Mycorrhizae transfer carbon from a native grass to an invasive weed: evidence from stable isotopes and physiology
Mycorrhizae transfer carbon from a native grass to an invasive weed: evidence from stable isotopes and physiology
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DOI：
10.1023/b:vege.0000026031.14086.f1
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发表时间：
2004-05-01
期刊：
影响因子：
1.7
通讯作者：
Callaway, RM
中科院分区：
文献类型：
--
作者：
Carey, EV;Marler, MJ;Callaway, RM
外来杂草的入侵是地球上最紧迫的环境问题之一。尽管许多外来入侵者完全消灭了一些群落中的本地植物物种，但生态学家对这些外来物种竞争性排斥其他物种的机制知之甚少。菌根真菌从根本上改变了自然群落中植物之间的竞争相互作用，最近的一项研究表明，丛枝菌根（AM）真菌为斑点矢车菊（Centaurea maculosa）提供了实质性的竞争优势，矢车菊是一种有毒的多年生植物，已遍布美国西北部大部分的原生草原。S.在这里，我们提出的证据表明，这种优势可能是由于菌根介导的碳从本地束草，羊茅，矢车菊。在温室中，在有和没有AM真菌的不完全析因设计中单独或与矢车菊一起生长Centaurea maculosa、Festuca idahoensis（爱达荷州羊茅，C-3）和Bouteloua gracilis（蓝革兰，C-4）。当土壤中存在真菌时，矢车菊生物量在所有处理中增加87-168%（P < 0.0001）。然而，矢车菊的生物量在真菌和羊茅同时存在的处理中显著高于任何其他处理组合（P < 0.0001）。即使矢车菊光合速率低14%，当与羊茅和真菌一起生长时，比与没有真菌的羊茅一起生长时，也能达到这种高生物量。无论是生物量还是光合速率的矢车菊与C-4草Bouteloua的竞争，无论有或没有真菌的影响。稳定同位素签名的矢车菊叶生长与羊茅和真菌更相似的羊茅，比当矢车菊单独生长与真菌（P = 0.06），或与羊茅，但没有真菌（P = 0.09）。这表明碳从羊茅属转移到了入侵杂草上。我们估计，菌根从Festuca转移的碳占矢车菊植物地上碳的15%。我们的研究结果表明，通过AM土壤真菌的碳寄生可能是一个重要的机制，入侵植物的竞争，他们的邻居，但这种相互作用是高度物种特异性。
Invasive exotic weeds pose one of the earth's most pressing environmental problems. Although many invaders completely eliminate native plant species from some communities, ecologists know little about the mechanisms by which these exotics competitively exclude other species. Mycorrhizal fungi radically alter competitive interactions between plants within natural communities, and a recent study has shown that arbuscular mycorrhizal (AM) fungi provide a substantial competitive advantage to spotted knapweed, Centaurea maculosa, a noxious perennial plant that has spread throughout much of the native prairie in the northwestern U. S. Here we present evidence that this advantage is potentially due to mycorrhizally mediated transfer of carbon from a native bunch-grass, Festuca idahoensis, to Centaurea. Centaurea maculosa, Festuca idahoensis (Idaho fescue, C-3), and Bouteloua gracilis (blue gramma, C-4) were grown in the greenhouse either alone or with Centaurea in an incomplete factorial design with and without AM fungi. Centaurea biomass was 87-168% greater in all treatments when mycorrhizae were present in the soil (P < 0.0001). However, Centaurea biomass was significantly higher in the treatment with both mycorrhizae and Festuca present together than in any other treatment combination (P < 0.0001). This high biomass was attained even though Centaurea photosynthetic rates were 14% lower when grown with Festuca and mycorrhizae together than when grown with Festuca without mycorrhizae. Neither biomass nor photosynthetic rates of Centaurea were affected by competition with the C-4 grass Bouteloua either with or without mycorrhizae. The stable isotope signature of Centaurea leaves grown with Festuca and mycorrhizae was more similar to that of Festuca, than when Centaurea was grown alone with mycorrhizae (P = 0.06), or with Festuca but without mycorrhizae (P = 0.09). This suggests that carbon was transferred from Festuca to the invasive weed. We estimated that carbon transferred from Festuca by mycorrhizae contributed up to 15% of the aboveground carbon in Centaurea plants. Our results indicate that carbon parasitism via AM soil fungi may be an important mechanism by which invasive plants out compete their neighbors, but that this interaction is highly species-specific.