New criteria for evaluation of soil bacterial complexes

The initial concentration of prokaryotic microorganisms, the type of their growth, doubling time, and the growth dynamics of bacteria and actinomycetes in three types of soil (meadow, chestnut, and soddy forest) were evaluated by the luminescence microscopic analysis of soil samples incubated in a humid chamber for 1 day. Soddy forest and chestnut soils differed in most of the parameters analyzed. Meadow soil was close to soddy forest soil in some parameters and to chestnut soil in other parameters. All soil suspensions exhibited high growth rates of bacteria and actinomycetes, indicating that the fraction of viable microorganisms in the soils was high.     

Microbial transformation of chitin in soil under anaerobic conditions

Anaerobic chitinolytic complex was studied in three soil types: chernozem, gray forest soil, and chestnut soil. The abundance and biomass of anaerobic chitinolytic microbial complex of fungi, bacteria, and actinomycetes were evaluated by luminescent microscopy. The dynamics of methane emission from soil during chitinolytic succession was studied by gas chromatography. All three studied microbial groups proved to participate in chitin transformation in soil under anaerobic conditions. The highest biomass growth was observed among prokaryotes, particularly actinomycetes, whose biomass doubled. The increase in methane emission during chitinolytic succession was most pronounced in soils with low organic matter content.     

Acidophilic soil actinomycetes

A clear-cut dependence of the distribution of acidophilic actinomycetes on the pH value of soil was established. Acidophilic actinomycetes were found to be present in soils whose pH does not exceed 6.8 (acid forest soils, lowland peaty soil, and ordinary chernozem) and not in slightly alkaline soils (chestnut sodic and alluvial meadow soils). In the acid lowland peaty soil, the species diversity of acidophilic streptomycetes was lesser than the species diversity of streptomycetes revealed in the same soil by using neutral medium.     

Acidophilic Soil Actinomycetes

A clear-cut dependence of the distribution of acidophilic actinomycetes on the pH value of soil was established. Acidophilic actinomycetes were found to be present in soils whose pH does not exceed 6.8 (acid forest soils, lowland peaty soil, and ordinary chernozem) and not in slightly alkaline soils (chestnut sodic and alluvial meadow soils). In acid lowland peaty soil, the species diversity of acidophilic streptomycetes was lesser than the species diversity of streptomycetes revealed in the same soil by using neutral medium.     

Microbial communities of frozen soils of the Tuimaada Valley in Central Sakha

This study determined the characteristic features of microbial communities inhabiting frozen soils of Central Sakha. All groups of microorganisms were present in high numbers comparable with the microbial densities in steppe soils of Transbaikalia; their distribution along soil profiles followed a specific pattern with no decrease in abundance with depth. In summer, the dominant groups of the microbial pool were actinomycetes and oligonitrophilic bacteria, while in autumn it was heterotrophic bacteria. A typical feature of the frozen soils of Central Sakha was the gradual penetration of microorganisms into deeper soil horizons during the vegetation season and their accumulation in the suprapermafrost horizon by autumn.     

Vertical structure of bacterial communities in peats of the Yakhroma river floodplain

The abundance and taxonomic structure of soil bacterial communities have been studied in different geomorphological parts of the Yakhroma floodplain. It has been found that the numbers of bacteria reach a peak in calcareous peat soil under forest near the floodplain terrace, decreasing to a minimum in soddy alluvial soil near the riverbed. All soils are characterized by the presence of different ecological-trophic bacterial groups capable of peat destruction. Seasonal dynamics of the structure of bacterial communities and, in some soil types, its spatial dynamics accounted for by changes in the botanical structure of peat across its profile have been revealed. All peat soils in the floodplain have high contents of organic matter and neutral pH and, therefore, are favorable biotopes for the development of saprotrophic bacteria. This, in turn, largely accounts for high productivity and stability of this agroecosystem as a whole.     

