Lara-Pérez Luis Alberto, Noa-Carrazana Juan Carlos, López Ángel de Jesús Landa, Hernández-González Sergio, Oros-Ortega Iván, Torres Antonio Andrade
Rev Biol Trop. 2014 Dec;62(4):1609-23.
Alsophila firma is a tree fern that is distributed mainly in tropical montane cloud forest (TMCF) and is considered as a threatened species. Arbuscular mycorrrhizal fungi (AMF) have been proposed as an alternative in rescue programs of endangered species. However, our knowledge about diversity of AMF and mycorrhizal status of the species of TMCF is limited. In Mexico TMCF shows different degrees of conservation because of fragmentation and land use change. In this study, we evaluated the level of colonization, richness and abundances of spores of AMF in three fragments with different conservation status: conserved (100 years), secondary vegetation (17 years) and disturbed. For this, soil samples and roots were collected from five individuals of A. firma per site, with at least 100 m away from each other; a total of 100 cm of roots were analysed per site. Root samples showed AMF and occasionally dark septate fungi (DSF) colonizations. For the overall study, 19 species of AMF were recorded: Gigaspora (7), Acaulospora (4), Glomus (4), Funneliformis (2), Sclerocystis (1) and Scutellospora (1). The dominant species in the three sites were Funneliformis geosporum and Acaulospora scrobiculata. The highest diversity (H') and evenness (J') (p < 0.05) were found in the conserved site (H' = 1.7, J' = 0.66), when compared to the secondary vegetation (H' = 1.5, J' = 0.61), and the disturbed site (H' = 0.74, J' = 0.41). Statistical analysis showed that the AMF degree of colonization was significantly higher (p < 0.05) in the conserved site; although, the disturbed site showed low richness and abundances of AMF, the degree of root colonization did not differ statistically (p < 0.05) with the secondary vegetation site. Chao2 (Richness estimation model) showed that the number of analysed samples were sufficient to represent the structure of the AME communities with values > 90%. The present study confirmed that A. firma is a mycorrhizal species that exhibits high levels of colonization even in disturbed sites. We suggest that F. geosporum and A. scrobiculata may have the potential to inoculate the gametophyte and young sporophyte of A. firma, to support restoration programs, because of their abundances and high tolerance to disturbed sites.
硬叶桫椤是一种主要分布在热带山地云雾森林（TMCF）中的树蕨，被视为濒危物种。丛枝菌根真菌（AMF）已被提议作为濒危物种拯救计划的一种替代方案。然而，我们对TMCF物种的AMF多样性和菌根状态的了解有限。在墨西哥，由于森林破碎化和土地利用变化，TMCF呈现出不同程度的保护状况。在本研究中，我们评估了处于不同保护状态的三个片段中AMF的定殖水平、孢子丰富度和丰度：受保护的（100年）、次生植被（17年）和受干扰的。为此，在每个地点从五株硬叶桫椤个体采集土壤样本和根系，个体之间至少相距100米；每个地点共分析100厘米长的根系。根系样本显示有AMF定殖，偶尔还有暗隔真菌（DSF）定殖。在整个研究中，记录了19种AMF：巨孢囊霉属（7种）、无梗囊霉属（4种）、球囊霉属（4种）、漏斗孢属（2种）、硬囊霉属（1种）和盾巨孢囊霉属（1种）。三个地点的优势种是地生漏斗孢和粗糙无梗囊霉。与次生植被地点（H' = 1.5，J' = 0.61）和受干扰地点（H' = 0.74，J' = 0.41）相比，在受保护地点发现了最高的多样性（H'）和均匀度（J'）（p < 0.05）（H' = 1.7，J' = 0.66）。统计分析表明，受保护地点的AMF定殖程度显著更高（p < 0.05）；尽管受干扰地点的AMF丰富度和丰度较低，但根系定殖程度与次生植被地点在统计学上没有差异（p < 0.05）。Chao2（丰富度估计模型）表明，分析的样本数量足以代表AME群落结构，值> 90%。本研究证实硬叶桫椤是一种菌根物种，即使在受干扰的地点也表现出高水平的定殖。我们建议，由于地生漏斗孢和粗糙无梗囊霉的丰度以及对受干扰地点的高耐受性，它们可能有潜力接种硬叶桫椤的配子体和幼孢子体，以支持恢复计划。
