Salinity is one of the major abiotic stresses limiting crop growth and yield.This study investigated the underlying mechanisms of Trichoderma asperellum Q1 in promoting cucumber growth under salt stress, including the...Salinity is one of the major abiotic stresses limiting crop growth and yield.This study investigated the underlying mechanisms of Trichoderma asperellum Q1 in promoting cucumber growth under salt stress, including the abilities of the strain to solubilize phosphate and to produce phytohormone.The results showed that T.asperellum Q1 could solubilize inorganic or organic phosphate and the activities of phosphatases and phytase could be detected in the culture supernatant.In hydroponic experiments, the growth of cucumber seedlings was increased in the hydroponic system treated by culture filtrate of strain Q1 with tricalcium phosphate or calcium phytate under salt stress.This strain also exhibited the ability to produce indole acetic acid（IAA）, gibberellic acid（GA） and abscisic acid（ABA） in liquid medium without any inducers.The levels of those three phytohormones in cucumber seedling leaves also increased after inoculated with this strain, along with increased root growth and root activities of the plant.These results demonstrated the mechanisms of T.asperellum Q1 in alleviating the suppression effect of salt stress involving the change of phytohormone levels in cucumber plant and its ability of phosphate solubilization.展开更多
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 p...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.展开更多
Rock phosphate （RP） is a low efficiency P fertilizer that is directly applied to the soil and can be solubilized by phosphate-solubilizing microorganisms （PSMs） in fermentation or soil conditions. This study inves...Rock phosphate （RP） is a low efficiency P fertilizer that is directly applied to the soil and can be solubilized by phosphate-solubilizing microorganisms （PSMs） in fermentation or soil conditions. This study investigated dynamic solubilization of 2 concentrations of rock phosphate in a liquid culture with different dosages of glucose by two fungal isolates,Aspergillus niger P39 and Penicillium oxalicum P66, from soybean and wheat rhizosphere soil. Although during the 20 day culture period A. niger P39 had a stronger ability to acidify the culture media than P. ozalicum P66, soluble P concentrations at glucose dosages of 30 and 50 g L^-1 with RP of 15 g L^-1 in the culture solution were much higher by P. oxalicum P66. The greater effectiveness of P. oxalicum P66 compared to A. niger P39 in the solubilization of RP was strongly associated with the production of organic acids. This study suggested that for RP solubilization the type rather than the concentration of PSM-produced organic acids was more important.展开更多
Rock phosphate (RP) is a low efficient P fertilizer when directly used in the soil. Phosphate-solubilizing microorganisms (PSMs) can solubilize RP in fermentation or soil condition. The effect of different concentrati...Rock phosphate (RP) is a low efficient P fertilizer when directly used in the soil. Phosphate-solubilizing microorganisms (PSMs) can solubilize RP in fermentation or soil condition. The effect of different concentration of lanthanum (La) on the solubilization of RP was investigated by two isolates of phosphate-solubilizing fungi (PSF) Aspergillus niger P39 and Penicillium oxalicum P66 in liquid culture. Experimental results show that relatively higher concentration of La in the culture solution inhibites fungal growth and delays RP solubilizing activity of two isolates. This inhibitory effect of La on RP solubilization varies with PSF (isolate P66 is more sensitive to La than P39 in this experiment). Comparing the pH value of culture media with soluble P content as affected by La application, only within individual isolate not different isolates the negatively significant relationship was observed.展开更多
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 ...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.展开更多
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 activit...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.展开更多
Low availability of phosphorus(P) is a major constraint for optimal crop production, as P is mostly present in its insoluble form in soil. Therefore,phosphate-solubilizing bacteria(PSB) from paddy field soils of the I...Low availability of phosphorus(P) is a major constraint for optimal crop production, as P is mostly present in its insoluble form in soil. Therefore,phosphate-solubilizing bacteria(PSB) from paddy field soils of the Indo-Gangetic Plain, India were isolated, and their abundance was attempted to be correlated with the physicochemical characteristics of the soils. Ninety-four PSB were isolated on Pikovskaya’s agar medium, and quantitative phosphate solubilization was evaluated using NBRIP medium. The isolates solubilized P up to a concentration of 1 006 μg mL-1 from tricalcium phosphate with the secretion of organic acids. These isolates were identified by 16 S rRNA gene sequence comparison, and they belonged to Gammaproteobacteria(56 isolates),Firmicutes(28 isolates), Actinobacteria(8 isolates), and Alphaproteobacteria(2 isolates). Phylogenetic analysis confirmed the identification by clustering the isolates in the clade of the respective reference organisms. The correlation analysis between PSB abundance and physicochemical characteristics revealed that the PSB population increased with increasing levels of soil organic carbon, insoluble P, K+, and Mg2+. The promising PSB explored in this study can be further evaluated for their biofertilizer potential in the field and for their use as potent bio-inoculants.展开更多
