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1.
铅胁迫对黄褐土微生物区系和功能多样性的影响 总被引：1，自引：0，他引：1
为了筛选出黄褐土中对铅污染敏感的指示微生物,本研究采用室内培养试验研究不同铅浓度对土壤微生物区系和功能多样性的影响。结果表明,向土壤中添加硝酸铅显著降低了可培养细菌、放线菌和真菌微生物的种群数量,这种抑制作用随着铅浓度的升高而增强,随着培养时间的延长而减弱。铅浓度、细菌、真菌和放线菌数量两两间呈极显著负相关关系。低浓度铅处理（100 mg kg?1）在培养初期（1 d）显著减少了可培养细菌和放线菌的数量,降低率分别为27.43%和30.89%;高浓度铅处理（2500 mg kg?1）在整个培养期内均对真菌数量产生显著抑制作用,且抑制率维持在90%左右。从培养初期到中期（1 ~ 14 d）,随着铅浓度升高土壤微生物群落活性和功能多样性指数显著下降（中浓度铅处理除外）,培养后期（28 d）各个浓度铅处理的土壤微生物的丰富度和优势度均显著增加。与对照、低浓度铅和高浓度铅处理相比,中浓度铅处理（500 mg kg?1）更有利于保持黄褐土较高的微生物的群落代谢活性和功能多样性。本研究中3 种可培养微生物功能群对黄褐土添加硝酸铅的敏感度依次是放线菌,细菌和真菌。研究表明,在黄褐土地区真菌可以用来指示较为严重的土壤铅污染状况,放线菌和细菌可以用来指示铅污染程度较轻的土壤环境状况。 相似文献
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重金属污染土壤的植物修复研究Ⅱ.金属富集植物Brassica juncea根际土壤中微生物数量的变化 总被引：1，自引：0，他引：1
本文在盆栽试验的基础上研究了在不同程度的外源重金单一及复合污染下富金属植物印度芥菜(Brassica juncea)根际土壤中微生物数量的变化.研究结果表明,根际中细菌的数量明显多于放线菌、真菌.细菌生长对重金属和植物生长最敏感,其次为放线菌.含高镉(200mg/kg)的金属复合污染处理对细菌、放线圈的生长有抑制作用;加铜(250mg/kg)对细菌有刺激效果.在低于重金属致死临界浓度时,植物根系的存在对细菌的数量的影响会大于重金属元素的影响.印度芥菜根际土壤中微生物数量的变化与微生物种类、重金属元素及组合和植物生长有关. 相似文献
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不同年龄麻疯树林地土壤微生物多样性研究 总被引：1，自引：0，他引：1
为了探明麻疯树林地土壤微生物类群的生态分布情况,研究了1～10年1,1～20年,21～30年的不同年龄麻疯树林地土壤细菌、真菌及放线菌的数量和类群组成。结果表明:3种林地土壤微生物的数量和种类组成有明显差异,随着林龄的增加微生物数量和种类呈递减趋势;不同土层的微生物数量变化也有所不同,但3种林地都有一个共同特点,即26～30 cm范围内的微生物总数最少;细菌在不同年龄麻疯树林地的各个土层中均有分布,数量明显高于放线菌和真菌;在林地内共分离出土壤真菌20属,其中,假丝酵母属为3个不同年龄麻疯树林地土壤中的优势菌属。 相似文献
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石墨烯施用后对土壤酶活性及土壤微生物群落的影响 总被引：2，自引：0，他引：2
将不同浓度的纯石墨烯和氧化石墨烯(0、100、1 000 mg/kg)分别加入潮土和红壤两种土壤中,培养56天后测定潮土和红壤中的脲酶、过氧化氢酶活性,微生物功能及遗传多样性变化。结果表明,培养0、7、14、56天后,100和1 000 mg/kg浓度的石墨烯和氧化石墨烯对红壤和潮土的脲酶和过氧化氢酶活性没有显著的影响。两种浓度的石墨烯和氧化石墨烯对红壤和潮土微生物的AWCD指数没有显著的影响,且两种土壤之间未表现出差异。对添加0、200和1 000 mg/kg氧化石墨烯的潮土进行DGGE测试分析,处理组与对照组相比增加了3个条带,测序分析认为这3个条带与鞘氨醇单细胞菌属和未被培养的细菌类似,可见氧化石墨烯对土壤中微生物有一定的影响,能引起耐受菌数量的增加。 相似文献
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通过盆栽模拟试验的方法研究外源添加铜对土壤线虫群落结构的影响,试验添加Cu浓度分别为50 mg kg-1,100 mg kg-1,200 mg kg-1,400 mg kg-1干土和不施加污染物的对照处理,在小麦的生长关键期取样。试验结果表明:线虫不同营养类群对铜污染物的响应在小麦拔节期比较明显,拔节期捕食/杂食线虫的数量在外源添加400 mg kg-1Cu处理中显著低于对照,而不同浓度铜对食细菌线虫和食真菌线虫的影响则表现为低浓度促进高浓度抑制。线虫的生态指数对不同浓度铜污染物反映比较敏感,在小麦苗期和拔节期,与对照相比,不同浓度铜处理中线虫多样性降低,而优势度增加;自由生活线虫成熟度指数对不同浓度铜反映相对滞后,只在小麦成熟期表现出差异,即高浓度铜处理中线虫成熟度指数显著低于对照。 相似文献
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土壤微生物数量及土壤酶活性是描述土壤的重要生物学指标。在实验室控制条件下,研究了农药乐果、Cd2＋单一污染及乐果与Cd2＋复合污染对土壤3大类群微生物数量和主要土壤酶活性的影响。结果表明,Cd2＋和乐果复合处理对土壤中微生物生长存在着明显的拮抗作用,复合抑制效应顺序为放线菌〉真菌〉细菌;而对土壤酶活性均有明显的协同作用,复合抑制效应顺序为蛋白酶〉蔗糖酶〉脲酶。单一污染时,100mg·kg-1乐果的处理可不同程度地抑制这些生物学指标,其中对土壤微生物数量的抑制效应顺序为真菌〉放线菌〉细菌,对土壤酶活性的抑制效应顺序与乐果和Cd2＋复合污染顺序一致;50mg·kg-1浓度的乐果对这些指标几乎无影响。 相似文献
