| Institution: | 1. Laboratorio de Biodiversidad Vegetal y Microbiana, IICAR (CONICET-UNR), Facultad de Cs Agrarias, Universidad Nacional de Rosario, Campo Exp. Villarino, Zavalla (2123), Argentina;2. Université Catholique de Louvain, Earth and Life Institute, Mycology, Croix du Sud, 2 box L7.05.06, B-1348 Louvain-la-Neuve, Belgium;1. Freie Universität Berlin, Institut für Biologie, Dahlem Center of Plant Sciences, Altensteinstr. 6, D-14195 Berlin, Germany;2. Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), D-14195 Berlin, Germany;1. Department of Botanical and Environmental Sciences, Guru Nanak Dev University, Amritsar, Punjab, 143005, India;2. Department of Botany, DAV University Sarmastpur, Jalandhar, 144012, India;1. Federal University of Santa Maria, Department of Soil Science, 97119-900, Santa Maria, RS, Brazil;2. Federal University of Santa Maria, Campus Cachoeira do Sul, 96506-322, Cachoeira do Sul, RS, Brazil;3. Federal University of Santa Maria, Department of Biology, 97105-900, Santa Maria, RS, Brazil |
| Abstract: | Changes in plant antioxidant enzymes (AOEs) in response to cadmium (Cd) pollution are an important mechanism for plant growth and tolerance to Cd-induced stress. The main objective of this greenhouse study was to determine the combined influence of earthworm and arbuscular mycorrhiza (AM) fungal inoculation and their interactions with Cd on AOEs and proline accumulation in leaves of two major crops under Cd stress. Maize (Zea mays L.) and sunflower (Helianthus annuus L.) plants were exposed to Cd stress (10 and 20 mg kg?1 soil), inoculated with either earthworm (Lumbricus rubellus L.) or AM fungi (Glomus intraradices and Glomus mosseae species) in a pot experiment for three months. Exposure to Cd decreased shoot dry weights, increased shoot Cd and P concentrations, leaf proline accumulation and the activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and polyphenol oxidase (PPO) in both mycorrhizal and non-mycorrhizal plants and both in the presence and absence of earthworms. Inoculation of both model plants with earthworms and AM fungi decreased shoot Cd concentrations and the activity of all AOEs, except PPO. Although earthworm activity enhanced the proline content of sunflower in Cd-polluted soils, the proline level of both plants remained unaffected by AM fungi. AM fungi and earthworms may decrease the activity of AOEs through a decline in shoot Cd toxicity and concentration, confirming that plant inoculation with these soil organisms improves maize and sunflower tolerance and protection against Cd toxicity. Generally, the effect of AM fungal inoculation on plant responses to Cd addition was greater than that of earthworm activity. Nonetheless, the interactive effect of AM fungus and earthworm is of minor importance for most of the plant AOEs in Cd-polluted soils. |
