龙游硫铁矿区农田土壤重金属污染的空间 变异及在水稻中的积累

为了解浙江龙游硫铁矿区农田重金属污染状况,采集矿区265件农田土壤样品,分析8种重金属Cu、As、Hg、Zn、Cd、Ni、Pb、Cr元素全量,利用地统计学软件GS+9.0对研究区土壤各元素指标进行半变异函数拟合,并利用普通克里格法进行插值并绘制空间分布图。采集30件水稻籽粒样品,分析重金属在研究区中水稻籽粒的累积特征,并进行了健康风险评价。结果表明:矿区土壤中8种重金属元素的变异系数从0.72到1.76,离散程度较高。8种重金属的土壤空间半变异函数Cu、As、Hg元素符合指数模型,Zn、Cd、Ni、Pb符合球状模型,Cr符合高斯模型。元素Cu、Pb、Zn、Cr、Ni的块金值与基台值的比值C0/C0+C都小于0.25,说明空间变化主要受地质背景等因素影响;元素Cd、Hg和As的块金值与基台值的比值C0/C0+C在0.25~0.75之间,说明除了地质背景因素,人为活动等随机因素也有影响。矿区水稻籽粒中重金属Ni和Cd的变异系数最高,分别为0.95和0.87,说明Ni和Cd元素可能存在异常积累。矿区水稻籽粒对重金属的富集能力由大到小依次为Cd、Zn、Cu、Ni、As、Hg、Cr、Pb。健康风险评价结果表明矿区农田水稻籽粒中元素As、Cd的风险商大于1,存在潜在健康风险;而其他6种重金属Cu、Hg、Zn、Ni、Pb和Cr基本属于安全范围。     

2CM-4型马铃薯播种施肥联合作业机的研制

针对马铃薯播种作业的机械化程度制约着马铃薯生产的发展的问题,在对国内马铃薯播种机现状研究分析的基础上,结合我国马铃薯播种的农艺要求,设计出了2CM-4型马铃薯播种施肥联合作业机。该机具采用交叉取种的方式,配合振动式排种部件,实现精量播种;采用种肥分施的技术,减少肥料对种薯的损伤;机具的排种单体、施肥部件、覆土部件、镇压部件均可调节,可适应不同行距种植。该机具操作简单、性能良好、作业效率高、故障率低,是马铃薯种植户的理想选择,市场前景广阔。     

成年桔园系统化管理及其效应

江西农大园林场通过4年(1987～1990)科学化栽培措施、程式化病虫害防治及合理化管理制度等系统化管理方法,挽救了23亩濒临死亡的22年生温州蜜柑.总产从1.25万公斤递增到6万公斤,主要病虫为害程度控制在经济允许水平以下,喷药次数、农药费用明显低于省内主要桔区.     

Deletions in the pyruvate pathway of Salmonella Typhimurium alter SPIl-mediated gene expression and infectivity

Background： Salmonella enter/ca serovar Typhimurium is a major foodborne pathogen worldwide. S. Typhimurium encodes type III secretion systems via Salmonella pathogenicity islands （SPI）, producing the major effector proteins of virulence. Previously, we identified two genes of Salmonella pyruvate metabolism that were up-regulated during chicken cell infection： pyruvate formate lyase I （pf/B） and b/functional acetaldehyde-CoA/alcohol dehydrogenase （adhE）. We were therefore interested in examining the role these genes may play in the transmission of Salmonella to humans. Methods： Mutant strains of Salmonella with single gene deletions for pflB and adhE were created. Invasion and growth in human HCT-8 intestinal epithelial cells and THP-1 macrophages was examined. Quantitative PCR was performed on 19 SPI-1 genes. Results： In HCT-8 cells, both mutant strains had significantly higher intracellular counts than the wild-type from 4 to 48 h post-infection. Various SPI-1 genes in the mutants were up-regulated over the wild-type as early as 1 h and lasting until 24 h post-infection. In THP-1 cells, no significant difference in internal Salmonella counts was observed; however, SPI-1 genes were largely down-regulated in the mutants during the time-course of infection. We also found five SPI-1 genes - hilA, hiIC hill）, sicP and rtsA - which were up-regulated in at least one of the mutant strains in log-phase broth cultures alone. We have therefore identified a set of SPI-1 virulence genes whose regulation is effected by the central metabolism of Salmonella.     

