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1.
J Appl Microbiol ; 135(4)2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38503567

ABSTRACT

AIMS: Determine the wheat rhizosphere competence of Trichoderma gamsii strain A5MH and in planta suppression of the Pythium root and Fusarium crown rot pathogens Globisporangium irregulare and Fusarium pseudograminearum. METHODS AND RESULTS: Wheat was continuously cropped (eight years) at a minimum tillage, low growing season rainfall (GSR ≤ 170 mm) site shown as highly conducive to Pythium root and Fusarium crown rots. Root isolation frequency (RIF) and qPCR were used to determine the rhizosphere dynamics of strain A5MH and the target pathogens at tillering, grain harvest, and in postharvest stubble over the final 2 years. Strain A5MH actively colonized the wheat rhizosphere throughout both growing seasons, had high root abundance at harvest [log 4.5 genome copies (GC) g-1] and persisted in standing stubble for at least 293-d postinoculation. Globisporangium irregulare was most abundant in roots at tillering, whereas F. pseudograminearum was only abundant at harvest and up to 9-fold greater in the drier, second year (GSR 105 mm). Strain A5MH decreased RIF of both pathogens by up to 40%, root abundance of G. irregulare by 100-fold, and F. pseudogaminearum by 700-fold, but was ineffective against crown rot in the second year when pathogen abundance was >log 6.0 GC g-1 root. Strain A5MH increased crop emergence and tillering biomass by up to 40%. CONCLUSIONS: Further trials are required to determine if the A5MH-induced pathogen suppression translates to yield improvements in higher rainfall regions where non-cereal rotations reduce crown rot inoculum.


Subject(s)
Fusarium , Hypocreales , Pythium , Seasons , Triticum , Fusarium/genetics , Rhizosphere , Plant Diseases/prevention & control , Edible Grain
2.
J Appl Microbiol ; 134(5)2023 May 02.
Article in English | MEDLINE | ID: mdl-37188640

ABSTRACT

AIMS: Develop quantitative assays (qPCR) to determine the wheat rhizosphere competence of inoculant strains Bacillus amyloliquefaciens W10 and Pseudomonas protegens FD6, and their suppressive efficacies against the sharp eyespot pathogen Rhizoctonia cerealis. METHODS AND RESULTS: Antimicrobial metabolites of strains W10 and FD6 decreased in vitro growth of R. cerealis. A qPCR assay for strain W10 was designed from a diagnostic AFLP fragment and the rhizosphere dynamics of both strains in wheat seedlings were compared by culture-dependent (CFU) and qPCR assays. The qPCR minimum detection limits for strains W10 and FD6 were log 3.04 and log 4.03 genome (cell) equivalents g-1 soil, respectively. Inoculant soil and rhizosphere abundance determined by CFU and qPCR were highly correlated (r > 0.91). In wheat bioassays, rhizosphere abundance of strain FD6 was up to 80-fold greater (P < 0.001) than strain W10 at 14 and 28 days postinoculation. Both inoculants reduced (P < 0.05) rhizosphere soil and root abundance of R. cerealis by up to 3-fold. CONCLUSIONS: Strain FD6 exhibited greater abundance in wheat roots and rhizosphere soil than strain W10 and both inoculants decreased the rhizosphere abundance of R. cerealis.


Subject(s)
Bacillus amyloliquefaciens , Bacillus amyloliquefaciens/genetics , Triticum , Rhizosphere , Soil , Amplified Fragment Length Polymorphism Analysis , Rhizoctonia , Plant Diseases/prevention & control
3.
Glob Chang Biol ; 23(4): 1400-1414, 2017 04.
Article in English | MEDLINE | ID: mdl-27670638

