A comparative cytological analysis of fungal endophytes in the sporophyte rhizomes and vascularized gametophytes of Tmesipteris and Psilotum
A comparative cytological analysis of fungal endophytes in the sporophyte rhizomes and vascularized gametophytes of Tmesipteris and Psilotum
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DOI：
10.1139/b05-102
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发表时间：
2005-11-01
期刊：
影响因子：
--
通讯作者：
Ligrone, R
中科院分区：
文献类型：
--
作者：
Duckett, JG;Ligrone, R
本文报道了在光镜和电镜下对毛蕨属和裸盖蕨属的根状茎和配子体中内生真菌和维管解剖的研究结果。Tmesipteris和Psilotum的根状茎和地下配子体的薄壁皮层细胞含有类似于在种子植物中发现的“巴黎型”丛枝菌根的细胞内无隔球状真菌。真菌分化成多核囊泡和菌丝线圈，两者都含有细菌样结构，并随着年龄的增长积累脂质物质和晶体。在同一个细胞中经过几个周期的感染后，退化的菌丝形成被宿主壁物质包裹的无定形团块。几乎相同的宿主真菌细胞学之间的自养孢子体和异养配子体表明，这些psilophyte协会是剥削的真菌在两个世代。继近60年前在裸盖蕨属配子体中描述管胞之后，首次在单倍体世代中描述了维管分子。在两个世代的水和食物传导元素之间的密切相似性，即导管分子与梯状穿孔板和筛细胞与折射小球和缺乏胼胝质在其发育的所有阶段，增加支持世代交替的同源理论。线粒体聚集，交联的小电子不透明杆，是常见的中柱细胞的两个世代，似乎是一个独特的功能psilophyte分支。
This article describes the results of it light and electron microscopic study of the fungal endophytes and vascular anatomy in the rhizomes and gametophytes of Tmesipteris and Psilotum. The parenchymatous cortical cells of the rhizomes and subterranean gametophytes of Tmesipteris and Psilotum contain intracellular aseptate glomeromycotean fungi resembling the "Paris-type" of arbuscular mycorrhizas found in seed plants. The fungi differentiate into multinucleate vesicles and hyphal coils, both containing bacteria-like structures and accumulating lipid masses and crystals as they age. After several cycles of infection in the same cell, degenerate hyphae form amorphous masses encased by host wall material. Nearly identical host-fungus cytology between the autotrophic sporophytes and the heterotrophic gametophytes suggests that these psilophyte associations are exploitative of the fungus in both generations. Following the description of tracheids nearly 60 years ago in the gametophytes of Psilotum, vascular elements are described for the first time in the haploid generation of Tmesipteris. Close similarities between the water- and food-conducting elements in both generations, viz. vessel elements with scalariform perforation plates and sieve cells with refractive spherules and lacking callose at all stages in their develoment, add support to the homologous theory of the alternations of generations. Mitochondrial aggregations, cross-linked by small electron-opaque rods, are common in the stelar cells of both generations and appear to be a unique feature of the psilophyte clade.