Screening Of Inter-rhizosphate Solubilizing Fungi Of Barley And Their Probiotic Properties

Highland barley as one of the main grain crops in Tibet area,its demand and planting amount is huge.Due to the geographical location and natural climate in Tibet,crop diseases or poor growth conditions occur.Due to the scarcity of soluble phosphorus in agricultural production,long-term application of large amounts of fertilizer and phosphate fertilizer to meet the demand for phosphorus leads to the excessive accumulation of phosphorus in plant soil,which affects the soil p H value and makes the soil excessively salinized,thus resulting in the decrease of crop productivity.In this study,328 strains of fungi were isolated from the barley rhizosphere soil,and 91 strains of phosphorus solutizing fungi were obtained.Finally,4 strains of fungi with phosphorus solutizing characteristics and taking into account a variety of different growth promoting abilities were selected,identified and combined in pairs to construct the dominant complex flora with better growth promoting ability.To observe the effect of phosphorus soluble fungi and complex bacteria on the growth of barley,the dish germination test and greenhouse pot test were carried out.The main conclusions of this study are as follows:1.Four strains of phosphate solubilizing fungi,HQK-1,HQK-6,XL22-6 and XL22-48,were isolated and screened from barley inter-rhizosphere soil with phosphate solubilizing characteristics and other good growth-promoting characteristics.2.By morphological observation and molecular sequencing,HQK-1,HQK-6 and XL22-6 were identified as Talaromyces purpureogenus and strain XL22-48 as Botryotinia ranunculi.3.In vitro co-culture antagonistic tests showed that the four dominant phosphorus solubilizing fungi strains could be combined in pairs.The abilities of phosphorus solubilization,nitrogen fixation,potassium solubilization and IAA production of all the complex bacteria were measured.The bacteria solution of the treatment group was non-toxic to seeds when the concentration was 1×10~3cfu/m L through in-dish seed germination test.Finally,four single bacterial colonies were selected for treatment and two groups of complex bacteria for follow-up test.Single colony treatment(HQK-1,HQK-6,XL22-6,XL22-48),complex bacterial community F3(HQK-1+XL22-48)and complex bacterial community F4(XL22-6+HQK-6).4.The results of greenhouse pot experiment showed that,among the various indexes of the growth of barley,the compound bacterial community F3(HQK-1+XL22-48)had the most significant growth promoting ability,the average plant height reached 24.12 cm,and the root length reached 19.31 cm.The ratio of plant height to water treatment increased by 31.54%and 16.09%compared with PDB control.The underground root length increased by 33.74%and 25.45%compared with PDB control.XL22-48 had the best single strain treatment effect.Under the condition of phosphorus deficiency,the effect of F4(XL22-6+HQK-6)was the most prominent,and the plant height reached 24.02cm,which increased by 22.57%compared with the highest single strain XL22-48.Compared with water control and PDB control without nitrogen and potassium,the increase was 61.33%and 50.19%.Total P content and available P content in soil increased compared with the control.The results of the above studies have positive impacts and important implications for agricultural production as well as crop yield increase in Tibet,and provide a theoretical basis for enriching the Tibetan mycorrhizal resource base.