ABSTRACT

Phenological changes in key seasonally expressed life-history traits occurring across periods of climatic and environmental change can cause temporal mismatches between interacting species, and thereby impact population and community dynamics. However, studies quantifying long-term phenological changes have commonly only measured variation occurring in spring, measured as the first or mean dates on which focal traits or events were observed. Few studies have considered seasonally paired events spanning spring and autumn or tested the key assumption that single convenient metrics accurately capture entire event distributions. We used 60 years (1955-2014) of daily bird migration census data from Fair Isle, Scotland, to comprehensively quantify the degree to which the full distributions of spring and autumn migration timing of 13 species of long-distance migratory bird changed across a period of substantial climatic and environmental change. In most species, mean spring and autumn migration dates changed little. However, the early migration phase (≤10th percentile date) commonly got earlier, while the late migration phase (≥90th percentile date) commonly got later. Consequently, species' total migration durations typically lengthened across years. Spring and autumn migration phenologies were not consistently correlated within or between years within species and hence were not tightly coupled. Furthermore, different metrics quantifying different aspects of migration phenology within seasons were not strongly cross-correlated, meaning that no single metric adequately described the full pattern of phenological change. These analyses therefore reveal complex patterns of simultaneous advancement, temporal stability and delay in spring and autumn migration phenologies, altering species' life-history structures. Additionally, they demonstrate that this complexity is only revealed if multiple metrics encompassing entire seasonal event distributions, rather than single metrics, are used to quantify phenological change. Existing evidence of long-term phenological changes detected using only one or two metrics should consequently be interpreted cautiously because divergent changes occurring simultaneously could potentially have remained undetected.


Subject(s)
Animal Migration , Birds , Animals , Environment , Scotland , Seasons
4.
Funct Integr Genomics ; 15(5): 599-610, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26231513

ABSTRACT

Trichoderma afroharzianum is one of the best characterized Trichoderma species, and strains have been utilized as plant disease suppressive inoculants. In contrast, Trichoderma gamsii has only recently been described, and there is limited knowledge of its disease suppressive efficacies. Comparative studies of changes in gene expression during interactions of these species with their target plant pathogens will provide fundamental information on pathogen antibiosis functions. In the present study, we used complementary DNA amplified fragment length polymorphism (cDNA-AFLP) analysis to investigate changes in transcript profiling of T. afroharzianum strain LTR-2 and T. gamsii strain Tk7a during in vitro interactions with plant pathogenic Rhizoctonia solani and Pythium irregulare. Considerable differences were resolved in the overall expression profiles of strains LTR-2 and Tk7a when challenged with either plant pathogen. In strain LTR-2, previously reported mycoparasitism-related genes such as chitinase, polyketide synthase, and non-ribosomal peptide synthetase were found to be differentially expressed. This was not so for strain Tk7a, with the only previously reported antibiosis-associated genes being small secreted cysteine-rich proteins. Although only one differentially expressed gene was common to both strains LTR-2 and Tk7a, numerous genes reportedly associated with pathogen antibiosis processes were differentially expressed in both strains, including degradative enzymes and membrane transport proteins. A number of novel potential antibiosis-related transcripts were found from strains LTR-2 and Tk7a and remain to be identified. The expression kinetics of 20 Trichoderma (10 from strain LTR-2, 10 from strain Tk7a) transcript-derived fragments (TDFs) were quantified by quantitative reverse transcription PCR (RT-qPCR) at pre- and post-mycelia contact stages of Trichoderma-prey interactions, thereby confirming differential gene expression. Collectively, this research is providing information to elucidate the antibiosis mechanisms and disease suppressive activities of T. afroharzianum and T. gamsii against soilborne fungal and oomycete plant pathogens.


Subject(s)
Antibiosis , Pythium/physiology , Rhizoctonia/physiology , Trichoderma/physiology , Fungal Proteins/genetics , Fungal Proteins/metabolism , Gene Expression Regulation, Fungal , Plant Diseases/microbiology , Transcriptome
5.
Bioinformatics ; 30(9): 1308-9, 2014 May 01.
Article in English | MEDLINE | ID: mdl-24443378

ABSTRACT

MOTIVATION: Rich collections of biodiversity information such as spatial distributions, species descriptions and trait data are now synthesized in publicly available online sources such as GBIF. Also phylogenetic knowledge now provides a sound understanding of the origin of organisms and their place in the tree of life. We demonstrate with PhyloJIVE that any phylogenetic tree can be linked to online biodiversity data in the browser. This evolutionary view of biodiversity data is demonstrated in a case study that suggests that this approach may be useful to scientists and non-experts users.


