Ecophysiological approach in allelopathy

Allelopathy is a process that can be present in many ecosystems, according to the literature. Nevertheless, the authors think that, due to the evoluti onary constraints, especially from a co-evolution point of view, this proce ss cannot be very extended except in some conditions. Allelopathy can be im portant when an invader plant affects to the autochthonous species, when so il microorganisms cannot cope with a new molecule and target plants have no t co-evolved. It can be important in some conditions when there is a contin uous release of allelochemicals into the environment or when there is a ver y limited metabolism of those substances. Most agricultural and forestry pr actices tend to increase the possibilities of such a process to be importan t. Allelopathy can be effective only when plants are in stress due to other me chanisms, for example, when there is a lack of water or competition for nut rients or light is strong. In those conditions, allelochemicals production has been shown to increase. Sometimes there are allelochemicals that are no t normally produced if the plant is not under stress. Under stress, the tar get plant is also more susceptible to the effect of the released phytotoxin s. A multidisciplinary ecophysiological approach is needed in studying allelop athy in conjunction with other mechanisms that affect plants. The study can range from the ecological level to the molecular one. New methods are requ ested to separate the effects of allelopathy from competition.