Canola (Brassica napus L.) seed germination influenced by cinnamic and benzoic acids and derivatives: effects on peroxidase

Canola (Brassica napus L. cv. Hyola 420) seed germination was analyzed under the action ofcinnamic acid (CIN), benzoic acid (BEN) and their derivatives caffeic (CAF), P-coumaric (P-CA), ferulic (FA), p-hydroxybenzoic (pHB), protocatechuic (PRO), gallic (GAL), vanillic (VA) and salicylic (SA) acids. After 120 hr, CIN, CAF,P-CA, BEN, p-HB and PRO reduced seedling fresh weight (FW), seedling length (SL) and root length (RL) but did not affect germination percentage (G). FA, GAL, VA and SA reduced all variables, and the most effective were FA and SA. Results of the effects of these two allelochemicals on peroxidase (POD) activity showed that FA increased root POD but did not alter cotyledon POD while SA increased both cotyledon and root POD. The physiological effects of allelochemicals on seed germination, root growth and POD activity are discussed.