Subject(s)
Biodiversity , Phylogeny , Acacia/genetics , Algorithms , Biological Evolution , Internet , Software Design
6.
Magn Reson Med ; 74(2): 589-98, 2015 Aug.
Article in English | MEDLINE | ID: mdl-25154815

ABSTRACT

PURPOSE: The goal of this study is to increase patient safety in parallel transmission (pTx) MRI systems. A major concern in these systems is radiofrequency-induced tissue heating, which can be avoided by specific absorption rate (SAR) prediction and SAR monitoring before and during the scan. METHODS: In this novel comprehensive safety concept, the SAR is predicted prior to the scan based on precalculated fields obtained from electromagnetic simulations on different body models. The radiofrequency fields and the global and local SAR are supervised in real time during the scan. This concept is integrated into a 3 T pTx MR scanner and validated experimentally. RESULTS: Phantom and in vivo experiments successfully validated the basic feasibility of the real-time SAR supervision concept. Supervising the SAR minimizes SAR overestimation. Monitoring the radiofrequency fields allows the detection of unsafe radiofrequency situations for the patient, which a SAR supervision system alone cannot detect. CONCLUSION: This study demonstrates safe scanning in a pTx system. This new safety concept is also applicable for field strengths above 3 T and represents an important step toward safe operation of pTx systems.


Subject(s)
Equipment Safety/instrumentation , Magnetic Resonance Imaging/instrumentation , Radiometry/instrumentation , Signal Processing, Computer-Assisted/instrumentation , Equipment Design , Equipment Failure Analysis , Magnetic Fields , Radiation Dosage
7.
Curr Microbiol ; 70(4): 618-22, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25561405

ABSTRACT

Trichoderma harzianum is an important commercial biocontrol fungal agent. The temperature has been shown to be an important parameter and strain-specific to the mycelia growth of fungi, but less report makes the known of the mechanisms in T. harzianum. In our study, a 6-h treatment of heat increased the thiobarbituric acid reactive substances (TBARS) and nitric oxide (NO) concentration in mycelia to 212 and 230 % the level of the control, respectively. The exogenous NO donor sodium nitroprusside (150 µM) reduced the TBARS concentration to 53 % of that under heat stress (HS). At the same time, the NO-specific scavenger at 250 µM, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-1-oxyl-3-oxide, prevented the exogenous NO-relieved TBARS accumulation under HS. The increased NO concentration under HS was reduced 41 % by the NO synthase (NOS) inhibitor L-N(G)-nitroarginine methyl ester, but not the nitrate reductase (NR) inhibitor tungstate. Our study exhibited that NO can protect the mycelia of T. harzianum from HS and reduce the oxidative damage by enhancing the activity of NOS and NR.


Subject(s)
Hot Temperature , Mycelium/metabolism , Mycelium/radiation effects , Nitric Oxide/metabolism , Oxidative Stress , Trichoderma/metabolism , Trichoderma/radiation effects , Mycelium/enzymology , Nitrate Reductase/metabolism , Nitric Oxide Synthase/metabolism , Trichoderma/enzymology
8.
Disasters ; 37 Suppl 2: S151-70, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23876011

ABSTRACT

For too long international humanitarian aid has neglected the primary responsibility of the state to assist and protect its citizens in times of disaster. A focus on the role of the state in contexts where governments are active parties to a conflict and are failing to live up to these responsibilities is difficult and underpins many of the recurring dilemmas of humanitarian action. The fundamental principles of humanitarian action should offer a framework for principled engagement with governments in situations of conflict but too often they are still interpreted as shorthand for ignoring governments. Using principles to inform engagement with both states and other international actors engaged in crises could provide a way forward. However, this would need to be a humanitarian agenda that engages with developing country governments, with non-OECD (Organisation for Economic Co-operation and Development) donors, and with the stabilisation and security agendas of Western governments, and not one that attempts to ring-fence an ever-shrinking isolationist humanitarian space.