长白山北坡自然保护区森林土壤微生物生态分布及其生化特性的研究

本文研究了长白山北坡自然保护区森林土壤微生物的生态分布和生化特性。土壤微生物的垂直分布与林型之间有着下列相关性:(1)阔叶林和针阔混交林下土壤中细菌的数量比针叶林下多;(2)不同土类中,放线菌的分布随海拔上升而减少;(3)亚高山针叶混交林下土壤中真菌数量很多。不同林型下土壤酶活性、内源呼吸、氧化代谢能力和土壤有机质中中性糖、氨基糖和糖醛酸的分布有很大差异,以阔叶林和针阔混交林下土壤中为最高,针叶林下土壤中为最低。针叶混交林下土壤中生化活性随阔叶树种增加而提高。不同海拔、不同植被和不同土类下,芽孢杆菌属、放线菌和真菌的生态分布及其种的组合不同。芽孢杆菌属的优势种和放线菌、真菌优势属的组成也不同。不同林型下优势种的组成与水热条件、植物残体的组成及土壤有机质的分解过程密切相关。     

广西岑溪县七坪林区土壤微生物生态分布及生化活性的研究

广西气候温和,雨量充沛,亚热带和热带森林资源十分丰富。为了合理利用和开发广西梧州、玉林等地区南亚热带的土地资源和充分发挥该地区森林资源的经济效益,1987年我们     

Comparison of microbial numbers in soils by using various culture media and temperatures

The influence of different media and incubation temperatures on the quantification of microbial populations in sorghum, eucalyptus and forest soils was evaluated. Microbial growth was compared by using complex (tryptone soybean agar, TSA, casein-starch, CS, and Martin) and saline (Thorton, M3, Czapeck) media and incubation temperatures of 25 and 30 degrees C. Higher numbers of total bacterial and fungal colony-forming units (CFU) were observed in sorghum soils, and of spore-forming and Gram-negative bacteria in forest soils than other soils. Actinomycetes counts were highest in forest soil when using CS medium at 30 degrees C and in sorghum soil at 25 degrees C in M3 medium. Microorganism counts were dependent on the media and incubation temperatures. The counts at temperatures of 30 degrees C were significantly higher than at 25 degrees C. Microbial quantification was best when using TSA medium for total and spore-forming bacteria, Thorton for Gram-negative bacteria, M3 for actinomycetes, and Martin for fungi.     

刺槐林魔芋健康高产的土壤微生态机制

通过对刺槐林和农田魔芋健株根区、根表及根外土壤微生物区系及养分含量比较,探索刺槐林魔芋健康高产的土壤微生态机制。结果表明:(1)刺槐林魔芋根外和根表土壤细菌数量分别较农田增加11.8%和588.9%,根区土壤真菌数量较农田显著减少74.4%。(2)刺槐林魔芋根区、根表及根外土壤中的有益优势微生物数量及其比例远高于农田魔芋,有害微生物数量远低于农田魔芋;在刺槐林魔芋根区、根表及根外土壤中,3种优势细菌为放射型根瘤菌(Rhizobium radiobacter)、苏云金芽孢杆菌(Bacillus thuringiensis)及摩氏假单胞菌(Pseudomonas mosselii),其中,根表土壤中放射型根瘤菌及苏云金芽孢杆菌数量分别为农田的25.7倍及13.0倍;2种优势真菌为黒附球菌(Epicoccum nigrum)和疣孢青霉(Penicillium verruculosum),1种优势放线菌为绿淀粉酶链霉菌(Streptomyces viridodiastaticus),其中刺槐林魔芋根表和根外土壤中黒附球菌数量分别较农田高159.2%和120.3%;大量存在于刺槐林下魔芋根外土壤中的疣孢青霉、以及根区、根表、根外土壤中的绿淀粉酶链霉菌在农田魔芋相应部位均未检出。(3)刺槐林下魔芋根外、根区土壤有机质含量分别较农田显著增加167.6%、39.6%,但速效P、K含量较农田分别显著降低85.6%~91.3%、12.4%~13.0%。研究认为,刺槐林魔芋健康高产与其根区、根表及根外土壤中特有的有益优势微生物数量多、有害微生物数量少以及土壤有机质含量高密切相关。     

Ecological and Biological Features of Soils in Fir Forests Defoliated by the Siberian Moth in the Southern Taiga Subzone of Middle Siberia

Experimental data are analyzed that concern the effect of zoogenic debris on the properties of soddy deep podzolic soils and raw-humus brown soils characteristic of southern taiga forests in the Yenisei region of Siberia. It is shown that the influence of excrements of Siberian moth larvae on the soil microflora lasts for two or, at most, three growing seasons. Zoogenic plant debris falling on the ground surface during tree stand defoliation is a short-acting but powerful stimulant of biological activity in the litter; hence, it has a considerable effect on soil properties. This effect is enhanced by changes in ecological conditions that occur upon defoliation. The influence of the cenotic factor on biogenic soil properties is manifested more strongly in the organogenic horizons. The communities of microorganisms involved in the nitrogen and carbon cycles are dominated by prototrophic forms in the normal fir forest and by pedotrophic forms in the forest defoliated by pests.     