Phosphorus(P)limitation in soil is a major concern for crop productivity.However,the use of chemical fertilizer is hazardous to the environment and costly.Therefore,the use of phosphate-solubilizing bacteria(PSB)is an...Phosphorus(P)limitation in soil is a major concern for crop productivity.However,the use of chemical fertilizer is hazardous to the environment and costly.Therefore,the use of phosphate-solubilizing bacteria(PSB)is an eco-friendly approach for a sustainable agricultural system.In the present study,a field trial was conducted for two consecutive years to study the effects of three PSB strains isolated,Bacillus licheniformis,Pantoea dispersa,and Staphylococcus sp.,with different P fertilizer rates on P uptake,P use efficiency(PUE),and grain yield of rice.The activities of soil enzymes were also studied in relation to PSB treatments.Comparative analysis of the yield and biochemical parameters revealed that inoculation of PSB consortium could reduce almost 50%of the recommended P dose in rice cultivation.Three PSB strains in combination with 50%P dose was most effective and showed the highest increases in P uptake and PUE as compared to the uninoculated control.Moreover,the PSB consortium combined with 50%P dose contributed to 50.58%and35.64%yield increases compared to the uninoculated control for 2018 and 2019,respectively.Significant increases in the activities of soil dehydrogenase,alkaline phosphatase,and acid phosphatase were also recorded under PSB treatment.展开更多
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 ...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.展开更多
Phosphate-solubilizing bacterial strains(6 Nos.) were isolated from the rhizosphere soils of two seagrasses(Halophila ovalis(R.Br.) Hook and Halodule pinifolia(Miki) Hartog) in the Vellar estuary.Experimental studies ...Phosphate-solubilizing bacterial strains(6 Nos.) were isolated from the rhizosphere soils of two seagrasses(Halophila ovalis(R.Br.) Hook and Halodule pinifolia(Miki) Hartog) in the Vellar estuary.Experimental studies found that the strain PSSG6 was effective in phosphate solubilization with Phosphate Solubilization efficiency index E = 375 ± 8.54,followed by the strain PSSG5 with Phosphate Solubilization efficiency index E = 275 ± 27.3.Of the 6 strains isolated,the strains PSSG4 and PSSG5 be-longed to the genus Bacillus,and PSSG1,PSSG2 and PSSG3 were identified as Citrobacter sp.,Shigella sp.,and Klebsiella sp.,respectively,by conventional method,and PSSG6 was identified as Bacillus circulans using conventional and molecular methods.展开更多
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 effe...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.展开更多
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...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.展开更多
Enhancing the growth of alfalfa(Medicago sativa L.)through inoculation with rhizobacteria represents a sustainable strategy for reclaiming saline soils.However,the lack of suitable strains and practical application gu...Enhancing the growth of alfalfa(Medicago sativa L.)through inoculation with rhizobacteria represents a sustainable strategy for reclaiming saline soils.However,the lack of suitable strains and practical application guidelines poses significant challenges to the utilization of Plant Growth-Promoting Rhizobacteria(PGPR)in saltaffected soils of Northwest China.In this study,we selected four PGPR strains derived from indigenous halophytes based on their growth-promoting characteristics.These strains underwent further selection via a petri dish assay.Subsequently,the effects of the selected PGPR strains on alfalfa growth and soil fertility were rigorously examined through pot trials.The results demonstrated that Bacillus filamentosus HL3,B.filamentosus HL6,Bacillus subtilis subsp.stercoris HG12,and Paenibacillus peoriae HG24 significantly produced indole-3-acetic acid(IAA),solubilized phosphorus,and fixed nitrogen(except for B.filamentosus HL6,which did not significantly fix nitrogen).Compared to non-inoculated plants,B.filamentosus HL6 and B.subtilis subsp.stercoris HG12 significantly enhanced seed germination,root elongation,and seedling biomass in a 150 mmol/L NaCl saline solution.In saline-alkaline soils,PGPR inoculation under brackish water irrigation did not restore alfalfa growth to the levels observed under freshwater irrigation.Principal Component Analysis(PCA)condensed ten indicators into two indices,explaining 86.85%of the variance.Using these two indices as weights,an evaluation model for the PGPR-alfalfa symbiosis indicated that B.subtilis subsp.stercoris HG12 had the most substantial effect under freshwater irrigation,while co-inoculation with B.subtilis subsp.stercoris HG12 and B.filamentosus HL6 had the most significant impact on alfalfa growth and soil improvement under brackish water irrigation.Available phosphorus was identified as the primary factor influencing alfalfa growth,contributing 82.3%to the growth variation.These findings provide suitable microbial strains for the utilization of saline-alkali land and underscore the potential of applying indigenous PGPR-alfalfa symbiotic techniques to improve soil fertility and crop yield in the arid regions of Northwest China.展开更多
