Abstract

Bioregulators are chemicals that affect the expression of biological responses in plant tissues. Their use is a unique facet of biotechnology and a new approach of manipulating plant biochemistry for enhancing productivity and quality. They act in low concentrations without any biocidal or nutritive action. Applications of bioregulators are reported to reduce biotic and abiotic stress in plants. Recent studies show that their application increases the growth, yield and nutritive value of food crops. Their use at different times or concentrations elicits diverse effects and in some cases significantly alters virus multiplication and pathogenesis. Increasingly, plant bioregulators are being recognised as important tools in pest and disease management. They have been instrumental in understanding morphological and growth phenomena in-vitro and are potential tools for elucidating biochemical pathways in plants. Plant growth and development are influenced by physical, chemical and biological components in the plants’ environment. Though, bioregulators are commonly used to improve plant growth, development, defence and productivity, the molecular mechanisms of their effects still remain to be fully elucidated. This article reviews the biochemical importance of bioregulator application in plants, current state of research on their effects and discusses their roles in insect and pest invasion as well as possible mechanism of action.

Key words: Bioregulation, plant growth, plant development, plant improvement, stresses

Abbreviation

GA₃, Gibberellic acid; IAA, indole-3-acetic acid; BR, brassinosteroid;SA, salicylic acid; ABA, abscisic acid; IBA, indole butyric acid; NAA, naphthalene acetic acid; MCPA, methyl 2-4-chlorophenoxy acetic acid; 4CPA, 2,4-D, 4-chlorophenoxyacetic acid; LEA, late embryogenesis abundant; PR, pathogen resistant; WTV, wound tumour virus; TMV, tobacco mosaic tobamovirus; TYMV,turnip yellow mosaic virus; TNV, tobacco necrosis virus; TRV, tobacco raffle virus;SAR, systemic acquired response; BCTV, beet curly top virus; CaMV, cauliflower mosaic virus.