Lichenological studies in india with reference to terricolous lichens

Abstract

The symbiotic association of fungi and algae/cyanobacteria, known as lichen, is one of the most successful associations in nature. Dominated by ascomycetous mycobiont majority (85∈%) of lichens have green algae as their photobionts, rest (15∈%) have cyanobacteria as their primary or secondary photobionts. Cyanolichens, owing to their ability to fix atmospheric nitrogen, help in nitrogen dynamics of terrestrial biomes. On the basis of substratum, lichens are categorized into saxicolous (inhabiting rocks and stones), corticolous (growing on tree barks), terricolous (soil inhabiting), ramicolous (growing on twigs), muscicolous (growing over mosses), and omnicolous (inhabiting various substrates and manmade structures). Among these, soil-inhabiting terricolous lichens are among the most sensitive lichens, used in biomonitoring studies. Lichenological researches in India in the past 50 years have accumulated a good amount of taxonomic knowledge and now, applied fields of lichenological researches are being explored such as bioprospection of lichen metabolites, lichen-based pollution monitoring, ethnopharmacological uses of lichens and functional ecophysiology of lichens. Indian terricolous lichens, besides being mentioned in taxonomic records and enumerations, have also been studied for their ethnopharmacological uses and their role in functional ecology (nutrient dynamics, photobiont specificity, altitudinal optimum, and biomonitoring of zooanthropogenic pressures) of their habitats.