This study investigates the nitrogen (N), phosphorous (P), and potassium (K) contents in raw biomasses of Camellia sinensis, Gliricidia sepium, and Musa acuminata. Therein, the highest N and P content was seen in Came...This study investigates the nitrogen (N), phosphorous (P), and potassium (K) contents in raw biomasses of Camellia sinensis, Gliricidia sepium, and Musa acuminata. Therein, the highest N and P content was seen in Camellia sinensis 116.80 ± 0.08 mg and 66.00 ± 0.14 mg respectively. The highest K content (106.80 ± 0.04 mg) was observed in Musa acuminata. Next, all three types of plant materials were allowed to decompose in water for 3 weeks, and a sample from each was analyzed for NPK after the 1st, 2nd, and 3rd week during decomposition. A significant increase in the release of N, P, and K by the Camellia sinensis to water (P Musa acuminate were not significantly changed (P > 0.05) over time. The ratio for N:P:K was calculated for raw biomass samples and decomposed samples to find the best fitting N:P:K ratio to apply to young tea plants as organic fertilizers. In addition to that, the microbial insight of these organic compounds was analyzed by observing how microbial population increased with decomposition by the enumeration of the total microbial count. A considerable increment in total microbial count was observed up to 3.28 × 10<sup>6</sup>, 1.21 × 10<sup>10</sup>, 2.18 × 10<sup>8</sup>, and 6.49 × 10<sup>7</sup> CFU/ml for Camellia sinensis, Gliricidia sepium, Musa accuminata (leaves), and Musa accuminata (trunk) respectively. The presence of phosphate solubilizing bacteria (PSB) and nitrogen solubilizing bacteria (NSB) throughout the decomposition period was confirmed by their growth on NBRIP and a modified nutrient medium that was specifically designed for the identification of ammonifiers respectively. Prepared fertilizer samples were applied to young tea plants that were grown in the Mawanella area in Sri Lanka (7°15'12.42"N 80°26'47.62"E) and according to the results, it is clear that fertilizer mixture 1 (N:P:K, 10:5:10, tea dust + Gliricidia + banana trunk) and fertilizer mixture 2 (N:P:K, 10:5:10, tea dust + Gliricidia + banana leaves) has the potential to increase the growth of young tea plants.展开更多
[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 ...[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.展开更多
Soil salinity diminishes soil health and reduces crop yield,which is becoming a major global concern.Salinity stress is one of the primary stresses,leading to several other secondary stresses that restrict plant growt...Soil salinity diminishes soil health and reduces crop yield,which is becoming a major global concern.Salinity stress is one of the primary stresses,leading to several other secondary stresses that restrict plant growth and soil fertility.The major secondary stresses induced in plants under saline-alkaline conditions include osmotic stress,nutrient limitation,and ionic stress,all of which negatively impact overall plant growth.Under stressed conditions,certain beneficial soil microflora are known to have evolved phytostimulating mechanisms,such as the synthesis of osmoprotectants,siderophores,1-aminocyclopropane-1-carboxylic acid(ACC)deaminase activity,phosphate solubilization,and hormone production,which enhance plant growth and development while mitigating nutrient stress.Beneficial soil-borne bacterial species such as Bacillus,Pseudomonas,and Klebsiella and fungal strains such as Trichoderma,Aspergillus,Penicillium,Alternaria,and Fusarium also aid in reducing salinity stress.Phosphate-solubilizing microorganisms also assist in nutrient acquisition via both enzymatic and non-enzymatic processes.In the case of enzymatic processes,they produce different enzymes such as alkaline phosphatases and phytases,whereas non-enzymatic processes produce organic acids such as gluconic,citric,malic,and oxalic acids.The native halotolerant/halophilic soil microbial gene pool with multifunctional traits and stress-induced gene expression can be developed as suitable bio-inoculants to enhance stress tolerance and optimize plant growth in saline soils.展开更多
Soil microbes play a vital role in improving plant growth,crop productivity,and soil health through solubilization of essential nutrients.Present investigation was conducted to access the efficacy of Bradyrhizobium sp...Soil microbes play a vital role in improving plant growth,crop productivity,and soil health through solubilization of essential nutrients.Present investigation was conducted to access the efficacy of Bradyrhizobium sp.LSBR-3 and the indigenous phosphate-solubilizing Pseudomonas oryzihabitans LSE-3 in improving the symbiosis,nutrient accumulation,and yield of soybean.The isolate LSE-3,selected on the basis of phosphate solubilization,was screened for beneficial traits,antagonistic activities,and pathogenicity.The levels of indole acetic acid production(50.34±2.35μg mL^(-1)),phosphate solubilization(184.4±7.4 mg L^(-1)),biofilm formation(optical density at 560 mm,1.3896±0.04),siderophore production(121.46±1.61μg mL^(-1)),and 1-aminocyclopropane-1-carboxylate deaminase activity(0.51±0.07 mmolα-ketobutyrateμg^(-1) protein h^(-1))were significantly higher with the dual inoculants(LSBR-3 and LSE-3)than with the single inoculant LSBR-3.The plant growth-promoting traits of single and dual inoculants were evaluated for the synergistic effects on soybean under field conditions.Soybean plots treated with LSBR-3+LSE-3 exhibited improvement in seed germination,plant height,plant biomass,and chlorophyll content compared with the uninoculated control.Dual inoculant treatments resulted in significantly higher symbiotic efficacy evidenced by increased nodulation(40.0±0.75 plant^(-1)),nodule biomass(188.52±6.29 mg plant^(-1)),and leghemoglobin content(11.02±0.83 mg g^(-1) fresh nodule),and significantly increased activities of phosphatase(75.16±3.17 and 58.77±6.08μg p-nitrophenol g^(-1) h^(-1) for alkaline and acid phosphatase,respectively)and dehydrogenase(32.66±1.92μg triphenylformazan g^(-1) h^(-1))compared with the control.Dual inoculation with LSBR-3 and LSE-3 enhanced the uptake of macro-and micronutrients,reduced Na content in shoots,and resulted in 10.85%higher grain yield and ca.US$96.80 ha^(-1) higher profit compared with the control.This is the first report on the effectiveness of combined inoculation of LSE-3 and LSBR-3 in promoting the growth,symbiotic efficacy,and yield of soybean for sustainable agriculture.展开更多
