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

Abstract

The search for sustainable alternatives to synthetic herbicides for weed control, has led the scientific community to an increased interest for plant allelopathic mechanisms. The utilisation 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 high-performance liquid chromatograpy (HPLC) analysis were evaluated. Overall, the allelopathic effects were both genotype- and weed species-dependent. Wild cardoon showed the highest allelopathic potential (–23.4%), followed by cultivated cardoon and globe artichoke, and P. oleracea was the most sensitive target species (–32%). Besides, root system length was the most affected parameter (–32.6%). The autoallelopathic effect of wild cardoon extract was also demonstrated on root system length, hypocotyl and epicotyl length and total dry weight. C. cardunculus leaf aqueous extract was characterised by 5 sesquiterpene lactones, 2 caffeoylquinic acids, 6 flavones and 1 lignan. 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-deacylcynaropicrin and 11,13-dihydroxi-8-deoxygrosheimin were characteristics of cultivated cardoon.

Evaluation of Pigments, Phenolic and Volatile Compounds, and Antioxidant Activity of a Spontaneous Population of Portulaca oleracea L. Grown in Tunisia

“…Common purslane (Portulaca oleracea L.) is best known as an invasive weed in the Mediterranean Basin [1,2], although its succulent leaves and stems are also completely edible. Purslane belongs to the Portulacaceae family containing more than 120 species of succulent herbs and shrubs, and it is ranked among the top eight common plants in the world [3].…”

Herbicidal Effects and Cellular Targets of Aqueous Extracts from Young Eucalyptus globulus Labill. Leaves

“…Even though great herbicidal activities against purslane seedlings have been found with the application of DLE at 250 g dry weight L −1 , its efficacy and practical applicability could be maximized if combined with preventive practices, like crop rotation and soil solarization, and other weed control methods, such as tillage [ 56 ]. Indeed, as commented by Scavo et al [ 57 ] and Scavo et al [ 58 ], synergies between sustainable aqueous extracts and conventional herbicides can be explored to achieve novel weed control methods. Therefore, the adoption of an integrative weed management system allows the reduction of weed populations to economically, agronomically, and ecologically acceptable thresholds, while decreasing synthetic herbicide application and their subsequent negative impacts, thus contributing to a more sustainable agriculture [ 56 ].…”

Integrated Weed Management in Herbaceous Field Crops

“…For example, the herbaceous field crop C. cardunculus was recently studied for the biological control of weeds, following a step-by-step approach. The allelopathic effects of the three C. cardunculus botanical varieties (globe artichoke, wild and cultivated cardoon) leaf aqueous extracts, at first, were evaluated on seed germination and seedling growth of some cosmopolitan weeds [138,139]. In a second phase, the set-up of the most efficient extraction method of its allelochemicals in terms of costs, yields and inhibitory activity was realized, selecting dried leaves as the best plant material and ethanol and ethyl acetate as the best solvents [140].…”