Filamentous saprobe fungi: an important component of mycorrhizosphere for growth and heavy metal resistance in AAA plants

摘要

Various man-made activities such as use of fertilizers and pesticides, burning of fossil fuels, mining, and smelting of metalliferous ores contaminate the environment, degrade the ecosystem, and make soil unsuitable for vegetation. Out of various unfavourable environmental conditions, contamination of soil with heavy metals is one of the more serious problems. Heavy metal pollution not only limits plant establishment but also decreases the number of useful soil micro-organisms and their activity (Gadd 1993; Smylla and Mroczkowska-Badner 1991;Weissenhorn, Leyval, and Berthelin 1993). High concentrations of heavy metals in soil have a selective effect on microbial populations which play a key role in the mobilization and immobilization of metal ions,thereby changing their availability to plants (Khade and Adholeya 2009). Soil micro-organisms are important in the recovery of disturbed and toxic environments because they produce plant growing substances, immobilize heavy metals in the soil and bind soil particles into stable aggregates which improve soil structure, reduce erosion potential, and can contribute to nutrient availability to plants (Gadd 1993).