Application of plant growth-promoting rhizobacteria （PGPR） has been shown to increase legume growth and development under field and controlled environmental conditions. The present study was conducted to isolate pla...Application of plant growth-promoting rhizobacteria （PGPR） has been shown to increase legume growth and development under field and controlled environmental conditions. The present study was conducted to isolate plant growth-promoting rhizobacteria （PGPR） from the root nodules of lentil （Lens culinaris Medik.） grown in arid/semi-arid region of Punjab, Pakistan and examined their plant growth-promoting abilities. Five bacterial isolates were isolated, screened in vitro for plant growth-promoting （PGP） characteristics and their effects on the growth of lentil were assessed under in vitro, hydroponic and greenhouse （pot experiment） conditions. All the isolates were Gram negative, rod-shaped and circular in form and exhibited the plant growth-promoting attributes of phosphate solubilization and auxin （indole acetic acid, IAA） production. The IAA production capacity ranged in 0.5-11.0μg mL-1 and P solubilization ranged in 3-16 mg L-1. When tested for their effects on plant growth, the isolated strains had a stimulatory effect on growth, nodulation and nitrogen （N） and phosphorus （P） uptake in plants on nutrient-deficient soil. In the greenhouse pot experiment, application of PGPR significantly increased shoot length, fresh weight and dry weight by 65%, 43% and 63% and the increases in root length, fresh weight and dry weight were 74%, 54% and 92%, respectively, as compared with the uninoculated control. The relative increases in growth characteristics under in vitro and hydroponic conditions were even higher. PGPR also increased the number of pods per plant, 1 000-grain weight, dry matter yield and grain yield by 50%, 13%, 2870 and 29%, respectively, over the control. The number of nodules and nodule dry mass increased by 170% and 136%, respectively. After inoculation with effective bacterial strains, the shoot, root and seed N and P contents increased, thereby increasing both N and P uptake in plants. The root elongation showed a positive correlation （R2 = 0.67） with the IAA production and seed yield exhibited a positive correlation （R2 = 0.82） with root nodulation. These indicated that the isolated PGPR rhizobial strains can be best utilized as potential agents or biofertilizers for stimulating the growth and nutrient accumulation of lentil.展开更多
Present study was carried out on Acacia nilotica seedlings grown under different bioinoculation treatments by using laboratory grown liquid cultures of 10 fungal isolates,11 Rhizobium isolates and 5 other bacterial is...Present study was carried out on Acacia nilotica seedlings grown under different bioinoculation treatments by using laboratory grown liquid cultures of 10 fungal isolates,11 Rhizobium isolates and 5 other bacterial isolates.Microbial cultures were screened for their effects on growth of Acacia nilotica grown in greenhouse conditions.The selected microbial inoculants were assessed as considering their individual performance or in combination with the other inoculants in specific ratios.The higher performance was shown with the combination of Penicillum chrysogenum Thom.1,B 5 bacterial isolate,R10 and/or R11 isolates of Rhizobium.Further,it was observed that the above microbial mixed culture inoculation was promoted plant growth specifically number of leaves and the leaf biomass.Therefore,nursery application of mixed microbial inoculants,specifically as above could be beneficial for the production of quality planting material(QPM)of Acacia nilotica and subsequent field applications.展开更多
[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 i...[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.展开更多
基金supported by the grant from the Shandong Provincial Natural Science Foundation,Shandong,China(ZR2009DM042)
文摘Salinity is one of the major abiotic stresses limiting crop growth and yield.This study investigated the underlying mechanisms of Trichoderma asperellum Q1 in promoting cucumber growth under salt stress, including the abilities of the strain to solubilize phosphate and to produce phytohormone.The results showed that T.asperellum Q1 could solubilize inorganic or organic phosphate and the activities of phosphatases and phytase could be detected in the culture supernatant.In hydroponic experiments, the growth of cucumber seedlings was increased in the hydroponic system treated by culture filtrate of strain Q1 with tricalcium phosphate or calcium phytate under salt stress.This strain also exhibited the ability to produce indole acetic acid（IAA）, gibberellic acid（GA） and abscisic acid（ABA） in liquid medium without any inducers.The levels of those three phytohormones in cucumber seedling leaves also increased after inoculated with this strain, along with increased root growth and root activities of the plant.These results demonstrated the mechanisms of T.asperellum Q1 in alleviating the suppression effect of salt stress involving the change of phytohormone levels in cucumber plant and its ability of phosphate solubilization.
