Effects Of Ficus Carica L.Aqueous Extract On Seedling Growth And Soil Microbial Community Of Taxus Cuspidata Sieb.et Zucc.

Ficus carica L.is a species of Ficus plant in the Moraceae family,which is one of the oldest medicinal and edible homologous trees in human cultivation history.Taxus cuspidata Sieb.et Zucc.is one of the endangered plant species under Class I protection in China and has high medicinal value.Our research group found in the early stage that the mixture of F.carica and T.cuspidata has a promoting effect on the growth of T.cuspidata.This article explores the promoting effect of F.carica on T.cuspidata from the perspective of allelopathy:using F.carica as allelopathic donor plant and T.cuspidata as allelopathic receptor plant,and conducted pot experiment to investigate the effect of root aqueous extract of F.carica on allelopathy of T.cuspidata.Basis on the promoting effect of F.carica rhizosphere soil extracts on the growth of T.cuspidata in different planting years,the effects of different concentrations(10.0 g·L^-1,20.0g·L^-1,40.0 g·L^-1)of root aqueous extract of F.carica on growth indexes,physiological indexes,soil physicochemical properties,soil enzyme activities and soil microbial diversity were systematically analyzed to clarify the allelopathy mechanism of F.carica on T.cuspidata.The main research findings are as follows:1.The root aqueous extract of F.carica promoted the growth of T.cuspidata plant height and basal diameter,while different concentrations of root aqueous extract of F.carica showed a trend of“low promotion and high inhibition”,and the order from large to small is:10.0 g·L^-1>20.0 g·L^-1>40.0 g·L^-1.The net photosynthetic rate,transpiration rate,stomatal conductance and intercellular CO₂ concentration of T.cuspidata increased first and then decreased with the increase in the root aqueous extract of F.carica concentration.The low concentration of root aqueous extract of F.carica was more beneficial to the accumulation of chlorophyll a,chlorophyll b and total chlorophyll.The activities of three protective enzymes,superoxide dismutase,peroxidase and catalase in T.cuspidata leaves increased first and then decreased with the concentration of root aqueous extract of F.carica.The malondialdehyde content decreased first and then increased with the concentration of root aqueous extract of F.carica,and the inhibitory effect was the strongest at the concentration of 10.0 g·L^-1.2.The root aqueous extract of F.carica improved soil p H and reduced soil electrical conductivity.With the increase in the concentration of root aqueous extract of F.carica,the contents of soil organic carbon,available nitrogen,available phosphorus and available potassium in T.cuspidata increased to a certain value at first and then decreased as the root aqueous extract of F.carica concentration increased,the whole value were above that of the control group.The promoting effect was more obvious in the treatment group of 10.0 g·L^-1 and 20.0 g·L^-1.The soil activities of urease,catalase,cellulase and sucrase in T.cuspidata increased first and then decreased with the increase in the root aqueous extract of F.carica concentration,the soil enzyme activities reached the peak at 105 days after treatment.3.Through high-throughput sequencing technology,it was analyzed that root aqueous extract of F.carica can improve the relative abundance of beneficial bacteria and fungi in T.cuspidata soil to a certain extent,and reduce the relative abundance of harmful pathogenic fungi.Different concentrations of root aqueous extract of F.carica decreased the bacterial diversity of T.cuspidata soil,and the soil bacterial diversity and abundance of T.cuspidata soil were the highest bacterial after 105 days of treatment.The abundance of Actinobacteria,Proteobacteria and Acidobacteria at the phylum level was increased after treatment with different concentrations of root aqueous extract of F.carica,and the relative abundance was the highest when the concentration was 40 g·L^-1.The abundance of beneficial microorganism Arthrobacter was enriched at genus level and the relative abundance was the highest when the concentration was20 g·L^-1.With the increase of the concentration of root aqueous extract of F.carica,the fungal diversity of T.cuspidata soil changed irregularly.The diversity and abundance of fungi in T.cuspidata soil were the highest after 180 days of treatment with root aqueous extract of F.carica.The beneficial microorganisms Basidiomycota and Mortierellomycota were enriched at the phylum level after treatment of different concentrations of root aqueous extract of F.carica,and the relative abundance was the highest when the concentration was 20 g·L^-1.The relative abundance of Mortierella was enriched at the genus level,the relative abundance of the harmful fungus Penicillium was decreased.To sum up,different concentrations of root aqueous extract of F.carica had a certain allelopathic effect on T.cuspidata,which mainly showed"low promotion and high inhibition"in growth index and physiological index.The irrigation of root aqueous extract of F.carica can effectively increase the soil physical and chemical properties and soil enzyme activity of T.cuspidata,and change the soil microbial diversity.The research results provide theoretical basis and technical support for the construction of F.carica and T.cuspidata forest drug compound management.