Chapter 12 - Plant growth coordination during stress conditions: Role of phytohormones

Abstract

Plants encounter multiple stresses which are associated with compromised plant growth and yield across the globe. Several studies have been done in the past few years to understand plant acclimatization under numerous stresses like nutrient deficiency, drought, salinity, temperature, and pathogen attack. The shoot and root system architecture in plants seems a promising approach as it is highly sensitive to edaphic and internal signals and plants adapt by modulating them to these stresses. Intrinsic factors such as growth hormones are the key components of the plant whose levels and signaling determine the extent of plant growth and performance. The major phytohormones that are involved in monitoring plant development for optimized plant growth during environmental stresses are auxin, brassinosteroids, cytokinin, abscisic acid, jasmonic acid, gibberellins, and ethylene. In recent years, detailed genetic and biochemical analysis of the signaling and biosynthesis genes and transcription factors of these hormones have been studied from the model plant Arabidopsis to different crops. Genetic studies have shown that these hormones regulate several biological processes of root and shoot growth including cell elongation, division and differentiation, root hair and lateral root formation, and floral and leaf morphology in response to altered environmental conditions. In this chapter, the current understanding of both above- and below-ground plant organs and their developmental plasticity during stress conditions along with the interplay of growth hormones has been summarized and discussed.