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11.
Disappearance of acetic acid from the bovine reticulorumen at basal and elevated concentrations of acetic acid. 总被引:2,自引:0,他引:2
Disappearance of acetic acid was quantified to determine whether removal of this acid from the reticulorumen is altered when ruminal acetic acid concentrations are elevated. Ruminally fistulated beef steers (n = 3 per experiment; BW = 320 +/- 9 kg) were fed eight times daily a 46% corn-based concentrate:54% mixed hay diet to meet maintenance energy requirements (3.5 kg of DM/d). In situ production of acetic acid, determined by pulsed-continuous infusion of [1-14C]acetic acid, was 530 mmol/h (CV = 12%). Disappearance from the reticulorumen (i.e., presumed absorption) was 460 mmol/h (CV = 2%) or 87% (CV = 2%) of ruminal production. Variation is described within an operational steady state. Acetic acid concentrations were increased by continuous infusion of unlabeled acetic acid into the reticulorumen. Ruminal disappearance (mmol/h) increased when this simulated production was elevated up to and exceeding in situ rates reported previously (530 to 2,700 mmol/h). These data suggest that two-thirds to three-fourths of ruminal acetate production disappeared across the reticuloruminal wall when concentration was elevated; the complement exited from the rumen with the liquid phase. The reticulorumen has an additional capacity to remove acetic acid; however, it does so with an apparent reduced efficiency at higher production rates. Liquid out-flow may affect the efficiency of reticuloruminal disappearance. Sites distal to the rumen become quantitatively important when ruminal acetic acid concentrations are increased. 相似文献
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花生区组四粒红与根茎区组Arachis glabrata杂交果针经离体培养克服了不亲和性,获得杂种。杂种二代性状出现疯狂分离,但有些性状仍分别倾向双亲。经叶片过氧化物同工酶分析,酶带的条数、宽窄、活性强弱及迁移率,杂种与双亲有明显差异,也有共同之处,初步证明了杂种的真实性。 相似文献
13.
分子标记用于赤眼蜂分子监测的研究 总被引:5,自引:0,他引:5
通过对松毛虫赤眼蜂(Trichogramma dedrolimi Matsumura)以及玉米螟赤眼蜂(Trichogramma ostriniae Pang et Chen)rDNA-ITS2基因的克隆测序,并联机检索GenBank核酸序列库中其它赤眼蜂的相关序列,利用核酸分析软件找到松毛虫赤眼蜂和玉米螟赤眼蜂ITS2序列中一段有鉴别意义的标志,并据此设计出蜂种的特异PCR引物,实现了松毛虫赤眼蜂和玉米螟赤眼蜂rDNA特异区带的PCR扩增。研究表明该特异区带具有种的特异性。我们认为该分子标记技术可用于目前我国生防中常用的松毛虫赤眼蜂和玉米螟蒌眼蜂的分子监测,如田间种群动态监控和寄生效果评估。 相似文献
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Ning De-juan Hou Pei-chen Hu Zan-min Shen Xin Chen Shao-liang College of Biological Sciences Biotechnology Beijing Forestry University Beijing P. R. China Institute of Genetics Developmental Biology Chinese Academy of Sciences Beijing P. R. China 《中国林学(英文版)》2006,8(4):15-19
For this paper, the plasma membrane (PM) H -ATPase gene has been cloned from Populus euphratica Oliv. through a homology based strategy. The isolated 3,210 bp cDNA contains a single 2,862 bp open reading frame (ORF) which encodes a putative H -ATPase protein of 953 amino acid residues, with a significant homology to plasma membrane H -ATPase of Primus persica, Phaseolus vulgaris, Sesbania rostrata and Daucus carota. The predicted protein has a molecular weight of 104,553 Da. The copy number analysis revealed multiple copies of the PM H -ATPase in the P. euphratica genome after digestion of their genomic DNA by the restriction enzymes EcoRI, NdeⅠ, FbaⅠand BglⅡ, and Southern blot. 相似文献
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盐分对碱茅种子发芽影响的机制 总被引:15,自引:0,他引:15
耐碱茅种子在盐(NaCl与Na2SO4)及干旱(PEG-6000模拟)胁迫下发芽及其机制的比较研究表明,种子发芽率随溶液渗透势的降低而下降,在等渗条件下三种溶液中的发芽率次序为Na2SO4>NaCl>PEG。NaCl与Na2SO4主要通过影响种子吸水量及对膜的毒性影响发芽,根据相关及通径分析结果,其机制为:(1)溶液渗透势及Na+浓度决定的种子吸水对发芽的直接正效应(通径系数0.73);(2)溶液Na+浓度引起的膜毒性对发芽的直接负效应(-0.51);(3)种子从溶液中吸收Na使种子吸水增加对发芽的间接正效应(0.30)及使膜毒性增大对发芽的间接负效应(-0.24)。 相似文献
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According to the requirements of the conversion of farmland to forests project (CFFP), we investigated the vegetation factors
and environmental factors from more than 6,105 sub-compartments in Liangcheng County, Inner Mongolia by using the Matlab,
analytic hierarchy process (AHP), and the hierarchical cluster method (HCM). The site conditions were classified quantitatively.
The results show that CFFP at this site comprises five site-type groups and 19 site types. A quantitative site classification
system method has been established in this paper.
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Translated from Journal of Beijing Forestry University, 2005, 27(6) [译自: 北京林业大学学报, 2005, 27(6)] 相似文献