有机肥施用对烟草根际微生物影响的研究

对烟草根系施用5种配方肥料,并分别检测烟草移栽前、后20,40,60,120 d的根际土壤微生物,比较研究了不同肥料对烟草根际微生物的影响．实验结果显示：随着有机肥比例的增加,烟草根际土壤中的真菌、细菌等数量均比不添加有机肥的处理（N0处理）呈增加趋势;其中,50％无机氮＋50％有机氮处理（N3处理）能显著增加烟草根际土壤中的微生物数量,真菌、细菌、霉菌数量分别达到2．46×10^5,2．96×10^8,2．95×10^4个/g ．在烟草种植中,施用50％无机氮＋50％有机氮的有机肥有利于提高烟草根际微生物的数量．     

蚯蚓对温室土壤中不同微生物类群数量的影响

为了揭示蚯蚓活动对温室土壤中不同微生物类群数量的影响,对接种蚯蚓的温室土壤和露地土壤中微生物的数量进行了初步研究.结果表明:接种蚯蚓显著提高了温室土壤中不同微生物类群的数量.与未接种蚯蚓的处理比较,12月时,温室土壤中细菌增加了24.53%,放线菌增加了39.46%,真菌增加了29.71%,总量增加了25.81%;露地土壤中细菌增加了18.18%,放线菌增加了29.45%,真菌增加了16.24%,总量增加了21.14%.4月时,温室土壤中细菌增加了42.71%,放线菌增加了39.08%,真菌增加了36.92%,总量增加了42.53%;露地土壤中细菌增加了33.69%,放线菌增加了22.29%,真菌增加了20.71%,总量增加了32.73%.接种蚯蚓的温室土壤中不同微生物类群数量的增幅均高于接种蚯蚓的露地土壤.其中4月时接种蚯蚓后的温室土壤的细菌增加量高于其他处理.     

土壤放线菌分离纯化实验的研究

通过精品实验项目"细菌纯种分离和培养"的实施,在环境专业本科生中开展了土壤放线菌的分离、纯化实验。在老师的带领下,学生从崇明岛采集了土壤样品,利用浇注平板法、划线分离法对土壤中的放线菌进行分离、纯化并得到其纯菌。由16S rDNA序列分析结果初步判断:该放线菌为灰黄链霉菌。通过实验中的学习,学生亲身体会了野外采样的过程,锻炼了学生的实践动手能力,激发了学生的学习热情,加深了学生对微生物基础理论知识的理解,促进了学生创新思维和创新能力培养和提高。     

Suppression of Meloidogyne javanica by antagonistic and plant growth-promoting rhizobacteria

INTRODUCTION Crops production in greenhouses is a method foreconomically maintaining a warm environment dur-ing cool seasons and to protect crops, especiallyvegetables, from unfavourable weather conditions.However, root-knot nematodes and soil borne fungigreatly affect plant growth and yield in greenhouses.Plant-growth promoting rhizobacteria (PGPR) havebeen identified as a biological control alternative topesticide use for disease suppression without negativeeffects on the user, consum…     

云南西双版纳香荚兰种植园土壤微生物类群初探

对采自西双版纳香荚兰11个不同种植区土样中的细菌、放线菌和真菌三大微生物类群进行了分析,分离出真菌优势种群14种、细菌31种、放线菌8种。细菌中芽胞杆菌占半数以上,放线菌中金色类群和白孢类群占优势。要从土壤的微生物区系对其病害进行调控,需要进一步摸清优势种群与病害的关系,并从中找出其有拮抗性的优势菌,分析研究诱发其有拮抗性的优势种群条件。     

土壤环境对菌肥移居微生物各生理群生长的影响

以灭菌茶园土壤施入混合菌肥,探讨茶叶专用菌肥微生物在不同土壤环境中存活状况、变化规律.结果表明菌肥细菌生长适宜的土壤环境条件是土壤含水量为20-25％,土壤温度为25℃,pH4左右的酸性土壤石灰添加量为0.4-0.8％（约土壤pH6.6-7.3）为宜;制约菌肥放线菌在土壤中生长繁殖因素主要为土壤pH和含水量,以土壤pH6.6-7.3,含水量为15-20％为宜.土壤环境因素对菌肥真菌生长的影响大小排序依次为pH、水分和温度,酸性土壤最有利于真菌的生长繁殖.     

