Effect of trifluoperazine and verapamil on herbicide stimulated growth of cotton

Abstract

Pretreatment of hydroponically‐grown cotton with trifluoperazine (TFP) and verapamil (VPL), respectively, inhibited 2,4‐dichlorophenoxyacetic acid (2,4‐D) and metribuzin [4‐amino‐6‐tert‐butyl‐3‐methylthiol,2,4‐triazin‐5(4H)‐one (MTZ)]‐induced hormetic growth as measured by total leaf areas and dry weights. Trifluoperazine, an anti‐calmodulin drug, proved to be a more effective inhibitor of hormetic growth than VPL, a calcium (Ca²⁺)‐channel antagonist. It is suggested that Ca²⁺ influx is involved in the growth increase observed in hormesis.