Characterization of ectomycorrhizae of Russula and Lactifluus (Russulaceae) associated with Shorea from Indian Shiwaliks
Kumar, Jitender; Atri, N.S.
Shiwalik Range, also called Outer Himalayas are geologically youngest and lowest mountain range of Himalaya which extends for more than 1,000 miles from the Teesta River in Sikkim state of northeastern India, through Nepal across northwestern India. Tropical moist deciduous forests of Shiwalik range are largely dominated by dipterocarp tree Shorea (sal), which is commonly known as sal forests. Ectomycorrhiza (ECM) play important role in sal ecosystem as it forms mutualistic association with a variety of basidiomycetous fungi. Occurrence of ECM fungi in tropical sal forests of Indian Shiwaliks was undertaken, and Russulaceae was found to be the dominant fungal family. In this paper the morphoanatomical details of mycorrhizal roots of dipterocarp tree Shorea associated with two russulaceous genera, Russula and Lactifluus were investigated for the first time. Ectomycorrhizae are distinguished by differences in the size and colour of mycorrhizal system, surface texture, extraradical mycelium, mantle, shape and size of hyphal cells, presence or absence of cystidia, cell shape of Hartig net, as well as the differing colour reaction in Melzer's reagent. Ectomycorrhizal roots of sal associated with Russula species were light brown to greyish brown, and have plectenchymatous gelatinised outer mantle layers having abundant cystidial elements. Ectomycorrhizae of Lactifluus species were reddish brown to light brown, lack cystidial elements and have thin walled emanating hyphae. The presence of simple, septate agaricoid hyphae and laticifers in the inner mantle layer indicate the association of this species with sal. Both ECM share a pseudoparenchymatous inner mantle, paraepidermal Hartig net, as well as absence of rhizomorphs and clamp connections.