Plant Bioregulators: A Stress Mitigation Strategy for Resilient Agriculture

Abstract

Plant growth and productivity are stimulated by plant bio-regulators (PBRs), which are biochemical compounds that are applied even in small quantities at appropriate plant growth stages. To enhance the productivity, particularly, PBRs are being extensively used in agriculture and horticultural crops. Though nutrient allocation and source-sink transitions have their central role in plant growth and development and, most of the PBRs stimulate redox signaling under abiotic stress conditions. Since climate change and degrading natural resources are projected to amplify the stresses, particularly soil moisture deficit, high temperature, and soil salinity, PBRs are likely to play a crucial role in plant growth regulation under these stress conditions. However, critical evaluation should consider the utility of PBRs to enhance crop productivity under stresses induced by abiotic factors. Research efforts so far have centered on the crop and agroecosystem specificity, optimal doses, and schedule of their application for optimizing crop yields under stress conditions. These efforts are being complemented by investigations on genes and gene regulatory network at molecular level to tailor crop plants for climate resilience. In addition to complying with regulation governing the use of biochemicals, case studies related to crop yield in major cereals are also reported. In this chapter, prospects and pathways of PBRs are described as an emerging stress-alleviating technology for crop production in harsh agroecosystems, specifically those featured by drought, heat, and salinity stress.