共查询到20条相似文献，搜索用时 31 毫秒
1.
选择两个不同杂交品种水牛和德宏水牛共15头,即尼本水牛(尼里水牛×德宏水牛)、摩本水牛(摩拉水牛×德宏水牛)的F1代和德宏水牛各5头,研究德宏水牛及其不同杂交组合品种的屠宰特性。结果显示,尼本与德宏水牛的宰前活重(433.00kg,339.09kg)、胴体重(271.84kg,197.37kg)、屠宰率(62.78%,58.26%)、净肉重(237.85kg,165.88kg)、净肉率(54.93%,48.96%)、胴体产肉率(87.48%,84.04%)、肉骨比(7.06:1,5.27:1)存在显著差异(P<0.05)。试验结果说明,通过尼里、摩拉水牛与德宏水牛杂交后显著提高了德宏水牛的屠宰性能,而且尼里水牛比摩拉水牛的杂交效果好。 相似文献
2.
云南龙陵黄山羊的核型及C－带和Ag－NORs研究 总被引：3，自引：0，他引：3
采用外周血淋巴细胞培养及染色体分带技术,分析了龙陵黄山羊的核型,C-带和银染核仁组织区(Ag-NORs),结果表明:龙陵黄山羊染色体数为2n=60,常染色体及X染色体为端部着丝粒染色体,Y染色体最小,为中部着丝粒染色体。常染色体着丝粒区均显示C-带,性染色体未显C-带。雌性银染核仁组织区(Ag-NORs)分布于No.1,2,3,4,5,25号染色体,雄性分布于No.1,2,25号染色体,显示了性别及分布多态性。研究还发现三种不同的联合(ASSOCIATION)。 相似文献
3.
通过设计简并引物和构建基因组文库的方法从链霉菌Streptomyces sp.S9中克隆得到β-l,4-木聚糖酶基因xynBS9。该基因全长1 023 bp,编码340个氨基酸。将不带原基因信号肽编码序列的xynBS9以正确阅读框架克隆到表达载体pET-22b(+)上,并在大肠杆菌BL2l(DE3)中诱导表达。重组蛋白经硫酸铵分级沉淀和疏水柱纯化后达到电泳纯。酶学性质分析表明,重组木聚糖酶最适温度为60℃,最适pH为6.5,在碱性条件下具有良好的稳定性。 相似文献
4.
本文在实地调研与资料收集的基础上,通过数据统计和案例分析对江苏省南京市六合区竹镇镇竹墩村、烟墩社区、宝贡村的土地流转对象、方式、期限、收益、满意度等具体问题作出具体分析,同时提出政策性建议,以期推进土地流转和农地产权制度改革。 相似文献
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6.
Na Wang Yajun Ma Cuiyun Yang Guanghui Dai Zhezhi Wang 《Frontiers of Agriculture in China》2008,2(3):317-320
To determine the pathogens of cucumber downy mildew and cucumber powdery mildew by molecular marker, we amplified and sequenced
the rDNA-ITS region of the pathogens of cucumber downy mildew and cucumber powdery mildew collected from the Shanghai region.
The intra-/interspecific sequence difference was analyzed by rDNA-ITS sequence. The results show that the length of rDNA-ITS1
and rDNA-ITS2 of cucumber downy mildew’s pathogen was 141 bp and 406 bp, respectively, with GC contents of 41.13% in ITS1
and 46.8% (Minhang and Jinshan District, sm1 and sm2) or 46.55% (Pudong District, sm3) in ITS2. The rDNA-ITS sequence was
intraspecific conservation. The interspecific difference was related with their kin relationship. The pathogen of cucumber
downy mildew was identified as Pseudoperonospora cubensis by molecular marker. The length of rDNA-ITS1 and rDNA-ITS2 of cucumber powdery mildew’s pathogen was 136 bp and 89 bp, respectively,
with GC contents being 59.56% and 66.29%, and rDNA-ITS sequence being highly conservative in this study that was the same
as Sphaerotheca cucurbitae. But the sequence difference between the strains in the Shanghai region in this study with S. fuliginea was 4.5%, which was identified by morphology. It is suggested that the pathogen of cucumber powdery mildew should be further
clarified and determined.