Review:Mycorrhizoremediation—an enhanced form of phytoremediation

INTRODUCTION Biosphere pollution by heavy metals and nu-cleotides was accelerated dramatically during the last few decades due to mining, smelting, manufacturing, treatment of agricultural soils with agro-chemicals and soil sludge, etc. Problems associated with the contamination of soil and water such as animal wel-fare, health, fatalities and disruptions of natural eco-systems are well documented (He et al., 2005). Heavy metals such as Pb, Cr, As, Cu, Cd, and Hg, being added to our so…     

Mycorrhizoremediation an enhanced form of phytoremediation

Study of plant roots and the diversity of soil micro biota, such as bacteria, fungi and microfauna associated with them, is important for understanding the ecological complexities between diverse plants, microbes, soil and climates and their role in phytoremediation of contaminated soils. The arbuscular mycorrhizal fungi （AMF） are universal and ubiquitous rhizosphere mi- croflora forming symbiosis with plant roots and acting as biofertilizers, bioprotactants, and biodegraders. In addition to AMF, soils also contain various antagonistic and beneficial bacteria such as root pathogens, plant growth promoting rhizobacteria including free-living and symbiotic N-fixers, and mycorrhiza helping bacteria. Their potential role in phytoremediation of heavy metal （HM） contaminated soils and water is becoming evident although there is need to completely understand the ecological complexities of the plant-microbe-soil interactions and their better exploitation as consortia in remediation strategies employed for contaminated soils. These multitrophic root microbial associations deserve multi-disciplinary investigations using molecular, biochemical, and physiological techniques. Ecosystem restoration of heavy metal contaminated soils practices need to incorporate microbial biotechnology research and development. This review highlights the ecological complexity and diversity of plant-microbe-soil combinations, particularly AM and provides an overview on the recent developments in this area. It also discusses the role AMF play in phytorestoration of HM contaminated soils, i.e. mycorrhizoremediation.     

两株降解纤维素真菌的分子鉴定及酶活分析

应用刚果红鉴定培养基,从土壤中筛选出两种分解纤维素能力较强的真菌,分别命名为NY01和NY02.滤纸条降解度分析显示,NY01的降解能力高于NY02.应用分子生物学手段,对两株菌rDNA的ITS区域序列分析显示,NY01与木霉的相似性高达99%,NY02与毛霉的相似性高达99%,暗示NY01可能是木霉的一个种,NY02可能是毛霉的一个种.培养基中碳氮比例对两株真菌纤维素降解酶活性的研究显示,在N/C比值较低和较高时,CMC酶和FPA酶活性都低,N/C比值在1∶8时酶活性最高,说明两株真菌降解纤维素的最佳N/C比值是1∶8.     

Study of cellulolytic soil fungi and two nova species and new medium

This study is aimed at identifying and determining the percentage of occurrence frequency of cellulose decomposing soil fungi. The soil samples were inoculated into culture plates prepared in Sabouraud medium under sterilized conditions and incubated at 30 ℃ for 4 to 7 d. The identified fungal species were incubated in self-designed cellulose medium for testing their cellulolytic ability. Forty-two species, including2 nova species, representing sixteen genera showed growth and sporulation in the cellulose medium. Most of the isolated species were from genus Aspergillus and Penicillium. Aspergillus niger and Mucor hiemalis showed highest occurrence frequency （45% and 36% respectively）, as these species were collected from about 80% of soil samples. Being agar free and cheaper, the new fungal medium designed showed results equivalent to Sabouraud medium.     

捕食线虫真菌的分布

采集思茅五个土壤剖面不同深层的土样,采集茶园、桔子园和剖面附近的表土,从中分离和鉴定捕食线虫真菌,统计检出率,结果是：有枯枝落叶层和较厚腐殖的土壤剖面,捕食线虫真菌分布较深,１００ｃｍ深层土中仍有分布,比１００ｃｍ更深层土中无分布;弯孢节丛孢、（Ａｒｔｈｒｏｂｏｔｒｙｓ ｍｕｓｉｆｏｒｍｉｓ）、少孢节丛孢少孢变种（Ａ．ｏｌｉｇｏｓｐｏｒａ ｖａｒ．ｏｌｉｇｏｓｐｏｒａ）、坚粘孢单顶孢（Ｍｏｎａｃｒ     

杂草五爪金龙对其入侵地土壤酶活性与微生物群落的影响

五爪金龙是粤东地区入侵性极强的外来杂草,其对入侵地土壤生态系统可能存在明显的改造作用．在野外调查的基础上,确定3个被五爪金龙重度入侵的生境作为采样地,通过室内实验测定与分析五爪金龙对入侵地土壤酶活性、土壤微生物群落的影响．结果表明：与非入侵地比较,杂草五爪金龙种群在粤东地区的入侵明显改变了入侵地的土壤生态系统的部分结构与功能,包括显著提高了入侵地土壤中蔗糖酶、脲酶、磷酸酶及硝酸还原酶的活性,其提高幅度均在2倍以上;增加了真菌、自生固氮菌及氨氧化细菌的数量,降低了细菌与反硝化细菌的数量,其改变率均大于20％．土壤酶活性与土壤微生物群落的改变可能导致土壤肥力的变化,因此,五爪金龙成功入侵的土壤微生物学机制有待进一步探讨．     