Subject(s)
Altruism , Government , International Cooperation , Warfare , Africa , Americas , Asia , Humans , Models, Organizational , Social Responsibility
9.
J Soc Psychol ; 153(1): 38-50, 2013.
Article in English | MEDLINE | ID: mdl-23421004

ABSTRACT

Recent work has begun to look at the impact of abusive supervision, a dysfunctional workplace behavior, on employee outcomes. This study extends this line of research by examining vicarious abusive supervision (abuse not directly experienced, but rumors about it or hearing about it, that is "experienced vicariously"). In particular, this research effort investigates whether vicarious abuse has effects above and beyond those accounted for by personally experienced abusive supervision on the outcomes of job frustration, coworker abuse, and perceived organizational support. Our sample is composed of 233 workers from a large variety of organizations. Results reveal that both personally experienced and vicarious abuse have negative impacts and these effects are heightened when both forms of abusive supervision are present. Practical and theoretical implications, as well as directions for future research, are offered.


Subject(s)
Bullying/psychology , Interprofessional Relations , Job Satisfaction , Leadership , Workplace/psychology , Adult , Authoritarianism , Employee Discipline , Employee Grievances , Female , Humans , Male , Organizational Culture , Personnel Management , Social Behavior
10.
Trials ; 24(1): 512, 2023 Aug 10.
Article in English | MEDLINE | ID: mdl-37563721

ABSTRACT

BACKGROUND: Vasovagal reactions (VVRs) are the most common acute complications of blood donation. Responsible for substantial morbidity, they also reduce the likelihood of repeated donations and are disruptive and costly for blood services. Although blood establishments worldwide have adopted different strategies to prevent VVRs (including water loading and applied muscle tension [AMT]), robust evidence is limited. The Strategies to Improve Donor Experiences (STRIDES) trial aims to reliably assess the impact of four different interventions to prevent VVRs among blood donors. METHODS: STRIDES is a cluster-randomised cross-over/stepped-wedge factorial trial of four interventions to reduce VVRs involving about 1.4 million whole blood donors enrolled from all 73 blood donation sites (mobile teams and donor centres) of National Health Service Blood and Transplant (NHSBT) in England. Each site ("cluster") has been randomly allocated to receive one or more interventions during a 36-month period, using principles of cross-over, stepped-wedge and factorial trial design to assign the sequence of interventions. Each of the four interventions is compared to NHSBT's current practices: (i) 500-ml isotonic drink before donation (vs current 500-ml plain water); (ii) 3-min rest on donation chair after donation (vs current 2 min); (iii) new modified AMT (vs current practice of AMT); and (iv) psychosocial intervention using preparatory materials (vs current practice of nothing). The primary outcome is the number of in-session VVRs with loss of consciousness (i.e. episodes involving loss of consciousness of any duration, with or without additional complications). Secondary outcomes include all in-session VVRs (i.e. with and without loss of consciousness), all delayed VVRs (i.e. those occurring after leaving the venue) and any in-session non-VVR adverse events or reactions. DISCUSSION: The STRIDES trial should yield novel information about interventions, singly and in combination, for the prevention of VVRs, with the aim of generating policy-shaping evidence to help inform blood services to improve donor health, donor experience, and service efficiency. TRIAL REGISTRATION: ISRCTN: 10412338. Registration date: October 24, 2019.