基金The financial assistance obtained from the Forest and Environment dept.,Govt.of Odisha(State plan 2016-17)is gratefully acknowledged.
文摘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.
基金Project supported by the Director Fund of the Northeast Institute of Geography and Agricultural Ecology, ChineseAcademy of Sciences, and the National Agricultural Key Project of China (No. 2001BA007).
文摘Rock phosphate （RP） is a low efficiency P fertilizer that is directly applied to the soil and can be solubilized by phosphate-solubilizing microorganisms （PSMs） in fermentation or soil conditions. This study investigated dynamic solubilization of 2 concentrations of rock phosphate in a liquid culture with different dosages of glucose by two fungal isolates,Aspergillus niger P39 and Penicillium oxalicum P66, from soybean and wheat rhizosphere soil. Although during the 20 day culture period A. niger P39 had a stronger ability to acidify the culture media than P. ozalicum P66, soluble P concentrations at glucose dosages of 30 and 50 g L^-1 with RP of 15 g L^-1 in the culture solution were much higher by P. oxalicum P66. The greater effectiveness of P. oxalicum P66 compared to A. niger P39 in the solubilization of RP was strongly associated with the production of organic acids. This study suggested that for RP solubilization the type rather than the concentration of PSM-produced organic acids was more important.
文摘Rock phosphate (RP) is a low efficient P fertilizer when directly used in the soil. Phosphate-solubilizing microorganisms (PSMs) can solubilize RP in fermentation or soil condition. The effect of different concentration of lanthanum (La) on the solubilization of RP was investigated by two isolates of phosphate-solubilizing fungi (PSF) Aspergillus niger P39 and Penicillium oxalicum P66 in liquid culture. Experimental results show that relatively higher concentration of La in the culture solution inhibites fungal growth and delays RP solubilizing activity of two isolates. This inhibitory effect of La on RP solubilization varies with PSF (isolate P66 is more sensitive to La than P39 in this experiment). Comparing the pH value of culture media with soluble P content as affected by La application, only within individual isolate not different isolates the negatively significant relationship was observed.
文摘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.
基金the National Key Sciences and Technology Program for Water Solutions, China (Nos.2009ZX07102-004 and2012ZX07102-003)the National Natural Science Foundation of China (Nos.30970100 and 31160376)+1 种基金the Zhengzhou Tobacco Research Institute of China (No.122009CZ0420)the Department of Science and Technology of Yunnan Province, China (Nos.2011FA002and 11N010905)
文摘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.
文摘Low availability of phosphorus(P) is a major constraint for optimal crop production, as P is mostly present in its insoluble form in soil. Therefore,phosphate-solubilizing bacteria(PSB) from paddy field soils of the Indo-Gangetic Plain, India were isolated, and their abundance was attempted to be correlated with the physicochemical characteristics of the soils. Ninety-four PSB were isolated on Pikovskaya’s agar medium, and quantitative phosphate solubilization was evaluated using NBRIP medium. The isolates solubilized P up to a concentration of 1 006 μg mL-1 from tricalcium phosphate with the secretion of organic acids. These isolates were identified by 16 S rRNA gene sequence comparison, and they belonged to Gammaproteobacteria(56 isolates),Firmicutes(28 isolates), Actinobacteria(8 isolates), and Alphaproteobacteria(2 isolates). Phylogenetic analysis confirmed the identification by clustering the isolates in the clade of the respective reference organisms. The correlation analysis between PSB abundance and physicochemical characteristics revealed that the PSB population increased with increasing levels of soil organic carbon, insoluble P, K+, and Mg2+. The promising PSB explored in this study can be further evaluated for their biofertilizer potential in the field and for their use as potent bio-inoculants.
