三种酚酸类物质在花生连作障碍中的生态效应分析

摘要

To elucidate the role of phenolic acids in the formation of continuous cropping obstacles in peanuts, ecological effects of cinnamic acid, phthalic acid, p-hydroxybenzoic acid and their mixtures with 4 different concentrations on soil were studied in indoor simulation culture in order to exclude the interference from field factors.The results showed that when the initial content of allelochemicals was low (15 mg·kg-1), the soil microbial biomass carbon and nitrogen, microbial activity, enzyme activities (urease, neutral phosphatase, sucrase, polyphenol oxidase, and catalase) and nutrient contents (alkali-hydrolyzable nitrogen, available phosphorus, and available potassium) in all treatments were slightly higher than those in the control, without significance (P＞ 0. 05). When the initial content of allelochemicals was 30 mg·kg-1 or more, all studied indicators were decreased with the increases of treatment concentration. The mixture of these 3 phenolic acids had the strongest allelopathic effect. Overall, with the extension of cultivation time, the allelopathic inhibition of phenolic acids increased first and then weakened. The strongest allelopathic inhibiton effect of p-hydroxybenzoic acid was on the 7 th day, while that of cinnamic acid, phthalic acid and the mixture of the three phenolic acids was on the 15 th day. It was assumed that the accumulation of phenolic acids was directly related to the deterioration of the micro-ecological environment of continuous cropping peanuts, which was one of the important factors for the formation of peanut continuous cropping obstacle.%为阐明酚酸类物质在花生连作障碍形成过程中的作用机理,本研究排除田间因素的干扰,通过室内模拟培养法,研究了4种不同浓度的肉桂酸、邻苯二甲酸、对羟基苯甲酸及其混合物对土壤的生态效应.结果表明,当酚酸类物质的初始含量较低(15mg·kg-1干土)时,各处理土壤微生物量碳氮、微生物活性、酶活性(脲酶、中性磷酸酶、蔗糖酶、多酚氧化酶和过氧化氢酶)及养分含量(碱解氮、有效磷、有效钾)均略高于对照,但差异不显著(P＞0.05);当其初始含量达到或高于30mg·kg-1干土时,各指标均降低,且随浓度增加降幅增大,以3种酚酸类物质混合物的化感抑制作用相对最强.总体来看,随培养时间的延长,酚酸类物质的化感抑制作用呈先增强后减弱的趋势.其中,对羟基苯甲酸在处理第7d化感抑制作用达到最强,而肉桂酸、邻苯二甲酸和3种酚酸类物质混合物的最强化感作用是在处理第15d.推测酚酸类物质的累积与连作花生土壤微生态环境的劣化有着直接关系,是花生连作障碍形成的重要因素之一.