外来杂草反枝苋对农作物的化感作用及其风险评价

Allelopathic Effects of Amaranthus retroflexus L.and Its Risk Assessment

利用改进的差时播种共培法,以麦田伴生恶性杂草播娘蒿为对照,在实验室条件下研究反枝苋根系分泌物及其不同浓度残枝浸提液对小麦、玉米、油菜种子萌发及生长的影响.结果显示:(1)反枝苋幼苗的根系分泌物能够显著抑制作物根长和苗高的生长;(2)反枝苋不同浓度浸提液均能抑制作物种子的萌发,其抑制作用随浓度的增加而增强;(3)除0.025 g·mL-1处理对小麦根长和苗高、玉米苗高有促进作用外,其余各浓度反枝苋浸提液对作物幼苗的根长和苗高有不同程度的抑制,且对根长的抑制作用更强;(4)反枝苋对作物幼苗的抑制作用强于恶性杂草播娘蒿,风险评估定量分析结果认定反枝苋为陕西省高度危险性植物.

Compared to Descurainia sophia L. ,we studied the effects of root secretion and water extracts of Amaranthus retro flexus L. on Triticum aestivum L. ,Brassica carnpestris L. and Zea ma ys L. seed germination and growth by using the relay seeding technique. The results showed：（1）the root secretion of Amaranthus retroflexus L. remarkably restrained the growth of crop; （2）Different concentration of Ama ranthus retroflexus L. restrained the seed germination. The higher concentration, the stronger effect; （3）Different concentration extracts restrained the growth of crop,except that 0. 025 g · mL^-1 accelerate the growth of Triticum aestivum L. and Zea mays L.. （4）The inhibitory action of Amaranthus retroflexus L. is stronger than that of Descurainia sophia L. The risk assessment proved that Amaranthus retroflexus L. is the plant with higher risks in Shaanxi Province.