The Allelopathic Effects of Sunflower and Wheat Root Exudates on Sinapis arvensis and Sinapis alba

In this study, we aimed to investigate the allelopathic effects of sunflower and wheat root exudates on the common weeds such as wild mustard and white mustard in our region. The root exudates which were obtained by soaking 8 weeks old sunflower and wheat seedlings (20 or 40 seedlings) in 100 mL of distilled water for 3 days were applied to the leaves of wild mustard and white mustard. In order to compare the allelopathic effect, the recommended dose (1 g.da(-1)) and twice the recommended dose (2 g.da(-1)) of Gromstor (Tribenuron-methyl), a herbicide preferred by farmers for the chemical control of these weeds was also applied. The allelopathy was performed for wild mustard and white mustard seedlings by the measurement of different physiological and biochemical parameters, such as chlorophyll a, chlorophyll b, total chlorophyll, carotenoid, proline, total protein amounts and superoxide dismutase enzyme activity. The amounts of total chl and carotenoid in wild mustard leaves decreased in all treatment groups compared to control. The highest decrease in total chl (50.93%) and carotenoid (46.69%) was oberved in the treatment of 40 wheat seedlings. 100 mL(-1) distilled water. In the white mustard leaves, the amount of total chl in all treatment groups except the treatment group of Gromstor 2 g.da(-1) and carotenoid in all treatment groups increased compared to the control. The highest increases again were observed in 40 wheat seedlings. 100 mL(-1) distilled water treatment. The proline amounts in wild mustard and white mustard increased in all treatment groups. The highest increase was observed for the treatment of 20 wheat seedlings. 100 mL(-1) distilled water in wild mustard (459.69%) and 40 sunflower seedlings. 100 mL(-1) distilled water in white mustard plant (104.70%). In superoxide dismutase enzyme activities, treatments decreased activity except treatment of 40 sunflower seedling root exudate in wild mustard, while increased activity outside commercial herbicide treatment in white mustard. The results showed that sunflower and wheat root exudates have allelopathic effects on wild mustard and white mustard weeds. It is thought that the study will be a reference for new studies that will enable the use of plant root exudates as bioherbicides or foliar fertilizers and will contribute to the fight against weeds in organic agriculture.