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[目的]研究黄土高原地区土壤微生物群落结构及其主要生理类群在杏树不同嵌套种植模式中的地位和作用。[方法]用"平板培养法"和常规方法,研究了不同嵌套模式下土壤微生物三大类群、主要功能群组成、土壤全氮及有机质含量的变化,并以系统聚类及主成分分析(PCA)等方法进行数据分析。[结果](1)土壤微生物总数量及三大类群数量以杏树与紫花苜蓿的嵌套模式最高(p0.05),杏树嵌套黄花菜和紫花苜蓿次之(p0.05),其余嵌套模式间无显著性变化(p0.05);(2)在杏树和紫花苜蓿的模式中土壤固氮菌数量、氨化细菌和纤维素分解菌数量最高(p0.05),杏树和黄花菜和紫花苜蓿嵌套模式次之(p0.05);(3)土壤微生物三大类群中,土壤放线菌数量对Shannon—Wiener指数的大小变化起着较大作用;(4)依据可培养微生物组成,5种嵌套模式可划分为3个类群,嵌套植被对土壤微生物组成的影响不同,紫花苜蓿对土壤微生物学性质的作用更强。[结论]杏树在不同嵌套种植模式下土壤微生物群落结构组成与嵌套植被类型关系密切且具有其独特的规律及变化原因。 相似文献
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为探讨不同污染方式的Pb对茶园土壤氮素转化的影响，采用盆栽试验对累积和一次性添加不同浓度Pb条件下茶园土壤中氮素含量、相关微生物和酶活性进行了研究。结果表明：累积污染处理的土壤中Pb全量和有效态含量高于一次污染处理。Pb污染对土壤、茶苗植株的氮含量影响表现为：增加土壤中全氮和15N含量，减少茶苗地上部全氮和15N含量。添加Pb浓度为900 mg/kg时，累积污染处理促进根系全氮和15N含量，一次污染则显著抑制；累积污染处理的茶苗根和地上部中的氮含量显著高于一次污染(P<0.05)。Pb污染对氮循环相关微生物的影响表现为：氨化细菌、自生固氮菌、亚硝酸细菌和硝酸细菌的数量减少，反硝化细菌的数量增加。Pb的不同污染方式对茶园土壤与氮循环相关微生物数量的影响不显著(P>0.05)。Pb污染抑制脲酶、亚硝化还原酶和硝酸还原酶活性，对蛋白酶活性存在“低促高抑”现象；高浓度Pb(900 mg/kg)污染时，累积处理显著增加土壤羟胺还原酶活性，一次处理则显著抑制。两种污染方式对土壤脲酶、硝酸还原酶和羟胺还原酶活性的影响因Pb... 相似文献
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采用温室盆栽土培方法,研究了土壤中不同浓度重金属铅（Pb,0-800 mg.kg^-1）、镉（Cd,0-50 mg.kg^-1）单一及其复合处理对玉米（Zea mays L.）生长及土壤微生物（细菌、放线菌、真菌）数量的影响。结果表明,在重金属Pb、Cd单一及其复合处理下,玉米的株高、干重均低于对照,重金属Pb、Cd处理对玉米的生长存在负面影响。重金属Pb、Cd单一处理抑制细菌、真菌的生长,中低浓度Pb（≤300 mg.kg^-1）、Cd（≤10 mg.kg^-1）单一处理促进放线菌数量的增加,高浓度（Pb≥800 mg.kg^-1、Cd≥50 mg.kg^-1）则呈现抑制效应;Pb、Cd复合在高中低浓度下都抑制土壤微生物生长,减少微生物数量。玉米株高同土壤微生物之间相关性不显著;玉米干重同土壤细菌、真菌显著相关,同土壤放线菌之间相关性不显著。 相似文献
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本文利用发光细菌法研究了土壤水提取液中2种汽油(90#和93#)的生物毒性。提取液中90#和93#汽油分别在63.2~90.1mg/L和62.7~91.1 mg/L范围内有较高的生物毒性,并随浓度的升高而增强,90#和93#汽油的土壤水提液EC50值分别为83.5 mg/L和83.7 mg/L,在土壤中的临界值为2308 mg/kg和3678 mg/kg。这些结果为发光细菌毒性测定方法在石油产品污染土壤生物毒性评价中应用提供了可能性。 相似文献
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植物修复对重金属镍污染土壤微生物群落的影响 总被引：10，自引：0，他引：10
采用室内盆栽试验方法,研究了外源镍污染土壤的植物修复对土壤微生物群落的影响。试验用水稻土中添加NiSO4.6H2O(100~1 600 mg kg-1)经过12周的驯化培养后,种植了2种超累积植物和1种耐性植物,经110 d的试验后进行了植物修复后土壤微生物活性的分析。结果表明,非根区土中添加镍的质量分数为100 mg kg-1时,对土壤中细菌、真菌和放线菌总数有一定的促进作用,土壤中微生物生物量最大;当添加镍的质量分数大于100 mg kg-1时,将对土壤微生物群落造成不利的影响。在植物修复过程中,通过植物的减毒(吸收重金属)作用和根系分泌物的作用,改善了土壤微生物的生存环境,提高了土壤微生物的数量和生物量。经过植物修复后,根区土壤微生物较非根区土壤的丰富,土壤微生物群落总DNA序列多样性指数相应增加,但不同植物对根区土壤微生物的贡献是不同的。 相似文献
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A greenhouse experiment was conducted to investigate the effect of surface film-forming material(SFFM),a mixture of 16-18-octadecanols by emulsification,on water evaporation,Air-dired soil with distilled water was incubated firstly for 7days to reestablish soil biological activity and then for another 7 days atfer treated with SFFM at rates of 0,1,2,4,6,8 and 8 g m^-2，respectively,Everyday during the 7-day incubation after addition of SFFM,water losses due to evaporation were measured by an electronic balance.The rate of water evaporation with the addition of SFFM was reduced