Growth Response and Cadmium Accumulation of Solanum lycopersicum L. Inoculated with Arbuscular Mycorrhizal Fungi Gigaspora margarita and Entrophospora sp

The growth and cadmium (Cd) accumulation of tomato (Solanum lycopersicum L.) associated with arbuscular mycorrhizal fungi (AMF) (Gigaspora margarita and Entrophospora sp.) were studied in artificially contaminated soil. This was done to address and ensure the food safety of tomatoes planted in agricultural areas that are continuously applied with fertilizers containing traces of Cd or planted in mine tailing sites with heavy metals such as Cd. Accumulation of Cd through the food chain can lead to various diseases such as cancer. Non-mycorrhizal or mycorrhizal tomatoes were planted in sand-soil mixture amended with increasing (0, 50, 100 and 150 ppm) Cd concentration. Results showed that AMF increased plant height, stem diameter, number of leaves, plant biomass and mycorrhizal root infection which were otherwise reduced by increasing concentrations of Cd. Plants inoculated with G. margarita with no Cd gave the highest plant height (93.41 cm) and total biomass (4.15 g plant(-1)) at harvest (wk 8). The roots of Entrophospora sp. inoculated plants gave the highest percentage (93%) of root colonization at 0% Cd and only 1% at 150 ppm. The highest Cd uptake was observed in the roots of Entrophospora sp. inoculated plants. The control plants gave the lowest bioconcentration factor but had the highest translocation factor as compared with the mycorrhiza-inoculated counterpart, which implied that Cd was translocated in the above-ground plant parts. Entrophospora inoculated plants had two- and five- times lower Cd uptake than controlled plants (38.46 mu g g(-1)) and those inoculated with G. margarita (84.15 mu g g(-1)), respectively. Thus, Entrophospora sp. would be a better choice than G. margarita to prevent the uptake of Cd in the above-ground parts of the plant. On the other hand, G. margarita can be a good candidate to clean up Cd in the soil (phytoremediation) and perhaps other heavy metals in heavy-metal-contaminated agricultural soils and mine tailing areas.