三种酚酸类化感物质对花生根际土壤微生物及产量的影响

为进一步探明花生连作障碍的机理，通过外源添加的方法研究了不同浓度肉桂酸、邻苯二甲酸、对羟基苯甲酸及其混合物对花生开花下针期、结荚初期、结荚末期根际土壤微生物及产量的影响。结果表明，与对照相比，各处理均降低了各生育期花生根际土壤细菌和放线菌的数量、微生物量生物量以及呼吸强度，增加了真菌的数量。随浓度增加，化感作用增强，以3种酚酸类化感物质混合物的化感作用最强。随处理时间的延长，对真菌的化感作用增强，对其他指标的化感作用减弱。各处理均显著降低了花生产量（P < 0.01），处理浓度越高，花生减产幅度越大。最高浓度（初始含量为90mg·kg-1干土）的肉桂酸、邻苯二甲酸、对羟基苯甲酸以及混合物处理使花生每盆荚果产量分别降低了43.2%、32.9%、40.2%和47.3%。这三种酚酸类物质的累积与连作花生根际土壤微生物群落结构的变化相关，是花生连作障碍产生的可能因素之一。

Effects of three phenolic acid allelochemicals on rhizosphere soil microbes and pod yield of peanut (Arachis hypogaea L.)

In order to further explore the mechanism of continuous cropping obstacle of peanut (Arachis hypogaea L.), effects of different concentrations of cinnamic acid, phthalic acid, p - hydroxybenzoic acid, and their mixture on peanut rhizosphere soil microbes at flowering period, early podding, end of podding stages and peanut yield were studied by using the method of exogenous add. The study results showed that at each growth period, compared with the control, all treatments decreased the quantities of peanut rhizosphere soil bacteria and actinomycetes, microbial biomass carbon and nitrogen content, respiration intensity, and increased the quantity of fungi. The allelopathy increased gradually with the increase of concentration, and the allelopathy of the mixture of the three phenolic acids was the strongest. The allelopathy of on soil fungi quantity strengthened, while weakened on the other indices with the prolonged treatment. All treatments decreased peanut production significantly (P < 0.01). The higher the concentration, the greater the reduction in peanut production. The highest concentration treatment of 90 mg kg-1 dry soil initial content for cinnamic acid, phthalic acid, p - hydroxybenzoic acid, and their mixture reduced the peanut pod yield per pot by 43.2%、32.9%、40.2% and 47.3% respectively. The accumulation of these three phenolic acids correlated with the alteration of soil microbial community structure, which was one of the possible reasons for peanut continuous cropping obstacle.