蟛蜞菊的生化他感作用及生化他感作用物的分离鉴定

ALLELOPATHIC POTENTIAL OF WEDELIA CHINENSIS AND ITS ALLELOCHEMICALS

蟛蜞菊（Ｗｅｄｅｌｌｉａｃｈｉｎｅｎｓｉｓ（Ｏｓｂ．）Ｍｅｒｒ．）是华南常见的园林绿化草本植物。植被调查表明其群落中杂草很少，形成蟛蜞菊纯群落。用琼脂培养基培养蟛蜞菊发现其分泌物对萝卜和黄瓜的种子萌发和幼苗生长有生化他感作用。蟛蜞菊的组织抽提物对萝卜、稗草、马唐、莴苣和苜蓿５种植物幼苗生长都有抑制作用。用蟛蜞菊作覆盖物对马唐、大画眉草和空心莲子草幼苗生长有抑制作用。用真空液相色谱、快速柱色谱等方法从蟛蜞菊地上部分离出２个纯化合物和１个较纯组分。纯化合物用质谱、红外光谱、核磁共振等方法鉴定为２个倍半萜内酯；Ｏｘｉｄｏｉｓｏｔｒｉｌｏｂｏｌｉｄｅ－６－０－ｉｓｎｂｕｔｙｒａｔｅ和Ｔｒｌｏｂｏｌｉｄｅ－６－０－ｉｓｏｂｕｔｙｒａｔｅ，生物测定表明此２个化合物有很强的生化他感作用。较纯组分经ＧＣ／ＭＳ测定和联机检索确定为５，２２－二烯－３－豆甾醇乙酸脂、十六烯酸甲酯和十八烯酸甲酯３个化合物的混合物，它的生化他感作用较弱。

Chinese Wedelia(Wedelia chinensis(Osb.,Merr.) a common garden herb in South China, tends to form a pure community. Field investigation showed there was few weeds in their community. The herd, when planted in the center of beakers, contained 1 % (W/W)agar, inhibited seed germination and seedling growth of nearby radish and cucumber. The extract of the plant tissue inhibited seeding growth of all the 5 tested receptor plants. W. Chinensir as a mulching material inhibited seedling growth of 3 weeds: Digitaria sanguinalis, Eragrastics cilianesis and Alternanthera Philoxeroides. From aerial parts of W. chinensis, 2 eudesmanolides;Oxidoisotrilobolide-6-0-isobutyrate and Trilobolide-6-0-isobutyrate, were isolated and identi fied. The bioassay showed that the 2 compunds, isofated from W. chinensis, had high appelo pathic potensials. Another fraction, identified as a mixture of 3 compoundsi stigmasta-5, 22-dien-3-01, acetates, methy 1 oleate and methyl hexadecenoate, had relative .low allelopathic potentials.