基于高通量测序的连作百合土壤细菌群落多样性研究

为了揭示连作对龙牙百合和铁炮百合根际土壤细菌群落结构和多样性的影响,本文采用高通量测序技术对连作2年、正茬的龙牙百合和铁炮百合根际土壤细菌群落进行16SrDNA基因V3+V4区域测序。结果显示:4个百合根际土壤样品中的有效序列注释为14068个操作分类单元(OTUs)。α多样性指数表明,连作提高了龙牙百合根际土壤细菌群落的丰度和多样性,降低了铁炮百合根际土壤细菌群落的丰度和多样性。β多样性分析表明,连作、正茬的龙牙百合和铁炮百合之间的根际土壤细菌群落多样性差异相对较大。细菌在门、属水平的相对丰度气泡图分析表明,龙牙百合和铁炮百合的根际土壤细菌群落优势菌门都主要有变形菌门、绿弯菌门、酸杆菌门、放线菌门、拟杆菌门。伯克霍尔德菌属、玫瑰弯菌属、芽单胞菌属、未命名Chloroflexi_bacterium属分别是正茬、连作2年的龙牙百合和铁炮百合根际土壤细菌群落的最优势菌属。连作2年后变形菌门、拟杆菌门菌群丰度的下降以及绿弯菌门菌群丰度的升高可能是铁炮百合更耐连作的原因,连作2年后变形菌门、拟杆菌门菌群丰度的升高以及酸杆菌门、放线菌门菌群丰度的下降可能是龙牙百合不耐连作的原因。研究结果对揭示百合连作障碍形成的原因具有一定参考价值。     

吖啶红-溴酸钾催化褪色光度法测定中药中的痕量铅

在硫酸介质中,抗坏血酸存在下,痕量铅能灵敏地催化溴酸钾氧化吖啶红褪色．研究了该催化褪色反应的最佳条件,建立了一种测定痕量铅的新方法．该方法的线性范围为20-85μg·L^-1,检出限为3×10^-7μg·L^-1．用于中药中铅的测定,相对标准偏差为1．73％～4．06％,加标回收率为97．1％～103．8％．实验结果表明,在三种中药中,山药中铅的含量最高,山楂中铅的含量最低．     

Organic nitrogen components in soils from southeast China

Objective:To investigate the amounts of extractable organic nitrogen(EON),and the relationships between EON and total extractable nitrogen(TEN),especially the amino acids(AAs) adsorbed by soils,and a series of other hydrolyzed soil nitrogen indices in typical land use soil types from southeast China.Under traditional agricultural planting conditions,the functions of EON,especially AAs in the rhizosphere and in bulk soil zones were also investigated.Methods:Pot experiments were conducted using plants of pakchoi(Brassica chinensis L.) and rice(Oryza sativa L.).In the rhizosphere and bulk soil zone studies,organic nitrogen components were extracted with either distilled water,0.5 mol/L K2SO4or acid hydrolysis.Results:K2SO4-EON constituted more than 30% of TEN pools.K2SO4-extractable AAs accounted for 25% of EON pools and nearly 10% of TEN pools in rhizosphere soils.Overall,both K2SO4-EON and extractable AAs contents had positive correlations with TEN pools.Conclusions:EON represented a major component of TEN pools in garden and paddy soils under traditional planting conditions.Although only a small proportion of the EON was present in the form of water-extractable and K2SO4-extractable AAs,the release of AAs from soil exchangeable sites might be an important source of organic nitrogen(N) for plant growth.Our findings suggest that the content of most organic forms of N was significantly greater in rhizosphere than in bulk soil zone samples.However,it was also apparent that the TEN pool content was lower in rhizosphere than in bulk soil samples without added N.     

Level of Abstraction as a Function of Modifer Load

Abstract

The purpose of this study was to ascertain the effects of Treatment TP (Prerequisite Principles) and Treatment TC (Conceptualization) on cognitive achievement of high school students varying in problem-solving ability. Treatment TP was designed according to Gagne’s hierarchy of learning, whereas Treatment TC was modified to include examples, analogies, mediators, cues, etc., to facilitate conceptualization. A sample of 80 high school students out of a group of 123. 33% with top problem-solving ability (PSA) scores and 33% with low PSA scores, was selected and randomly assigned to the two treatment groups. The scores on a final test of cognitive achievement served as the criterion measure (CM) of students’ achievement. A two-way ANOVA was used for analysis of the data.

