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

Abstract

Quercus acutissima seedlings were cultivated in growth pouches and inoculated with Scleroderma verrucosum in order to assess the changes in polyphenol contents in epidermal cells during ECM development. Semithin sections stained with metachromatic Toluidine Blue O (TBO) were compared among non-inoculated lateral roots, early mantled lateral roots, and mycorrhizal roots with a mature mantle. Hyphae adhered closely or were embedded in mucilage-like materials on the epidermis. Epidermal cells and root hairs of the non-inoculated second-order lateral roots developing from the taproot harbored polyphenolic compounds that were stained by TBO. At non-inoculated stage, the average numbers of epidermal cells stained entirely (PC2), stained partially (PC1) or remaining unstained (PC0) were 16.5 ± 0.7, 0 ± 0, and 0 ± 0, respectively. At the early mantled stage, the numbers were 6.5 ± 1.6, 5.2 ± 1.4, and 4.2 ± 1.0, and at the mycorrhizal stage, it was 0 ± 0, 0 ± 0, and 32.8 ± 1.3 for PC2, PC1, and PC0, respectively. Total phenolic content in the root tips at each developmental stage declined with ECM development. The early mantled stage involved a dynamic process of polyphenol localization. However, some epidermal cells and endodermal cells of the proximal zone accumulated polyphenols. Eventually, polyphenolic compounds, which were found abundantly in the epidermal cells and root hairs of the non-inoculated lateral roots of the host, disappeared at the mycorrhization process with the symbiont.

Decoupling of Plant Growth and Accumulation of Biologically Active Compounds in Leaves, Roots, and Root Exudates of Hypericum perforatum L. by the Combination of Jasmonate and Far-Red Lighting

“…A weak positive correlation was found between root hair length and root phenolic concentration, while a strong positive correlation was determined between root hair density and root phenolic concentration ( Figure 6 G,H); these correlations might reflect the high accumulation of phenolic compounds in root hairs [ 46 ]. By contrast, no correlation was found between root hair density and the amount of phenolics in root exudates ( Figure 6 I), indicating that phenolic exudation was independent of root hair density.…”

Phytochemical prospection, total flavonoids and total phenolic and antioxidant activity of the mushroom extract Scleroderma verrucosum (Bull.) Pers

“…There is little information about the genus Scleroderma regarding phytochemical characteristics (Vrkoč et al, 1976;Gonzalez et al, 1983;Jung;Tamai, 2012;Morandini et al, 2016) and biological activities, mainly regarding antioxidant activity.…”