Comparative anatomy of ectomycorrhizas synthesized on Douglas fir by Rhizopogon spp. and the hypogeous relative Truncocolumella citrina

Abstract

The morphology and anatomy of ectomycorrhizas of Rhizopogon parksii, Rhizopogon vinicolor and Rhizopogon subcaerulescens, and a hypogeous relative, Truncocolumella citrina, synthesized on Douglas fir in glasshouse conditions using spore slurries as inoculum, are described and compared. Mycorrhizas formed with R. parksii and R. vinicolor did not exhibit their characteristic subtuberculate morphology in these tests, but rather had a pinnate form. All species had diagnostic features of ectomycorrhizas : a well-developed Hartig net and a fungal mantle. In addition, several species exhibited crystal inclusions in the outer mantle, usually at the interface between the mantle and soil. Truncocolumella citrina had crystal-like inclusions within the mantle but external to fungal hyphae, a feature rarely described in ectomycorrhizas.

Ectomycorrhizas of Rhizopogon himalayensis on Cedrus deodara

“…These features are in agreement with the study conducted by Mohan et al [88] with Rhizopogon luteolus and Pinus patula; Sulzbacher et al [89] with Rhizopogon verii and Pinus sylvestris; Raidl et al [90] with Rhizopogon melanogastroides + Pinus mugo; Raidl and Agerer [91] with Rhizopogon roseolus + P. sylvestris; Jakucs et al [92] with R. vulgaris + P. nigra; Singh [29] and Thakur [25] observed racemose to coralloid branching in R. himalayensis + C. deodara association. Species within the genus Rhizopogon are known for their abundant formation of specialized structures called rhizomorphs, believed to have a significant role in water uptake [93]. In accordance with the findings of Mohan et al [88] concerning the R. luteolus + Pinus patula association, the extraradicle hyphae were observed to be hyaline, septate, unbranched, and lacking clamp connections.…”

Morpho-anatomical characterization of Rhizopogon himalayensis - Cedrus deodara mycorrhiza

“…In the present study, root morphology in ectomycorrhiza of R. himalayensis and C. deodara roots was found to be analogous to the observations of Singh (1992), who noticed racemose to coralloid branching in this association. Similar branching was illustrated in various mycorrhizal associations of Rhizopogon species, for instance, coralloid in R. vulgaris-Pinus contorta Agerer et al, 1996); monopodial to dichotomous in R. subcaerulescens -Pseudotsuga menziesii (Massicotte et al, 1999); pinnate in R. vinicolor and R. parksii with P. menziesii (Massicotte, et al, 2000). Although, different root morphologies have also been reported in other Rhizopogon species, i.e.…”

“…In both systems, hyphal contact induced significant modifications in root hair structure, causing deformation and subsequent incorporation of root hair in the fungal mantle. On the contrary, in Betula alleghaniensis-Laccaria bicolor (Massicotte et al, 1989) and Pseudotsuga menziesii-R. parksii mycor-rhiza (Massicotte, 2000), hyphal contact caused wall thickening in root hair, preventing the collapse of root hair. Colour had also been found as an important feature while describing ectomycorrhizal morphology (Zak, 1973;Agerer et al, 1986) and which also showed variations with the advancement of age of mycorrhiza (Haug and Oberwinkler, 1987).…”

“…Present findings, hence, corroborates with their observations, strongly resonating with their descriptions of R. vulgaris-Pinus contorta association (loose hyphae at surface and compact on the inner side) in particular. Many species of Rhizopogon-are known to produce prolific, dark brown rhizomorphs (Massicotte, 1994(Massicotte, , 2000Yamada, 2001…”

Anatomical observation of polyphenol changes in epidermal cells during the development of Quercus acutissima–Scleroderma verrucosum ectomycorrhizae

“…Root hairs respond by developing thickened cell walls as the interaction progresses (Massicotte et al 2000). In this study, hyphal clusters covered root hair zones on early colonizing lateral roots and the root hairs bent and collapsed in contact with hyphae, which adhere closely to mucilage materials and were embedded in the epidermis.…”