Effects of Nano-Silica and Multi-Walled Carbon Nanotubes on Grape Seedlings under Salt Stress

To improve the salt tolerance of grape seeds and seedlings under salt stress, this study was conducted including two control groups (CK, S) and five experimental groups (S + Si40, S + Si60, S + Si80, S + C90, S + Si40 + C90), and the physiological characteristics of grape seed germination and seedlings were studied using 40, 60, and 80 mu g/mL of nano-silica treatments and by mixing 40 mu g/mL of nano-silica with 90 mu g/mL of multi-walled carbon nanotubes (MWCNTs), respectively. The combined treatment of 40 mu g/mL nano-silica and 90 mu g/mL MWCNTs resulted in the best rate of growth in grape seeds and root length and an increased germination rate when compared with the other concentrations. The combined treatment reduced the MDA content in the grape seedling leaves and increased the activities of superoxide (SOD), peroxidase (POD), catalase (CAT), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDHAR), ascorbate peroxidase (APX), glutathione-s-transferase (GT), and glutathione reductase (GR). In addition, the scavenging activity of DPPH center dot was also maintained by the combined treatment. In conclusion, a combined treatment with 40 mu g/mL nano-silica and 90 mu g/mL MWCNTs significantly increased the reduction capacity through the direct and indirect antioxidant systems (AsA-GSH cycle) and maintained a high antioxidant capacity of grape seedlings under salt stress.