Plant Growth Regulators and Secondary Metabolites, Downregulation and Upregulation

Abstract

Plant growth regulators (PGRs) are naturally occurring or synthetic compounds that affect developmental or metabolic processes in plants, mostly at low dosages. PGRs have been measured to beneficially improve plant germination, growth, and development by modifying hormonal activity within a plant. The factors that control plant growth behavior in response to PGRs include the type of plant and stimulant, amount of stimulant applied, timing of application, stage of growth, and location of stimulant application. It is well documented that a wide range of secondary metabolites such as alkaloids, anthocyanins, flavonoids, quinones, lignans, steroids, and terpenoids are being synchronized in response of PGRs. The mechanism of the biosynthesis and accumulation of plant secondary metabolites in such an appropriate pattern attracted more attention. Both stimulators and inhibitors of PGRs were analyzed in this chapter in regard to the accumulation of secondary metabolites. The interaction between the metabolites and PGRs were clearly demonstrated in the literature. Besides, a complex network of interactions including the synergistic and antagonistic effects between the PGRs is available when it comes to the secondary metabolite production. Further investigation will fulfill the network structure and develop the application of PGRs in agriculture, especially in plants with valuable secondary metabolites.