Allelopathy Journal

Toxicity effects of aqueous root extracts of 4 plant species on the maize growth and arbuscular mycorrhizal fungal (AMF; Glomus mosseae) colonization were studied in a greenhouse experiment. The root extracts (0.15%, w/v) of 2 dicotyledons [stinging nettle (Urtica dioica L.) and red clover (Trifolium pratense L.)] and 2 monocotyledons [meadow fescue (Festuca pratensis Huds.) and maize (Zea mays L.)] were applied weekly to non-inoculated and AMF-inoculated maize plants. The root extracts of monocots (F. pratensis and Z. mays) contained 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), allelopathic to neighbouring plants, whereas it was not found in dicots root extracts. Maize root dry weight was lower in non-inoculated maize plants watered with fescue and maize root extracts, showing toxicity and autotoxicity effects, respectively, that were not observed in equally treated AMF-inoculated plants. However, watering with maize root extract resulted in decreased AMF colonization in maize roots [AMF frequency (F%) and intensity (M%)]. These results indicate the potential of AMF application in continuous monoculture of maize to alleviate autotoxicity.