Efeitos dos fungos micorrÃzicos arbusculares sobre o crescimento de espÃcies arbustivas e atividade microbiana em solo contaminado com metais pesados




The arbuscular mycorrhizal fungi (AMF) have been used in soil reabilitation programs due to the benefits to their hosts. In this work, microbial activity and tolerance of plants (Senna spectabilis, Caesalpinia ferrea, Erythrina velutina, Mimosa tenuiflora, M. caesalpiniaefolia and Ricinus communis) to heavy metal contaminated soils were evaluated. Samples of contaminated and non contaminated soils were taken during the dry (august/2004) and wet (april/2005) periods, in areas of metallurgic industry in Belo Jardim- PE. In the experiment, contaminated soil was added to the control soil in the proportions: 0, 7.5, 15, 30% (v/v), corresponding respectively to 7.6, 58.6, 97.2 e 95. 8 mg Pb. Kg soil-1. Plant height, shoot diameter and dry matter of plants inoculated or not with native AMF were evaluated after 100 days at the greenhouse. Microbial biomass and basal respiration were lower during the dry period (70 μmC.g soil-1 and 41 mgC-CO2.g soil-1) than in the wet period (252 μmC.g soil-1 and 52 mgC-CO2.g soil-1), while CO2 was higher (7,7 and 0,3 mgC-CO2.μm C. gsoil-1) during the dry period, indicating environmental stress. The phosphatase acid activity was stimulated in the rhizosphere of mycorrhized plants, but presence of AMF was not effective to improve plant growth in the contaminated soil. Among the tested plants, Erythrina velutina was the most tolerant in the treatment receiving 15% of contaminated soil


fungo micorrÃzico arbuscular heavy metal metal pesado microbial activity arbuscular mycorrhizal fungi atividade microbiana micologia

Documentos Relacionados