significantly compared with the control treatment and the effectiveness of SFFM on water evaporation reduced with time.According to the equation expressions of the effect of SFFM on water evaporation ,the half-life of effectiveness of SFFM on water evaporation was introduced and calculated to analyze quantitative relationship between the effectiveness of SFFM on water evaporation and the addition rate of SFFM.The calculaed half-life increased with the addition rate of SFFM and the confidence of the calculated values of the half-life was high,suggesting that the half-life of effectiveness of SFFM on water evaporation could be described quantitaively and may be helpful for ameliorating application method of SFFM and screening surface-film forming materials in order to improve nitrogen fetilizer use efficiency in floodey rice fields. 相似文献
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Soil tillage alters crop residue placement, soil moisture and soil physical properties, which in turn may affect soil chemical and microbial properties. The impact of tillage on microbial populations was investigated by studying soil microbiological, physical and chemical properties after 11 years of a tillage management experiment with continuous sorghum (Sorghum bicolor L. Moench) on an Orelia sandy clay loam (fine-loamy, mixed, hyperthermic Typic Ochraqualf). Soil from 0–7.5 and 7.5–15 cm depths was sampled from four replications of moldboard plow (MB), conventional till (CT), minimum till (MT) and no-till (NT) treatments in March (before planting) and May (during the growing season), 1989. Heterotrophic bacteria (HB) and actinomycete populations differed among tillage treatments before planting. Soil microbial populations differed with soil depth among all tillage treatments before the growing season (when no plants were present), but were similar among tillage treatments when counts by soil depth were composited, indicating that, although microbial distribution differed, total populations were similar. During the growing season, actinomycetes were lower in NT treatments, while HB counts were not significantly different between treatments. The similarity between treatments was attributed to drier soil conditions and the effect of plant roots in all treatments, which may have stimulated microbes similarly in all treatments. Ammonium oxidizers were lowest and dentrifiers highest in the NT soil a the 0–7.5 cm depth before planting. The sample obtained during the growing season indicated that soil nitrifier populations were usually greater in MT and NT treatments. The MB and CT treatments had significantly larger amounts of soil moisture, clay and nitrate than the NT and MT treatments, indicating that