ABSTRACT
There is a competition among neighboring plants (intraspecies as well as interspecies) for environmental resources. Allelopathy is a biological phenomenon in which some plants produce specific biochemicals called allelochemicals that affect relationships, performance, and survival of the neighboring plants. The common sites of allelochemical action are photosynthesis, specific enzyme action, nutrient uptake, pollen germination, and cell division. A mixture of different allelochemicals is often more deleterious than an individual one. Allelopathic reactions are greatly influenced by pests and diseases, herbicides, solar radiation, temperature, suboptimal nutrients, moisture, and physiological and environmental stresses. The allelochemicals play an important role to influence and determine ecological processes, such as plant diversity, nutrient dynamics, soil fertility, microbial populations, and succession and may have long-term consequences in the evolution of natural ecosystems. Allelopathy can serve as a kind of panacea in cropping-system management, weed control, breeding of allelopathic cultivars, reducing NO3 leaching, curbing N2O pollution, etc. Allelopathic mechanisms exert their influences on soil ecology, photosynthesis, respiration, enzyme functions, the plant-growth regulator system, antioxidant system, protein and nucleic acid synthesis, water and nutrient uptake, and cell division and elongation. Allelopathic relations are potent to phenomenally affect soil chemistry, microbial ecology, nutrient dynamics, phytodiversity, species richness, species’ invasion, ecological succession, and ecosystem structure and, thus, to determine the natural evolution of ecosystems. Allelopathic relationships can be selectively applied for enhancing the processes of ecological regeneration and ecosystem restoration.
