Amelioration of Salt Stress on Wheat Plants Growth in Coastal Saline Soil by a Phosphate Solubilizing Bacterium Enterobacteria sp. EnHy-401

A pot experiment was conducted to examine the effects of a phosphate solubilizing bacterium（PSB）,Enterobacteria sp.EnHy-401,on the availability of insoluble accumulative phosphorus（P）and growth of wheat（Triticum Ningmai No.13）plants in sterile saline soil.Our results showed that the strain EnHy-401 had the ability to activate the insoluble accumulated phosphorus in saline soil and enhanced nutrient uptake efficiency by wheat plants,then conferred resistance in wheat plants to salt stress and resulted in a significant growth increase.In saline soil inoculated with Enterobacteria sp.EnHy-401,available phosphorus and exchangeable calcium was increased from 6.4 mg/kg and 1 162 mg/kg to 10.3 mg/kg and 1 214 mg/kg,respectively.Wheat seedling grown in soil inoculated with the EnHy-401 strain increased shoot weight by 28.1% and root weight by 14.6% when compared to the control.P,Ca,K and Mg contents in shoots increased 34.4%,36.3%,31.5%,and 6.3% compared to the control,respectively.the fact that the increases in available P,biomass P,and Ca2＋ concentration in saline soil treated with PSB Enterobacter sp.EnHy-401 inocula,and high relativity between the P,Ca,K,and Mg content in wheat tissue and dry matter indicated that PSB Enterobacter sp.EnHy-401 suppressed the adverse effect of salinity stress in plants through nutrient（P and Ca）supply and nutrient（K and Mg）uptake enhancement.The phosphate solubilizing activity of Enterobacteria sp.EnHy-401 and the amelioration of salt stress on wheat plants by the strain varied with the salinity levels and content of organic matter in the saline soil.

Assessment of biotechnological potential of phosphate solubilizing bacteria isolated from soils of Southern Kazakhstan

Phosphorus (P) is a vital plant nutrient, available to plant roots only in soluble forms that are in short supply in the soil. Adding phosphate- based fertilizers to increase agricultural yields is a widely used practice;however, the bio- availability of P remains low due to chemical transformations of P into insoluble forms. Thus, phosphate solubilizing bacteria (PSB) play an important role in reducing P deficiency in soil. The goal of this study was to assess biotechnological potential of phosphate-solubilizing bacterial strains. In this study, phosphate solubilizing microorganisms (PSM) were isolated from different soil samples of Southern regions of Kazakhstan. The biological activity of PSM was studied based on their effect on the growth of wheat seeds. The different taxonomic genera of these PSM were identified: Arthrobacter spp., Aureobacterium spp., Azotobacter spp., Bacterium spp., Baccillus spp. Finally, phosphate- solubilizing activity of isolated strains of PSM was assessed.

A Feasible Way of Degrading Malathion Pesticide under Laboratory Condition Using Phosphate Solubilizing Bacteria

An experiment was carried out for identification and determination of malathion degrading phosphate solubilizing bacteria isolated from the agricultural fields. In this study, malathion degrading phosphate solubilizing bacteria were identified using NBRIP (National Botanical Research Institute’s phosphate growth medium) media. A number of bacterial colonies were screened from agricultural fields. From primarily screened colonies 4 isolates were identified as phosphate solubilizing bacteria through qualitative and quantitative analysis. The isolated 4 bacterial colonies were inoculated in NBRIP broth media enriched with malathion pesticides to observe degradation of malathion pesticide under incubation study at three different temperatures (25°C, 30°C and 37°C). However, all the four isolates showed capability in degrading malathion pesticide. The study clearly revealed that phosphate solubilizing bacteria can be used in bioremediation of environmental pollution caused by malathion pesticide.

