The beneficial or harmful effect of one plant to another plant is allelopathy. Plants produce bio chemicals known as allelochemicals that may be beneficial or harmful to other plants. The chemicals are released by leaching, root exudation, residue decomposition and other processes. Allelopathic chemicals can be present in any part of the plant. They can be found in leaves, flowers, roots, fruits, stems. The production of allelochemicals are affected by biotic factors such as nutrients availability, and abiotic factors such as temperature, pH.
Target species are affected by these chemicals in many different ways.The allelo chemicals may inhibit/stimulate shoot/root growth, they may inhibit nutrient uptake. They also affect the germination of the seeds positively or negatively. The allelopathic effect of the plants isused for the weed control. It isjust a mechanism of nature to create a balance of the plant population.