Allelopathic potential of leaf aqueous extracts from Cynara cardunculus L. on the seedling growth of two cosmopolitan weed species

The utilization of plant extracts as possible bioherbicides represents an important solution. In the present study, laboratory experiments were carried out to investigate, for the first time, the differences in the allelopathic activity of the three Cynara cardunculus L. botanical varieties (globe artichoke, cultivated and wild cardoon) leaf aqueous extracts on the seedling growth of Amaranthus retroflexus L. and Portulaca oleracea L. In addition, the autoallelopathic effect on wild cardoon growth and the qualitative profile of the aqueous extract through HPLC analysis were evaluated. Overall, the allelopathic effects were both genotype- and weed species-dependent.From the HPLC analysis we found that apigenin and luteolin 7-O-glucoronide were detected only in wild cardoon, apigenin 7-O-glucoside was typic of globe artichoke, and 11,13-dihydro-desacylcynaropicrin and 11,13-dihydroxi-8-desoxygrosheimin were characteristics of cultivated cardoon.