入侵植物土荆芥对川西北高寒草甸2种培育牧草的化感作用

Allelopathy of Chenopodium ambrosioides on Two Cultivated Pastures of Alpine Meadow in Northwestern Plateau of Sichuan Province

为了评估土荆芥入侵对川西北高寒草甸生态系统潜在的生态风险,采用盆栽试验研究了土荆芥残渣对在退化高寒草甸恢复和重建过程中常用的2种培育禾本科牧草老芒麦(Elymus sibiricus)和垂穗披碱草(Elymus nutans)的化感作用。结果表明:土荆芥(Chenopodium ambrosioides L.)残渣对牧草种子萌发具有抑制效应,其中,老芒麦的萌发指数与对照相比,呈显著下降趋势;在幼苗生长阶段,土荆芥残渣对地上部分生长和生物量无显著影响,但却抑制了根的生长,这种抑制效应具有剂量效应。老芒麦对土荆芥化感胁迫的敏感性大于垂穗披碱草。这些结果说明土荆芥化感作用主要延迟种子萌发,抑制根系生长。当土荆芥入侵高寒草甸后,可能会减少牧草尤其是老芒麦的产量,影响草地畜牧业可持续发展,威胁到高寒草甸生态系统的结构与功能。

To evaluate invasion potential risk of Chenopodium ambrosioides on alpine meadow,its allelopathy on germination and seedling growth of two dominant pastures of alpine meadow,Elymus sibiricus and Elymus nutans by using pot experiment were studied in restoration and reestablishment of degraded alpine meadow in the Northwestern Plateau of Sichuan Province.The results showed that the residue of C.ambrosioides inhibited seed germination,and the germination index of E.sibiricus decreased significantly.In the process of seedling growth,the residue had no significant effects on the above-ground parts growth and biomass,but inhibited the root growth of pastures,and this effect was dose dependent,increasing with the dose increase.E.sibiricus were more sensitive to allelochemical stress from C.ambrosioides than E.nutans.These results suggestted that allelopathy of C.ambrosioides on two pastures delayed seed germination and inhibited growth of root system.The invasion of C.ambrosioides maybe shrinks production of pastures and influence sustainable development of grassland agriculture and the structure and function of alpine meadow ecosystem.