Can plant bio-regulators minimize crop productivity losses caused by drought, heat and salinity stress? An integrated review

Abstract

Plant bio-regulators (PBRs), are biochemical compounds which stimulate plant growth and productivity when applied, even in small quantities at appropriate plant growth stages. These are being extensively used in agriculture to enhance the productivity particularly in horticultural crops but are not as prevalent in field crops. Their central role in plant growth and development is through nutrient allocation and source-sink transitions while some of the PBRs stimulate hormones related to abiotic stress tolerance. 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. However, the utility of PBRs to enhance crop productivity under stresses induced by abiotic factors needs critical evaluation. Research efforts so far have centered on the crop and agro-ecosystem 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 use of bio-chemicals, issues related to crop yield losses in case of excessive doses as well as their impacts on soil health are being addressed. In this review, prospects and pathways of PBRs are thrashed out as an emerging stress alleviating technology for crop production in harsh agro-ecosystems, specifically those featured by drought, heat and salinity stress.

Keywords

• abiotic stress
• bio-regulator technologies
• exogenous application
• drought
• heat stress
• salinity