AM fungi effects on the growth and physiology of Zea mays seedlings under diesel stress

The effects of an arbuscular mycorrhizal fungus (AMF) (Glomus constrictum Trappe) on the growth and some physio-biochemical indexes of Zea mays L. seedlings under different levels of diesel stress were investigated in a pot study. Generally, the symbiotic relationship between corn and AMF can be well established under diesel stress. This was reflected by the better physio-biochemical index of the plants inoculated with G. constrictum whose colonization rates were between 47.30% and 91.50%. Compared with the non-inoculated ones, the heights and basal diameters of the inoculated seedlings increased by 0.08–47.20% and 6.74–35.71% respectively. The relative contents of chlorophyll and soluble proteins increased by 1.88–38.79% and 3.87–77.27% respectively, while the contents of malondialdehyde and free proline decreased by 2.74–52.74% and 24.69–32.86%. Three antioxidant enzymes reacted differently under the diesel stress. The activities of superoxide dismutase (SOD) and catalase (CAT) increased at low diesel concentration, but decreased at high concentration. In contrast, peroxidase (POD) had a decreased activity at low diesel concentration, but an increased activity at high concentration. On the whole, the activity of three antioxidant enzymes in the plants inoculated with AMF were higher than those without AMF inoculation. Our results support the view that antioxidant enzymes have great influence on the biomass of plants, and AMF can improve the capability of scavenging the reactive oxygen and alleviate Z. mays seedlings from diesel stress.