西洋参与紫苏、薏苡轮作效应的研究

目的 :为西洋参合理的轮作方案提供科学依据。方法 :采用水培和土培的方法培育 4年生西洋参 ,并用西洋参茎叶、须根及紫苏子、薏苡根的水提物进行生物测试。以前作是紫苏和薏苡的土壤种植西洋参 ,观察其轮作效应。结果 :西洋参茎叶和须根中含有自毒性物质 ,每 1kg土壤含 1g该物质 ,西洋参几乎不能生长 ,当其含量为0.2g·kg^-1时 ,西洋参存苗率下降 2 5 %以上。在前作为紫苏和施入紫苏子的土壤上种植西洋参 ,其存苗率及生物学重量比对照处理分别提高 2 6 .8%和 11.5 %。结论 :西洋参宜与紫苏轮作 ,此期间若用紫苏子作西洋参的肥料 ,轮作效应更佳。

Study on the rotation of crops among Panax quinquefolium,Perilla frutescens and Coix lacryma-jobi

Objective: To provide evidence for establishing an efficient method of growing Panax quinquefolium by rotation of crops. Method: Four-year old P. quinquefolium was cultivated in water and soil cultures. Biological assays were conducted with the aqueous extracts of P. quinquefolius, Fructus Perillae and roots of Coix lacryma-jobi. P. quinquefolium was cultivated in the soil where purple Perilla frutesens and C. lacryma-jobi were grown previously. The effects of rotation were determined. Result: The stems, leaves and fibrous roots of Panax quinquefolium contained allelopathic substances. When the concentration of the allelopathic substances exceeded 1g per kg soil, P. quinquefolius could not grow. On the other hand, when the concentration of allelopathic substances fell below 0.2 g per kg soil, the rate of seedling growth was decreased by 25%. When P. quinquefolius was cultivated in the soil in which purple Perilla frutesens had previously grown, or in the soil supplemented with Fructus Perillae, the rates of seedling growth and the yield were raised by 26.8% and 11.5% respectively, in comparison with the controls. Conclusion: Rotation of Panax quinquefolium and Perilla frutesens was shown to be a good way for the cultivation of the former. During the growing process, application of Fructus Perillae to the soil could further enhance the growth and production of Panax quinquefolium.