Allelopathic effects of Artemisia frigida Willd. on growth of pasture grasses in Inner Mongolia, China

Research on the causes of grassland degradation in the Inner Mongolia has mostly focused on anthropogenic activities. Few studies examined plant interactions during the processes of grassland degradation. In this study, we found that the major constituents of the VOCs from undamaged Artemisia frigida were eucalyptol, camphene, (E)-3-hexen-1-ol acetate, alpha-terpineol, beta-terpineol, (R)-(-)-p-menth-1-en-4-ol, p-cymene and camphor. The content and amount of these VOCs increased when A. frigida was damaged. The VOCs from A. frigida significantly decreased the seedling growth of three common grass species (Elymus dahuricus, Agropyron cristatum and Leymus chinensis) in the Inner Mongolia pastures. The inhibition effect of the VOCs on the tested grass species was significantly greater from damaged than from undamaged plants of A. frigida. Findings from this study suggest that the dominance of A. frigida in degraded grasslands may affect the recovery of other native plant species through mechanisms of allelopathic effect of VOCs emission, especially when under severe disturbance by overgrazing. (C) 2011 Elsevier Ltd. All rights reserved.