The effects of Gallic acid on broomrape and antioxidant enzyme activity in tomato (Lycopersicum esculentum)

Broomrapes are one of the plant parasites limiting the growth and crop production yield. The present research aimed to assess the potential of gallic acid in preventing the tomato plant host from interaction with this parasite. The soil medium was supplemented with three gallic acid concentrations (0, 1 and 3 mM) at three time intervals (20, 25 and 30 days) after planting the tomato seedlings. This experimental design was done in a randomized complete block design with four replications. The activities of the antioxidant enzymes in the roots and shoots as well as the leaf phenol and anthocyanin contents were determined by spectroscopy techniques. The broomrape growth was significantly deceased upon treatment with 3 mM gallic acid at 25 and 30 days. The 1 mM gallic acid at 25 d increased the protein contents and catalase activity in the leaves and decreased the protein contents and the catalase activities in the roots. The 3 mM gallic acid at 30 d increased the leaf and root ascorbate peroxidase activities as well as the phenol and anthocyanin contents of the leaves. This treatment significantly reduced the broomrapes association with tomato plants. These findings propose gallic acid as one of the key phenolic compounds in controlling the germination or blossom connections.