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Translated from Journal of Northwest A & F University (Nat. Sci. Ed.), 2007, 35(10): 155–158 [译自: 西北农林科技大学学报(自然科学版)] 相似文献
7.
三元复混肥和鸡粪肥中重金属含量特征分析与评价 总被引：1，自引：0，他引：1
何飞飞 《湖南农业大学学报(自然科学版)》2011,37(6):665-668
为了解施肥对山东寿光市设施蔬菜土壤重金属输入的影响,采用随机取样的方法在寿光市收集了10个氮磷钾三元复混肥和21个鸡粪肥样品,测定了肥料中重金属Cu、Zn、Cd、Pb的含量.结果表明:鸡粪肥中Cu、Zn、Cd、Pb含量高于氮磷钾三元复混肥,但与中国有机-无机复混肥标准(GB18877-2002)相比,鸡粪肥中Cd未超标... 相似文献
8.
详细研究了甜菜夜蛾[Spodoptera exigua(Huebner)]在胚胎发育中呼吸、消化、神经、生殖系统的发育过程及特点。呼吸系统由中、后胸及1～8腹节外胚层内陷而成，到发育后期，中胸气门移至前胸，后胸气门退化；前肠、后肠分别来自原口陷和原肛陷，前肠分化为食道、嗉囊和前胃，后肠分化为前后肠和直肠，中肠来自中肠前基和中肠后基两群内胚层细咆，6条马氏管的末端插入直肠后端的肠壁内形成“隐肾”；腹神经索呈梯状，口道神经系出现额神经节和嗉囊神经节两大细胞群；原始生殖细胞来自极细胞，分两团移至胚胎腹部侧背面，被中胚层细胞包裹，形成生殖脊。 相似文献
9.
绵羊实验性变异黄芪和黄花棘豆中毒的比较 总被引：1，自引：0，他引：1
利用饲喂试验比较了变异黄芪和黄花棘豆对绵羊的毒性作用.结果表明,变异黄芪和黄花棘豆的毒性作用极为相似.主要临床症状为沉郁、被毛粗乱、消瘦、体重减轻、僵硬,采食时头部水平震颤,神经机能紊乱及心律不齐.从试验的第18d开始,两组的循环淋巴细胞中出现胞浆空泡,血清碱性磷酸酶活性、谷草转氨酶活性及血清尿素氮含量均明显升高.各组的血糖、肌酐、血钙、血钾、总蛋白、谷丙转氨酶均无明显变化.2组E-玫瑰花环形成率均显着降低(P<0.05).2组的特征病理组织学变化均为神经细胞及实质细胞胞浆空泡化.电镜观察表明,空泡是由溶酶体样结构及线粒体肿胀所致.变异黄芪中毒和黄花棘豆中毒的症状、病理变化、临床病理学及细胞免疫功能变化的相似性充分说明,变异黄芪中毒亦可归属于疯草中毒. 相似文献
10.
Formation causes and recovery of the “Black Soil Type” degraded alpine grassland in Qinghai-Tibetan Plateau 总被引：1，自引：0，他引：1
The formation causes and ecological rebuilding of the “Black Soil Type” degraded alpine grassland are summarized. The formation
of the “Black Soil Type” degraded grassland was caused mainly by climate warming, decreasing glaciers, overgrazing, and damage
by rats. The ecological restoration of the “Black Soil Type” degraded alpine grassland relies not only on grassland building,
but also on reasonable management and planning of grassland resources. Guaranty measures for developing the alpine grassland
animal husbandry in a healthy way include intensifying the educational investment in pasture regions, practicing long-term
contracts for grassland, and strengthening the grassland legislation. The authors believe that the Qinghai-Tibetan Plateau
ecosystem has a special characteristic intertia or “inert gases”, which weaken the self-renewing capability of the ecosystem
and makes its structure frail. The inertia characteristic may be the important reason that makes ecological rebuilding so
difficult; in addition, other problems need to be studied deeply to provide scientific bases for the ecological building in
the Qinghai-Tibetan Plateau.
