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采用根箱盆栽法,研究了甲磺隆对我国南方小麦根际与非根际土壤中特殊微生物生理群区系,包括氮素转化生理群区系、硫素转化生理群区系和芳香族分解群区系的影响.结果表明:固氮菌对甲磺隆不敏感,亚硝化菌和反硝化菌受甲磺隆毒害严重,但小麦根系的生长可在一定程度上缓解甲磺隆的抑制作用;硫化细菌和反硫化细菌的生长也受到了甲磺隆的强烈抑制,根际效应亦明显;甲磺隆驯化以及作物根系的协同作用,共同促进了芳香族化合物分解菌的生长和繁殖,为利用植物和微生物联合修复受甲磺隆等芳香族化合物污染的土壤提供了理论依据. 相似文献
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西宁地区春小麦土壤微生物根际效应的研究 总被引:5,自引:0,他引:5
本文研究了西宁地区春小麦主要生育期根际微生物的变化规律。结果表明,在春小麦分蘖期至开花期根际效应显著,土壤根际微生物的生态分布具有特定的规律。 相似文献
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柑桔根际土壤微生物种群动态及根际效应的研究 总被引:2,自引:0,他引:2
在柑桔根际土壤微生物的种群结构中,细菌占优势,最高达76871×107个每克干土;真菌次之,达17549个每克干土;放线菌最少,达12462个每克干土。三种菌的根际效应非常显著,根际细菌最高约为对照的67.6倍,真菌约为12.4倍,放线菌约为26.9倍,柑桔中,温州密柑根际土壤细菌最多,年平均为6490×107个每克干土;红桔的放线菌及真菌最多,年均分别为1326个每克干土及1728个每克干土。柑桔根际土壤微生物区系的种群结构和数量变动,受土壤理化性质的影响,并随树种、树龄、砧木及季节而变化。柑桔根部及根颈部对脚腐病、根腐病及线虫病的感病性和耐病性同柑桔同柑桔根际土壤微生物区系中,有益微生物与有害微生物的种类、数量及分布有密切的关系。柑桔根际土壤有益微生物有促进生长发育和保护的作用。 相似文献
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南亚热带不同植被根际微生物数量与根际土壤养分状况 总被引:28,自引:0,他引:28
研究了包括尾叶桉、广东凤丫蕨、柳叶竹、大叶相思、青皮、木荷、湿地松在内的7种南亚热带不同植物植被下土壤根际微生物与根际养分状况及其相关关系。结果表明,根际环境对细菌有明显的正效应,对放线菌和真菌有正、负两方面的影响,但对根际微生物总量具有根际效应明显;在南亚热带森林生态系统中,在植物的某些生长季节,微生物的根际效应与土壤养分的根际效应一致。 相似文献
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苯磺隆和2,4-D胁迫对土壤微生物影响的研究 总被引:3,自引:0,他引:3
以盆栽试验研究了除草剂苯磺隆、2,4-D对石灰性褐土中土壤微生物群落的影响。结果表明,在供试浓度下,土壤微生物对两种除草剂的感应存在一定的差异性。苯磺隆高浓度处理在最初3d极显著地抑制细菌生长,之后对土壤细菌具有刺激作用,特别是培养结束时激活率还高达917.6%,低浓度处理呈极显著的刺激作用;苯磺隆对土壤放线菌具有显著的刺激作用,对土壤真菌有强烈的抑制作用,最高抑制率达100%,到培养结束时(60d)真菌数量还未恢复到对照水平。2,4-D处理对土壤放线菌具有明显的抑制、激活的波动性,对土壤细菌、真菌有强烈的抑制作用。 相似文献
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Metsulfuron-methyl is one of the widely used sulfonylurea herbicides. However, approximately half of the applied metsulfuron-methyl may remain as bound residues in soil. To characterize the response of rice plants to residual metsulfuron-methyl in soil, the activities of acetolactate synthase (ALS), superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were investigated in two rice varieties that differed in susceptibility to the herbicide. Changes in the activity of these enzymes in leaves and roots of Xiushui 63, a sensitive rice variety, were greater than those in a resistant variety Zhenong 952. Irrespective of variety, changes in the enzyme activity were greater in the roots than in the leaves. The activities of ALS and CAT decreased, while the SOD activity increased with the increase in the amounts of bound residues of metsulfuron-methyl (BRM) in soil. The POD activity increased at the BRM level of 0.025 mg kg^-1, but decreased at the BRM level of 0.05 mg kg^-1. The results showed that the bound residues of sulfonylurea herbicides may affect metabolism of rice plants. 相似文献
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《Applied soil ecology》2010,46(3):232-237
A pot experiment was carried out to study the sulfur (S) and lead (Pb) interaction and its impact on soil microbial community composition in rice rhizosphere soil under flooded conditions. Paddy soil was treated with a Pb gradient with and without thiosulfate addition and then planted with rice. The increasing addition of Pb resulted in plant yield reduction and high, phytotoxic concentrations of Pb in roots with relatively low concentration of Pb in shoots. Under the impact of thiosulfate, Pb uptake in plants and NH4OAc extractable Pb did not increase dramatically. PCR-DGGE experiment suggested that S action led to new bands. Specific clones (T3 and T6) found in S addition soils had high similarity to Thiobacillus, which indicated relatively high rates of potential S oxidation. S addition did not affect the availability Pb and the composition of soil microbial community. S addition is not a suitable amendatory tool of phytoremediation for Pb polluted soil. 相似文献
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Effects of soil storage on the microbial community and degradation of metsulfuron-methyl 总被引:2,自引:0,他引:2
Trabue SL Palmquist DE Lydick TM Singles SK 《Journal of agricultural and food chemistry》2006,54(1):142-151
The effect storage had on the microbial biomass in two soils (Trevino and Fargo) was compared to the effect storage had on each soil's capacity to degrade metsulfuron-methyl. Soils were collected from the field and used fresh (<3 weeks old) or stored at 20 and 4 degrees C for 3 or 6 months. The phospholipid fatty acid content of the soils was used to monitor changes in the microbial biomass during storage and incubation in a flow-through apparatus. In both soils, [phenyl-U-14C]metsulfuron-methyl was used to monitor changes in the route and rate of degradation along with 14CO2 evolution (mineralization). Total microbial biomasses in both soils were significantly reduced for soils incubated in the flow-through apparatus, whereas only the Trevino soil's microbial biomass was significantly reduced as a result of storage. The microbial communities of both soils were significantly different as a result of storage as shown by discriminant