The Ability of Phosphate Solubilizing Bacteria Isolated from Coffee Plant Rhizosphere and Their Effects on Robusta Coffee Seedlings

Phosphate solubilizing bacteria isolated from rhizosphere of coffee plants may play an important role in improving phosphate availability for the plants. However, one of the factors influencing the degree of phosphate solubilization by these bacteria is the ability of the microorganisms to utilize phosphate. The objective of this study was to determine the ability of phosphate solubilizing bacteria isolated from coffee plant rhizosphere and their effects on robusta coffee seedling growth. This research was carried out by taking soil samples from Andungsari （Bondowoso District） and Kaliwining （Jember District） coffee plantations, both located in East Java. Liquid medium of Pikovskaya was used for isolation of phosphate solubilizing bacteria from the soil samples. Results of this study showed that 12 phosphate solubilizing bacteria were obtained from this isolation, eight isolates from Andungsari and four isolates from Kaliwining. Selection of those bacteria isolates was based on the qualitative ability in phosphate solubilizing by measuring the clear zone surrounding the colonies and quantitatively by measuring the solubilized phosphate using spectrophotometer. The results showed that four isolates, in the order of PFpKW1, PFpC61, PFsC62a, and PFsB 11, had the highest qualitative ability in solubilizing phosphate, while for the highest quantitative ability the order was PFpKW 1, PFpC61, PFsC62a, and PFsB 11. In a green house study, inoculation of these selected isolates onto Robusta coffee seedlings positively enhanced the coffee seedling growth. Phenotypic test indicated that the four isolates are similar to the genus of Pseudomonas.

Growth Characteristics of Mixed Bacteria and Its Solubilizing Effect on Low-grade Phosphate Rock

In this paper, the growth characteristics of Acidithiobacillus ferrooxidans （At.f） and Acidithiobacillus thiooxidans （At. f） in mixed culture has been studied, explored mixed bacteria phosphate solubilization effect, from a kind of low-grade phosphate rock. The results show that mixed bacteria has strong ability to produce acid, and have stronger oxidation activity to energy source -Fe^2＋. Mixed bacteria can significantly increase the rate of phosphate solubilization from phosphate rock in low concentration pulp. It goes against mixed bacteria reproduction when pulp concentration increased, makes phosphate solubilization rate decreased.

Selection of Cocoa Tree (<i>Theobroma cacao</i>Linn) Endophytic Bacteria Solubilizing Tri-Calcium Phosphate, Isolated from Seedlings Grown on Soils of Six Producing Regions of C&ocirc;te d’Ivoire

Phosphorus (P) is an essential macronutrient for the growth and development of cocoa tree (Theobroma cacao Linn). Most of the soils used for cocoa farming in C?te d’Ivoire are low in phosphorus. But cocoa farmers generally have a widespread reluctance to invest in chemicals fertilizers due to high costs and environmental associated risk. Phosphate Solubilizing Bacteria (PSB) are kwon to play an important role in supply of phosphorous to plants in a sustainable manner in P deficient soils. The aim of this research was to screen the endophytic bacteria of cocoa nurseries able to solubilize tri-calcium phosphate. Seedlings of two varieties of cocoa (P7 and NA32) and seedlings of an all-comer, were grown on eighteen (18) samples soils collected in six producing regions of C?te d’Ivoire. A total of 218 endophytic bacteria were isolated and tested on the Pikovskaya’s agar medium, containing Ca3 (PO4) 2. The colonies with clear zone around the microbial growth were suspected as phosphate solubilizing bacteria. Out of 218 bacteria, 90 (41.28%) showed a clear zone around colonies after 7 days of incubation. The Phosphate Solubilization Index (PSI) ranged from 20% to 200%. Bacterial isolated from the soils of Duékoué locality showed the highest mean index of 137.67%. Five PSB (CEBSP5, CEBSP6, CEBSP7, CEBSP8, and CEBSP9) from Duékoué soils and two PSB (CEBSP12 and CEBSP13) from Soubré soils have a PSI ranged from 150% to 200%. Further study in greenhouse and in field condition will confirm the use of these PSB as biofertilizer to increase the available P content in soils, reduce environmental pollution and promote sustainable agriculture.

