Rhizosphere Microbial Community And Fruit Quality Of Winter Jujube In Saline Soil

Soil salinization has an important effect on fruit yield and quality.Dongzao(Ziziphus Jujuba Mill CV.Dongzao)is a fresh jujube variety originating from Bohai Bay area of China,with excellent quality and salt-resistance.Rhizosphere microorganisms play an important role in plant growth and development,which can alleviate plant salt stress to a certain extent.Therefore,it is of great significance to study the rhizosphere microorganism of winter jujube in saline-alkali land.In order to study the rhizosphere soil microbial diversity and community structure of winter jujube in salt-alkali soil and its effect on fruit quality,we selected winter jujube orchard in he salt-alkali area along the Yellow River in Dali County,Shaanxi Province.We collected soil around the root of the fruit tree,and determined the physical and chemical properties of the soil.16 S r DNA and ITS amplicon sequencing technology were used to conduct high-throughput sequencing of rhizosphere soil bacteria and fungi,and the leaves and fruits of early red stage were collected to determine leaf growth and fruit quality.The main conclusions are as follows:(1)Proteobacteria,Acidobacteriota,Actinobacteriota and Firmicutes are the dominant bacteria in the rhizosphere of winter jujube in saline soil.The predominant fungal phyla were Ascomycota,Mortierellomycota,Basidiomycota and Chytridiomycota.The increase of soil salinity reduced the diversity of rhizosphere microbial community and the overall function of rhizosphere microbial community.Compared with bacteria,fungi contributed more to the stability of rhizosphere community of winter jujube under high salinity conditions.It was also found that Halomonas and other salt-tolerant microorganisms were highly enriched in the rhizosphere of winter jujube under high salinity conditions,and these salt-tolerant microorganisms may be available resources for winter jujube cultivation and salt-alkali soil improvement.(2)The increase of soil salinity would lead to the decrease of leaf thickness and weight.At the same time,the increase of soil salinity can increase the flavor and nutritional quality of winter jujube fruits,but also lead to the decrease of fruit size and weight,and the deterioration of comprehensive quality.The increase of soil phosphorus content will lead to the increase of fruit hardness and brittleness ratio.Due to the extremely high soil potassium content in the garden,excessive potassium will lead to the decrease of fruit soluble solid.(3)Rhizosphere microbial diversity was correlated with fruit quality and leaf growth of winter jujube.There was a positive correlation between bacterial diversity and soluble sugar in winter jujube fruit,a positive correlation between fungal diversity and leaf circumference,area and weight,and a negative correlation between bacterial diversity and fruit diameter and leaf density.In conclusion,this study clarified the rhizosphere microbial diversity and community structure of Jujube jujube in salt-alkali soil,and revealed the effects of soil salinization and rhizosphere microorganisms on fruit quality and leaf growth of winter jujube.It provides a foundation for the high quality and efficient cultivation of winter jujube in saline-alkali land,utilization and improvement of saline-alkali land.At the same time,it also provides support for the study of interaction between jujube and other fruit trees,microorganisms and environment.