Isolation of Actinomycetales from the soil of Kazakhstan on selective media with antibiotics

About 3000 actinomycetes were isolated from various soil samples collected in 11 regions of Kazakhstan. 62.7 per cent of them proved to be antagonists. For isolation of the strains, selective media supplemented with antibiotics were used. Kanamycin promoted growth of Actinomadura and Nocardia. Rubomycin promoted growth of Actinomadura. Tavromycetin and roseofungin were used as selective agents for the first time. Tavromycetin favoured isolation of Actinomadura and Nocardia. Roseofungin favoured isolation of Actinomadura. Light chestnut and serozemic soils were the most rich in antagonists (67.1 and 61.3 per cent, respectively) while saline and chestnut soils were the poorest in antagonists (32.2 and 30.6 per cent, respectively). Actinomadura were more frequent in light-chestnut light-loamy and serozemic soils. Half of the antibiotics isolated in the form of concentrates were identified with the known antibiotics or classified as belonging to various groups. A culture producing a novel antibiotic was isolated.     

荒漠草原区土壤粒径组成对柠条根际土壤微生物数量及酶活性的影响

柠条(Caragana korshinskii)是荒漠草原区主要的造林绿化树种,研究其根际土壤微生物和酶活性与不同土壤类型土壤粒径组成的关系有重要意义,然而土壤粒径对荒漠草原柠条根际土壤微生物数量和酶活性的影响知之甚少,探讨土壤颗粒组分与微生物数量、土壤酶活性之间的关系,以及土壤颗粒组成对荒漠草原区固沙灌木植物柠条根际土壤微生物数量及酶活性的影响,可为揭示荒漠草原土壤退化及生态修复提供参考。以宁夏荒漠草原区土壤粒径组成差异显著的灰钙土、红黏土、风沙土环境下栽植的柠条为研究对象,研究不同土壤颗粒组成对根际土壤微生物数量及酶活性的相互关系与影响。结果表明:土壤微生物的数量表现为细菌放线菌真菌。根际土壤中的细菌、真菌数量显著高于非根际,且在3种不同类型的土壤中随着细砂粒的增多,真菌和放线菌数量逐渐降低,而细菌数量呈先增大后减小的趋势;根际与非根际土壤的蔗糖酶、碱性磷酸酶及过氧化氢酶活性均呈现出灰钙土红黏土风沙土的趋势,红黏土根际土壤中的脲酶活性显著高于灰钙土与风沙土;除过氧化氢酶外,土壤酶活性表现为根际高于非根际,在3种不同类型的土壤中随着细砂含量的增加,土壤酶活性均呈递减趋势。土壤颗粒组成与微生物数量之间没有明显的相关性,而与土壤酶活性之间显著相关,土壤酶活性与黏粒、粉粒呈正相关,与细砂、中砂呈负相关关系,根际土壤中酶活性更高,能够为植物及微生物提供更多的营养。     

南亚热带赤红壤地区不同人工林下的土壤微生物特性

对南亚热带赤红壤地区、广州市花县不同薪材用材林型下土壤微生物特性研究表明,不同林型下的年均土壤微生物（主要是细菌、真菌和放线菌）总量由高到低依次为：混交林＞豆科纯林＞纯桉树林＞裸露生荒地。大叶相思与按树混交林地土壤具有较高的纤维素酶和转化酶活性,而豆科纯林土壤中则有较高的脲酶、蛋白酶和触酶活性。土壤的呼吸作用强度以马占相思纯林及其混交林为高,纯桉树林较低。经过五年垦荒造林后,土壤中的微生态环境有很大改善,这种变化由地下微生物特性和地面上林木的生物量充分反映出来,而未开垦生荒地土壤微生物数量和生物化学活性则仍处于低水平的衰退状态。     

