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首页 » Mol Ecol:研究揭示兰花生长依赖其伴生真菌数量

Mol Ecol:研究揭示兰花生长依赖其伴生真菌数量

来源:中国科学报 2012-02-09 11:00

FIG Source:Melissa McCormick/Smithsonian Institution

近日,来自美国的研究人员在国际杂志《分子生态学》Molecular Ecology网络版上报告了他们研究团队的最新研究成果“Limitations on orchid recruitment: not a simple picture”,在文章中,作者揭示了兰花生长依赖其伴生真菌的数量。

年轻的兰花完全依赖共生的真菌提供生长所需的能量,同时新的研究表明,这些真菌真的非常讲究,只喜欢那些更为古老的森林。

科学家之前曾推测,真菌的分布影响兰花的分布。然而想要区分开土壤条件的影响——例如湿度和酸度——则是非常困难的。

因此美国马里兰州滨水市史密森环境研究中心的研究人员Melissa K. McCormick和同事,在该州的6处场所——有3处位于较年轻的50年到70年的森林,另3处位于更成熟的120年到150年的森林——种植了3种濒危兰花的种子。

在其中一半的场所中,科学家们在每株兰花上添加了共生真菌。

4年之后,他们发现,真菌在那些更为成熟的森林中丰度最高,并且兰花的发芽和生长依赖于其伴生真菌的数量,而并非仅有一点真菌便能成功。

研究人员认为,这些发现将促进濒危兰花的保护与恢复计划。(生物谷Bioon.com)

Limitations on orchid recruitment: not a simple picture

MELISSA K. McCORMICK1, D. LEE TAYLOR2, KATARINA JUHASZOVA1, ROBERT K. BURNETT JR1,†, DENNIS F. WHIGHAM1, JOHN P. O’NEILL1

Mycorrhizal fungi have substantial potential to influence plant distribution, especially in specialized orchids and mycoheterotrophic plants. However, little is known about environmental factors that influence the distribution of mycorrhizal fungi. Previous studies using seed packets have been unable to distinguish whether germination patterns resulted from the distribution of appropriate edaphic conditions or the distribution of host fungi, as these cannot be separated using seed packets alone. We used a combination of organic amendments, seed packets and molecular assessment of soil fungi required by three terrestrial orchid species to separate direct and indirect effects of fungi and environmental conditions on both seed germination and subsequent protocorm development. We found that locations with abundant mycorrhizal fungi were most likely to support seed germination and greater growth for all three orchids. Organic amendments affected germination primarily by affecting the abundance of appropriate mycorrhizal fungi. However, fungi associated with the three orchid species were affected differently by the organic amendments and by forest successional stage. The results of this study help contextualize the importance of fungal distribution and abundance to the population dynamics of plants with specific mycorrhizal requirements. Such phenomena may also be important for plants with more general mycorrhizal associations.

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