哈茨木霉菌Tri41对连作人参根际土壤中酚酸物质的消减作用

Trichoderma harzianum Tri41 Degrades the Phenolic Acids in Rhizosphere of Continuously Cropped Ginseng

由于酚酸物质的积累而产生的自毒作用是导致人参连作障碍的重要原因之一。为减缓自毒酚酸物质在人参连作障碍中的影响,选用前期试验中筛选出的生防菌株——哈茨木霉菌Tri41消减连作人参根际土壤中的自毒酚酸物质。采用HPLC法对连作人参根系土壤中的酚酸物质进行分离测定,结果表明,人参根系分泌物中含有没食子酸(GA)、水杨酸(SA)、3-苯基丙酸(3-PA)、苯甲酸(BA)和肉桂酸(CA)共5种酚酸物质。将哈茨木霉菌Tri41分别与这5种酚酸物质在PDB培养基中培养发现,哈茨木霉菌Tri41对5种酚酸物质均有消减作用,各酚酸物质的消减率在48~170h时间内均高于自然消减率,170h后消减率均接近100%,同时还发现,哈茨木霉菌Tri41在酚酸处理组中的平均菌丝干重在48h开始显著增加,170h达到最大值10.88g·L^(-1),显著高于同期无酚酸处理组的菌丝干重6.93g·L^(-1)。盆栽试验结果表明,在自然消减状态下,人参根际土壤中的各酚酸含量呈缓慢下降趋势,哈茨木霉菌Tri41处理对人参根际土壤中的这5种酚酸物质有消减作用,5种酚酸物质的含量在10~20d期间显著下降且在30d时趋近于0。另外,盆栽试验结果也表明,经过5种酚酸物质处理后的人参锈腐病发病率和病害严重度指数均显著上升,而经过哈茨木霉菌Tri41处理后,哈茨木霉菌Tri41可以通过对5种酚酸物质的消减作用显著降低人参锈腐病发病率及病害严重度指数。

The autotoxicity produced by the accumulation of phenolic acid is one of the important causes of ginseng continuous cropping obstacle. In this study, Trichoderma harzianum Tri41 is used to degrade the Phenolic Acids in Rhizosphere of Continuously Cropped Ginseng to alleviate the influnce of phenolic acid of ginseng successive cropping obstacle. Five phenolic compounds in ginseng rhizosphere soil were identified by HPLC, including gallic acid, salicylic acid, 3 -Phenylpropionic acid, benzoic acid and cinnamic acid. Degradation effect was found that the Tri41 cultivated with the five phenolic acids in the PDB medium respectively. The degradation efficiencies of Tri41 were higher than the nature degradation efficiencies from 48-170 h and the degradation efficiencies of Tri41 were close to 100% at 170h. It is found that the dry weight of Tri41 mycelium increased significantly compared to the treatment without acid. The dry weight of Tri41 mycelium began to increase on 48h and got to 10.88 g＊L-1 on 170h while the dry weight of no phenolic acids was 6.93 g＊L-1 at the same period. Pot experiment showed that the most obvious degradation efficiency of the five phenolic acids appeared from 10d to 20 d after Tri41 released and the degradation efficiency were approached to 0 at 30d. The Tri41 treatment reduced the incidence and severity of Cylindrocarpon destructans significantly by degradated phenolic acids.K