Effect Of Potassium-solubilizing Bacteria On Potassium Nutrition Of Solidago Canadensis

Solidago canadensis is one of the most invasive alien plants in China.In recent years,with the gradual expansion of the invasive scope of Solidago canadensis,the ecosystem and biodiversity of many regions in China are constantly threatened.Therefore,understanding the invasion mechanism of Solidago canadensis has become the focus of research.Previous studies on invasion mechanism of Solidago canadensis mainly focused on reproductive characteristics and allelopathy,but with the deepening of research,more and more studies showed that physiological characteristics and microbial response of Solidago canadensis played an important role in its invasion process.In this paper,Solidago canadensis was taken as the main object of study.The effects of potassium nutrition on the growth of Solidago canadensis,the potassium nutrition effects of potassium-solubilizing bacteria on Solidago canadensis,and the regulation effects of root exudates and litters on Rhizosphere potassium-solubilizing bacteria were studied.The mechanism of Rhizosphere potassium-solubilizing bacteria and the effect of potassium-solubilizing bacteria on potassium nutrition level in Solidago canadensis was prelimina To provide reference for further understanding of its invasion process,comprehensive understanding of its harm and putting forward feasible prevention and control measures.This paper mainly obtains the following research results:1.Through sand culture and soil culture experiments,the effects of different potassium nutrition treatments on the growth index,biomass accumulation,potassium content in plantsand soil available potassium,slow-acting potassium and available potassium content were studied.It was found that the more potassium content in soil,the more potassium content in plant,the more potassium content in soil,the more potassium content in plant growth index and biomass.Accumulation and potassium content increased.Compared with the associated indigenous plants,Solidago canadensis has a relatively strong ability to absorb potassium.In addition,the contents of available potassium,slow-acting potassium and available potassium in soil were significantly reduced after the invasion of Solidago canadensis.2.After counting culture with potassium-dissolving medium,it was found that the number of Rhizosphere potassium-solubilizing bacteria of Solidago canadensis is 3.51 times that of Imperata cylindrica.After isolated culture,the strains with potassium-dissolving rings were identified,and the amount of potassium-dissolving was determined by liquid culture experiment of potassium-dissolving.Then it was found that among the 15 strains of potassium-solubilizing bacteria isolated from the rhizosphere soil of Solidago canadensis,9of them had the ability to dissolve potassium efficiently,the content of K~+in the treatment solution was higher than that in the blank control 85.11%~192.54%.Among them,strain H2-20 had the strongest potassium-solubilizing ability,and the amount of potassium dissolved is 10.657 mg/L,The results of T test showed that the potassium-solubilizing effect of Rhizosphere Potassium-solubilizing Bacteria of Solidago canadensis was significantly higher than that of Rhizosphere Potassium-solubilizing Bacteria of Imperata cylindrica.According to 16SrDNA identification,15 strains of Rhizosphere potassium-solubilizing bacteria of Solidago canadensis were divided into 11 genera,of which 6 genera have been reported to have potassium-solubilizing ability.Therefore,this study preliminarily considered that the number of Rhizosphere potassium-solubilizing bacteria of Solidago canadensis was relatively rich,and most of them had high potassium-solubilizing activity,which may play an important role in potassium enrichment.3.By collecting root exudates and litters of Solidago canadensis and its associated Aboriginal plants and applying them to soil,the difference of the number of potassium-degrading bacteria in soil under different plant root exudates and litter treatments was determined.It was found that the number of potassium-degrading bacteria in soil increased significantly under the treatment of root exudates and litter of Solidago canadensis.Secrets and litter also promoted soil Potassium-solubilizing bacteria,but far less than Solidago canadensis.Solidago canadensis may change the rhizosphere soil environment in the invaded area through root exudates and litter,forming a soil micro-environment conducive to the survival of soil potassium-solubilizing bacteria,thus promoting the accumulation of soil potassium-solubilizing bacteria in the root soil of Solidago canadensis.Through the potassium-solubilizing effect of potassium-solubilizing bacteria,it can supply abundant Potassium nutrition to Solidago canadensis,and ultimately promote the absorption of potassium nutrition in Solidago canadensis.This may be one of the mechanisms of invasion of Solidago canadensis.The above studies showed that Solidago canadensis has a strong potassium absorption capacity,and potassium nutrition can significantly promote its growth and development and biological accumulation.In addition,Solidago canadensis may alter its rhizosphere soil microenvironment through the interaction of root exudates and litter,promote the accumulation of Potassium-solubilizing bacteria in the rhizosphere,thereby regulating the content of K nutrition in the rhizosphere soil of Solidago canadensis,and indirectly promote the potassium nutrition of Solidago canadensis.