基金support provided by the All India Co-ordinated Research Project(AICRP),Indian Council of Agricultural Research(ICAR),New Delhi,India during the field study。
文摘Phosphorus(P)limitation in soil is a major concern for crop productivity.However,the use of chemical fertilizer is hazardous to the environment and costly.Therefore,the use of phosphate-solubilizing bacteria(PSB)is an eco-friendly approach for a sustainable agricultural system.In the present study,a field trial was conducted for two consecutive years to study the effects of three PSB strains isolated,Bacillus licheniformis,Pantoea dispersa,and Staphylococcus sp.,with different P fertilizer rates on P uptake,P use efficiency(PUE),and grain yield of rice.The activities of soil enzymes were also studied in relation to PSB treatments.Comparative analysis of the yield and biochemical parameters revealed that inoculation of PSB consortium could reduce almost 50%of the recommended P dose in rice cultivation.Three PSB strains in combination with 50%P dose was most effective and showed the highest increases in P uptake and PUE as compared to the uninoculated control.Moreover,the PSB consortium combined with 50%P dose contributed to 50.58%and35.64%yield increases compared to the uninoculated control for 2018 and 2019,respectively.Significant increases in the activities of soil dehydrogenase,alkaline phosphatase,and acid phosphatase were also recorded under PSB treatment.
基金Supported by Key Technologies R&D Program of Shanghai Municipal Agricultural Commission(X9810)~~
文摘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.
文摘Phosphate-solubilizing bacterial strains(6 Nos.) were isolated from the rhizosphere soils of two seagrasses(Halophila ovalis(R.Br.) Hook and Halodule pinifolia(Miki) Hartog) in the Vellar estuary.Experimental studies found that the strain PSSG6 was effective in phosphate solubilization with Phosphate Solubilization efficiency index E = 375 ± 8.54,followed by the strain PSSG5 with Phosphate Solubilization efficiency index E = 275 ± 27.3.Of the 6 strains isolated,the strains PSSG4 and PSSG5 be-longed to the genus Bacillus,and PSSG1,PSSG2 and PSSG3 were identified as Citrobacter sp.,Shigella sp.,and Klebsiella sp.,respectively,by conventional method,and PSSG6 was identified as Bacillus circulans using conventional and molecular methods.
文摘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.
文摘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.
基金funded by the National Natural Science Foundation of China (No. 42107513)the Key Projects of Natural Science Foundation of Gansu Province (No. 22JR5RA051)+1 种基金the Key Research and Development Program of Gansu Province (No. 21YF5FA151)the Gansu Province science and Technology project (21JR7RA070)
文摘Enhancing the growth of alfalfa(Medicago sativa L.)through inoculation with rhizobacteria represents a sustainable strategy for reclaiming saline soils.However,the lack of suitable strains and practical application guidelines poses significant challenges to the utilization of Plant Growth-Promoting Rhizobacteria(PGPR)in saltaffected soils of Northwest China.In this study,we selected four PGPR strains derived from indigenous halophytes based on their growth-promoting characteristics.These strains underwent further selection via a petri dish assay.Subsequently,the effects of the selected PGPR strains on alfalfa growth and soil fertility were rigorously examined through pot trials.The results demonstrated that Bacillus filamentosus HL3,B.filamentosus HL6,Bacillus subtilis subsp.stercoris HG12,and Paenibacillus peoriae HG24 significantly produced indole-3-acetic acid(IAA),solubilized phosphorus,and fixed nitrogen(except for B.filamentosus HL6,which did not significantly fix nitrogen).Compared to non-inoculated plants,B.filamentosus HL6 and B.subtilis subsp.stercoris HG12 significantly enhanced seed germination,root elongation,and seedling biomass in a 150 mmol/L NaCl saline solution.In saline-alkaline soils,PGPR inoculation under brackish water irrigation did not restore alfalfa growth to the levels observed under freshwater irrigation.Principal Component Analysis(PCA)condensed ten indicators into two indices,explaining 86.85%of the variance.Using these two indices as weights,an evaluation model for the PGPR-alfalfa symbiosis indicated that B.subtilis subsp.stercoris HG12 had the most substantial effect under freshwater irrigation,while co-inoculation with B.subtilis subsp.stercoris HG12 and B.filamentosus HL6 had the most significant impact on alfalfa growth and soil improvement under brackish water irrigation.Available phosphorus was identified as the primary factor influencing alfalfa growth,contributing 82.3%to the growth variation.These findings provide suitable microbial strains for the utilization of saline-alkali land and underscore the potential of applying indigenous PGPR-alfalfa symbiotic techniques to improve soil fertility and crop yield in the arid regions of Northwest China.