Subject(s)
Blood Donors , Syncope, Vasovagal , Humans , State Medicine , Syncope, Vasovagal/diagnosis , Syncope, Vasovagal/etiology , Syncope, Vasovagal/prevention & control , Water , Blood Donation
11.
Anal Chem ; 84(15): 6501-7, 2012 Aug 07.
Article in English | MEDLINE | ID: mdl-22788980

ABSTRACT

A rapid approach for comprehensive two-dimensional gas chromatographic data analysis is introduced, providing important environmental metrics including total petroleum hydrocarbon concentration as well as chemical-class distribution. The approach, comprising transformation of exported data files to two-dimensional retention time arrays, blank subtraction, alignment and projection onto new axes, subdivision of the aligned two-dimensional data matrix, and compilation of summary data is able to be performed without user intervention. The approach satisfies critical goals of rapid batch analysis with repeatability and traceability. Application to assessment of petroleum hydrocarbon contaminated soil samples from Macquarie Island, a remote Southern Ocean island, is shown to illustrate the utility of this new data analysis strategy.

12.
Magn Reson Med ; 68(5): 1664-74, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22231647

ABSTRACT

The specific absorption rate (SAR) is a limiting factor in high-field MR. SAR estimation is typically performed by numerical simulations using generic human body models. However, SAR concepts for single-channel radiofrequency transmission cannot be directly applied to multichannel systems. In this study, a novel and comprehensive SAR prediction concept for parallel radiofrequency transmission MRI is presented, based on precalculated magnetic and electric fields obtained from electromagnetic simulations of numerical body models. The application of so-called Q-matrices and further computational optimizations allow for a real-time estimation of the SAR prior to scanning. This SAR estimation method was fully integrated into an eight-channel whole body MRI system, and it facilitated the selection of different body models and body positions. Experimental validation of the global SAR in phantoms demonstrated a good qualitative and quantitative agreement with the predictions. An initial in vivo validation showed good qualitative agreement between simulated and measured amplitude of (excitation) radiofrequency field. The feasibility and practicability of this SAR prediction concept was shown paving the way for safe parallel radiofrequency transmission in high-field MR.


Subject(s)
Algorithms , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Humans , Reproducibility of Results , Sensitivity and Specificity
15.
Biotechnol Lett ; 34(2): 287-93, 2012 Feb.
Article in English | MEDLINE | ID: mdl-21972146

ABSTRACT

Burkholderia vietnamiensis P418 is a plant growth-promoting rhizobacteria. A chitinase gene from Bacillus subtilis was cloned and stably integrated into the chromosome of using the transposon delivery vector, pUTkm1. Chitinase activity was detected in recombinant P418-37 but not in wild type P418. Recombinant P418-37 retained the in vitro growth rate, N(2)-fixation and phosphate and potassium-solubilizing characteristics of the wild type. P418-37 significantly (P < 0.05) increased in vitro inhibition of the plant pathogenic fungi Rhizoctonia solani, Fusarium oxysporum f.sp. vasinfectum, Rhizoctonia cerealis, Bipolaris sorokiniana, Verticillium dahliae and Gaeumannomyces graminis var. tritici compared with P418. In planta disease suppression assays indicated that P418-37 significantly (P < 0.05) enhanced suppression of wheat sheath blight (R. cerealis), cotton Fusarium wilt (F. oxysporium f.sp. vasinfectum) and tomato gray mould (Botrytis cinerea), relative to the wild type.


Subject(s)
Bacillus subtilis/enzymology , Burkholderia/enzymology , Burkholderia/physiology , Chitinases/genetics , Plant Diseases/prevention & control , Antibiosis , Bacillus subtilis/genetics , Burkholderia/genetics , Burkholderia/growth & development , Chitinases/metabolism , Cloning, Molecular , DNA Transposable Elements , Fungi/growth & development , Gene Expression , Mutagenesis, Insertional , Nitrogen Fixation , Organisms, Genetically Modified , Phosphates/metabolism , Plant Diseases/microbiology , Potassium/metabolism
16.
Disasters ; 36(1): 140-60, 2012 Jan.
Article in English | MEDLINE | ID: mdl-21623891

