One of the important goals of plant physiology in water ecosystems, is biomass and growth increment of green microalgae which led to access to their valuable production. In this regard, many factors are able to influence the increment and decrement of algal biomass. In this research different levels of vanillin (C8H8O3), as 0 (control), 10, 25, 40, 50, 70, 90 and 100 mg. L-1, were investigated ...