Cephalanthera longifolia (Neottieae, Orchidaceae) is mixotrophic:: a comparative study between green and nonphotosynthetic individuals
Cephalanthera longifolia (Neottieae, Orchidaceae) is mixotrophic:: a comparative study between green and nonphotosynthetic individuals
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DOI：
10.1139/b06-101
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发表时间：
2006-09-01
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影响因子：
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通讯作者：
Selosse, Marc-Andre
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作者：
Abadie, Jean-Claude;Puttsepp, Ulle;Selosse, Marc-Andre
我们调查了一个爱沙尼亚的兰花Cephalanthera longifolia（L.）弗里奇（Neottieae tribe），其中含有绿色和无叶绿素的个体（=aalbinos），以了解白化病的生存和比较两种表型的菌根关联、发育和营养。白化株在14年以上不发生表型变化，其生长发育与绿色株相似，叶绿素含量降低99.4%，属异养型。真菌基因间转录间隔区的聚合酶链反应扩增和显微镜分析的分子分型表明，Thelephoraceae（担子菌，通常形成外生菌根与树木）的两个表型上的菌根。分子分型还表明，额外的真菌存在于根，包括许多内生菌（如Helotiales）和各种外生菌根类群，其作用和模式的殖民化仍然不清楚。菌根定植增加白化约两倍，但没有明显的差异，真菌的合作伙伴相比，绿色个人证明。稳定同位素组成（N和C）的分析表明，白化依赖于他们的真菌碳（真菌异养），而绿色个人回收33%的碳从真菌（混合营养）。周围的树木与至少一种在兰花中发现的Thelephoraceae形成外生菌群，可能是最终的碳源。这些数据进行了讨论的兰花，特别是在Neottieae真菌异养的进化框架。
We investigated an Estonian population of the orchid Cephalanthera longifolia (L.) Fritsch. (Neottieae tribe), which harbours green and achlorophyllous individuals (=aalbinos), to understand albino survival and compare mycorrhizal associates, development, and nutrition of the two phenotypes. Albinos never changed phenotype over 14ayears and had development similar to green individuals; their chlorophyll content was reduced by 99.4%, making them heterotrophic. Molecular typing by polymerase chain reaction amplification of fungal intergenic transcribed spacer and microscopic analyses showed that Thelephoraceae (Basidiomycetes, usually forming ectomycorrhizae with trees) were mycorrhizal on both phenotypes. Molecular typing also demonstrated that additional fungi were present on roots, including many endophytes (such as Helotiales) and various ectomycorrhizal taxa, whose role and pattern of colonization remained unclear. Mycorrhizal colonization was increased in albinos by about twofold, but no obvious difference in fungal partners compared with green individuals was demonstrated. Analysis of stable isotope composition (N and C) showed that albinos were dependent on their fungi for carbon (mycoheterotrophy), while green individuals recovered 33% of their carbon from fungi (mixotrophy). Surrounding trees, which formed ectomycorrhizae with at least one Thelephoraceae found in orchids, were likely the ultimate carbon source. These data are discussed in the framework of evolution of mycoheterotrophy in orchids, especially in Neottieae.