EFFECTS OF BRASSINOLIDE ON PHYSIOLOGICAL PARAMETERS OF ROBINIA PSEUDOACACIA SEEDLINGS IN CRUDE OIL CONTAMINATED SOIL

摘要

We conducted pot experiments to investigate the physiological effects of brassinolide on one-year-old Robinia pseudoacacia seedlings planted in crude oil contaminated soil. In the experiment, the oil concentration in soil of the pots was regulated to 10, 15 and 20 g/kg. The roots of seedlings were soaked in different concentrations of brassinolide (0, 0.1, 0.3 and 0.5 mg/L) before planting followed by a foliar application of brassinolide when the seedlings leafed out. After the seedlings were established, some physiological parameters were measured. The results showed that application of brassinolide significantly increased the contents of leaf osmotic regulation substances such as proline, soluble sugar and soluble protein of seedlings in different levels of crude oil contaminated soil during main growth period, simultaneously increased the activities of leaf enzymatic antioxidants including superoxide dis-mutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR), as well as the contents of leaf non-enzymatic antioxidants as ascorbic acid (AsA) and glutathione (GSH), however decreased the content of leaf malondialdehyde (MDA). The best results were observed in 0.3 mg/L brassinolide treatment. The results indicate that brassinolide could alleviate the adverse effects of dehydration and toxicity of crude oil pollution on R. pseudoacacia seedlings by improving the osmotic regulation and antioxidant defense abilities of seedlings. Consequently, it enhances crude oil resistance of seedlings. In conclusion, treatment of seedlings with brassinolide may be a useful management tool for phytoremediation in oil contaminated areas.