Integrated Effects of Phosphate Rock and Chemical Fertilizers on the Dynamics of Soil Bacterial in Acidic Rice Paddy Soils of Man (Ivory Coast)

In agricultural soils, phosphorus is often limited, leading farmers to employ artificial supplementation through both inorganic and organic fertilization methods due to its restricted availability. Soil fertilization has the potential to augment both the abundance and diversity of bacterial communities. Our study aimed to assess the effects of phosphate amendments, derived from natural phosphate rock, and chemical fertilizers (TSP, NPK), on the density and diversity of bacterial communities within the study plots. We developed and applied eight phosphate amendments during the initial cultivation cycle. Soil samples were collected post 1st and 2nd cultivation cycles, and the quantification of both total and cultivable phosphate-solubilizing bacteria (PSB) was conducted. Additionally, we analyzed bacterial community structure, α-diversity (Shannon Diversity Index, Evenness Index, Chao1 Index). The combination of natural phosphate rock (PR) and chemical fertilizers (TSP, NPK) significantly increased (p 7 bacteria/g dry soil) and phosphate-solubilizing bacteria (0.01 to 6.8 × 107 PSB/g dry soil) in comparison to unamended control soils. The diversity of bacterial phyla (Firmicutes, Actinobacteria, Proteobacteria, Halobacterota, Chloroflexia) observed under each treatment remained consistent regardless of the nature of the phosphate amendment applied. However, changes in the abundance of the bacterial phyla populations were observed as a function of the nature of the phosphate amendment or chemical fertilizer. It appears that the addition of excessive natural phosphate rock does not alter the number and the diversity of soil microorganisms population despite successive cultivation cycles. However, the addition of excessive chemical fertilizer reduces soil microorganisms density and structure after the 2nd cultivation cycle.

Phosphorus Solubilizing Capability,IAA Secretion and Characteristics of Phosphorus-solubilizing Bacteria in Rhizosphere of Alfalfa in Guizhou Province

[Objective] The study aimed to isolate and screen efficient phosphorus-sol- ubilizing strains from the root soil of alfalfa in Guizhou, and investigate its growth promoting mechanism. [Method] Phosphorus solubilizing bacteria were isolated from rhizosphere of alfalfa with inorganic and organic phosphorous medium and the strains with higher capacity of dissolving phosphorus were screened through dissolv- ing phosphate zone and further researched. Meanwhile the phosphorus solubilizing capability of strains cultured in liquid medium was investigated by molybdenum blue colorimetric method. [Result] The capacity of dissolving calcium phosphate of 11 se- lected strains differed significantly and tended to be volatile from 150.40 to 268.20 μg/ml; phosphate solubilization capacity, IAA secretion and the pH of culture media did not show any significant correlation; all strains could produce IAA, and the se- cretion was from 12.09 to 22.16 μg/ml; the selected strains all could produce alka- line matter, and most of colonies were pale or milky white, irregular, opaque, jagged, flat and non-pigmented; utilization of carbon sources by different strains varied signifi- cantly. [Conclusion] The study laid the foundation for relieving phosphorus in unpro- ductive land, saving phosphate resources, reducing environmental pollution and pro- viding fertilizer in alfalfa production.

Phosphate solubilization potential of native rhizospheric microflora and their impact on growth of Madhuca latifolia(Mahua):An oil yielding medicinal plant of India

Madhuca latifolia is an economically important medicinal and oil yielding plant of India having slow growth rate.As microbial application to the rhizosphere of host plant are beneficial for growth and development of plants,a comprehensive experimental study by using native microflora of Madhuca latifolia had been carried out in the nursery conditions.Isolation and identification of native rhizospheric soil revealed the occurrence of 17 different types of bacteria(gram negative and positive)and 30 numbers of fungi belonging to myceloid type,Aspergillus,Alternaria,Colletotrichum,Fusarium and Penicillium.Present study was confined to phosphate solubilizing microbes for which solubilization potential(solubilization index and solubilization efficiency)was evaluated.Inoculation experiments in pot culture with red laterite soil were set in two experimental categories(1)non-transplanted and(2)transplanted.Plants grown under both the conditions with and without microbial application were maintained up to 120 days and final data recorded for morphological,physiological growth and as soil parameters.The mineral solubilizing potential of native microbial strains has been expressed.Fungal inoculants were more effective than the bacterial inoculants as far as the growth and development of plants concerned.Among all,bacteria MLB-1,MLB-6,Aspergillus terreus and non-sporulating dematiaceous form of fungi were prominent in improving plant growth.This has also been confirmed the useful and beneficial impact of indigenous organism.The records made during the study is useful for development of bioinoculants for forest trees,nursery of quality planting material which will also helps in establishment at plantation site.

