Study On Mutual Effect Between The Allelopathy Of Eucalyptus.urophylla×Eucalyptus. Grandis Leaves And Soil Microbe

E.urophylla x E.grandisis is one of Eucalyptus plants.Due to its rapid growth,high yield,wood quality and stability,it can be widely used for furniture plate and paper raw materials,is a kind of excellent speed raw timber forest,which is planted for a large area in Guangxi.The environment of the large area of artificial forest effect has been widely concerned.Plants release substances through leaching,litter decomposition ways into the soil,so the soil micro ecological environment is theimportant factor that influences allelopathic effect and change.And soil microbial is closely related to allelopathic effect,but few people have study on mutual effect between the allelopathy of E.urophylla×E.grandis leaves and soil microbial effect.In order to study the interaction allelopathic composition of E.urophylla x E.grandis leaves and soil microorganisms,so can provide scientific reference to the formulation of relevant policies and development of Eucalypt industry.In this paper,biological activity determination,biolog micro plate method,16SrDNA PCR and high-throughput sequencing means were applied to study the mutual effect between of allelopathic effect of E.urophylla×E.grandis leaves and environmental factors.The processing method,plant height,the germination number,soil nutrient,microbe species and function data were analyzed.The results are as follows:1.Allelopathic effects of E.urophylla×E.grandis leaves on the growth of understory plant Evodia lepta.In order to study allelopathic effects of E.urophylla×E.grandis leaves on the common eucalyptunderstory plants of Guangxi forest,we use Evodia lepta as the object,developing experiment with different amounts and kinds of E.urophylla×E.grandis leaves(the green one was old leaf that was still on the tree,the yellow one was that just fell to the ground and the grey one was that fell on the ground for several days)to determine how seedling growth was influened and what is the mechanism.Results showed as following:The effect of different leaves on receptor plants was very obvious.Before 30 days.The plant height showed no significant difference,but after 45 days,the high concentration of gray leaves and yellow leaves treatment began to show inhibitory effect.With the extension of time,the inhibitory effect was more obvious,and showed the dose respond.And at the end of this test,the grey leaves has a certain role in promoting Evodia lepta growth and high concentration treatment displayed greater promotion.The decomposition of E.urophylla×E.grandis leaves in the soil make the soil pH value decrease to some extent.Effect of different leaves on the number of microorganism in soil is also various,low concentration treatment of yellow leaves more obvious inhibitory effect on the quantity of microorganisms.Adding E.urophylla×E.grandis leaves to soil also affected the photosynthesis,stomatal conductance,intercellular CO2 concentration,transpiration rate of Evodia leptaplants.2.Effects of soil microorganisms on allelopathy of E.urophylla×E.grandis leaves.There was certain relevance between allelopathy of E.urophylla×E.grandis leavesand soil microbial exsiting in the growth experiment of Evodia lepta.In order to verify more directly the impact of soil microorganism on allelopathy,we compared the seed germination of Chinese cabbage onsterilization,adding leaves treated soils and untreated ones.The results showed that E.urophylla×E.grandis leaves inhibited seed germination and seedling growth of Chinese cabbage,and such inhibition was more obvious in sterilized soil,meaning that Eucalyptus allelopathy and soil microbial was correlation.3.Effects of E.urophylla ×E.grandis leaves on soil microorganisms.In order to study the effect of E.urophylla×E.grandis leaves on soil microbial,the degradation ability of microbe in leaves treated soil was determined by Biolog eco micro plate.The results showed that the total decomposition ability of Guangxi Institute of Botany soil microbial(the control)was greater than that of eucalyptus plantation,and the E.urophylla×E.grandis leaves’s adding increased the former one’s ability but reduced the latter one’s.Two kinds of soil utilization of different substrates are not consistent.E.urophylla×E.grandis leaves can enhance the utilization ability of some substrates,the majority of sugars,but also inhibit the use of another substrates,suggesting that microbial functional diversity was affected by the E.urophylla×E.grandis leaves.4.The correlation between the leaves of E.urophylla×E.grandis and soil microbial function.Through the correlation analysis of E.urophylla×E.grandis leaves’s allelopathy and soil microbial function,the results show that when the Chinese Cabbage seed germination number was inhibitedbyE.urophylla×E.grandis leaves,microbial utilizing activity of saccharide substrates was enhanced.The amino acids utilizing ability of E.uropbylla×E.grandisplantation soil microbial,and the seed germination of the Chinese Cabbage is positively related.The utilization of different amino acid substateswas promoted by each other.The stronger ability of soil microbial to use lipid substrates,the higher number of Chinese cabbage seed germination.Soil microbial utilization ability of sugar is stronger,soil K content is higher.Amino acids were used more completely,K content and N content in soilswere lower.Soil microbial utilization ability of carbohydrate substrates is stronger,soil P content is higher.It showed that there was a certain correlation between the functional changes of soil microbes and the changes of soil affecting components.5.A comparative study on genetic diversity of soil microorganisms between eucalyptus forest soils and other soils.In order to inspecte the soil microbial genetic diversity between eucalyptus forest soilsand other soils,the eucalyptus forest soil(a),soil from Guangxi Institute of botany test groud(d),hardwood forest soil(z)and fir forest soil(s)were collected and their soil microbial diversity were compared by high throughput sequencing technology.The results are as follows:(1)Soil microbial quantity would be influenced by the soil utility pattern,so the structure and diversity soil microbial community were various:bacterial numbers(from PCR):d>s>z>a,OTU quantity:d>s>a>z,endemic OUT:d(4783)>a(2697)>s(2427)>z(2265),bacterial species:(chaoland\ace index)d>a>s>z,community diversity index(Simpson):d>s>z>a,heterogeneity(Shannon index):d>s>a>z.It showed that the number,structure and diversity of soil microbial biomass of Eucalyptus plantation had certain influence.(2)The more bacteria in the soil,the lower the germination number of Chinese cabbage seeds,the higher the N.P.K content of the soil.These results indicate that the allelopathy of E.urophylla×E.grandis leaves is related to the number of soil microorganisms.In conclusion,we found that the species and quantity of soil microorganisms played an important role in the process of exploring the allelopathic effects of E.urophylla×E.grandis leaves to the plant.