文摘This study investigates the nitrogen (N), phosphorous (P), and potassium (K) contents in raw biomasses of Camellia sinensis, Gliricidia sepium, and Musa acuminata. Therein, the highest N and P content was seen in Camellia sinensis 116.80 ± 0.08 mg and 66.00 ± 0.14 mg respectively. The highest K content (106.80 ± 0.04 mg) was observed in Musa acuminata. Next, all three types of plant materials were allowed to decompose in water for 3 weeks, and a sample from each was analyzed for NPK after the 1st, 2nd, and 3rd week during decomposition. A significant increase in the release of N, P, and K by the Camellia sinensis to water (P Musa acuminate were not significantly changed (P > 0.05) over time. The ratio for N:P:K was calculated for raw biomass samples and decomposed samples to find the best fitting N:P:K ratio to apply to young tea plants as organic fertilizers. In addition to that, the microbial insight of these organic compounds was analyzed by observing how microbial population increased with decomposition by the enumeration of the total microbial count. A considerable increment in total microbial count was observed up to 3.28 × 10<sup>6</sup>, 1.21 × 10<sup>10</sup>, 2.18 × 10<sup>8</sup>, and 6.49 × 10<sup>7</sup> CFU/ml for Camellia sinensis, Gliricidia sepium, Musa accuminata (leaves), and Musa accuminata (trunk) respectively. The presence of phosphate solubilizing bacteria (PSB) and nitrogen solubilizing bacteria (NSB) throughout the decomposition period was confirmed by their growth on NBRIP and a modified nutrient medium that was specifically designed for the identification of ammonifiers respectively. Prepared fertilizer samples were applied to young tea plants that were grown in the Mawanella area in Sri Lanka (7°15'12.42"N 80°26'47.62"E) and according to the results, it is clear that fertilizer mixture 1 (N:P:K, 10:5:10, tea dust + Gliricidia + banana trunk) and fertilizer mixture 2 (N:P:K, 10:5:10, tea dust + Gliricidia + banana leaves) has the potential to increase the growth of young tea plants.
基金Supported by Key Agricultural Program of Guizhou Province([2009]3067)Science and Technology Foundation of Guizhou Province([2012]2199)~~
文摘[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.
文摘Soil salinity diminishes soil health and reduces crop yield,which is becoming a major global concern.Salinity stress is one of the primary stresses,leading to several other secondary stresses that restrict plant growth and soil fertility.The major secondary stresses induced in plants under saline-alkaline conditions include osmotic stress,nutrient limitation,and ionic stress,all of which negatively impact overall plant growth.Under stressed conditions,certain beneficial soil microflora are known to have evolved phytostimulating mechanisms,such as the synthesis of osmoprotectants,siderophores,1-aminocyclopropane-1-carboxylic acid(ACC)deaminase activity,phosphate solubilization,and hormone production,which enhance plant growth and development while mitigating nutrient stress.Beneficial soil-borne bacterial species such as Bacillus,Pseudomonas,and Klebsiella and fungal strains such as Trichoderma,Aspergillus,Penicillium,Alternaria,and Fusarium also aid in reducing salinity stress.Phosphate-solubilizing microorganisms also assist in nutrient acquisition via both enzymatic and non-enzymatic processes.In the case of enzymatic processes,they produce different enzymes such as alkaline phosphatases and phytases,whereas non-enzymatic processes produce organic acids such as gluconic,citric,malic,and oxalic acids.The native halotolerant/halophilic soil microbial gene pool with multifunctional traits and stress-induced gene expression can be developed as suitable bio-inoculants to enhance stress tolerance and optimize plant growth in saline soils.
