ABSTRACT
Some considerations are made here on the ecological relevance of the degradation processes of allelochemicals, concerning the activity of some of the degradation products produced in soil. Once the allelochemical is in contact with different organisms and environmental conditions, they can become new products. Sometimes these new compounds are less active than the initial ones, but at other times the new chemical is as active or even much more than the ones excreted by plants. Thus, in nature allelopathy occurs due to complex mixtures of compounds, some of them transformed from those exuded by plants. So, a complete understanding of the allelopathic phenomenon requires the study of degradation products of allelochemicals. An extended study of degradation of benzoxazinoids in two different wheat crop soils is described and the activity shown on seven species (Triticum aestivum L., Allium cepa L., Lycopersicon esculentum Will., Lepidium sativum L., Lactuca sativa L., Echinochloa crus-galli L., Lolium rigidum L., and Avena fatua L.) by the initial compounds (DIBOA-Glc, DIBOA and DIMBOA) as well as the main degradation products detected (BOA, MBOA, APO and AMPO). The most active compound was the degradation product APO, instead of the commonly accepted allelochemicals DIBOA and DIMBOA. It can be inferred from these data that the fate and degradation studies of allelochemicals are a necessary stage in allelopathic research if we want to have a complete understanding of allelopathy.