Translated from Chinese Journal of Ecology, 2005, 24(6): 652–656 [译自: 生态学杂志] 相似文献
11.
Jie Liu Xi Zhang Bharat Kumar Poudyal Yuxing Zhang Zhan Jiao Jing Qi 《Frontiers of Agriculture in China》2009,3(1):60-66
The pear (Pyrus spp.) is one of the most important temperate fruit crops. The technique of adventitious shoot regeneration from leaves is considered to be one of the shortcuts in the research on pear genetic modification and cellular engineering, which, however, has not been widely used. As the regeneration frequency of pear leaves is usually very low, the research on adventitious shoot regeneration from pear leaves is eagerly needed. In this experiment, the factors affecting shoot and bud regeneration from the leaves of ‘Zhongli 1’ pear were studied, and an efficient protocol for shoot regeneration was established. The results showed that different types of basic media, different combinations of plant growth regulators, leaf placement on medium, periods of dark culture and the use of silver nitrate (AgNO3) on culture media all significantly affected the adventitious shoot regeneration frequency of ‘Zhongli 1’ pear. The details are as follows: (1) Among three kinds of basic media, NN69 was better for ‘Zhongli 1’ shoot regeneration, followed by half (½) MS, while full MS had no effect on shoot regeneration; (2) Thidiazuron (TDZ) was better than 6-benzylaminopurine (6-BA) for ‘Zhongli 1’ regeneration, with an optimal concentration of 1.5 mg · L?1, and the regeneration rate under this concentration could reach 85%, with 2.72 buds per leaf. 0.5 mg · L?1 indole-3-butyric acid (IBA), which induced a higher regeneration frequency, was a better choice for pear regeneration compared with 0.3 mg · L?1 naphthaleneacetic acid (NAA). Among the different combinations of plant growth regulators, TDZ + IBA was better for inducing high regeneration frequency; (3) The abaxial surface of leaves touching the medium was beneficial for leaves to uptake nutrients from the medium, and because of that, the regeneration frequency of leaves was significantly higher than that of leaves touching the medium with their adaxial surfaces (obverse side of leaf); (4) Dark culture was necessary for bud regeneration, and the best duration for dark culture of ‘Zhongli 1’ pear was 21 days; (5) The addition of 1.0 mg · L?1 AgNO3 into the culture medium could promote adventitious shoot regeneration significantly. A high adventitious shoot regeneration frequency was obtained in this research, which will be beneficial for further research on efficient and stable in vitro plant regeneration systems and genetic modification of pear. 相似文献
12.
将D2类山羊草［粗厚山羊草(Ae.crassa)、牡山羊草(Ae.juvenalis)和瓦维洛夫山羊草(Ae.vavilovii)］细胞质普通小麦核代换系于1997～1998年分别种植在不同纬度的5个地点,并进行分期播种。从不同地点核代换系和核亲本的育性表现,分析D2类山羊草细胞质核代换系对日长、温度的敏感性及其差异。结果表明:（1）D2类山羊草细胞质小麦核代换系的3种类型存在差异,粗厚山羊草对日长、温度反应最为敏感,其次是瓦维洛夫山羊草,牡山羊草对光周期较钝感。（2）日长和温度两种生态因子对D2类山羊草细胞质核代换系的育性变异的作用程度不同,日长是主控因子,温度在日长因子相近时方显示其作用。（3）核质互作是D2类山羊草细胞质小麦核代换系育性对光温反应的遗传方式。 相似文献
13.