Phosphate Solubilizing Ability and Phylogenetic Diversity of Bacteria from P-Rich Soils Around Dianchi Lake Drainage Area of China

The phylogenetic diversity of phosphate solubilizing bacteria （PSB） distributed in P-rich soils in the Dianchi Lake drainage area of China was characterized, and the tricalcium phosphate （TCP） solubilizing activities of isolated PSB were determined. Among 1 328 bacteria isolated from 100 P-rich soil samples, 377 isolates （28.39% of the total） that exhibited TCP solubilization activity were taken as PSB. These PSB showed different abilities to solubilize TCP, with the concentrations of solubilized P in bacterial cultures varying from 33.48 to 69.63 mg L^（-1）. A total of 123 PSB isolates, with relatively high TCP solubilization activity （〉 54.00 mg L^（-1））, were submitted for restriction fragment length polymorphism （RFLP） analysis, which revealed 32 unique RFLP patterns. Based on these patterns, 62 representative isolates, one to three from each RFLP pattern, were selected for 16S rRNA sequencing. Phylogenetic analysis placed the 123 PSB into three bacterial phyla, namely Proteobacteria, Aetinobacteria and Firmicutes. Members of Proteobacteria were the dominant PSB, where 107 isolates represented by 26 RFLP patterns were associated with the genera of Burkholderia, Pseudomonas, Acinetobacter, Enterobacter, Pantoea, Serratia, Klebsiella, Leclercia, Raoultella and Cedeeea. Firmicutes were the subdominant group, in which 13 isolates were affiliated with the genera of Bacillus and Brevibacterium. The remaining 3 isolates were identified as three species of the genus Arthrobacter. This research extends the knowledge on PSB in P-rich soils and broadens the spectrum of PSB for the development of environmentally friendly biophosphate fertilizers.

解磷菌PSBHY-3对池塘底泥的解磷效果

【目的】研究解磷菌PSBHY-3对池塘底泥的解磷效果,为解磷菌在养殖池塘中的推广应用提供参考依据。【方法】以模拟池塘环境系统为平台,探究不同浓度(103、104、105和106CFU/mL)PSBHY-3对池塘底泥的解磷效果;并在无菌池塘底泥水体系统中分别设P组(PSBHY-3)、D组(有机物降解菌De)、P-D组(PSBHY-3与De的初始菌量比1∶1)、P-3D组(PSBHY-3与De的初始菌量比1∶3)、3P-D组(PSBHY-3与De的初始菌量比3∶1)和对照组,分析PSBHY-3与De复配使用的解磷效果。【结果】至试验结束(第8 d)时,与对照组相比,J-3(103CFU/mL)、J-4(104CFU/mL)、J-5(105CFU/mL)和J-6(106CFU/mL)组的池塘底泥总磷(TP)含量均显著降低(P<0.05,下同),对应的TP降解率分别为7.05%、6.60%、4.03%和9.17%。在PSBHY-3和De复配试验中,2株菌株间不仅未出现生长拮抗现象,还能促进De生长。至试验结束(第8 d)时,各加菌组对池塘底泥TP的降解率均显著高于对照组,其中,以P组的TP降解率(8.17%)最高,而P-3D、P-D、D和3P-D组的TP降解率分别为5.38%、4.97%、4.38%和3.91%,各加菌组间均无显著差异(P>0.05)。经16S rDNA序列分析和Biolog微生物自动分析系统鉴定,确定PSBHY-3为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。【结论】PSBHY-3为解淀粉芽孢杆菌,对池塘底泥沉积磷具有较好的降解效果,可作为研发水产养殖用解磷菌菌剂的备选菌株。