analysis. In both soils, degradation rate, pathway of degradation, and mineralization of metsulfuron-methyl were significantly affected by storage compared to fresh soil. The half-life of metsulfuron-methyl increased significantly (P < 0.05) in the Trevino soil from 45 days (fresh) to 63 days (stored soil), whereas in the Fargo soil half-lives increased significantly (P < 0.05) from 23 days (fresh) to 29 days (soils stored for 6 months). In both soils, mineralization of [14C]metsulfuron-methyl was significantly (P < 0.05) higher in fresh soils compared to stored soils. The degradation pathways of metsulfuron-methyl changed with storage as evidenced by the loss of formation of one biologically derived metabolite (degradate) in stored soils compared to fresh soils. 相似文献
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Response of soil microbial biomass to straw incorporation 总被引:2,自引:0,他引:2
The response of the soil microbial biomass to cereal straw incorporation was assessed for three sites in Eastern Scotland. Increases in the C:N ratio of the biomass, due to straw inputs, were greater for soil with a history of straw incorporation than soil with no previous incorporation history. The biomass C:N ratio response to straw inputs was associated with increases in the fungal component of soil microbial respiration, fungal plate count (total and cellulolytic) and FDA-active lengths of fungal hyphae. 相似文献
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Response of soil microbial communities to compost amendments 总被引:1,自引:0,他引:1
Ana Pérez-Piqueres 《Soil biology & biochemistry》2006,38(3):460-470
Soil organic matter is considered as a major component of soil quality because it contributes directly or indirectly to many physical, chemical and biological properties. Thus, soil amendment with composts is an agricultural practice commonly used to improve soil quality and also to manage organic wastes. We evaluated in laboratory scale experiments the response of the soilborne microflora to the newly created soil environments resulting from the addition of three different composts in two different agricultural soils under controlled conditions. At a global level, total microbial densities were determined by classical plate count methods and global microbial activities were assessed by measuring basal respiration and substrate induced respiration (SIR). Soil suppressiveness to Rhizoctonia solani diseases was measured through bioassays performed in greenhouses. At a community level, the modifications of the metabolic and molecular structures of bacterial and fungal communities were assessed. Bacterial community level physiological profiles (CLPP) were determined using Biolog™ GN microtiter plates. Bacterial and fungal community structures were investigated using terminal restriction fragment length polymorphism (T-RFLP) fingerprinting. Data sets were analyzed using analysis of variance and ordination methods of multivariate data. The impact of organic amendments on soil characteristics differed with the nature of the composts and the soil types. French and English spent mushroom composts altered all the biological parameters evaluated in the clayey soil and/or in the sandy silty clay soil, while green waste compost did not modify either bacterial and fungal densities, SIR values nor soil suppressiveness in any of the soils. The changes in bacterial T-RFLP fingerprints caused by compost amendments were not related to the changes in CLPP, suggesting the functional redundancy of soil microorganisms. Assessing the density, the activity and the structure of the soil microflora allowed us not only to detect the impact of compost amendment on soil microorganisms, but also to evaluate its effect at a functional level through the variation of soil disease suppressiveness. Differences in disease suppressiveness were related to differences in chemical composition, in availability of nutrients at short term and in microbial composition due to both incorporation and stimulation of microorganisms by the compost amendments. 相似文献
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The use of mathematical analysis made it possible to show that prometryn applied in pot experiments affected indirectly (via plants) the microbial community in the spring wheat rhizosphere. On the one hand, prometryn inhibited photosynthesis and reduced plant productivity, resulting in a decrease in the amount of root exudates and the number of their consumers. On the other hand, it promoted dying off of root tissues and activated fresh organic matter decomposition with participation of fast growing heterotrophs at first, and at the final stages of the microbial succession, cellulolytic microorganisms appeared. Against this background, the biologically active substrate intensified the soil microbiological processes, reduced the adverse effect of prometryn on the development of plants, and created more favorable conditions for the functioning of microorganisms. 相似文献
