刚果12号桉对4种豆科植物的化感作用

采用室内生物检测的方法研究了刚果12号桉叶片自然释放的挥发性物质、叶片水抽提物、叶片经水蒸气蒸馏所得的桉油、含挥发性水溶性物质的冷凝水和含水溶性非挥发性物质的渣汁3个组分以及桉树根际土壤水浸液对绿豆、大豆、柱花草与大翼豆4种受体植物的化感活性。结果表明：刚果12号桉叶片释放的挥发性物质对4种受体植物种子的萌发有强烈的抑制作用：桉叶水抽提物与根际土壤水浸液对绿豆、大豆、柱花草与大翼豆4种受体植物种子萌发与幼苗生长不但有一定抑制作用，而且土壤水浸液对绿豆、大豆和柱花草幼苗的根生长还有不同程度的促进作用，处理分别比对照高出13％、2％、23％。从桉油、冷凝水与渣汁3个组分的化感活性来看，渣汁的最强，桉油次之，冷凝水最低，即单位叶片中水溶性物质的化感活性比挥发性的高。这表明水溶性化感活性物质可能是刚果12号桉的主要化感作用物质。

Allelopathic Effects of Eucalyptus 12ABL on Four Legume Species

The allelopathic potential of Eucalyptus 12ABL was examined by way of bioassay with fresh leaf volatiles, leaf water extracts, leaf distillate oil, leaf distillate condensate and leaf distillate residue as well as rhizosphere soil leachate on seed germination and seedling growth of Phaseolus radiata Linn, Stylos anthes guianensis cv. Reyan No2., Glycine max(Linn.) Merr., Macroptilium atropurpureum (DC)Urban. The leaf volatiles under desicator environment showed considerable inhibitory effect on seed germination and seedling growth of the four recipient legume plant species. The leaf water extracts and the rhizosphere soil leachate did not only present certain inhibitory activity but also exhilarating effect as well, in that a 13 %, 2 % and 23 % higher in radicle growth was recorded in the treatments than the respective controls in case of Phaseolus radiata Linn., Glycine max(Linn.) Merr. and Stylosanthes guianensis cv. Reyan No2. The overall inhibition on seed germination and shoot and root elongation that occurred as a result of allelopathic effect, in decreasing order, the leaf distillate residue containing water soluble substances, the leaf distillate oil containing volatile substances, the leaf distillate condensate containing water soluble volatile substances, indicated that water soluble compounds may play more important role than volatile allelochemicals in the allelopathic potential of Eucalyptus 12ABL.