外来入侵杂草空心莲子草与本土杂草莲子草的化感作用潜力比较

 为确定外来入侵杂草空心莲子草的化感作用潜力，以我国本土生长的莲子草为对照采用“三明治”生测法，测定了空心莲子草和莲子草及其不同器官对靶标莴苣和无芒稗根长和芽长的抑制率。 结果表明，空心莲子草叶片处理对莴苣和无芒稗根长的抑制率分别为81%和51%，对莴苣和无芒稗芽长的抑制率分别为49%和48%，显著高于空白对照。但与莲子草相比，差异不显著。空心莲子草根系对莴苣的根长平均抑制率为54%，显著高于茎和叶片。随着样品用量增加，空心莲子草对莴苣根长的抑制率显著提高，其50 mg叶片处理对莴苣根长的抑制率为83%，显著高于10 mg处理的54%和30 mg处理的61%。

Comparison of Allelopathy Potential Between an Exotic Invasive Weed Alternanthera philoxeroides and a Local Weed A. sessilis

To estimate the allelopathy potential of Alternanthera philoxeroides, the inhibition rates of different organs of the exotic invasive weed A. philoxeroides on seedlings of lettuce (Lactuca sativa L.) and barnyardgrass Echinochloa crusgalli (L.) Beauv. var. mitis (Pursh) Peterm.] were measured with a Chinese native weed A. sessilis as a control by the sandwich method. Under the treatment of 50 mg leaves of A. philoxeroides, the root growth of the lettuce and barnyardgrass was inhibited by 81% and 51%, respectively, and for the shoot growth by 49% and 48%, respectively, significantly higher than the control. However, there were no significant difference compared with that of the treatment of A. sessilis. The inhibition rate on the root length of barnyardgrass was 54% on average under the treatment of the root of A. philoxeroides, much higher than that of the treatments of its stem and leaf. In addition, with the dose of sample of A. philoxeroides increasing, the inhibition rate against the root growth of lettuce enhanced significantly, and the values were 54%, 61% and 83% under the treatments of 10 mg, 30 mg and 50 mg leaf of A. philoxeroides, respectively.