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The effects of organic and mineral fertilization on four soil organic matter (SOM) fractions (non-protected, physically protected, chemically protected, and biochemically protected) and microbial community composition were investigated by sampling soil of a 35-year-long fertilization experiment. The SOM fractions were investigated by combined physical and chemical approaches, while microbial community composition was determined by phospholipid fatty acid analysis (PLFA). Organic C (SOC) was primarily distributed within the microaggregate-protected particulate organic matter (iPOM) and the hydrolysable and non-hydrolysable silt-sized (H-Silt, NH-Silt) fractions, which accounted for 11.6–16.9, 23.4–28.9, and 25.4–30.6% of the total SOC content, respectively. The contributions of these “slow” fractions (iPOM, H-Silt, NH-Silt) to the increased SOC were 178–293, 118–209, and 85–109% higher after long-term sole manure or manure in combination with inorganic N fertilization compared with unfertilized soil (control). The combination of manure and mineral fertilizers increased the coarse and fine non-protected C (cPOM and fPOM) contents much more (34.1–60.7%) than did manure alone. PLFAs, bacteria, G (+) bacteria, and actinomycete abundances were the highest in soil with manure, followed by soil treated with manure combined with mineral N. The addition of inorganic and organic fertilization both altered the microbial community composition compared with the control. All SOM fractions contributed to 81.1% of the variance of the PLFAs-related microbial community composition by direct and indirect effects. The change in coarse unprotected particulate organic matter (cPOM) was the major factor affecting soil microbial community composition (p < 0.001). Our study indicates that physical, chemical, and biochemical protection mechanisms are important in maintaining high SOC level after the addition of manure. A close linkage between soil microbial community composition and cPOM suggests that C availability is an important factor for influencing microbial composition after long-term inorganic and organic fertilization. 相似文献
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Water and N availability are the major limiting factors of primary production in desert ecosystems, and the response of soil
biota to these two factors is of great importance. We examined the immediate response of soil nematodes and the microbial
biomass to a single pulse of water amendment in N-treated plots in the Israeli Negev desert. Plots were treated with 0, 50
and 100 kg NH4NO3 ha–1 in December 1992, and at the end of the summer period (August 1993) the plots were exposed to a 15 mm water. Soil samples
from the 0–10 cm layer were collected daily and analysed soil moisture, total soluble N, nematode populations and microbial
biomass. Soil moisture increased to 8.5%, then gradually decreased to 2% during the 11 days of the study. Microbial biomass,
soil respiration and metabolic quotient values did not exhibit any significant correlation with soil N levels. Free-living
nematode population levels in the different plots were found to increase from a mean level of 45 500 to a mean level of 92 300
individuals m–2. N treatment was found to affect the patterns of free-living nematode population dynamics. The results of this study demonstrated
the importance of moisture availability levels and the ability to mobilize previous N inputs into available N which, occurring
in pulses, can affect the microbial ecophysiological status, nematode population dynamics and the interrelationship between
these two important components in the desert soil milieu.
Received: 5 November 1998 相似文献
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两个小麦品种对根际土壤中磷的吸收 总被引:1,自引:0,他引:1
Inorganic soil phosphorus extractable with sodium bicarbonate(NaHCO3-Pi),soil pH and root hairs length and density in the rhizosphere of two winter wheat cultivars (Tritium aestivum L.cv.Shichum,Sleipner)grown on a high pH Chinese silt loam(52.7 mg NaHCO3-Pikg^-1) and a Danish sandy loam(43.4mg NaHCO3-Pi kg^-1)wer studied to assess how these wheat cultivars differed in phosphorus uptake.The rhizosphere soil pH of two wheat cultivars grown on the two soils were fairly unchanged with increasing distrance from the roo surface.However the root hairs of Shichun were 2.1 times longer than those of Sleipner,Root surface area(RSA) of Shichun increased by 192% due to root hairs whereas root hairs of Sleipner increased RSA by 68% only.Hence the root system of Shichun was in contact with more soil than that of Sleipner,even though Sleipner had a longer root,Grown at the lower pH and level of NaHCO3-Pi in the Danish soil Shichun absorbed more inorganic phosphorus than Sleipner whereas at the higher pH and level of NaHCO3-Pi in the Chinese soil there was no phosphorus uptake difference between the two wheat culivars. 相似文献