ABSTRACT
Phytohormones are essential, small signalling molecules that have a significant impact on plant development and yield output. Phytohormones (PHs) play a critical role in the modulation of numerous physiological and biochemical processes that control plant development and production under both ideal and stressful circumstances. Hormonal cross-regulation sets off a chain of events that precisely adjusts physiological processes in plant design, enabling plants to develop in less-than-ideal circumstances. Plant hormones generally can be divided into two groups based on their metabolism. Plant growth-promoting processes like cell division, cell lengthening, seed and fruit development and differentiation patterns come under the purview of class one phytohormones. The reaction of plants to biotic and abiotic stressors is influenced by the second class of hormones. In this chapter, the timeline of phytohormone research and development will be described briefly. It will also deal with the development of phytohormones in the past and present, how they are developing and how the progress in future research mainly concentrates on areas around abiotic stress.