ABSTRACT

Corruption is a threat to the purpose of humanitarian assistance. Until fairly recently, humanitarian assistance has not been considered an important arena in broader efforts aimed at curbing corruption, and corruption has not always been considered a particularly important concern for humanitarian assistance despite the obviously challenging nature of the context of humanitarian emergencies. Corruption, though, is a threat to humanitarian action because it can prevent assistance from getting to the people who most need it, and because it can potentially undermine public support for such assistance. This paper examines perceptions of corruption and its affects, documents best practices, and outlines gaps in understanding. It suggests recommendations for improving the capacity of humanitarian agencies to prevent and manage the risk of corruption. Agencies have taken steps to combat corruption and improve accountability--downwards and upwards--but scope remains for improvement and for greater sharing of learning and good practice.


Subject(s)
Altruism , Fraud/prevention & control , Relief Work/ethics , Risk Management/organization & administration , Disasters , Global Health , Humans , Relief Work/organization & administration , Social Responsibility
17.
Sci Total Environ ; 811: 151984, 2022 Mar 10.
Article in English | MEDLINE | ID: mdl-34871683

ABSTRACT

Household dust has been considered as an important pathway for children's environmental Pb exposure. Shanghai was one of the first cities in China that removed Pb from petrol and has been shown in our previous study to have the lowest childhood blood Pb levels in China. This study therefore examines household dust Pb (PbHD) in Shanghai in order to determine the extent and exposure risks of PbHD. Household vacuum cleaner dust samples (n = 40) were collected and analyzed for total Pb concentration, bio-accessible Pb concentration and Pb isotopic compositions (PbIC). The mean concentration of PbHD was 195 mg/kg, which is between 7 and 10 times the Pb concentration of background soil samples from Shanghai. Among the investigated homes, those living in neighborhoods with lower average estate prices have higher dust Pb exposure risks for children. Bio-accessibility of Pb in household dust ranged between 53 and 91%, with a mean value of 71%. Analysis of PbIC of household dust samples (208Pb/206Pb: 2.1096 ± 0.0054; 207Pb/206Pb: 0.8648 ± 0.0025) are a close match to PbIC of coal combustion and solid waste incineration and fit well with those of outdoor air PbIC and urban surface soil PbIC of Shanghai. The study shows that children living in Shanghai are subject to PbHD exposure, with children living in the homes with lower average price having increased susceptibility to PbHD exposure. The data indicate that PbHD is derived primarily from contemporary coal combustion and solid waste incineration rather than common legacy Pb sources (e.g., Pb petrol and paint). Practices including closing doors and windows on days with poor air quality or high wind and preventing shoe wearing inside homes will aid in minimizing outdoor surface soil and ambient particulate intrusion indoors.


Subject(s)
Dust , Lead , Child , China , Dust/analysis , Environmental Exposure/analysis , Environmental Monitoring , Humans , Soil
18.
Genes (Basel) ; 13(12)2022 12 05.
Article in English | MEDLINE | ID: mdl-36553557

ABSTRACT

The bacterium Pseudomonas sp. strain JP233 has been reported to efficiently solubilize sparingly soluble inorganic phosphate, promote plant growth and significantly reduce phosphorus (P) leaching loss from soil. The production of 2-keto gluconic acid (2KGA) by strain JP233 was identified as the main active metabolite responsible for phosphate solubilization. However, the genetic basis of phosphate solubilization and plant-growth promotion remained unclear. As a result, the genome of JP233 was sequenced and analyzed in this study. The JP233 genome consists of a circular chromosome with a size of 5,617,746 bp and a GC content of 62.86%. No plasmids were detected in the genome. There were 5097 protein-coding sequences (CDSs) predicted in the genome. Phylogenetic analyses based on genomes of related Pseudomonas spp. identified strain JP233 as Pseudomonas asiatica. Comparative pangenomic analysis among 9 P. asiatica strains identified 4080 core gene clusters and 111 singleton genes present only in JP233. Genes associated with 2KGA production detected in strain JP233, included those encoding glucose dehydrogenase, pyrroloquinoline quinone and gluoconate dehydrogenase. Genes associated with mechanisms of plant-growth promotion and nutrient acquisition detected in JP233 included those involved in IAA biosynthesis, ethylene catabolism and siderophore production. Numerous genes associated with other properties beneficial to plant growth were also detected in JP233, included those involved in production of acetoin, 2,3-butanediol, trehalose, and resistance to heavy metals. This study provides the genetic basis to elucidate the plant-growth promoting and bio-remediation properties of strain JP233 and its potential applications in agriculture and industry.


