ABSTRACT
<p><b>OBJECTIVE</b>To reveal the allelopathy effect of Astragalus membranaceus var. mongholicus seeds and provide information for the intercrop production.</p><p><b>METHOD</b>The A. membranaceus. var. mongholicus seeds were soaked in distilled water for different time (12, 24, 36, 48, 60 h) , and then the seed extracts were used to study their effects on the seed germination, seedling growth and development of two Codonopsis pilosula.</p><p><b>RESULT</b>The A. membranaceus var. mongholicus seeds contained some allelopathy compounds. Their soaked liquid had significantly influence on the seed germination and seedling growth of C. pilosula. The seed germination rate, germination power, germination index and vigor index of two C. pilosula calrivar were improved and then inhabited with soaking time elongation. The extract soaking for 24 h significantly improved the germination traits but the extract for 60 h appeared different degrees of inhibiting vigor. The seed extracts soaking ranging between 12 and 60 h all significantly improved the above plant growth of C. pilosula but significant inhibited their radicle growth in length. And with the soaking time elongation the facilitation effect weakened and the inhibiting effect enhanced, especially more significant in the C. pilosula caltivar (Baitiaodangshen).</p><p><b>CONCLUSION</b>The A. membranaceus var. mongholicus seeds have allelopathic compounds and the endogenous inhibitor can be extracted when soaked for more than 24 h in water with intact seeds, resulting in improvement of seed germination rate. The C. pilosula could be intercropped in A. membranaceus var. mongholicus field, however, when intercroped it should notice that the intercrop proportion should vary with the caltivar.</p>