ABSTRACT
Effect of Arbuscular Mycorrhizal Fungi Glomus spp. Inoculation on Alfalfa Growth in Soils with Copper

Daniela Novoa M.1, Soledad Palma S.1, and Hernán Gaete O.1*
 
Soils near mining centers usually have high heavy metal (HM) levels. It has been found that some plants associated with arbuscular mycorrhizal fungi (AMF) improve growth and tolerance to HM in soils. This symbiosis is a biological resource for degraded soil recovery. The objective of this study was to determine the effect of inoculating AMF (Glomus spp.) on alfalfa (Medicago sativa L.) growth in agricultural soils with different copper (Cu) levels for degraded soil recovery. To this effect, alfalfa seeds were grown in soils from the Catemu and Casablanca valleys and inoculated with AMF. Plant height, stem diameter, and number of leaves were measured weekly. Dry matter, mycorrhizal colonization, and Cu concentration in alfalfa plant tissues were measured after 81 days. Inoculation increased plant height by 24%, stem diameter by 11%, and number of leaves by 34%. Inoculation had a significant effect (p £ 0.05) on alfalfa plants that were grown in soil with the highest Cu concentration, but had no effect on Cu accumulation in alfalfa plant tissues. A direct relationship was observed between Cu accumulation in alfalfa and Cu concentration in soils. It was concluded that alfalfa inoculated with Glomus spp. is applicable to the soil recovery process whenever soil properties can ensure inoculum effectiveness on alfalfa growth, and avoid toxicity by excessive Cu in alfalfa plant tissues.
Keywords: Medicago sativa, mycorrhizal colonization, soil recovery.
1Universidad de Valparaíso, Facultad de Ciencias, Av. Gran Bretaña 1111, Playa Ancha, Valparaíso, Chile. *Corresponding author (hernan.gaete@uv.cl).