MESSUTI Maria ines
capítulos de libros
Co-ocurrence of arbuscular mycorrhizas and dark septate endophytes in pteridophytes from a Valdivian temperate rainforest in Patagonia, Argentina
Mycorrhiza: occurrence and role in aquatic and riparian environments.
Nova Science Publishers Inc.
Lugar: Nueva York; Año: 2012; p. 99 - 125
Plant roots are colonized by several fungi species, including those that form arbuscular mycorrhizas (AM). The contribution of AM to plant productivity, plant nutrition and soil composition is crucial, and in natural ecosystems plant diversity and community structure are strongly influenced by these organisms. Despite the importance of pteridophytes (lycophytes and ferns) in the origin and evolution of vascular plants, little is known about AM in this group of plants. The aim of this chapter is to describe the occurrence of AM in different species of pteridophytes present in the Valdivian temperate rainforest of Puerto Blest (Patagonia, Argentina), and to discuss different factors that might determine not only the mycorrhizal status but also the development of different AM morphologies in these plants (Arum, Paris or Intermediated-type). Sporophytes were sampled by random walk from terrestrial, epipetric and epiphytic habitats. The samples were stained and the percentage of root length colonized by these symbiotic fungi was quantified in all of them. A total of 21 species belonging to 10 families and 12 genera were found. Arbuscular mycorrhizas were present in 47.6% of these species. Fifty percent of the families included only consistently mycorrhizal species (Blechnaceae,Dryopteridaceae, Gleicheniaceae, Lophosoriaceae and Pteridaceae), 20% facultatively mycorrhizal species (Equisetaceae and Lycopodiaceae) and 30% non-mycorrhizal species (Aspleniaceae, Grammitidaceae and Hymenophyllaceae). It was observed that while facultative species have an Intermetiate-type AM, consistently mycorrhizal species were only colonized by Paris-type associations. In addition to AM, another group of fungi were present within the roots of all the species considered in this study. They corresponded to dark septate endophytes (DSE) and were characterized by regularly septate hyphae and microsclerotia. The colonization pattern of DSE is described and its importance as possible ?mycorrhizal associations? is discussed.