Abstract: Artemisia halodendron is one of the dominant species in vegetation succession for sand land restoration.At the initial stage of vegetation regeneration over sand land,A.halodendron was one of the dominant specie over semi-fixed dune.Thereafter it is replaced by other annual or perennial species,such as Lespedeza bicolor,Corispermum macrocarpum and Agropyron cristatum with the development of sand land recovery.However,the mechanism of its succession is still unclear.In this study,we focused on the allelopathic effect of leaf water extract with different concentrations (0,10,20,40,60,80 and 100 g·L^-1) from A.halodendron on seed germination of one symbiosis specie Seteria virids and three competitive species in terms of L.bicolor,C.macrocarpum and A.cristatum.The results showed that the leaf water extract of A.halodendron affected seed germination of S.virids slightly,and which was promoted under low concentration of the foliage water extract of A.halodendron.However,the seed germination was significantly inhibited by the foliage water extract of A.halodendron,and this allelopathic inhabitation was increased with the increase of the concentration.In conclusion,A.halodendron showed a strong allelopathic effect to other species in vegetation regeneration in the process of sand land restoration.Allelopathic effect was induced by the matters released from the fallen leaves,which may be one of the vital strategies to keep competitiveness.

Key words: Artemisia halodendron, allelopathic effect, seed germination, allelopathic index, vegetation succession, Tongliao