Germination characteristics and phytotoxic inhibition of germination in Artemisia adamsii, a low-palatability weed in the Mongolian steppe

Abstract

AbstractArtemisia adamsii is a weed with low palatability to livestock and is thus recognized as an indicator of rangeland degradation in Mongolia. We investigated the germination characteristics of this species, phytotoxic suppression of its germination by its own residue, and the applicability of such germination behaviour to the control of this species. We also discussed the ecological consequence of these factors regarding the vegetation dynamics of the Mongolian steppe. Germination of A. adamsii was tested at different light and temperature conditions. Germination was also tested for A. adamsii and four native grassland species in the presence or absence of A. adamsii residue. Germination of A. adamsii was light-demanding and temperature-dependent. Artemisia adamsii residue showed autotoxic but sub-fatal suppression of germination, and the chemicals causing that suppression were shown to be aqueous and volatile. Phytotoxicity of A. adamsii residue on the germination of grassland species was low, except for in Artemisia frigida. The applicability of the observed sub-fatal autotoxicity for controlling this species was likely to be low, but the elucidated germination characteristics could contribute to developing a strategy for controlling this species. The autotoxicity in A. adamsii germination was suggested to have an ecological consequence that mediates species transition from A. adamsii to other species in degraded land occupied by A. adamsii. As low-palatability A. adamsii can act as a nurse plant of palatable species under grazing conditions, the invasion of A. adamsii into disturbed grasslands may facilitate the recovery of such grasslands in terms of improving pasture quality.