Allelopathic potential of Allium ursinum L.

Abstract

Allium ursinum L. (wild garlic) represents a widely distributed plant species in beech and mixed beech-fir forests of Serbia. It forms dense populations in which the other species are either sparsely present or absent. Its allelopathic influences were studied using both the seeds and seedlings of test plants (lettuce, amaranth and wheat) and by analyzing phenolic acids and total phenolics in the leaves, bulbs and soil. Aqueous extract and volatile compounds of the bulbs were stronger inhibitors of seed germination and seedling growth compared to those of the leaves. The soil and phenolic-containing fraction of the soil under Allium ursinum also inhibited seed germination and growth of test plant seedlings. The bulbs and the leaves were found to contain 2.30 mg/g and 3.24 mg/g (dry weight) of total free phenolics, respectively, and the same amount of bound phenol forms (1.0 mg/g). Among allelopathic matter in bulb and leaf extracts, p-coumaric, ferulic, p-hydroxybenzoic and vanillic acids as free and bound forms were identified (25.43-87.93 mug/g). The soil contained 0.16 mg/g free and 1.61 mg/g total bound phenolics and p-coumaric, ferulic, p-hydroxybenzoic, vanillic and syringic acids as free (1.00-9.65 mug/g) and bound forms (26.45-44.76 mug/g) were found. These results suggest that A. ursinum influences other herbaceous plants in plant community via soil and volatile compounds which inhibit seed germination and plant growth. (C) 2003 Elsevier Ltd. All rights reserved.