太子参茎叶和连作土壤对莴苣的化感作用

为研究太子参连作障碍的成因,进行了太子参茎叶和连作土壤水浸液对莴苣种子萌发和种苗生长的影响试验。结果表明:高浓度的太子参茎叶浸提物抑制莴苣种子的发芽,延长平均发芽时间;太子参连作土壤浸提物对莴苣种子的发芽率和平均发芽时间均无显著影响;在一定浓度范围内(0.01～0.1g/mL),高浓度太子参茎叶浸提物抑制莴苣胚根生长,促进胚芽生长,浓度过高(1g/mL)则胚根胚芽生长均受到抑制;高浓度的太子参连作土壤浸提物抑制莴苣胚根生长,促进胚芽生长,但作用强度均小于茎叶浸提物。化感作用可能是导致太子参连作障碍的重要原因。

Allelopathic Effect of Extracts of Pseudostellaria heterophylla Stem Leaf and the Continuous Cropping Soil on Lactuca sativa

Lactuca sativa seeds were treated with the extracts of P.heterophylla stem leaf and continuous cropping soil to study the effect on seed germination and seedling growth of L.sativa and to probe the cause of P.heterophylla continuous cropping obstacle.The results showed that the extract of P.heterophylla stem leaf with a higher concentration could inhibit seed germination and prolong mean germination time of L.sativa and the extract of continuous cropping P.heterophylla soil had no significant influence on seed germination and mean germination time of L.sativa.The extract of P.heterophylla stem leaf with a higher concentration could inhibit radicle growth and promote embryo growth when the concentration was 0.01~0.1 g/mL,but the extract of P.heterophylla stem leaf with over 1g/mL could inhibit radicle and embryo growth of L.sativa.The extract of continuous cropping soil with a higher concentration could inhibit radicle growth and promote embryo growth but its effect intensity was lower than the extract of P.heterophylla stem leaf.The allelopathy may be an important cause for P.heterophylla continuous cropping obstacle.