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Chemical composition and Zn bioavailability of the soil solution extracted from Zn amended variable charge soils

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Journal of Environmental sciences 2010年第9期22卷 1398-1406页

作者： Mariavittoria Zampella Paola Adamo department of soil Plant Environmental and Animal Production Sciences University of Naples Federico II

A study on variable charge soils （volcanic Italian and podzolic Scottish soils） was performed to investigate the influence of soil properties on the chemical composition of soil solution. Zinc speciation, bioavallability and toxicity in the soil solution were examined. The soils were spiked with increasing amounts of Zn （0, 100, 200, 400 and 1000 mg/kg） and the soil solutions were extracted using rhizon soil moisture samplers. The pH, total organic carbon （TOC）, base cations, anions, total Zn and free Zn^2＋ in soil solution were analysed. A rapid bioassay with the luminescent bacterium Escherichia coli HB 101 pUCD607 was performed to assess Zn toxicity. The influence of soil type and Zn treatments on the chemical composition of soil solution and on Zn toxicity was considered and discussed. Different trends of total and free Zn concentrations, base cations desorption and luminescence of E. coli HB 101 pUCD607 were observed. The soil solution extracted from the volcanic soils had very low total and free Zn concentrations and showed specific Zn^2＋/Ca^2＋ exchange. The soil solution from the podzolic soil had much higher total and free Zn concentrations and showed no evidence of specific Zn^2＋/Ca^2＋ exchange. In comparison with the subalkaline volcanic soils, the acidic podzol showed enhanced levels of toxic free Zn^2＋ and consequently stronger effects on E. coli viability.

关键词： rhizosamplers chemical speciation fractionation ecotoxicological test

Influence of Long-Term Fertilization on Selenium Accumulation in soil and Uptake by Crops

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Pedosphere 2016年第1期26卷 120-129页

作者： WANG Qingyun ZHANG Jiabao ZHAO Bingzi XIN Xiuli DENG Xihai Hailin ZHANG State Key Laboratory of soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences plant and soil sciences department Oklahoma State University

Continuous applications of organic and inorganic fertilizers can affect soil and food quality with respect to selenium （Se） concen- trations. A long-term （over 20 years） experimental field study, started in 1989, was conducted to investigate the changes in soil Se fractions and its uptake by crops, as affected by different fertilizer practices, in the North China Plain with an annual crop rotation of winter wheat and summer maize. The long-term experiment was arranged in a complete randomized block design consisting of 4 replications with 7 fertilizer treatments： 1） organic compost （OC）, 2） half organic compost plus half N-P-K chemical fertilizers （OC ＋ NPK）, 3） N-P-K fertilizers （NPK）, 4） N-P fertilizers （NP）, 5） P-K fertilizers （PK）, 6） N-K fertilizers （NK）, and 7） an un-amended control. soil samples from the surface （20 cm） were collected in 1989, 1994, 1999, 2004 and 2009 to characterize Se and other soil properties. In 2009, the average soil Se concentrations in the treatments （149 ± 8 beg kg-1） were higher than those in the soil samples collected in 1989 at the beginning of the experiment （112 4- 4 beg kg-1）, and decreased in the order of OC 〉 OC ＋ NPK 〉 NPK NP 〉 PK NK 〉 control. Sequential extraction showed the oxidizable fraction （50.06%± 3.94%） was the dominant form of Se in the soil, followed by the residual fraction （24.12% ± 2.89%）, exchangeable fraction （15.09% ± 4.34%） and Fe-Mn oxides fraction （10.73%±4.04%）. With an increase of soil K, the exchangeable Se concentrations in the soil increased. The Se concentrations in the soil tillage layer （0-20 cm） were mainly related to soil organic carbon （SOC）, although different contributions came from atmospheric deposition, irrigation and fertilizers. With the accumulation of SOC, the uptakes of soil Se by two crops were inhibited. For the OC and OC ＋ NPK treatments, Se concentrations in wheat grains were lower than the critical standard of Se in stable food （100 μg kg·1]. Additionallv. Se concentrations in

