Detection of arbuscular mycorrhizal fungi in the litter of different tree species: review of three clarification techniques.

Abstract

Background and aims: Arbuscular mycorrhizal fungi (AMF) are obligate symbionts with plant roots, and they colonize the surrounding soil and leaf litter. A unique clarification technique has been used for studying AMF in decomposing leaves, but it is not optimal for all types. This study aimed to evaluate and adjust three clearing techniques on leaf litter of diverse plant species for the detection of AMF structures.

M&M: We collected leaf litter of Quercus robur, Tipuana tipu, Ulmus minor, Fraxinus pennsylvanica, Platanus acerifolia, Laurus nobilis, Populus alba and Melia azedarach from soil surface of two parks in Buenos Aires (Argentina). Also, we inoculated leaf litter of F. pennsylvanica with Rhizoglomus intraradices in a pot culture under semi- controlled conditions. Three clarification techniques were tested: the “5-5-5 staining technique” by Arambarri, the root clarification technique by Phillips & Hayman, and Peterson et al. The time and temperature to reagent exposure were adjusted according to each decomposing leaf.

Results: The clarification technique of Peterson et al. was the most appropriate for all the tested leaf litters. An effective clarification, conservation of leaf structure and visualization of extraradical spores and mycelia of AMF was achieved.

Conclusions: The selection of the appropriate technique greatly depends on the quality and composition of leaf litter. By the optimization of Peterson et al. Technique, we were able to detect structures of AMF on decomposing leaves of F. pennsylvanica and T. tipu.