富纳米硒沼泽红假单胞菌对镉胁迫下连翘生长、活性成分及镉积累的影响OA

Forsythia suspensa is a valuable traditional Chinese medicinal herb.However,cadmium pollution in its cultivation soil has become increasingly prominent,posing a serious threat to the yield and medicinal quality safety of F.suspensa.In order to explore regulatory approaches for the high-quality cultivation of F.suspensa in Cd-contaminated soil,in this study,F.suspensa(Thunb.)Vahl was used as the experimental material,three treatments including soil Cd concentration of 7.5 mg/kg+irrigation of 200 mL deionized water(Cd),soil Cd concentration of 0.3 mg/kg+irrigation of 200 mL SR bacterial solution(SR),and soil Cd concentration of 7.5 mg/kg+irrigation of 200 mL SR bacterial solution(Cd-SR)were set,and soil Cd concentration of 0.3 mg/kg+irrigation with 200 mL of deionized water as taken as the control(CK).The regulatory effects of selenium nanoparticles-enriched Rhodopseudomonas palustris(SR)on the growth indicators,chlorophyll content,bioactive component accumulation,antioxidant capacity,and leaf Cd content of F.suspensa under Cd stress was systematically analyzed.The results showed that compared with the Cd group,the growth inhibition of F.suspensa in the Cd-SR group was significantly alleviated,with the leaf number increasing by 44.98％(recovering to the level number of the CK group)and the chlorophyll content significantly increasing by 51.92％.SR exerted a significant promoting effect on the accumulation of bioactive components in F.suspensa leaves:the total flavonoid content and total phenolic acid concentration in the Cd-SR group were 320.15％and 153.07％significantly higher than those in the Cd group,respectively,whereas the forsythin content showed a slight increase without statistical significance.The DPPH+·radical scavenging rate and ABTS+·radical scavenging rate in the Cd-SR group were 145.78％and 109.19％significantly higher than those in the Cd group,respectively.The leaf Cd content in the Cd-SR group was significantly reduced by 37.88％compared with the Cd group.Correlation analysis revealed that leaf Cd content had an extremely significantly negative correlation with total phenolic acid concentration,total flavonoid content,and DPPH+·radical scavenging rate,chlorophyll content showed an extremely significantly positive correlation with leaf number and leaf fresh weight,had a significantly positive correlation with leaf area and DPPH+·radical scavenging rate,both total flavonoid content and total phenolic acid concentration exhibited an extremely significantly positive correlation with DPPH+·radical scavenging rate and a significantly positive correlation with ABTS+·radical scavenging rate.In conclusion,the application of SR could effectively alleviate the Cd stress on F.suspensa by promoting plant growth,enhancing the function of the antioxidant system,increasing bioactive component accumulation,and reducing leaf Cd content.