses of variance were used to assess changes in these param-eters across growing environments,as well as seasonally for each *** regression analyses were also performed to inves-tigate the influence of vapor pressure deficit(D)and leaf tempera-ture(T_(leaf))on A_(sat) and *** Findings Light-saturated photosynthesis was significantly greater in ***-difolia growing in sun than in the shade(P0.001)and early in th