解磷菌PSBHY-3的发酵培养工艺参数优化

【目的】优化解磷菌PSBHY-3的培养参数,为水产养殖专用解磷菌的工业化发酵生产提供技术支持。【方法】通过单因素试验筛选适合解磷菌菌株PSBHY-3生长的发酵培养基碳氮源及其含量;采用Plackett-Burman试验筛选获得对菌量影响最显著的3个因子;通过最陡爬坡试验和Box-Behnken试验确定显著因子的最佳水平,建立主要培养参数的回归方程,得出优化后显著因子的最佳值及预测菌量;通过摇瓶试验验证,检验模型方程的准确性。【结果】菌株PSBHY-3的最佳碳源、氮源分别为可溶性淀粉和蛋白胨—酵母膏(1∶1)。以温度(A)、蛋白胨—酵母膏(B)和转速(C)为因素变量,菌株PSBHY-3的菌量为响应值,拟合得到二次多元回归方程Y=17.10-0.88A+0.55B+1.27C+0.24AB+0.34AC-0.24BC-3.57A^(2)-2.78B^(2)-6.13C^(2)。优化得到的解磷菌菌株PSBHY-3最佳发酵培养参数为:可溶性淀粉10.0 g/L,蛋白胨10.18 g/L,酵母膏10.18 g/L,氯化钠3.0 g/L,硫酸镁1.0 g/L,pH 7,培养温度35.54℃,转速164 r/min,接种量1%,装液量60%(V/V)。在最佳发酵培养条件下,菌量实际值为1.81×10^(9) CFU/mL,与理论菌量(1.72×10^(9) CFU/mL)间无显著差异(P>0.05),但显著高于优化前采用营养肉汤培养的菌量(1.90×10^(8) CFU/mL)(P<0.05)。【结论】通过单因素试验、Plackett-Burman试验、最陡爬坡试验和Box-Behnken试验等优化了菌株PSBHY-3的发酵参数,显著提高了目的菌量,回归方程预测准确,优化后的发酵参数可用于水产养殖专用解磷菌的工业化发酵生产。

热带土壤解磷细菌PSB26的筛选鉴定及拮抗初探

以有机磷液体培养基进行生物富集,无机磷固体培养基平板法从海南、广东、云南等地热带土壤中筛选出解磷效果较好的一株解磷细菌PSB26。通过细菌16S rRNA通用引物PCR扩增菌株的16SrDNA序列,测得该菌株的序列长度为1095bp,经B lastn搜索进行序列比对,结果表明:该菌株属于Klebsiellasp.。进一步的室内平板对峙培养实验表明,PSB26对Fusarium oxysporum piperis等11个供试病原菌中的6个具有不同程度的拮抗作用。

产气肠杆菌PSB28的解磷机理研究

解磷微生物在提高土壤肥力及促进作物对磷的吸收方面具有重要作用,明确其利用难溶性无机磷的本质在实际应用中具有重要的意义。分别在以Ca3(PO4)2和K2HPO4为唯一磷源的培养基中,检测了PSB28的解磷能力,并比较了生长动态和代谢产物的方面差异以分析其代谢难溶性无机磷的机理。结果表明,与含K2HPO4的培养基相比,在以Ca3(PO4)2为唯一磷源的培养基中菌体生长量较大但生长速率较慢,pH略高,呈逐渐降低趋势。HPLC测定结果发现,有机酸种类和含量变化明显,且酸性磷酸酶活性明显增强。因此菌株PSB28解磷的主要原因是有机酸的螯合作用,酸性磷酸酶起到间接作用。

Selection,Identification and Growth Promotion of Inorganic Phosphorus-dissolving Bacterial Strains in Rhizosphere of Trifolium repens

