Allelochemicals: Role in Plant-Environment Interactions

Abstract

During evolution, the plants developed new biosynthetic pathways to produce secondary metabolites (flavonoids, alkaloids, cyanogenic glycosides, glucosinolates, phenolics and tannins) known as allelochemicals. These provide adaptative advantages to plants for survival against herbivores, pests (Insects, nematodes, pathogens, weeds), environmental stresses and other plants. They can be considered as the chemical language of plants, which continuously changes and increases in complexity with their evolution. Allelopathy phenomenon refers to inhibitory or stimulatory biochemical interactions between the plant-plants, plant-predators and plant-pathogens mediated by plant allelochemicals released into the environment as leachates, volatiles, root exudates and decomposition of plant residues. The allelochemicals affects numerous biochemical reactions/metabolic processes (photosynthesis and respiration etc) in plants and such actions may be determined at molecular, structural, biochemical, physiological and ecological levels. This book aims to provide an overview of structure, origin and mode of release of plant allelochemicals and their biological roles in allelopathic interactions.