羊草草原枯枝落叶积累的研究：枯枝落叶积累对草原生态环境及生产力的作用   总被引：5，自引：0，他引：5  

郭继勋  祝廷成 《草业科学》1994,11(6):12-16

枯枝落叶积累可改变原生态环境，地表温度、土壤ＰＨ值积累量呈线性负相关，蒸发量、土壤容重与积累量呈指数负相关，土壤水分、土壤孔隙度与积累量呈线性正相关，枯枝落叶积累可为植物生长创造良好的生境。土壤中主要营养物质随着枯枝落叶积累均有明显提高当积累量达６００ｇ／ｍ＾２时，有机质、Ｎ、Ｐ、Ｋ含量分别比无枯枝落叶层提高１．８倍、８８．２％、２．１５倍和３７％。枯枝落叶积累对草原生产力有促进作用，在一定范围内  相似文献   

牛瘤胃胃电频谱分析中窗函数的选择     

苏枋  马素贞 《新疆农业大学学报》1999,22(3):181-184

采用三种常用的窗口函数，对牛瘤胃４ 种生理状态下胃电（峰电位和慢电位）的频谱进行了分析比较，得出了不同窗函数下频谱中幅值的特性，并分析确定了作者课题组频谱分析时的窗口函数——汉宁窗。  相似文献   

白背飞虱和稻纵卷叶螟同时危害时的复合防治指标分析     

黄涛  王兴琴 《现代农业科技》2013,(6):110-111

针对白背飞虱和稻纵卷叶螟田间发生和防治的实际情况,通过试验建立"两迁"害虫同时危害时的回归方程,依据当地农业生产现状,计算得出实际经济允许损失N=16.16。由满足0.013X1+0.287X2-0.539=16.16,测得"两迁"害虫同时危害的一组动态的复合防治指标。  相似文献   

缺硫胁迫对水稻膜脂过氧化及保护酶系统活性的影响   总被引：2，自引：0，他引：2  

张秋芳  黄跃东  林真 《上海交通大学学报(农业科学版)》2003,21(1):25-28,33

以正常硫素营养为对照，通过水培试验。研究缺硫胁迫下不同品种水稻叶片活性氧代谢和相关酶活性的变化情况。结果表明：缺硫胁迫会引起水稻叶片膜脂过氧化程度提高和可溶糖浓度增加。并导致超氧化物歧化酶（SOD），过氧化物酶（POD），过氧化氢酶（CAT）和苯丙氨酸解氨酶（PAL）活性的改变，其变化幅度因品种的差异而有所不同。  相似文献   

Fat globule membrane of sow milk as a target for adhesion of K88-positive Escherichia coli   总被引：1，自引：0，他引：1  

F Atroshi  T Alaviuhkola  R Schildt  M Sandholm 《Comparative immunology, microbiology and infectious diseases》1983,6(3):235-245

Membrane adhesion of K88-positive Escherichia coli was studied on intestinal brush-border membranes on 237 Finnish Landrace pigs. Forty-one per cent of the brush-border membrane preparations aggregated E. coli (positive adhesion). Similar dualism of adherence/nonadherence was observed on sow milk fat globule membranes. Washed milk fat globules (washed cream) can be used as a convenient source of material for adhesion studies. Bacterial adherence on to milk fat globules is evident as agglutination of the globules (dark-field microscopy). By this procedure the sows can be typed according to their receptor phenotype. This simple principle of fat globule agglutination due to receptors for K88-positive E. coli might be complicated by SigA-mediated bacterial adherence. Fat globule membranes were shown to contain SigA, which may act as a mediator of bacterial adherence onto fat globules. The significance of this adhesive property of milk fat globule might be to provide alternative receptors for E. coli thus preventing bacterial adhesion on to gastro-intestinal epithelium of the offspring. Sow milk fat globules can be used for typing E. coli for membrane adhesiveness. The adhesiveness of the strains showed a good correlation with the presence of the K88 antigen, as well as the hydrophobicity of the bacterial strain as determined by an association on Phenyl-Sepharose beads.  相似文献   

禾谷类花粉培养的生物学基础研究进展(英文)     

王学华  罗小仁  戴力 《农业科学与技术》2016,(3)

从植物生理代谢的角度总结禾谷类花粉培养中一系列过程的生理代谢机制,同时探讨了小孢子脱分化和愈伤组织形成、分化及转化等几个关键过程的生理学或细胞学机制。对该领域当前面临的问题和未来发展的方向进行了总结和展望。  相似文献   

Detection of all Chlamydophila and Chlamydia spp. of veterinary interest using species-specific real-time PCR assays     