三株丝孢虫生真菌对松墨天牛幼虫的感染效应 总被引：4，自引：0，他引：4
生物测定了球孢白僵菌（Beauveria bassiana）Bb050715,Bb060721菌株和粉拟青霉（Paecilomyces farinasus）Pf0607菌株对松墨天牛（Monochamus alternatus Hope）的感染效应。结果表明,球孢白僵菌及粉拟青霉对松墨天牛幼虫的毒力有一定的差异,3株丝孢真菌侵染三龄幼虫后,均造成虫体血淋巴中蛋白质含量降低,且球孢白僵菌侵染后血淋巴中总蛋白含量明显低于经粉拟青霉接种处理感染后的虫体。供试3菌株中,球孢白僵菌菌株处理后天牛累积死亡率明显高于粉拟青霉菌株,对天牛幼虫感染的剂量效应参数分别为0.45,0.45和0.39,对松墨天牛三龄幼虫的毒力回归方程分别为Y=13.537X-4.6032(R2=0.97),Y=15.361X+0.444 4(R2=0.97)和Y=9.138X-3.100 1(R2=0.99)。在1.36×104～1.36×109孢子/mL下处理后第4d才出现死亡,Bb050715,Bb060721和粉拟青霉3菌株接种处理后第4～8d的累积死亡率分别为13.3%～80.0%,13.3%～86.7%,6.7%～53.3%,LT50依次为5.1,5.1和7.7d,第5 d的LC50分别为7.23×108孢子/mL,1.53×108孢子/mL,7.27×109孢子/mL。 相似文献
14.
黑嘴病及生殖对虾夷马粪海胆五种生理生化指标的影响 总被引：1，自引：1，他引：0
对虾夷马粪海胆(Strongylocentrotus intermedius) 患“黑嘴病”及生殖后体腔液中5种生理生化指标进行了检测,结果表明病理情况下的虾夷马粪海胆过氧化氢含量和丙二醛含量明显高于对照组,而过氧化氢酶活性、超氧化物歧化酶活性和总抗氧化能力明显低于对照组,其中,过氧化氢含量、总抗氧化能力和超氧化物歧化酶活性差异显著（P<0.05）,丙二醛含量、过氧化氢酶活性差异极显著（P<0.01）。生殖后除过氧化氢含量外其他4种生理生化指标均降低,其中总抗氧化能力和丙二醛含量差异显著（P<0.05）,过氧化氢酶和超氧化物歧化酶活性差异极显著（P<0.01）。研究表明以海胆体腔液中丙二醛含量和过氧化氢酶活性作为海胆黑嘴病发生的监测指标是可行的。 相似文献
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16.
Lihong Zhu 《Frontiers of Agriculture in China》2007,1(4):389-396
Views and comments concerning rice high-yielding breeding in China had been touched upon: (1) historical development of rice
breeding in China and its prominent contributions recounted; current challenges evolved from rapid population increase, erosion
of key natural resources and socioeconomic changes envisaged; (2) concept of extra or super high-yielding rice breeding and
related ideas embraced nowadays in the main rice-producing countries assessed; the conception of so-called superrice in China
could have been misled and misunderstood, and no substantial genetical differences could be affirmed yet between superrice
and modern high-yielding rice; (3) two strategical approaches of rice production and breeding in China would have been persistent
in the construction of most favorable-to-growth rice fields to plant rice varieties with high-yielding potentiality as well
as renovation and rejuvenation of less favorable rice fields to plant most adaptable-to-ecoenvironment varieties with promising
productivity; in addition, breeding for rice varieties compatible with the specific rice regions ridden by adverse ecoenvironments;
(4) overview of the relationship between the development of genetical researches and the perspective of rice breeding; integration
of the classical genetical principles and breeding methods and techniques wherefrom with molecular biotechniques underscored.
Finally, appeal to the breeders to adhere to due attentions to the development of genetics and promote pragmatism and traditional
ethic solemnly so as to live up to implementing the national rice breeding mandates.
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Translated from Journal of Nanjing Agricultural University, 2007, 30(1): 129–135 [译自: 南京农业大学学报] 相似文献
17.