soil physical properties and nitrate levels were altered by tillage treatment. Soil nitrate was significantly correlated with nitrogen-transforming bacteria in several instances, although there was no predictable effect from soil depth or sampling date. In some instances, nitrifier counts fell and denitrifier counts increased as soil nitrate increased. HB and actinomycete population levels were not significantly correlated with the soil physical or chemical properties measured in this study. Although there were tillage treatment differences in soil physical (moisture, bulk density and clay content), chemical (nitrate-nitrogen, NO3---N) and microbiological properties (HB, actinomycetes, and denitrifier, nitrifier and ammonium oxidizer activity), generalizations about tillage system effects on soil microbiological properties were difficult to confirm because of the temporal nature of these differences. 相似文献
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兽药磺胺二甲嘧啶在土壤中的生态行为 总被引：10，自引：0，他引：10
通过室内培养和土壤薄层层析等实验方法，研究了磺胺二甲嘧啶对土壤微生物的毒性及其在土壤中的降解、迁移特性。结果显示：在土壤磺胺二甲嘧啶浓度为1mg kg^-1时，土壤中细菌和真菌数量明显减少（p〈0．05），但随时间延长，该抑制作用变缓；磺胺二甲嘧啶在土壤中降解缓慢，持留时间久，在灭菌土和未灭菌土中的半衰期分别为223．9d和102．4d，并容易在土壤中迁移和渗漏，迁移系数R大于0．7，迁移和渗漏速度受介质pH的影响，在非中性环境下，移动和渗漏能力增强。表明磺胺二甲嘧啶是一种在土壤中不易被降解、容易迁移和渗漏到水体、对土壤微生物和水体产生危害的新型污染源。 相似文献
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DECOMPOSITION OF SOIL POLYSACCHARIDE 总被引：2，自引：0，他引：2
Polysaccharide material was isolated by absorption on charcoal from the acidified, non-humic fraction extracted by alkali from three soils. The polysaccharides were used as substrates in soil incubation, perfusion, and suspension experiments. Concordant results were obtained with freely drained Countess-wells and Insch Association soils derived from acidic and basic igneous parent materials respectively. Polysaccharide material added to soil at low concentration (I per cent) was apparently totally decomposed after 8 weeks when the amounts of polysaccharide in control and amended soils were statistically indistinguishable. At higher concentrations (2-3 per cent) a significant difference in reducing sugar, equivalent to about 30 per cent of the substrate, remained after 32 weeks. Partial neutralization of the polysaccharide material with calcium hydroxide increased the rate of decomposition in Countesswells Association soil but had an opposite, smaller effect in Insch Association soil. Soil polysaccharide material was decomposed slightly faster in perfusion and suspension experiments than in moist soil. Only 20 per cent of the carbohydrate in the unfractionated alkali–soluble organic matter of soil was decomposed during incubation in soil for up to 133 weeks. There was usually little change in the carbohydrate content of soil incubated alone. The soil microbial population showed a marked increase in response to added polysaccharide material but only slight qualitative changes were detected. It is concluded that the persistence of naturally occurring polysaccharide in soil is related to inaccessibility caused by chemical combination, complexing or insolubility but not to a biologically-stable molecular structure. 