Linking Microbial Community Dynamics Associated with Rhizosphere Carbon Flow in a Biofuel Crop (Jatropha curcas L.)     

Doongar R. Chaudhary  Richard P. Dick 《Communications in Soil Science and Plant Analysis》2016,47(9):1193-1206

Photosynthetically derived rhizodeposits are an important source of carbon (C) for microbes in root vicinity and can influence the microbial community dynamics. Pulse labeling of carbon dioxide (¹³CO₂) coupled with stable isotope probing techniques have potential to track recently fixed photosynthate into rhizosphere microbial taxa. Therefore, the present investigation assessed the microbial community change associated with the rhizosphere and bulk soil in Jatropha curcas L. (a biofuel crop) by combining phospholipid fatty acid (¹³C-PLFA) profiling using a stable isotope ¹³CO₂ labeling approach. The labeling (¹³C) took place after 45 days of germination, PLFAs were extracted from both soils (rhizosphere and bulk) after 1 and 20 days pulse labeling and analyzed by gas chromatography-isotope ratio mass spectrometry. There was no significant temporal effect on the PLFA profiles in the bulk soil, but significantly increased abundance of Gram positive (i15:0) and Gram negative (16:1ω7c and 16:1ω5c) biomarkers was observed in the rhizosphere soil from day 1 to day 20 after labeling. The Gram negative (16:1ω7c) decreased and fungal (18:2ω6,9c) increased significantly in rhizospheric soil compared to bulk soil after day 1 of labeling. Whereas, after 20 days of labeling, the Gram negative biomarker (16:1ω7c and 18:1ω7c) decreased and Gram positive (a15:0) increased significantly in rhizospheric soil compared to bulk soil. One day following labeling, i15:0, a15:0, i16:0, 16:1ω5c, 16:0, i17:0, a17:0, 18:2ω6,9c, 18:1ω9c, and 18:0 PLFAs were significantly more enriched in δ¹³C in the rhizosphere than in the bulk soil. Twenty days after labeling, 16:1ω5c (Gram negative) and 18:2ω6,9c (fungal) were significantly more enriched in δ¹³C in the rhizosphere than in the bulk soil. These results shows the effectives of PLFA coupled using the pulse chase labeling technique to examine the microbial community changes in response to recently fixed photosynthetic C flow in rhizodeposits.  相似文献   

Effects of different chloroform stabilizers on the extraction efficiencies of phospholipid fatty acids from soils     

Andrea Fuhrmann  Martin H. Gerzabek  Andrea Watzinger 《Soil biology & biochemistry》2009,41(2):428-430

Chloroform is commonly used as an organic solvent to extract phospholipid fatty acids from soil samples. However, the extraction efficiency of the fatty acids depends on the particular chloroform stabilizers used. The effect of chloroform stabilizers 2-methyl-2-butene and ethanol was investigated at different steps of the extraction procedure. Only the ethanol stabilized chloroform prevented the loss of certain phospholipid fatty acids. In particular, the unsaturated fatty acids 16:1ω7c, 16:1ω6c, 16:1ω5, 17:1ω8, 18:1ω7c, 18:1ω5, the fungal biomarker 18:2ω6,9 and the saturated fatty acid 17:0 were absent when chloroform stabilized with 2-methyl-2-butene was used. In addition, the total phospholipid fatty acid concentrations were also significantly reduced when chloroform stabilized with 2-methyl-2-butene was used. Thus, the proper choice of chloroform stabilizer for the analysis of phospholipid fatty acids is very important.  相似文献   

Effect of biochar amendment on soil carbon balance and soil microbial activity   总被引：2，自引：0，他引：2  

S. Steinbeiss  G. Gleixner 《Soil biology & biochemistry》2009,41(6):1301-1310

We investigated the behavior of biochars in arable and forest soil in a greenhouse experiment in order to prove that these amendments can increase carbon storage in soils. Two qualities of biochar were produced by hydrothermal pyrolysis from ¹³C labeled glucose (0% N) and yeast (5% N), respectively. We quantified respiratory losses of soil and biochar carbon and calculated mean residence times of the biochars using the isotopic label. Extraction of phospholipid fatty acids from soil at the beginning and after 4 months of incubation was used to quantify changes in microbial biomass and to identify microbial groups utilizing the biochars. Mean residence times varied between 4 and 29 years, depending on soil type and quality of biochar. Yeast-derived biochar promoted fungi in the soil, while glucose-derived biochar was utilized by Gram-negative bacteria. Our results suggest that residence times of biochar in soils can be manipulated with the aim to “design” the best possible biochar for a given soil type.  相似文献   

Residue chemistry and microbial community structure during decomposition of eucalypt, wheat and vetch residues     