[Objective] The aim was to select and identify inorganic phosphorus-dissolving bacteria in rhizosphere of Trifolium repens,and to research related effects of growth promotion.[Method] Phosphate solubilizing bacteria in rhizosphere of Trifolium repens in Guizhou Province were separated and selected to determine its ability of phosphate solubilizing and IAA secretion,and growth promotion effect.[Result] Phosphate solubilizing bacteria were multiple and varied in rhizosphere of Trifolium repens;solubilizing quantities of phosphorus from calcium phosphate by RW2,RW6 and RW18 were 337.39,447.45 and 462.03 μg/ml;solubilizing quantity was none of linear relation with organic acid;RW2 proved the one secreted most IAA at 12.69 μg/ml,followed by RW18 at 12.34 μg/ml;the three strains were all of Leclercia sp.,but were of none pathogenicity for seedlings of Trifolium repens,instead,a kind of growth promotion was found.Detailedly,RW18 was most effective in growth promotion for Trifolium repens and plant height,root length and weight,and aboveground biomass increased by 110.98%,9.17%,46.17% and 2% respectively.Hence,RW18 is of great potential.[Conclusion] The research provides scientific references for developing phosphate solubilizing bacteria and compound inoculation and develops a novel way to relieve barren soils,save phosphorus resource,reduce environment pollution,and guarantee sustainable development of agriculture and animal husbandry.

解磷菌PSB-R全基因组测序鉴定及其解磷特性分析

采用生理生化指标结合分子生物学技术对解磷菌PSB-R进行分类学鉴定,确定为粘质沙雷氏菌(Serratia marcescens),通过二代测序平台Illumina NovaSeq PE150对PSB-R进行全基因组测序,分析预测了与解磷能力相关基因及其他植物促生基因组成情况。通过响应面优化试验检测了PSB-R最大解磷能力为805.199 mg/L,连续培养10代后解磷能力稳定且对多种难溶性磷酸盐均具有溶解能力。本研究为解磷菌解磷机制的进一步研究提供了基因组数据基础,同时证实PSB-R具有应用于菌肥的潜力,为后续解磷菌肥的研制提供了研究基础。

PGPR调控植物响应逆境胁迫的作用机制

盐碱、干旱等非生物胁迫是限制植物生长和产量的重要环境因子。植物根际促生菌(PGPR)是一类定殖于植物根系的有益微生物,利用其生物学功能制成的生物菌剂具有低成本、高效和环保等优点,不仅可促进植物生长与作物产量,还能提高植物对非生物胁迫的耐受性。本研究对PGPR定义和种类、生物学功能及其在植物响应盐碱、干旱、高低温及重金属等非生物胁迫中的作用加以综述,并对其未来研究方向进行展望,以期为今后PGPR介导植物抗逆性的研究与生物菌剂的开发和应用提供理论支撑。

溶磷菌剂对玉米幼苗生长及根际土壤细菌群落结构和磷素形态的影响

以FD11(普瑞斯特氏菌Priestia sp.)和CH07(阿氏芽孢杆菌Bacillus aryabhattai)两种溶磷菌剂为试验材料,进行菌剂灌根盆栽试验,测定溶磷菌剂施用对玉米生长、根际土壤养分、土壤微生物特性及土壤不同形态磷含量的影响。结果表明,施用溶磷菌剂可改善根际土壤养分特征和微生物学特性,增加根际土壤的活性磷源含量,对玉米幼苗表现出良好的促生作用。与不施菌剂相比,FD11处理玉米幼苗的株高、茎粗、地上部干重分别增加31.88%、36.39%、104.00%;根际土壤碱解氮、有效磷、速效钾分别增加了21.90%、107.67%、5.77%。施用溶磷菌剂的土壤H_(2)O-Pi(Pi为无机磷)、NaHCO_(3)-P和NaOH-P含量增加,但HCl-Pi和Residual-P含量显著降低。施用溶磷菌剂改变了玉米根际土壤细菌的群落结构,在细菌属分类学水平上,不动杆菌属、假单胞菌属、海洋杆菌属、鞘氨醇单胞菌属、节杆菌属等功能细菌的相对丰度显著增加。综合以上分析,施用溶磷菌剂显著提高了土壤速效养分含量,改变了根际土壤细菌的群落结构,增加了活性磷源的含量,从而改善了土壤肥力,促进玉米根系发育和幼苗生长。此项研究可为新型微生物菌肥的研发提供理论依据。

