Biodegradation of benzoic acid and p-hydroxybenzoic acid in the strawberry planting soil by two strains of actinomyces | 2株放线菌对土壤中苯甲酸和对羟基苯甲酸的降解作用

Chinese. 研究2株放线菌对土壤中草莓根泌自毒物质苯甲酸和对羟基苯甲酸的降解效果。以2株对草莓有促生作用的放线菌Act11和Act12为材料，将其接种于含有定量苯甲酸和对羟基苯甲酸的土壤中,模拟自然条件下培养，定期测定其对土壤中苯甲酸和对羟基苯甲酸的降解量和相对降解率。供试放线菌在模拟田间条件下对土壤中苯甲酸和对羟基苯甲酸有较强的降解能力。培养150 d后，Act11和Act12对苯甲酸的降解量分别达到700～888和747～867 mg/kg，对对羟基苯甲酸的降解量分别达到94～218和117～118 mg/kg。在土壤中加入有机质对2种酚酸相对降解率的影响不同，其中有机质对苯甲酸的相对降解率无显著影响；但Act11在培养15，60，150 d及Act12在培养60 d时，加入有机质能显著提高对羟基苯甲酸的相对降解率。所有接菌土壤中，苯甲酸与对羟基苯甲酸平均降解速度较CK均有所提高。供试放线菌对土壤中的苯甲酸和对羟基苯甲酸有较强的降解能力，加入有机质对对羟基苯甲酸的降解有明显促进作用。

English. Benzoic acid and p-hydroxybenzoic acid are the two main autotoxins produced by strawberry in soil. The experiment was to study the degradation effect on the two acids by two strains of actinomyces. Two strains of actinomyces, Act11 and Act12, which can promote the growth of strawberries, were taken as study materials. Certain amounts of actinomyces were inoculated into the soil which contained benzoic acid and p-hydroxybenzoic acid. The relative degradation rates of the two acids by the actinomyces were measured regularly after 15 days’ incubation under field conditions. Both the two actinomyces had a high ability to degrade benzoic acid and p-hydroxybenzoic acid in soil under field conditions. After 150 days’ incubation, the degradation amounts of benzoic acid by Act11 and Act12 were in the range of 700－888 mg/kg and 747－867 mg/kg, respectively. Correspondingly, 94－218 mg/kg of p-hydroxybenzoic acid was degraded by Act11 and 117－118 mg/kg by Act12. The effects of organic matter on the degradation rate of the two phenolic acids were different. There was no significant influence on the relative degradation rates of benzoic acid, while the relative degradation rates of p-hydroxybenzoic acid significantly increased in the Act11 treatment of the 15th, 60th, 150th day and in the Act12 treatment of the 60th day (P＜0.05). Both the average degradation velocities of benzoic acid and p-hydroxybenzoic acid in the inoculated treatment were higher than those in CK treatment. Both actinomyces are able to degrade benzoic acid and p-hydroxybenzoic acid in soil. Organic matter added into the soil can increase the degradation rate of p-hydroxybenzoic acid.