相似文献
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Growth of many soil microorganisms was inhibited on culture media containing heptachlor. At a concentration of 25 mg/l., heptachlor killed 63 per cent of the bacteria transferred from soil dilution plates. Heptachlor, at 100 mg/1. in agar media used for isolating microorganisms from soil, prevented the development of 89 per cent of the bacteria, 81 per cent of the actinomycetes, and 50 per cent of the fungi that appeared on isolation plates without heptachlor. After heptachlor was added to soil, fungal populations declined and bacterial populations increased. Numbers of bacteria were related to amount of heptachlor added; higher concentrations of heptachlor in soil resulted in larger populations. A selective increase in numbers of fungi which would grow on media containing heptachlor at 100 mg/l. occurred in soils amended with heptachlor in amounts ordinarily used in field practices, but a similar increase of heptachlor-resistant bacteria occurred only in soils amended with higher amounts of heptachlor. 相似文献
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The hydrolysis of the organophosphorus insecticide, parathion (O,O-diethyl O-p-nitrophenyl phosphorothioate) in a silty loam sierozem soil (Gilat, Israel) occurred primarily through microbial action. Parathion (labelled with 14C in the alkyl chain) was applied at levels of 10–160 μg dry soil?1 to soil remoistened to 20% and incubated at 25°C for 8 days. Bacterial numbers increased to a maximum 4–5 days after application of parathion and the increase was proportional to the concentration of parathion added. The rate of hydrolysis of parathion per μg applied was independent of the concentration of parathion. A model developed to predict the relationship between parathion concentration, microbial numbers and hydrolysis kinetics was in general agreement with the data experimentally obtained. The course of decomposition of successive additions of parathion, determined experimentally and predicted by the model, was characterized by rapid hydrolysis of parathion and successive increases in bacterial numbers. A portion of the 14C applied in these experiments was strongly absorbed by the soil and was not used by the soil microorganisms during the incubation period tested. 相似文献