Glomalin and its association with the rhizosphere soils of some trees in Warangal district, A.P, India

摘要

Plant and soil health are dependent upon the interactions of biological, physical, and chemical components of the soil. The symbiotic relationship between roots and Arbuscular Mycorrhiza (AM) fungi may also benefit the formation of soil structure (Hallett et al. 2009). Rillig et al. (2010) revealed that AM fungal mycelium alone could be sufficient to form and/or maintain water-stable soil macro-aggregates. AM fungi are considered to be the most common and ubiquitous underground endophytic fungi — serving as a crucial link within the plant and soil continuum (Wilson et al. 2009) and are treated as a principal functional component in the belowground ecosystem (Smith and Read 2008; Siddiky 2011).The rhizosphere, or root zone, is the location of the greatest flow of energy and minerals among these components (Wright and Millner, 1994). In this highly productive region, a vital symbiotic relationship exists between roots and soil-borne AM fungi (Smith and Read 1997). Mycorrhiza is the most efficient mechanism for Phosphorus (P) acquisition, especially under stress conditions. Although these fungi are not host-specific, host and fungal genotypes and soil abiotic and biotic variables have been shown to influence the nature of the symbiosis (Brundrett, 1991; Gianinazzi et al, 1995; Varma, 1995). Even though AM fungi may be important in natural and managed systems (Bever et al, 2009; Wilson et al, 2009; Klironomos et al, 2011), little is known about the factors that determine their community structure and symbiotic functioning as drivers of plant productivity; as a result, their adaptive evolution is less known (Rosendahl, 2008; Antunes et al, 2011). In addition to improving plant health, mycorrhizal fungi also contribute to soil health. Fungal hyphae improve soil structure by helping to form water-stable soil aggregates (Miller and Jastrow, 1990;Tisdall et al, 1997; Rillig and Steinberg, 2002). Mycorrhizal fungi also improve rhizosphere health by stimulating root exudation which promotes the growth ofother beneficial soil microbes (Borowicz, 2001; Paul and Clark, 1996).