华西雨屏区天然常绿阔叶林土壤可培养微生物数量对模拟氮沉降的响应

为了解氮沉降对华西雨屏区天然常绿阔叶林土壤微生物数量的影响,从2013年11月至2014年12月,通过野外模拟N(NH_4NO_3)沉降,氮沉降水平分别为对照(CK 0 kg N hm~(-2)a~(-1))、低氮沉降(L 50 kg N hm~(-2)a~(-1))、中氮沉降(M 150 kg N hm~(-2)a~(-1))和高氮沉降(H 300 kg N hm~(-2)a~(-1)),研究了氮沉降对天然常绿阔叶林0—10cm和10—20cm土层土壤可培养微生物数量的影响。结果表明:华西雨屏区天然常绿阔叶林0—10cm土层的细菌、真菌和放线菌数量均显著大于10—20cm土层,氮沉降未改变原有垂直分布格局。L处理对0—10cm和10—20 cm土层土壤微生物总量无显著影响,M和H处理则显著降低了土壤微生物总量。氮沉降降低了0—10cm和10—20cm土层的细菌数量,且抑制作用随氮沉降量的增加而增强。氮沉降降低了0—10cm土层的真菌数量,但下降幅度与氮沉降量之间无明显规律;在10—20cm土层,M和H处理在夏季显著增加了真菌数量,表明适量氮沉降能有效缓解夏季土壤真菌的氮限制状态。氮沉降对0—10cm土层放线菌数量的影响表现为先促进再抑制,L和M处理增加了放线菌数量,H处理降低了放线菌数量;氮沉降增加了10—20cm土层的放线菌数量,其中M处理的促进作用最大。氮沉降对土壤微生物数量的影响随土壤深度的增加而减弱。     

Microflora of soils under pine forests area affected by gradation of leaf-eating insects

Soils of pine forests in the Bytnica Forestry District, Poland, are poor in nutrients readily accessible to plants. The excessively acidic reaction of the soils, typical for soils under pine forests, unfavourably affects the growth of microorganisms whose numbers are lower than in soils under deciduous and mixed forests. In the pine forests of the studied forestry there were outbreaks of a defoliating insect - pine beauty moth (Panolis flammea L.), which resulted in over 60% defoliation of the trees. The studies were carried out on the area of tree stands subjected to gradation by leaf-eating insects (sprayed and not sprayed) and healthy stand of the same age class (age 60 to 70 years). The studies revealed increased number of soil microorganisms in samples taken from the area affected by pine beauty moth gradation in the case of both unsprayed areas and those sprayed with the pesticide. The occurrence in these soils of larger numbers of ammonifying and denitrifying bacteria points to the presence of conditions favouring the growth of heterotrophic organisms. Changes in the number of actinomycetes and fungi in soils under tree stands subjected to gradation by insects, compared to healthy stands, can be a consequence of a change of environmental conditions (e.g. % content of organic carbon). Soils under defoliated tree stands show higher biochemical activity related to nitrogen cycling in the pine forest ecosystem. This leads to higher availability of organic nitrogen for conversion to inorganic forms of nitrogen, which are utilised by trees. Further changes occurring in soils under forest stands affected by gradation by leaf-eating insects would allow to gain knowledge on the ecological consequences of the use of insecticides in the protection of pine stands against harmful insects, with particular stress on those situations in which pine stands not threatened by complete defoliation are sprayed.     

Phenotypic characterization of microbes in the rhizosphere of Alyssum murale

Metal hyperaccumulator plants like Alyssum murale are used for phytoremediation of Ni contaminated soils. Soil microorganisms are known to play an important role in nutrient acquisition for plants, however, little is known about the rhizosphere microorganisms of hyperaccumulators. Fresh and dry weight, and Ni and Fe concentrations in plant shoots were higher when A. murale was grown in non-sterilized compared to sterilized soils. The analysis of microbial populations in the rhizosphere of A. murale and in bulk soils demonstrated that microbial numbers were affected by the presence of the plant. Significantly higher numbers of culturable actinomycetes, bacteria and fungi were found in the rhizosphere compared to bulk soil. A higher percent of Ni-resistant bacteria were also found in the rhizosphere compared to bulk soil. Percentage of acid producing bacteria was higher among the rhizosphere isolates compared to isolates from bulk soil. However, proportions of siderophore producing and phosphate solubilizing bacteria were not affected by the presence of the plant. We hypothesize that microbes in the rhizosphere of A. murale were capable of reducing soil pH leading to an increase in metal uptake by this hyperaccumulator.     

