以小白菜(Brassica campestris L ssp.Pekinensis(Lour.)Olsson),萝卜(Raphanus sativus L.),水稻(Oryza sativaa L.),热研2号柱花草(Stylosanthes guianensis cv.Reyan No.2)作为测试植物,研究新鲜假臭草(Praxelis clematidea(Criseb.)King and Robinson)水浸提液对种子发芽,新鲜假臭草和风干假臭草水浸提液对幼苗早期生长的化感效应以及不同生长环境下的假臭草浸提液对萝卜幼苗早期生长的化感作用.结果表明:新鲜假臭草浸提液对4种测试植物的种子发芽都有抑制作用.假臭草叶和完整植株水浸提液的化感作用明显大于其它器官水浸提液化感作用,叶可能是似臭草释放化感物质的主要器官.风干和新鲜假臭草水浸提液在低浓度时抑制所有测试植物幼苗根系生长.在逆境(如干旱和养分胁迫)中,假臭草会释放更多的化感物质,从而导致其化感作用增强.%The allelopathic effect of aqueous extracts of fresh Praxelis(Praxelis clematidea)material on germination and of all extracts from fresh and dry Praxelis material on initial seedling growth were studied on the following crops: Chinese cabbage(Brassica campestris L. ssp. Pekinensis(lour.)Olsson), radish(Raphanus sativus L.), rice (Oryza sativa L.) and Stylosanthes CIAT184(Stylosanthes guianensis cv. Reyan No. 2). Allelopathic effect of extracts of Praxelis in various habitats were also studied. All aqueous extracts from fresh Praxelis inhibited seed germination of all four test species. Leaf and whole plant extracts exhibited greater phytotoxicity than extracts from other plant parts. Leaves might be the parts of Praxelis that mainly released the allelochemicals. Dry matter extracts of Praxelis severely inhibited the root growth of the crop species and there was an indication of a similar trend with extracts of fresh material at lower concentrations. Allelopathic activity of P. clematidea increased under adverse(arid or nutriental stress)conditions under which more allelochemicals might be released.
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