中文摘要：

目的研究5种化感物质对人参根系酶活性的影响，探讨化感物质对根系保护性酶活性的作用规律。方法采用营养液培养方法，研究了苯甲酸、邻苯二甲酸二异丁酯、丁二酸二异丁酯、棕榈酸和2，2-二（4-羟基苯基）丙烷对苗期人参根系过氧化物酶（POD）、过氧化氢酶（CAT）和苯丙氨酸解氨酶（PAL）酶活性的影响。结果苯甲酸在3种浓度下均抑制人参幼苗根系POD酶活性，邻苯二甲酸二异丁酯和丁二酸二异丁酯仅在低浓度时抑制POD酶活性，棕榈酸和2，2-二（4-羟基苯基）丙烷3种浓度下均促进POD酶活性，且与化感物质浓度呈正相关。除丁二酸二异丁酯和棕榈酸外，其余3种化感物质均表现为处理浓度与CAT酶活性正相关，且与对照相比，化感物质对CAT酶活性的影响均表现促进作用。苯甲酸和丁二酸二异丁酯在低浓度时抑制PAL酶活性，中浓度处理对PAL酶活性的促进作用大于高浓度处理；棕榈酸在低浓度时对PAL酶活性的促进作用最强，2，2-二（4-羟基苯基）丙烷在高浓度时对PAL酶活性的促进作用最强，邻苯二甲酸二异丁酯对PAL酶活性的促进作用与浓度呈正相关。研究还发现，对照及5种化感物质处理中的POD、CAT、PAL酶活性均随处理时间延长而变化，但酶活性与处理时间无明显相关性。结论人参根系分泌物中5种化感物质对人参根系POD、CAT和PAL酶活性有显著影响。

英文摘要：

Objective To study the effect and action rules of five allelochemicals on protective enzyme activity of Panax ginseng roots. Methods By the method of solution culture, the effects of benzoic acid, diisobutyt phthalate, diisobutyl succinate, palmitic acid, and 2,2-bis（4-hydroxyphenyl） propane on the activity of peroxidase （POD）, eatalase （CAT）, and phenylalanine ammonia-lyase （PAL） of P. ginseng roots at seedling stage were studied. Results Benzoic acid inhibited POD activity at three concentration tested, diisobutyl phthalate and diisobutyl succinate inhibited POD activity at low concentration only, palmitic acid, and 2,2-bis（4-hydroxyphenyl） propane enhanced POD activity at three concentration tested, which was positively correlated to alle-lochemical concentration. Except for diisobutyl suceinate and palmitic acid, the other allelochemicals enhanced CAT activity, and their concentration was positively correlated to the activity. Benzoic acid and diisobutyl succinate inhibited PAl. activity at low concentration, and the enhancement of PAIr activity at middle concentration was higher than that at high concentration. Palmitic acid at low concentration and 2,2-bis（4-hydroxyphenyl） propane at high concentration enhanced the PAIr activity most, and the PAL activity was positively correlated to concentration for 2-benzenedicarboxylic acid bis（2-methylpropyl） ester. Furthermore, the activities of POD, CAT, and PAl. fluctuated with time at both control and five allelochemical treatments, but no significant correlation among them. Conclusion Five allelochemicals identified from of P. ginseng roots could significantly influence the activities of POD, CAT, and PAIr.