Results indicated that students with high problem-solving ability (HPSA) scored significantly higher on CM than did students with low problem-solving ability (LPSA). No significant difference was found in the two treatments. However, pair-wise comparison indicated that HPSA and LPSA students in TC and HPSA students in TP scored significantly higher on CM than LPSA in TP. Results imply that more examples, analogies, cues, mediators, etc., to facilitate conceptualization should be designed for students with LPSA. And PSA tests should be employed for selecting students to reach higher cognitive achievement.     

体育锻炼能够促进青少年的认知能力发展吗?——基于中国教育追踪调查数据的实证研究

本文利用中国教育追踪调查数据(2014—2015),采用普通最小二乘法、分位数回归以及倾向得分匹配法,实证检验了体育锻炼对青少年认知能力的影响,结果发现:(1)利用普通最小二乘法测得经常参与体育锻炼的青少年在认知能力测试上比不经常参与的青少年高出0.149个标准分,当控制前期能力后,青少年参加体育锻炼的时间每上升1个单位值,能将认知能力提高0.049个标准分;(2)利用分位数回归发现参加体育锻炼对认知能力处于中位数上的青少年具有最强的促进作用,体育锻炼的异质性特征突出表现为“倒V”型曲线,而利用无条件分位数回归发现经常参与体育锻炼能够缩小低–高分位点上认知能力的组内差异;(3)利用Probit模型发现学校作业并非青少年参与体育锻炼的决定因素,看电视、玩网络游戏等课余活动的时间则对青少年参与体育锻炼构成了挤出关系,文化资本、人力资本以及教育期望与青少年的体育运动参与率呈正相关;(4)利用倾向得分匹配法发现体育锻炼影响认知能力的平均处理效应落入[0.095,0.117]的取值区间,而忽视选择性偏差将会高估体育锻炼的净效应。     

Microbial activity and community diversity in a variable charge soil as affected by cadmium exposure levels and time

Effects of cadmium (Cd) on microbial biomass, activity and community diversity were assessed in a representative variable charge soil (Typic Aquult) using an incubation study. Cadmium was added as Cd(NO3)2> to reach a concentration range of 0～16 mg Cd/kg soil. Soil extractable Cd generally increased with Cd loading rate, but decreased with incubation time. Soil mi-crobial biomass was enhanced at low Cd levels (0.5～1 mg/kg), but was inhibited consistently with increasing Cd rate. The ratio of microbial biomass C/N varied with Cd treatment levels, decreasing at low Cd rate (<0.7 mg/kg available Cd), but increasing progressively with Cd loading. Soil respiration was restrained at low Cd loading (<1 mg/kg), and enhanced at higher Cd levels. Soil microbial metabolic quotient (MMQ) was generally greater at high Cd loading (1～16 mg/kg). However, the MMQ is also affected by other factors. Cd contamination reduces species diversity of soil microbial communities and their ability to metabolize different C substrates. Soils with higher levels of Cd contamination showed decreases in indicator phospholipids fatty acids (PLFAs) for Gram-negative bacteria and actinomycetes, while the indicator PLFAs for Gram-positive bacteria and fungi increased with increasing levels of Cd contamination.     

不同种植模式对烟田土壤微生物数量的影响

通过对毕节市赫章六曲不同烤烟种植模式土壤中微生物的数量的实验,结果发现：套种模式下,土壤微生物的数量与对照相比,存在极显著的差异,而且套种并还田的种植模式下,对土壤中微生物的数量影响最大。     

油泥和校园土壤中两株放线菌的比较

通过对菌落特征的观察,从油泥中筛选出一株区别于校园土壤中的放线菌;并通过对两菌株摇瓶发酵代谢产物的核磁共振氢谱比较,为后续研究的深入提供理论依据.结果表明,从油泥和校园土壤中分离纯化的两菌株其菌落都与培养基牢固结合、不透明、较干燥、正反颜色不同,有泥腥味.但菌落正面＂干粉＂前者呈浅灰色,而后者呈白色;菌落反面呈棕褐色,前者明显深于后者;核磁共振氢谱表明两种菌的代谢产物有明显差异.因此,不同环境中的放线菌菌落特征有差异,其色泽表现出对环境的适应;其代谢产物也有差异.