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.