What term describes when a plant produces a chemical toxin that impairs the growth of a different plant?

The term that describes the phenomenon when a plant produces a chemical toxin that impairs the growth of a different plant is allelopathy. This process involves the release of allelochemicals into the environment, which can inhibit seed germination, growth, and overall vitality of nearby competing plants. Allelopathy serves as a survival strategy for many plants, allowing them to maintain a competitive edge in their habitat by limiting the resources available to other vegetation.

The other terms listed do not pertain to this specific interaction. Photosynthesis refers to the process by which plants convert sunlight into energy, bioaccumulation describes the accumulation of substances, such as pesticides, in living organisms over time, and symbiosis pertains to a mutually beneficial relationship between two different species. None of these concepts relate to the competitive and inhibitory relationship established through allelopathy.