1ZML-210深松型联合整地机的研制

为了解决传统联合整地机不能完成超深松的问题,在研究分析传统联合整地机的基础上,研制出可与大马力拖拉机配套的新型耕整地机具1ZML-210深松型联合整地机。该机具在灭茬刀轴和旋耕刀轴中间增加一组超深松装置。从而可以打破犁底层,提高土壤透气、透水性能,提高土壤抵抗自然灾害能力。该机具一次作业能够完成垄上灭茬、深松、旋耕、起...     

南京地区农业综合生产力的灰关联分析

在对现有原始数据进行分析研究的基础上，采用了多层次灰关联评价方法，对南京地区五县的农业综合生产力进行了科学评价，从而为发掘南京郊县农村的农业生产力、确立未来农业发展方向提供了一种理论依据。     

菊芋全粉对刺参生长性能及灿烂弧菌刺激下免疫因子应答变化的影响

为研究菊芋全粉对刺参生长性能及灿烂弧菌刺激下体液中免疫因子活力变化的影响,试验选取初始体重为(4.7±0.1)g的刺参360只,随机分为3组。对照组喂食基础日粮,试验Ⅰ、Ⅱ组分别在基础日粮中添加菊芋全粉5、15g/kg,试验期为42d,分为养殖试验期(0~28d)和感染试验期(29~42d)。试验结果表明:(1)养殖试验期,相较于对照组,菊芋全粉处理组刺参的日增重无显著变化(P>0.05),但试验Ⅰ组(5g/kg)刺参的饲料利用率降低0.75%,试验Ⅱ组(15g/kg)刺参的饲料利用率提高了21.05%(P<0.05);(2)感染试验期,灿烂弧感刺激后,15g/kg菊芋全粉可显著改善酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、超氧化物歧化酶(SOD)的免疫应答变化(P<0.05);而相较于对照组,5g/kg菊芋全粉可显著增强刺激前期刺参的溶菌酶(LYZ)活力(P<0.05)。综上,灿烂弧菌刺激下,15g/kg菊芋全粉可显著增强刺参免疫因子活力。     

Effects of Jerusalem artichoke powder on the growth performance,nonspecific immunity,and gastrointestinal microbiota of sea cucumber

This study investigated how Jerusalem artichoke powder (JAP) affected the growth, immunity, and gut microbiota of the sea cucumber, Apostichopus japonicus Selenka. Animals were fed diets containing antibiotic (1 ppm) or five levels of JAP (0, 2.5, 5, 10, and 15 g/kg). After the feeding trial, three sea cucumbers were sampled per tank to assay for immunity and gut microbiota composition. Dietary supplementation of 2.5 g/kg JAP significantly improved the growth rate and phenoloxidase activity of sea cucumbers. The diet containing 5 g/kg of JAP increased the survival rate and phagocytic activity, and the diet containing 15 g/kg of JAP increased the growth rate and total coelomocyte count of sea cucumbers. Moreover, exposure to antibiotics significantly changed the microbiota of sea cucumbers, while the JAP supplementation stimulated the development of microbiota communities, which could be more homogeneous. Supplementing the diets with 15 g/kg of JAP increased the growth of Rhodobacterales, and this may underlie the higher growth rate of sea cucumbers in this treatment. Considered together, our results suggest that supplementing the diet of sea cucumber with JAP may be beneficial for nonantibiotic farming of sea cucumber.     

Accumulation of PAHs of the soils and assessment of their health risks at a village with plastic manufacturing in Taizhou,Zhejiang Province,Southeast China

Journal of Soils and Sediments - Accumulation of polycyclic aromatic hydrocarbons (PAHs) in soil had drawn increasing attention for their potential toxic effects on human health and ecological...