When one plant produces chemicals that inhibit the establishment and growth of another plant, this phenomenon is called?

• A. Allelopathy
• B. Competition
• C. Mutualism
• D. Parasitism

Answer: (A)

Allelopathy is the chemical inhibition of neighboring plants by a plant through the release of allelochemicals into the environment. These chemicals can prevent seed germination, stunt root or shoot growth, or hamper establishment of other plants when they come into contact with soil, litter, or air. Plants can release these compounds via root exudates, fallen leaves, or volatile emissions, creating a chemical barrier that affects nearby species. This differs from simple competition, which is about competing for light, water, and nutrients; from mutualism, where both sides benefit; and from parasitism, where one organism benefits by feeding on another. In short, the described phenomenon is allelopathy.