SHORT COMMUNICATION: Allelopathic potential of invasive weeds: Alternanthera philoxeroide, Ipomoea cairica and Spartina alterniflora

摘要

Biological invasion of exotic weeds is a global problem for scientists and farmers (10). Invasive plant species usually suppress the native species and disturb the structure and functioning of native communities (13), leading to the reduction in biodiversity (12) and huge economic losses (14). To solve the problem, many researches have been done to understand the mechanisms of exotic plant invasion (2,15,20). However, plant invasion is very complex problem, even the most famous theory "natural enemies hypothesis" cannot explain (7,9). In different invasive cases, the decisive factor may vary, so studies should include more factors. Allelopathy is defined as any direct or indirect effect (stimulation or inhibition) of one plant, including microorganisms, on another plant through production and release of chemical compounds into the environment (16). If one plant specie is allelopathic, it may be more competitive than others in communities. Numerous studies have shown the allelopathic potential of various invasive plants and allelopathy helps in their invasion. Centaurea diffusa is invasive Eurasian forb in North America. Callaway et al. (3,4,22) found that North American species were more sensitive to the allelopathy of C. diffusa than Eurasian species. Their results revealed that allelopathy was major factor in the invasion of C. diffusa.