Rhizosphere: A fascinating paleovegetational and paleoclimatic new intermediary in the Quaternary fluvio-lacustrine set-up of the Purna alluvial basin, central India

Abstract

The rhizosphere, a fascinating vegetational and climatic negotiator, has been discovered and being reported from widespread Quaternary fluvio-lacustrine sediments of the Purna alluvial basin, central India. These organo-sedimentary structures representing diversified morphologies i.e., rounded to sub-rounded, spherical to sub-spherical, small to large surfaced, calcretized bodies of 7–20 cm diameter, are confined principally within the constraints of paleosol horizons belonging to the Early Pleistocene period, uncovered at the lower reaches of the Purna river course. These structures, developed in the lower niches/specialities around plant roots, are formed due to the mutual exercises of soil and fungi. Based on morphological criteria and surficial feature demonstrations, four distinctive morphotypes of the same have been categorized i.e., i) concentric, ii) rimmed, iii) concentric disrupted, and iv) nodular or mottled. The initial two sorts are conceived to be formed by fungi associated with living trees, whereas, last two are created by contagious exercise with rotting plant roots. A model portrayed shows their development in open spaces having a close relationship of plant roots belonging to both forests (C3) and grassland (C4) categories with microbial communities underneath the ground. Consequently, the spaces made by plant roots and microbial community are occupied by the calcium carbonate leached out from the encompassing soils during arid to semi-arid climate.