Subject(s)
Phosphates , Pseudomonas , Phosphates/metabolism , Phylogeny , Genomics
19.
Front Microbiol ; 13: 892533, 2022.
Article in English | MEDLINE | ID: mdl-35572684

ABSTRACT

Phosphorus (P) is one of the most limiting nutrients in global agricultural ecosystems, and phosphorus-solubilizing bacteria (PSB) can convert insoluble P into soluble P, thereby improving the absorption and use of soil P by plants. Increasing leaching loss of soil P due to PSB that could lead to water eutrophication is a major concern, although no direct experimental evidence is available to evaluate these effects. In this study, a highly efficient PSB strain, Pseudomonas sp. JP233, was isolated from soil and its P-solubilizing agent was identified by metabolomics and HPLC analyses. The effects of JP233 on P contents in soil leachates were also analyzed by microcosm leaching experiments in the absence and presence of maize. JP233 could solubilize insoluble P into soluble forms, and the molybdate reactive phosphorus (MRP) content reached 258.07 mg/L in NBRIP medium containing 5 g/L Ca3(PO4)2 within 48 h. Metabolomics analysis demonstrated that the organic acid involved in JP233 P solubilization was primarily 2-keto gluconic acid (2KGA). Further, HPLC analysis revealed that 2KGA contents rapidly accumulated to 19.33 mg/mL within 48 h. Microcosm leaching experiments showed that MRP and total phosphorus (TP) contents in soil leaching solutions were not significantly higher after JP233 inoculation. However, inoculation with JP233 into maize plant soils significantly decreased MRP and TP contents in the soil leaching solutions on days 14 (P < 0.01), 21 (P < 0.01), and 28 (P < 0.05). Inoculation with strain JP233 also significantly increased the biomass of maize aerial components and that of whole plants (P < 0.05). Thus, strain JP233 exhibited a significant plant-growth-promoting effect on maize development. In conclusion, the application of PSB into soils does not significantly increase P leachate loss. Rather, the application of PSB can help reduce P leachate loss, while significantly promoting plant absorption and use of soil P.

20.
New Phytol ; 191(3): 819-827, 2011 Aug.
Article in English | MEDLINE | ID: mdl-21534968

ABSTRACT

• Theoretically, communities at or near their equilibrium species number resist entry of new species. Such 'biotic resistance' recently has been questioned because of successful entry of alien species into diverse natural communities. • Data on 10,409 naturalizations of 5350 plant species over 16 sites dispersed globally show exponential distributions both for species over sites and for sites over number of species shared. These exponentials signal a statistical mechanics of species distribution, assuming two conditions. First, species and sites are equivalent, either identical ('neutral') or so complex that the chance a species is in the right place at the right time is vanishingly small ('idiosyncratic'); the range of species and sites in our data disallows a neutral explanation. Secondly, the total number of naturalizations is fixed in any era by a 'regulator'. • Previous correlation of species naturalization rates with net primary productivity over time suggests that the regulator is related to productivity. • We conclude that biotic resistance is a moving ceiling, with resistance controlled by productivity. The general observation that the majority of species occur naturally at only a few sites, and only a few species occur at many sites, now has a quantitative (exponential) character, offering the study of species' distributions a previously unavailable rigor.


Subject(s)
Biodiversity , Biomass , Models, Biological , Plant Development , Population Dynamics , Ecology , Plant Physiological Phenomena , Population Density
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