Alexandra Pantchev  Reinhard Sting  Rolf Bauerfeind  Judith Tyczka  Konrad Sachse   《Comparative immunology, microbiology and infectious diseases》2010,33(6):473-484

The aim of the present study was to analyse the occurrence of chlamydiae in several mammalian host species. Clinical samples that previously tested positive in a Chlamydiaceae-specific real-time PCR were retested using six species-specific real-time PCR assays to identify the chlamydial species involved. Chlamydophila (Cp.) abortus was the agent most frequently found in cattle, sheep, horses, goats, and pigs. Detection in cattle of Cp. psittaci (11% of samples) and Chlamydia (C.) suis (9%), as well as Cp. psittaci in a goat sample was somewhat unexpected. DNA of two different chlamydiae was identified in 56 (12.7%) of 440 samples tested. Cp. felis was the predominant species found in cats, while in guinea pigs and rabbits only Cp. caviae was detected. Interestingly, the latter two pathogens were also identified in samples from dogs. The data show that mixed chlamydial infections are not rare and suggest an extended host range of individual species.  相似文献   

空心莲子草不定根膨大过程中主要营养物质含量的变化     

陈中义  李华成 《湖北农业科学》2016,(24):6459-6463

利用空心莲子草(Alternanthera philoxeroides)地上茎段扦插育苗,在空心莲子草生长20、45、70、95 d时,研究其不定根膨大过程中可溶性蛋白质、可溶性总糖、蔗糖、淀粉含量的动态变化。结果表明,空心莲子草不定根膨大过程中,随着根直径不断增加,可溶性蛋白质含量呈上升趋势,可溶性总糖和蔗糖含量呈急剧上升趋势并保持在较高含量水平,淀粉含量低且变化不大。不同膨大时期,蔗糖占可溶性总糖的比例均较高。可溶性蛋白质含量、可溶性总糖含量、蔗糖含量与空心莲子草宿根的主要生长指标(宿根直径、根长、表面积、体积、干重、根冠比)均呈现极显著正相关关系(P0.01),淀粉含量与其他各项指标均无显著相关性(P0.05)。表明可溶性蛋白质、可溶性总糖、蔗糖是空心莲子草不定根膨大的物质基础,其中可溶性总糖、蔗糖是宿根的重要组成物质和贮藏成分。而淀粉在空心莲子草宿根形成中并不是重要物质。  相似文献   

稻田除草剂对固氮蓝藻的毒性研究   总被引：6，自引：0，他引：6  

王秀红  沈健英  陆贻通 《上海交通大学学报(农业科学版)》2004,22(4):400-405

通过4种稻田除草剂对固氮鱼腥藻(AnabaenaazoticaLey)、球胞鱼腥藻(AnabaenasphaericaBorn)、多变鱼腥藻(AnabaenavariabilioKutzing)的毒性进行了研究。结果表明,二甲四氯对3种藻的生长有促进作用,而丁草胺和乙草胺在低浓度(8mg·L-1以下)表现为促进,当浓度为16mg·L-1时,则显著抑制其生长,且高浓度时对3种藻产生较强毒性,处理96h时的EC50值分别为12.87、25.36、20.21mg·L-1及50.52、18.37、45.43mg·L-1。3种藻对扑草净极为敏感,在低浓度时其生长受到严重抑制,继而迅速死亡。因此选择对固氮蓝藻安全的稻田除草剂,对维护稻田生态、促进农业可持续发展具有重要意义。  相似文献   

Isolation of pathogenic Listeria monocytogenes in faeces of wild animals in captivity     

Kalorey DR  Kurkure NV  Warke SR  Rawool DB  Malik SV  Barbuddhe SB 《Comparative immunology, microbiology and infectious diseases》2006,29(5-6):295-300

The isolation of pathogenic Listeria spp. in faecal samples of captive wild animals was studied. Isolation of the pathogen was attempted from the samples by selective enrichment in University of Vermont Medium and plating onto Dominguez-Rodriguez isolation agar, PALCAM agar and modified McBride Listeria agar. Pathogenicity of the isolates was tested by Christie, Atkins, Munch Petersen test, phosphotidylinositol-specific phospholipase C assay, mice inoculation test and chick embryo bioassay. Listeria monocytogenes was isolated from eight (16%) of 50 faecal samples from six different mammals and one bird. Out of eight isolates, one isolate from jackal proved to be pathogenic by all the pathogenicity testing assays. PCR amplification of virulence genes suggested that the isolate was potentially pathogenic.  相似文献