The competitive advantage of a constitutive CAM species over a C 4 grass species under drought and CO 2 enrichment
The competitive advantage of a constitutive CAM species over a C 4 grass species under drought and CO 2 enrichment
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干旱和 CO 2 富集条件下组成型 CAM 物种相对于 C 4 禾本科物种的竞争优势
DOI：
10.1002/ecs2.2721
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发表时间：
2019
期刊：
影响因子：
2.7
通讯作者：
Bartlett, Mark
中科院分区：
文献类型：
--
作者：
Yu, Kailiang;D'Odorico, Paolo;Collins, Scott L.;Carr, David;Porporato, Amilcare;Anderegg, William R. L.;Gilhooly, III, William P.;Wang, Lixin;Bhattachan, Abinash;Bartlett, Mark
具有景天科酸代谢的植物在世界各地旱地的分布和数量都在增加，但其根本驱动因素仍然未知。我们调查的影响，极端干旱和CO2富集的幼苗之间的竞争关系的adopuntia imbricata（CAM种）和Bouteloua eriopoda（C4草），在美国西南部的半干旱生态系统中共存。通过改变水分和CO2水分条件的实验表明，在极端干旱条件下，覆瓦杜鹃对CO2浓度升高有积极的响应，而毛豆则在干旱胁迫下出现衰退，干旱结束后仍未恢复。相反，在水分充足的条件下，毛柄双歧杆菌对覆瓦状山慈菇具有较强的竞争优势，使得覆瓦状山慈菇与毛柄双歧杆菌共同生长时的光合速率和生物量（单株）相对于单独生长时较低。一项对全球旱地多个植物家族进行的Meta分析显示，CAM光合作用和生产力对CO2富集有积极的反应。总的来说，我们的研究结果表明，在干旱和CO2浓度升高，预计与气候变化，植物功能群的竞争优势可能会转移和CAM植物的优势可能会增加半干旱生态系统。
Plants with crassulacean acid metabolism (CAM) are increasing in distribution and abundance in drylands worldwide, but the underlying drivers remain unknown. We investigate the impacts of extreme drought and CO2enrichment on the competitive relationships between seedlings ofCylindropuntia imbricata(CAM species) andBouteloua eriopoda(C4grass), which coexist in semiarid ecosystems across the Southwestern United States. Our experiments under altered water and CO2water conditions show thatC. imbricatapositively responded to CO2enrichment under extreme drought conditions, whileB. eriopodadeclined from drought stress and did not recover after the drought ended. Conversely, in well‐watered conditionsB. eriopodahad a strong competitive advantage onC. imbricatasuch that the photosynthetic rate and biomass (per individual) ofC. imbricatagrown withB. eriopodawere lower relative to when growing alone. A meta‐analysis examining multiple plant families across global drylands shows a positive response of CAM photosynthesis and productivity to CO2enrichment. Collectively, our results suggest that under drought and elevated CO2concentrations, projected with climate change, the competitive advantage of plant functional groups may shift and the dominance of CAM plants may increase in semiarid ecosystems.