关键词： agricultural soil essential nutrient fertilizer practices Se deficiency Se fractions

Nutrient stress-primed microbial communities improve plant resilience

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Science Bulletin 2024年第20期69卷 3180-3183页

作者： Xiaocheng Yu Hongyan Zhu department of plant and soil sciences University of KentuckyLexington KY 40546USA

plants live in close association with microbial communities that comprise a diverse array of bacteria,fungi,and *** microorganisms thrive in various niches within and around plants,including the rhizosphere(the zone of soil surrounding a plant root),phyllosphere(above-ground plant surfaces),and endosphere(interior of plant tissues).

关键词： soil Nutrient rhizosphere

New insights on molecular regulation of biofilm formation in plant-associated bacteria

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Journal of Integrative plant Biology 2016年第4期58卷 362-372页

作者： Luisa F.Castiblanco George W.Sundin department of plant Soil and Microbial Sciences and Center for Microbial Pathogenesis Michigan State University

Biofilms are complex bacterial assemblages with a defined three-dimensional architecture, attached to solid surfaces, and surrounded by a self-produced matrix generally composed of exopolysaccharides, proteins, lipids and extracellular DNA. Biofilm formation has evolved as an adaptive strategy of bacteria to cope with harsh environmental conditions as well as to establish antagonistic or beneficial interactions with their host. plant-associated bacteria attach and form biofilms on different tissues including leaves, stems,vasculature, seeds and roots. In this review, we examine the formation of biofilms from the plant-associated bacterial perspective and detail the recently-described mechanisms of genetic regulation used by these organisms to orchestrate biofilm formation on plant surfaces. In addition, we describe plant host signals that bacterial pathogens recognize to activate the transition from a planktonic lifestyle to multicellular behavior.

关键词： Cyclic-di-GMP Erwinia amylovora small RNAs Xanthomonas campestris Xylella fastidiosa

Variation in soil organic matter accumulation and metabolic activity along an elevation gradient in the Santa Rosa Mountains of Southern California, USA

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Journal of Arid Land 2015年第6期7卷 814-819页

作者： Amitava CHATTERJEE George D JENERETTE department of soil Science North Dakota State University department of Botany and plant sciences University of California

Variations in soil organic matter accumulation across an elevation can be used to explain the control of substrate supply and variability on soil metabolic activity. We investigated geographic changes in soil organic matter and metabolic rates along an elevation gradient（289–2,489 m） in the Santa Rosa Mountains, California, USA from subalpine and montane pine forests through chaparral to desert. From base（289 m） to summit（2,489 m）, 24 sites were established for collecting soil samples under canopies and inter-canopy spaces, at 0–5 and 5–15 cm soil depths increments. soil organic matter（SOM） content was determined using weight loss on ignition at 550°C and soil CO2 efflux（R） was measured at day 5（R5） and day 20（R20） of incubation. Changes in SOM content along the elevation gradient showed a significant relationship（P〈0.05） but R5 and R20 were not related to either elevation or SOM content. However, the ratio of R and SOM（R5/SOM） showed a strong relationship across the mountains at both soil depths. R5/SOM, as an indicator of carbon use efficiency, may be applicable to other semi-arid transects at larger scale modeling of soil metabolic processes.

关键词： elevation gradient soil organic matter CO2 efflux metabolic activity

Isolation and Characterization of Chlorothalonil-Degrading Bacterial Strain H4 and Its Potential for Remediation of Contaminated soil

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Pedosphere 2014年第6期24卷 799-807页

作者： ZHANG Man-Yun TENG Ying ZHU Ye WANG Jun LUO Yong-Ming P.CHRISTIE LI Zhen-Gao T.K.UDEIGWE Key Laboratory of soil Environment and Pollution Remediation Institute of Soil ScienceChinese Academy of Sciences University of Chinese Academy of sciences department of plant and soil Science Texas Tech.University