Karen Baumann  Petra Marschner  Ronald J. Smernik  Jeffrey A. Baldock 《Soil biology & biochemistry》2009,41(9):1966-1975

Previous studies have shown that residue chemistry and microbial community structure change during decomposition, however little is known about the relationship between C-chemistry and microbial community structure. To address this knowledge gap, we studied C-chemistry and microbial community structure during the decomposition of eucalypt, wheat and vetch residues with and without additional inorganic N. Bags containing ground residues of eucalypt, wheat, and vetch were buried in sand microcosms after inoculation with a diverse microbial community. Respiration was measured over an incubation period of 150 days. At different times during incubation, total C and N of the residues were analysed and residue carbon chemistry was determined by ¹³C-NMR (nuclear magnetic resonance) spectroscopy. Microbial communities were assessed by phospholipid fatty acid (PLFA) analyses.Results indicated that during decomposition, residue C-chemistry and microbial community composition changed over time and differed between residue types. Changes in microbial community structure were associated with changes in residue C-chemistry, mainly the relative content of aryl-C and O-alkyl-C. Addition of N increased cumulative respiration, altered C-chemistry during decomposition, particularly in high C/N residues (wheat and eucalypt), and changed microbial succession leading to an earlier establishment of a stable microbial community structure. N addition to eucalypt and wheat reduced the decomposition of aryl-C compounds.  相似文献   

Decomposition and spatial microbial heterogeneity associated with native shrubs in soils of agroecosystems in semi-arid Senegal     

S. Diedhiou  A.N. Badiane  M. Sène 《Pedobiologia》2009,52(4):273-286

  相似文献   

Microbial response to exudates in the rhizosphere of young beech trees (Fagus sylvatica L.) after dormancy     

J. Esperschütz  F. Buegger  J.B. Winkler  J.C. Munch  M. Schloter  A. Gattinger   《Soil biology & biochemistry》2009,41(9):1976-1985

Plants act as an important link between atmosphere and soil: CO2 is transformed into carbohydrates by photosynthesis. These assimilates are distributed within the plant and translocated via roots into the rhizosphere and soil microorganisms. In this study, 3 year old European beech trees (Fagus sylvatica L.) were exposed after the chilling period to an enriched ¹³C–CO₂ atmosphere (δ¹³C = 60‰ – 80‰) at the time point when leaves development started. Temporal dynamics of assimilated carbon distribution in different plant parts, as well as into dissolved organic carbon and microbial communities in the rhizosphere and bulk soil have been investigated for a 20 days period. Photosynthetically fixed carbon could be traced into plant tissue, dissolved organic carbon and total microbial biomass, where it was utilized by different microbial communities. Due to carbon allocation into the rhizosphere, nutrient stress decreased; exudates were preferentially used by Gram-negative bacteria and (mycorrhizal) fungi, resulting in an enhanced growth. Other microorganisms, like Gram-positive bacteria and mainly micro eucaryotes benefited from the exudates via food web development. Overall our results indicate a fast turnover of exudates and the development of initial food web structures. Additionally a transport of assimilated carbon into bulk soil by (mycrorhizal) fungi was observed.  相似文献   

Overstory-specific effects of litter fall on the microbial carbon turnover in a mature deciduous forest     

Christel Baum  Mirko Fienemann  Stephan Glatzel  Gerd Gleixner 《Forest Ecology and Management》2009

Mature deciduous forests can serve as important carbon (C) sinks, but the C storage differs significantly in dependency on the tree species. To specify the significance of overstory-specific effects of litter fall on the soil microbial C turnover, we have investigated the ¹³C isotopic signature of microbial biomarker phospholipid fatty acids (PLFAs). Samples were taken under pure Fagus sylvatica and mixed overstory (F. sylvatica and Fraxinus excelsior or F. excelsior, Acer spp. and F. sylvatica) in a mature temperate deciduous forest in Central Germany 4 weeks prior to and 3 weeks after litter fall. Accordingly, the CO₂ emission from soil was measured before, during and after the litter fall to investigate the response of decomposition. At all sites and at both sampling dates the fungal biomarker PLFA 18:2ω6,9 had predominantly lower δ¹³C values (from −32 to −43‰) than the bacterial biomarker PLFAs (δ¹³C values from −23 to −39‰). This difference indicated that fungi generally used preferentially plant derived C, whereas the bacterial populations include groups which used SOM derived C, independent on the overstory trees. Under pure F. sylvatica overstory the δ¹³C values of microbial biomarker PLFAs were slightly decreased (up to 2‰ for 17:0br) or unchanged after litter fall. By contrast, under both variants of mixed overstory the δ¹³C values of biomarker PLFAs of fungi (18:2ω6,9) were increased after litter fall (+3.5 and +3.8‰). This might be explained partly by a faster initial decomposition of foliar litter from mixed overstory already during litter fall as confirmed by higher CO₂ emission under mixed F. excelsior, Acer spp. and F. sylvatica than under pure F. sylvatica in this period. However, the involved microbial populations differed overstory-specific. Bacterial biomarker PLFAs with strongest overstory-specific differences in the response on litter fall were 17:0br (Gram-positive bacteria), 18:1 and 19:0cy (Gram-negative bacteria). The present results indicate that a tree species conversion even exclusively between deciduous tree species might alter the soil microbial C turnover during litter decomposition and suggest that it would in the long-term change the SOM stability and C storage.  相似文献   

