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41.
神农香菊(Dendranthema indicum (L.) Des Monl. var. aromaticum Q. H. Liu et S. F. Zhang, var. nov.)是我所多年来通过调查,在鄂西神农架首先发现的一种新的资源植物。这种植物与野菊[D. indicum (L.) Des Monl.]很近似,其主要区别在于神农香菊的花、叶具有浓郁的特殊香气。经化学初步分析和药理试验结果表明,本植物含α—侧柏酮、β—侧柏酮、龙脑等萜类化合物成分,并无剧毒性及致癌因素反应。可广泛应用于化工、饮料和医药等方面的原料,是一种很有经济价值的香料和药用的植物资源。本文着重阐述和讨论了本植物的地理分布,习性生境、自然繁殖概况及蕴藏量。并提出进一步开发利用神农架山区植物资源,合理利用和发展神农香菊生产等方面的途径和科学依据。 相似文献
42.
本文通过对枯草芽孢杆菌BR151衍生株与北京棒杆菌1134衍生株的赖氨酸高产融合子Q4413株的形态学、生理生化特性等方面的研究,揭示了融合子与双亲株在这些方面的差异,为Q4413株确系双亲株的重组子或新的融合子增加了佐证. 相似文献
43.
本文通过研究提出了一种由大肠杆菌细胞中提取重组猪生长激素的方法。提取回收率为52.4%,纯度为94.1%,具有生物学活性。 相似文献
44.
草鱼血液学的研究:Ⅱ.血清电解质和尿素氮的周年变化 总被引:1,自引:0,他引:1
本文研究了草鱼稚鱼血清钾、钠、钙、氯、无机磷和尿素氮含量的周年变动规律,分析了水温、体重对上述血液化学成分的影响。结果显示其周年变动无一定规律性可循。血清钠、氯变动辐度较小,无机磷和尿素氮变动幅度较大,幅值约有4倍。水温与血清钾显示正相关(P≤0.05),与钠、钙显示负相关(P≤0.01,P≤0.05)。血清钠、尿素氮有随体重增加含量增高的趋势,而钾却显著减少。 相似文献
45.
抑菌生的研究总结报告 总被引:6,自引:1,他引:5
本文报告一种由枯草杆菌制成的生态制剂,并命名为抑菌生(Subtilobiogen)。该制剂对创、烧伤感染有治疗作用。经过安全试验、急性毒性试验、Ames试验和微核试验证明,该制剂是一种无害、无毒和有致突变作用的活菌制剂。抑菌生有膏剂、乳剂及粉剂3种剂型。抑菌生在试管和体内对金黄色葡萄球菌、绿脓杆菌和大肠杆菌均具有抑菌作用。临床观察证明,将抑菌生喷洒在创面上,对浅Ⅱ°度、深Ⅱ°度及混合型烧伤感染均具有明显疗效。实验组(181例)与对照组(174例)相比较,在统计学上具有显著性差异。抑菌生的作用机制,经过初步试验证明,与营养争夺和占位性保护有关,因为枯草杆菌的生长速度超过金黄色葡萄球菌、绿脓杆菌和大肠杆菌的生长速度。 相似文献
46.
Three B. subitilis serine tRNAs were sequenced including modified nucleosides. All the serine tRNAs contained 1-methyl-adenosine in the D-loop. As other characteristic modified nucleosides, 5-methoxyuridine was found in the first letter of the anticodon in the tRNA(UGA). 相似文献
47.
Steroidal saponins from Smilax lebrunii. 总被引:5,自引:0,他引:5
Two new steroidal saponins, (25 R)-spirostan-3 beta-ol-6-one-3-O-[alpha-L-arabinopyranosyl (1----6)]-beta-D-glucopyranoside and (25 R)-spirostan-3 beta-ol-6-one-3-O-[beta-D-glucopyranosyl(1---4)] [alpha-L-arabinopyranosyl(1----6)]-beta-glucopyranoside, were isolated from the rhizomes of Smilax lebrunii. Their structures have been established by chemical and spectral methods. 相似文献
48.
Two new compounds, pedicularioside E and F, were isolated from whole plants of Pedicularis lasiophrys, along with the four known compounds, verbascoside, cistanoside C, cistanoside D and 8-epiloganin. On the basis of spectral and chemical evidence, pedicularioside E and F were identified to be 1'-O-beta-D-(3-methoxy-4-hydroxy-beta-phenyl)-ethyl-6'-O-feruloyl- alpha-L-(2-acetyl)-rhamnosyl-(1----3')-4'-acetylglucopyranoside and shanzhisin methyl ester cellobioside, respectively. 相似文献
49.
Genomic in situ hybridization to identify alien chromosomes and chromosome segments in wheat 总被引:15,自引:0,他引:15
T. Schwarzacher K. Anamthawat-Jónsson G. E. Harrison A. K. M. R. Islam J. Z. Jia I. P. King A. R. Leitch T. E. Miller S. M. Reader W. J. Rogers M. Shi J. S. Heslop-Harrison 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1992,84(7-8):778-786
Summary Genomic in situ hybridization was used to identify alien chromatin in chromosome spreads of wheat, Triticum aestivum L., lines incorporating chromosomes from Leymus multicaulis (Kar. and Kir.) Tzvelev and Thinopyrum bessarabicum (Savul. and Rayss) Löve, and chromosome arms from Hordeum chilense Roem. and Schult, H. vulgare L. and Secale cereale L. Total genomic DNA from the introgressed alien species was used as a probe, together with excess amounts of unlabelled blocking DNA from wheat, for DNA:DNA in-situ hybridization. The method labelled the alien chromatin yellow-green, while the wheat chromosomes showed only the orange-red fluorescence of the DNA counterstain. Nuclei were screened from seedling root-tips (including those from half-grains) and anther wall tissue. The genomic probing method identified alien chromosomes and chromosome arms and allowed counting in nuclei at all stages of the cell cycle, so complete metaphases were not needed. At prophase or interphase, two labelled domains were visible in most nuclei from disomic lines, while only one labelled domain was visible in monosomic lines. At metaphase, direct visualization of the morphology of the alien chromosome or chromosome segment was possible and allowed identification of the relationship of the alien chromatin to the wheat chromosomes. The genomic in-situ hybridization method is fast, sensitive, accurate and informative. Hence it is likely to be of great value for both cytogenetic analysis and in plant breeding programmes. 相似文献
50.
A difference equation model for the dynamics of a semelparous size-structured species consisting of juvenile and adult individuals
is derived and studied. The adult population consists of two size classes, a smaller class and a larger more fertile class.
Negative feedback occurs through slowed juvenile growth due to increased total population levels during the developmental
period and consequently a smaller adult size at maturation. Intra-specific competition coefficients are size dependent and
measure the strength of intra-specific competition between juveniles and adults. It is shown that equilibrium states in which
adults and juveniles occur together at all times are in general destabilized by significantly increased juvenilevs adults competition with the result that stable periodic cycles appear, in which the generations alternate in time and hence
avoid competition. This result supports the tenet that intra-specific competition between juveniles and adults is destabilizing.
Exceptions to this destabilization principle are found, however, in which populations exhibiting non-equilibrium, aperiodic
dynamics can be equilibrated by increase competition between juveniles and adults. This occurs, for example, when adult fertility
and competition coefficients are significantly size class dependent.
The author gratefully acknowledges the support of the Applied Mathematics Division and the Population Biology/Ecology Division
of the National Science Foundation under NSF grant No. DMS-8902508.
Research supported by the Department of Energy under contracts W-7405-ENG-36 and KC-07-01-01. 相似文献