A chlorothalonil(CTN)-degrading bacterial strain H4 was isolated in this study from a contaminated soil by continuous enrichment culture to identify its characteristics and to investigate its potential for remediation of CTN in contaminated soil. Based on the morphological, physiological and biochemical tests and 16 S r DNA sequence analysis, the strain was identified as Stenotrophomonas sp. After liquid culture for 7 d, 82.2% of CTN was removed by strain H4. The isolate could degrade CTN over a broad range of temperatures and p H values, and the optimum conditions for H4 degradation were p H 7.0 and 30℃. Reintroduction of the bacteria into artificially contaminated soil resulted in substantial removal of CTN(> 50%) after incubation for 14 d. soil samples treated by H4 showed significant increases(P soil dehydrogenase activity, soil polyphenol oxidase activity, average well-color development obtained by the Biolog Eco plate TM assay and Shannon-Weaver index, compared with the control. Strain H4 might be a promising candidate for application in the bioremediation of CTN-contaminated soils.

关键词： biodegradation fungicide soil bioremediation Stenotrophomonas sp.

CPSF30-L: A direct connection between mRNA polyadenylation and m^(6)A RNA modification in plants

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Molecular plant 2021年第5期14卷 711-713页

作者： Arthur G.Hunt department of plant and soil sciences University of KentuckyLexingtonKY 40546-0312USA

Alternative polyadenylation-the series of events that leads to the production of different mRNA isoforms from a primary transcript via usage of different polyadenylation sites within the transcript-is an important facet of gene expression in *** the proteins that control alternative polyadenylation in plants is CPSF30,a core subunit of the polyadenylation complex(Chakrabarti and Hunt,2015).In plants,CPSF30 integrates cellular signaling with numerous growth and developmental processes through an interaction with calmodulin(Chakrabarti and Flunt,2015).

关键词： CPSF integrate modification

Spatial Variability of soil Properties at Capulin Volcano,New Mexico,USA:Implications for Sampling Strategy

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Pedosphere 2010年第2期20卷 185-197页

作者： D.C.WEINDORF School of soil Plant and Environmental SciencesLouisiana State University

Non-agricultural lands are surveyed sparsely in ***,soils in these areas usually exhibit strong spatial variability which requires more samples for producing acceptable *** Volcano National Monument,as a typical sparsely-surveyed area,was chosen to assess spatial variability of a variety of soil properties,and furthermore,to investigate its implications for sampling *** hundred and forty one composited soil samples were collected across the Monument and the surrounding *** properties including pH,organic matter content,extractable elements such as calcium (Ca),magnesium (Mg),potassium (K),sodium (Na),phosphorus (P),sulfur (S),zinc (Zn),and copper (Cu),as well as sand,silt,and clay percentages were analyzed for each *** of all properties were constructed,standardized,and compared to estimate the spatial variability of the soil properties in the *** on the similarity among standardized semivariograms,we found that the semivariograms could be generalized for physical and chemical properties,*** generalized semivariogram for physical properties had a much greater sill value (2.635) and effective range (7 500 m) than that for chemical *** sampling density (OSD),which is derived from the generalized semivariogram and defines the relationship between sampling density and expected error percentage,was proposed to represent,interpret,and compare soil spatial variability and to provide guidance for sample scheme *** showed that chemical properties exhibit a stronger local spatial variability than soil texture parameters,implying more samples or analysis are required to achieve a similar level of precision.

关键词： generalized semivariogram GIS optimal sampling density sampling design

Advances in Understanding Seed Dormancy at the Whole-seed Level: An Ecological, Biogeographical and Phylogenetic Perspective

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云南植物研究 2008年第3期30卷 279-294页

作者： BASKIN Carol C BASKIN Jerry M department of Biology University of Kentucky department of plant and soil sciences University of Kentucky Lexington KY 40546 USA department of plant and soil sciences University of Kentucky

Following a brief account of the early foundations of seed germination ecology sensu lato, some historical and recent developments pertaining to the ecology, biogeography and phylogeny of seed dormancy are discussed.

关键词：种子休眠系统发育生物状态植物学