土壤微生物群落表征中磷脂脂肪酸(PLFA)方法研究进展   总被引：3，自引：0，他引：3  

张瑞娟  李华  林勤保  张强  郜春花 《山西农业科学》2011,39(9):1020-1024

土壤是生物圈的主要成员之一,而土壤微生物群落被认为是土壤生态系统变化的预警及敏感指标,指示土壤质量变化。磷脂脂肪酸(PLFA)方法是一种新兴的用来表征微生物群落结构的方法,已在土壤微生物学研究中得到广泛应用。对其研究进展进行了综述。  相似文献   

硝化抑制剂和秸秆对潮棕壤碳氮转化和微生物群落特征的短期影响   总被引：2，自引：1，他引：1       下载免费PDF全文

杨立杰  张丽莉  李东坡  宫平  薛妍  于春晓  王成柱  武志杰 《中国土壤与肥料》2017,(1):86-91

氮是植物和微生物生长繁殖的必需营养元素,而氮矿化表征了土壤供氮能力。通过盆栽实验,采用同位素稀释法和磷脂脂肪酸(PLFA)法,研究了添加硝化抑制剂和秸秆条件下,潮棕壤碳氮矿化和微生物群落组成变化特征。结果表明,与施氮量N 0.1 g·kg~(-1)的单施氮肥处理(NF)相比,氮肥配施1%硝化抑制剂(NFI)的土壤铵态氮提高32%,而硝态氮降低53%。氮肥与施用量为5 g·kg~(-1)的秸秆配施(NS),土壤氮素总矿化速率增加36%,微生物生物量碳提高51%,β-葡萄糖苷酶活性提高36%,同时显著增加了土壤总PLFA以及细菌、真菌、真菌/细菌和革兰式阴性菌(P0.05),土壤呼吸熵降低50%。与氮肥配施秸秆处理(NS)相比,氮肥、秸秆和硝化抑制剂配施处理(NSI),土壤铵态氮提高33%,硝态氮下降47%。综上所述,氮肥和秸秆配施可以提高土壤微生物生物量,改变土壤微生物群落组成,配施1%(N)硝化抑制剂后降低土壤硝化速率,增加土壤供氮能力。  相似文献   

芭蕉属植物内生细菌磷脂脂肪酸(PLFA)生物标记特性研究   总被引：4，自引：0，他引：4  

蓝江林  刘波  陈璐  肖荣凤  史怀  苏明星 《中国农业科学》2010,43(10):2045-2055

【目的】分离、鉴定芭蕉属植物内生细菌,了解内生细菌的种群结构及其脂肪酸生物标记特性。【方法】采用平板分离纯化芭蕉、威廉斯蕉和野生蕉植株内生细菌,利用细菌脂肪酸鉴定技术进行鉴定。【结果】共获得内生细菌11属14种,野生蕉植株分离得到9种,威廉斯蕉植株7种,芭蕉植株3种。共检测到35个磷脂脂肪酸生物标记,这些生物标记分为4种类型,即(1)高频次分布:在14株细菌中出现10—14次,属于细菌总体类群(general)的生物标记。(2)中频次分布:在14株细菌中出现4—6次,可以用于代表细菌属类群(genus)识别生物标记。(3)低频次分布:在14株细菌中出现2—3次,可以用于指示特定细菌种间差异的生物标记。(4)微频次分布:仅在一种细菌种类出现,是细菌种(species)特征生物标记。利用磷脂脂肪酸生物标记分析内生细菌群落结构,可将14种细菌分为3类;运用多样性、丰富度、均匀度及优势度指数等生态学概念,分析了磷脂脂肪酸生物标记总量与各生态学参数之间的关系,结果表明,磷脂脂肪酸生物标记16:0、18:1W7C、14:0、12:0、18:0、17:0CYCLO的丰富度皆相对较高;磷脂脂肪酸生物标记的Response值总和较高,均匀度(J)较低,其Simpson优势度指数(D)、Shannon-Wiener(H1)、Brillouin(H2)、Mcintosh(H3)多样性指数也相对较高。【结论】芭蕉属植物内生细菌及其磷脂脂肪酸生物标记存在多样性。  相似文献