不同抗连作障碍品种草莓根系分泌物化感物质差异分析及其化感效应

以不同抗连作障碍品种‘土特拉’、‘丰香’和‘全明星’为试材,研究了三者根系分泌物中主要酚酸种类和含量的差异、接种镰刀菌后根际微生物的变化、根系分泌物对组培苗和尖孢镰刀菌的化感效应.结果表明:‘全明星’根系分泌物中对羟基苯甲酸和苯甲酸含量分别高达0.0624 mg/g DW和0.0173 mg/g DW,均明显高于‘土特拉’.根系分泌物对‘全明星’株高、根数和鲜重等均表现很强的抑制作用,化感效应指数均在0.50以上；但对‘土特拉’抑制作用最弱,低浓度分泌物能促进根系生长.‘全明星’根系分泌物对尖孢镰刀菌生长的抑制作用最小.接菌后‘全明星’根际细菌和放线菌数量均明显下降,真菌总量和尖孢镰刀菌数量上升；‘土特拉’根际各种微生物数量均呈上升趋势,变化率由高到低依次为尖孢镰刀菌、真菌总量、放线菌和细菌；‘丰香’根际微生物数量变化趋势与‘土特拉’相似,但各变化率均小于‘土特拉’.接菌后各品种根际微生物均由“细菌型”向“真菌型”转化,‘全明星’最明显,‘丰香’和‘土特拉’次之.

Allelochemicals and allelopathy of the root exudates of different resistant strawberry cultivars to replant disease

Three strawberry cultivars with different resistance to replant disease,‘Tutela’,‘All-star’ and ‘Toyonoka’,were used to study the differences on the species and contents of main phenolic acid in root exudates and the structures of rhizospheric microorganism after inoculation of F.oxysporum.Allelopathy of root exudates on the growth of different resistant strawberry cultivars and F.oxysporum were also studied,respectively.The results showed that the contents of p-hydroxybenzoic acid and benzoic acid in root exudates of ‘All-star’ were 0.062 4 and 0.017 3 mg/g DW,respectively,which was significantly higher than that of ‘Tudela’.The root height,root number and root fresh weight of ‘All-star’ were strongly inhibited at a higher concentration of root exudates with the value of allelopathic index more than 0.50,while ‘Tutela’ was not inhibited with an encouragement effect on the root growth at a lower concentration.The inhibit effect of ‘All-star’ root exudates was the weakest on the growth of F.oxysporum.There was a sharp decline on the population of bacterium and actinomycete with a significant increase on the population of fungi and F.oxysporum in rhizosphere of ‘All-star’ after inoculation,but in rhizosphere of ‘Tutela’,the population of bacterium,actinomycete,fungi and F.oxysporum all grew up significantly and the change rate was in the order of F.oxysporum,fungi,actinomycete,bacterium from high to low.The change tendency of rhizospheric microorganism of ‘Toyonoka’ was similar to that of ‘Tutela’ but with a smaller change rate.The microorganism structure in rhizosphere of the three cultivars had changed from bacterium-type to fungi-type,of which ‘All-star’ was the most obvious,followed by ‘Toyonoka’ and ‘Tutela’.