Abstract: Four kinds of exogenous phenolic acids, including salicylic acid, fumalic acid, pcoumaric acid and phydroxybenzonic acid, were used to investigate their regulatory effect on allelopathy of the wild rice (Oryza longistaminata) S37. The results showed that though low in weedsuppressive activity, the four kinds of exogenous phenolic acids induced the enhancement of the allelopathic potential of the wild rice S37 in target weed plants, and the inducible effects were dependent on the kinds of exogenous phenolic acids, concentration and treatment time. After foliar spraying the exogenous phenolic acids, the inhibitory effects of the wild rice S37 on plant height, root length and fresh weight of Echinochloa crusgalli were significantly higher than that of the control. Especially at the concentration of 100 mg/L, the plant height and fresh weight inhibition rates of fumalic acid were 38.12 and 26.31 percent points higher than that of the control, showing fumalic acid was more effective compared with other phenolic acids for weed control. Furthermore, the weedsuppressive activity of aqueous extracts from wild rice S37 leaves was increased after treatment with exogenous phenolic acids and peaked at 48 h after treatment, and then gradually declined.

Key words: salicylic acid, fumalic acid, pcoumaric acid, phydroxybenzoic acid, allelopathy, inducible effect, Oryza longistaminata

摘要： 以长雄蕊野生稻S37为材料，生物测定外源水杨酸（salicylic acid）、阿魏酸（fumalic acid）、香豆酸（pcoumaric acid）和对羟基苯甲酸（phydroxybenzoic acid）在不同浓度和诱导时间下对长雄蕊野生稻S37化感抑草效应的影响，以探讨外源酚酸类物质对水稻化感效应的调控作用。结果表明，外源4种酚酸单剂对稗草的抑制活性较低，但能够诱导长雄蕊野生稻S37使其化感抑草效应增强，且这种诱导效应与外源酚酸的种类、浓度和诱导时间显著相关。叶面喷施4种酚酸后，野生稻S37对伴生稗草株高、根长和鲜质量的抑制率显著提高，其中阿魏酸处理组对稗草的抑制作用最强，在剂量为100 mg/L时，对稗草株高和鲜质量的抑制率分别高出对照38.12和26.31个百分点。此外，长雄蕊野生稻S37在酚酸处理后不同时间的叶片水提液对稗草的抑制效应存在差异，处理后48 h叶片水提液对稗草的抑制作用最强，后逐渐减弱。

关键词: 水杨酸, 阿魏酸, 香豆酸, 对羟基苯甲酸, 化感作用, 诱导效应, 长雄蕊野生稻