Effects of monosodium glutamate wastewater on yield and quality of tomato fruit, SOD, CAT, POD activities and MDA content in tomato leaves

A medium culture experiment of tomato using edible fungi culture medium waste as the main component of culture medium was conducted to study the effects of different nutrient solutions, i.e. monosodium glutamate wastewater (MGW), inorganic nutrient solution (INS) and water, on the yield, fruit quality, activities of enzymes which protected against active oxygen and malondialdehyde (MDA) content in leaves on 50 d and 75 d after transplanted. The yield of MGW treatment was the highest among the three treatments. There was significant difference in yield between MGW and water treatment, while the yield of MGW increased 36.62% compared with that of INS treatment. Except the VC and nitrate content in fruit, the soluble protein content and carobohydrate content increased, furthermore, the fruit flavor was improved, compared with that of INS treatment. Activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) in MGW and INS treatment were both higher than that of water treatment, while MDA content was in reverse. However, there was no significant difference showed in the activities of SOD, CAT, POD between MGW and INS treatments except that SOD activity in MGW treatment at 75 day was higher than that of INS treatment. It was obvious that MGW used as nutrition solution in substrate culture can increase the yield and improve some items of quality, which also would not damage the physiology as some other wastewater during the growth.