Evidence of a mycorrhizal mechanism for the adaptation of Andropogon gerardii (Poaceae) to high- and low-nutrient prairies.
Evidence of a mycorrhizal mechanism for the adaptation of Andropogon gerardii (Poaceae) to high- and low-nutrient prairies.
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Andropogon gerardii（禾本科）适应高营养和低营养草原的菌根机制的证据。
DOI：
10.2307/3558410
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发表时间：
2001
影响因子：
3
通讯作者：
J. Bever
中科院分区：
文献类型：
--
作者：
P. Schultz;R. Miller;J. Jastrow;C. Rivetta;J. Bever
从堪萨斯和伊利诺斯州获得的天竺葵种子在受控环境中在它们自己的和彼此的土壤中生长，有和没有丛枝菌根真菌（AMF）。各生态型在各自的土壤中生长相对较好，表明对原产地土壤的适应。总体而言，A.在低养分的堪萨斯土壤上，gerardii从AMF中获益大于伊利诺伊土壤。然而，这两个生态型，没有同样受益于菌根感染。堪萨斯生态型是三倍以上的响应菌根感染的堪萨斯土壤比伊利诺伊州的生态型。我们的研究结果表明，植物适应当地土壤的养分水平可能是由于，至少部分地，在他们的依赖菌根真菌的转变。伊利诺伊生态型A. Gerardii已经进化出对这些真菌的依赖性降低，并且更依赖于更高度分支的根系。相比之下，堪萨斯生态型有一个显着粗糙的根系和投资proportionally更大的碳在共生协会与AMF孢子生产。这项研究首次证明，植物可以通过改变对AMF的依赖来适应不断变化的土壤养分水平。这一结果对我们理解这些真菌在农业系统中的作用具有广泛的意义。
Andropogon gerardii seed obtained from Kansas and Illinois was grown in a controlled environment in their own and each other's soils, with and without arbuscular mycorrhizal fungi (AMF). Each ecotype grew comparatively better in its own soil indicating adaptation to its soil of origin. Overall, A. gerardii benefited more from AMF in low-nutrient Kansas soil than Illinois soil. The two ecotypes, however, did not benefit equally from mycorrhizal infection. The Kansas ecotype was three times more responsive to mycorrhizal infection in the Kansas soil than was the Illinois ecotype. Our results indicate that plant adaptation to the nutrient levels of their local soils is likely to be due, at least in part, to a shift in their dependence on mycorrhizal fungi. The Illinois ecotype of A. gerardii has evolved a reduced dependence upon these fungi and greater reliance on a more highly branched root system. In contrast, the Kansas ecotype had a significantly coarser root system and invested proportionately greater carbon in the symbiotic association with AMF as measured by spore production. This study provides the first demonstration that plants can adapt to changing soil nutrient levels by shifting their dependence on AMF. This result has broad implications for our understanding of the role of these fungi in agricultural systems.