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 evolutionary constraints, especially from a co-evolution point of view, this process cannot be very extended except in some conditions. Allelopathy can be important when an invader plant affects to the autochthonous species, when soil microorganisms cannot cope with a new molecule and target plants have not co-evolved. It can be important in some conditions when there is a continuous release of allelochemicals into the environment or when there is a very limited metabolism of those substances. Most agricultural and forestry practices tend to increase the possibilities of such a process to be important. Allelopathy can be effective only when plants are in stress due to other mechanisms, for example, when there is a lack of water or competition for nutrients or light is strong. In those conditions, allelochemicals production has been shown to increase. Sometimes there are allelochemicals that are not normally produced if the plant is not under stress. Under stress, the target plant is also more susceptible to the effect of the released phytotoxins. A multidisciplinary ecophysiological approach is needed in studying allelopathy in conjunction with other mechanisms that affect plants. The study can range from the ecological level to the molecular one. New methods are requested to separate the effects of allelopathy from competition.