Dear Dr. Anuj Kumar ,

It depends on many variables surrounding your genes, like the receptors, the transducers, and regulating factors. However, generally phytohormones occurr between millimolar and nanomolar concentrations. Mind that some, like ABA, could have different effects depending on the concentration. For instance, ABA is supposed to be a growth inhibitor in millimolar concentrations whereas a promoter in nanomolar concentrations.