Wheat coleoptile and weed phytotoxicity bioassays.
The wheat coleoptile and weed phytotoxicity bioassays were performed as reported by Scavo et al. (Scavo et al. 2019f e). Tested extract concentrations were 800, 400 and 200 ppm. A negative control (0 ppm), represented by a phosphate-citrate buffer containing 2% sucrose at pH 5.6, and a positive control (the commercial herbicide Logran®) were used. The allelopathic activity on seed germination, root and shoot length of the weeds Amaranthus retroflexus L. and Portulaca oleracea L. was evaluated in a completely randomized block design with four replicates of 20 seeds for each species. Petri dishes of both weeds were placed inside a Memmert ICE 700 controlled environment chamber at 25 °C in continuous darkness.