基金the Indian Council of Agricultural Research(ICAR),India for the Junior Research Fellowship(ICAR-JRF)awarded toward conducting the M.S.research project。
文摘Soil microbes play a vital role in improving plant growth,crop productivity,and soil health through solubilization of essential nutrients.Present investigation was conducted to access the efficacy of Bradyrhizobium sp.LSBR-3 and the indigenous phosphate-solubilizing Pseudomonas oryzihabitans LSE-3 in improving the symbiosis,nutrient accumulation,and yield of soybean.The isolate LSE-3,selected on the basis of phosphate solubilization,was screened for beneficial traits,antagonistic activities,and pathogenicity.The levels of indole acetic acid production(50.34±2.35μg mL^(-1)),phosphate solubilization(184.4±7.4 mg L^(-1)),biofilm formation(optical density at 560 mm,1.3896±0.04),siderophore production(121.46±1.61μg mL^(-1)),and 1-aminocyclopropane-1-carboxylate deaminase activity(0.51±0.07 mmolα-ketobutyrateμg^(-1) protein h^(-1))were significantly higher with the dual inoculants(LSBR-3 and LSE-3)than with the single inoculant LSBR-3.The plant growth-promoting traits of single and dual inoculants were evaluated for the synergistic effects on soybean under field conditions.Soybean plots treated with LSBR-3+LSE-3 exhibited improvement in seed germination,plant height,plant biomass,and chlorophyll content compared with the uninoculated control.Dual inoculant treatments resulted in significantly higher symbiotic efficacy evidenced by increased nodulation(40.0±0.75 plant^(-1)),nodule biomass(188.52±6.29 mg plant^(-1)),and leghemoglobin content(11.02±0.83 mg g^(-1) fresh nodule),and significantly increased activities of phosphatase(75.16±3.17 and 58.77±6.08μg p-nitrophenol g^(-1) h^(-1) for alkaline and acid phosphatase,respectively)and dehydrogenase(32.66±1.92μg triphenylformazan g^(-1) h^(-1))compared with the control.Dual inoculation with LSBR-3 and LSE-3 enhanced the uptake of macro-and micronutrients,reduced Na content in shoots,and resulted in 10.85%higher grain yield and ca.US$96.80 ha^(-1) higher profit compared with the control.This is the first report on the effectiveness of combined inoculation of LSE-3 and LSBR-3 in promoting the growth,symbiotic efficacy,and yield of soybean for sustainable agriculture.
基金Supported by the University of Azad Jammu and Kashmir, Pakistan and the Pakistan Agriculture Research Council, Pakistan (No. ALP NR-27)
文摘Application of plant growth-promoting rhizobacteria （PGPR） has been shown to increase legume growth and development under field and controlled environmental conditions. The present study was conducted to isolate plant growth-promoting rhizobacteria （PGPR） from the root nodules of lentil （Lens culinaris Medik.） grown in arid/semi-arid region of Punjab, Pakistan and examined their plant growth-promoting abilities. Five bacterial isolates were isolated, screened in vitro for plant growth-promoting （PGP） characteristics and their effects on the growth of lentil were assessed under in vitro, hydroponic and greenhouse （pot experiment） conditions. All the isolates were Gram negative, rod-shaped and circular in form and exhibited the plant growth-promoting attributes of phosphate solubilization and auxin （indole acetic acid, IAA） production. The IAA production capacity ranged in 0.5-11.0μg mL-1 and P solubilization ranged in 3-16 mg L-1. When tested for their effects on plant growth, the isolated strains had a stimulatory effect on growth, nodulation and nitrogen （N） and phosphorus （P） uptake in plants on nutrient-deficient soil. In the greenhouse pot experiment, application of PGPR significantly increased shoot length, fresh weight and dry weight by 65%, 43% and 63% and the increases in root length, fresh weight and dry weight were 74%, 54% and 92%, respectively, as compared with the uninoculated control. The relative increases in growth characteristics under in vitro and hydroponic conditions were even higher. PGPR also increased the number of pods per plant, 1 000-grain weight, dry matter yield and grain yield by 50%, 13%, 2870 and 29%, respectively, over the control. The number of nodules and nodule dry mass increased by 170% and 136%, respectively. After inoculation with effective bacterial strains, the shoot, root and seed N and P contents increased, thereby increasing both N and P uptake in plants. The root elongation showed a positive correlation （R2 = 0.67） with the IAA production and seed yield exhibited a positive correlation （R2 = 0.82） with root nodulation. These indicated that the isolated PGPR rhizobial strains can be best utilized as potential agents or biofertilizers for stimulating the growth and nutrient accumulation of lentil.
基金We are thankful to Ministry of environment,forest,climate change,Govt.of India for financial support through project no 23/22/2006-RE。
文摘Present study was carried out on Acacia nilotica seedlings grown under different bioinoculation treatments by using laboratory grown liquid cultures of 10 fungal isolates,11 Rhizobium isolates and 5 other bacterial isolates.Microbial cultures were screened for their effects on growth of Acacia nilotica grown in greenhouse conditions.The selected microbial inoculants were assessed as considering their individual performance or in combination with the other inoculants in specific ratios.The higher performance was shown with the combination of Penicillum chrysogenum Thom.1,B 5 bacterial isolate,R10 and/or R11 isolates of Rhizobium.Further,it was observed that the above microbial mixed culture inoculation was promoted plant growth specifically number of leaves and the leaf biomass.Therefore,nursery application of mixed microbial inoculants,specifically as above could be beneficial for the production of quality planting material(QPM)of Acacia nilotica and subsequent field applications.
基金Supported by Guizhou Program for Agricultural Development([2009]3067)Guizhou Science and Technology Foundation([2012]2199)~~
文摘[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.