不同龄级速生杨人工林土壤微生物数量与养分动态变化

通过稀释平板法和常规化学分析法, 对伊犁河谷地区3种龄级(5年、10年、15年)的速生杨欧美黑杨(Populus × euramericana)人工林的土壤微生物数量、组成和土壤养分变化进行了研究。结果表明, 3种不同林龄林地土壤微生物集中分布在10-40 cm土层, 数量和种类组成随季节变化有明显差异。随着林龄的增长, 土壤微生物总数、细菌数量减少, 真菌和放线菌数量在10年生人工林最高, 这一规律随季节变化。三大类土壤微生物的组成比例相对稳定, 不随季节变化而变化。土壤有机碳、氮含量主要集中在0-20 cm土层, 随土壤深度的增加逐渐减少, 其含量及分布受季节和土壤深度不同程度的影响。土壤有机碳含量随林龄的增长而逐渐增高, 有机氮则先减后增。相关分析表明, 土壤微生物总数与土壤有机碳呈负相关, 真菌数量与土壤有机氮呈正相关。3种林地土壤有机C/N比与土壤细菌数量/真菌数量比例一致, 说明速生杨人工林在一定生长年龄内能提高土壤的固碳能力, 改善土壤肥力。     

氮添加诱导的磷限制改变了亚热带黄山松林土壤微生物群落结构

土壤微生物在陆地生态系统的生物地球化学循环中起着重要作用。然而目前尚不清楚氮(N)添加量及其持续时间如何影响土壤微生物群落结构,以及微生物群落结构变化与微生物相对养分限制状况是否存在关联。本研究在亚热带黄山松林开展了N添加试验以模拟N沉降,并设置3个处理:对照(CK, 0 kg N·hm^-2·a^-1)、低N(LN, 40 kg N·hm^-2·a^-1)和高N(HN, 80 kg N·hm^-2·a^-1)。在N添加满1年和3年时测定土壤基本理化性质、磷脂脂肪酸含量和碳(C)、N、磷(P)获取酶活性,并通过生态酶化学计量分析土壤微生物的相对养分限制状况。结果表明: 1年N添加对土壤微生物群落结构无显著影响,3年LN处理显著提高了革兰氏阳性菌(G⁺)、革兰氏阴性菌(G^-)、放线菌(ACT)和总磷脂脂肪酸(TPLFA)含量,而3年HN处理对微生物的影响不显著,表明细菌和ACT对N添加可能更为敏感。N添加加剧了微生物C和P限制,而P限制是土壤微生物群落结构变化的最佳解释因子。这表明,N添加诱导的P限制可能更有利于部分贫营养菌(如G⁺)和参与P循环的微生物(如ACT)的生长,从而改变亚热带黄山松林土壤微生物群落结构。     

除草剂二氯喹啉酸对水稻田土壤中微生物种群的影响

对好氧微生物采用平板稀释法,厌氧微生物采用最大或然计数法和滚管法研究土壤中施入0．33、0．67、1．00、1．33、2．00μg·g^-1干土除草剂二氯喹啉酸后对土壤可培养微生物种群数量的影响。结果表明,各种微生物对二氯喹啉酸的反应随其施加浓度的不同而有差异．二氯喹啉酸对水稻田土壤中好氧性细菌、水解发酵细菌、反硝化细菌数量的影响都是短暂的,第33d时均能恢复至接近对照水平,浓度在1．33μg·g^-1干土以下时二氯喹啉酸促进真菌数量增加,高于该浓度时则具有抑制作用．施用各浓度二氯喹啉酸初期,对土壤中放线菌和产甲烷菌有一定程度的抑制效应,但低浓度时抑制效应在培养后期消失．正常土壤施用量的二氯喹啉酸(即0．67μg·g^-1干土)对水田土壤微生物各种群无实质危害级农药。