Zinc phosphate dissolution by bacteria isolated from an oligotrophic karst cave in central China

Biogeochemical processes are fundamental to sustain the ecosystem in subsurface caves, but to date they are still far from well understood. To investigate micro-bially mediated phosphorus and zinc cycles, we isolated three bacterial strains from the dripping water in Heshang cave, central China, identified as Exiguobacterium aurantiacum E11, Pseudomonas fluorescens P35, and Pseu- domonas poae P41, respectively. Microbial capabilities in the dissolution of phosphorus-containing minerals were tested with zinc phosphate （Zn3（PO4）2） in batch culture at 30~C. A spectrophotometer, atomic absorption spectrum, and scanning electronic microscopy were used to measure the microbial growth, soluble Zn（II） concentration, and to observe the morphology of Zn3（PO4）2 before and after microbial dissolution. P. fluorescens and P. poae, the well- known phosphorus solubilizing bacteria （PSB）, are observed to solubilize Zn3（PO4）2 with an efficiency of 16.7% and 17.6%, respectively. To our knowledge, E. aurantiacum is firstly reported in this study to dissolve phosphorous-containing minerals with a higher efficiency of 39.7%, expanding our understanding about the ubiquitous occurrence of PSB in natural environments. Aqueous Zn（II） concentration positively correlates with H＋ activity, confirming the presence of acidification mechanisms widely exploited by PSB. Few itching pits were observed on the surface of Zn3（PO4）2 after microbial dissolution, inferring that microbial dissolution is not always associated with the direct contact with minerals. Even though the soluble Zn（II） concentration reached up to 370 mg/L in the system inoculated with E. aurantiacum Ell, inhibition of microbial growth was not detected by spectrophotometer. Our laboratory data revealed the importance of microbially-mediated P and Zn cycles in the subsurface ecosystem.

解磷生物肥对设施土壤养分及细菌群落结构的影响

为了揭示解磷生物肥对设施土壤养分及细菌群落结构的影响,将解磷菌P623-9与腐熟鸡粪复配,制成解磷生物肥,盆栽试验以设施土壤作为研究对象,以北方温室广泛栽培的辣椒为试验材料,设置4个处理:CK:空白对照;SY:解磷生物肥3000 kg/hm^(2);Y:腐熟鸡粪3000 kg/hm^(2);S:解磷菌240 L/hm^(2)。采用传统统计学方法对土壤养分含量进行统计分析,结果表明,SY处理的土壤中AP、TN、MBC、MBN及MBP含量均增加,与其他处理相比呈现显著增加差异(P<0.05);采用Illumina Miseq高通量测序分析土壤细菌丰度、群落结构及差异特征,结果显示,门水平中放线菌门(Actinobacteria)、芽单胞菌门(Gemmatimonadetes)、绿弯菌门(Chlo-roflexi)、拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)、酸杆菌门(Acidobacteria)、变形菌门(Proteobacteria)为优势菌门,SY处理的土壤样品中变形菌门、厚壁菌门和绿弯菌门细菌相对丰度较高;属水平中相对丰度较高的依次为芽胞杆菌(Bacillus)、节杆菌(Arthrobacter)、刺单胞菌(Sphingomonas)、链霉菌(Streptomyces)。SY处理的土壤中相对丰度较高为Arthrobacter(3.95%),与对照组相比丰度上升。Beijerinckiaceae与有效磷、全氮、微生物量磷、微生物量氮存在正相关,与总磷存在负相关;Nocardioidaceae与微生物氮存在显著正相关,但与全氮和有效磷的相关性较弱;Microscillaceae与全氮、微生物量碳、微生物量氮、微生物量磷等均存在正相关。由此得出结论,施用解磷生物肥能够显著提高土壤养分含量,增加有益菌群丰度和细菌菌群多样性。本研究揭示了施用解磷生物肥对设施土壤养分及细菌群落多样性的影响,为市场化应用和推广提供参考。