球孢白僵菌对烟草甲幼虫的毒力测定 总被引：2，自引：0，他引：2
为筛选对烟草甲幼虫高毒力的生防真菌,生物测定了球孢白僵菌Beauveria bassiana菌株Bb050722在28℃,25℃,21℃,18℃下对烟草甲Lasioderma serricorne (Fabricius)二龄幼虫的毒力。结果表明,25℃下烟草甲二龄幼虫开始死亡时间较早,其中1.46×108,1.46×107,1.46×106孢子/mL处理后第9d,11d,12d死亡率达到100%。21℃时第4d出现死亡,但是死亡率上升缓慢,只有1.46×108孢子/mL处理在接种后第12d死亡率达100%,在28℃和18℃,烟草甲二龄幼虫分别在第6d和第4d开始死亡。用时间—剂量一死亡率模型处理数据得到:在1.46×108孢子/mL浓度处理下,18℃,21℃,25℃,28℃时球孢白僵菌对烟草甲二龄幼虫的LT50分别为6.3d,3.9d,3.6d,4.1d。结果表明菌株Bb050722对烟草甲防治有一定潜力。 相似文献
18.
基于海表温度和光合有效辐射的西北太平洋柔鱼冬春生群体栖息地热点预测 总被引：6，自引：4，他引：2
柔鱼是大洋洄游性头足类种类,具有重要的生态地位和经济价值,目前是日本、韩国和中国等国家在西北太平洋捕捞的主要对象。柔鱼属于短生命周期生物,其栖息地适宜性受气候和海洋环境变化的显著影响。本文根据中国远洋渔业数据中心提供的2006—2015年9—11月中国鱿钓捕捞数据和海表面温度(SST)以及光合有效辐射(PAR)两个关键环境因子,构建基于捕捞努力量和算术平均算法的柔鱼综合栖息地热点预测模型,并对比分析柔鱼栖息地适宜性在超强厄尔尼诺和强拉尼娜条件下的变动规律及其成因。结果表明:基于SST和PAR的栖息地模型能够有效地预测西北太平洋柔鱼栖息地热点海域;9—11月柔鱼各月适宜的SST和PAR范围具有显著月间变化且逐渐减小;柔鱼产量、捕捞努力量和单位捕捞努力量渔获量(CPUE)随栖息地指数值的增加呈现线性增加趋势。对比2007年强拉尼娜年份和2015年超强厄尔尼诺年份,研究发现,2007年柔鱼CPUE和栖息地适宜性显著高于2015年,其主要原因可能是2007年强拉尼娜现象导致柔鱼渔场内适宜的SST和PAR面积显著增加,而2015年超强厄尔尼诺现象导致两者适宜面积急剧下降,从而导致柔鱼栖息地适宜性变差,柔鱼CPUE降低。 相似文献
19.
采用Fre-Primont指数方法(FP指数),对1985—2013年我国28个省(市、区)的农业全要素生产率进行测算及分解。通过方差分解法从构成角度对农业全要素生产率地区差距及来源进行分析。结果表明:1)1985—2013年我国农业全要素生产率地区差距呈现扩大趋势,与农业技术进步及剩余混合效率的波动趋势相吻合;2)从省际差距看,剩余混合效率差距在整体地区差距中的贡献率逐渐降低,技术效率差距逐渐占主导地位,其中东部地区差距主要来源于农业技术进步和剩余混合效率,而中西部地区差距主要来源于技术效率和剩余混合效率;3)基于投入产出数据指标进行聚类分析,表明技术效率和剩余混合效率是我国农业全要素生产率地区差距的主要来源。 相似文献
20.
StKU80, a component in the NHEJ repair pathway,is involved in mycelial morphogenesis,conidiation, appressorium development,and oxidative stress reactions in Exserohilum turcicum 
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下载免费PDF全文 Xiao-dong GONG Yu-wei LIU Huan-huan BI Xiao-rong YANG Jian-min HAN Jin-gao DONG Shou-qin GU 《农业科学学报》2021,20(1):147-158
Homologous recombination(HR) and nonhomologous end joining(NHEJ) are considered the two main double-strand break(DSB) repair approaches in eukaryotes. Inhibiting the activities of the key component in NHEJ commonly enhances the efficiency of targeted gene knockouts or affects growth and development in higher eukaryotes. However, little is known about the roles of the NHEJ pathway in foliar pathogens. Here we identified a gene designated St KU80, which encodes a putative DNA end-binding protein homologous to yeast Ku80, in the foliar pathogen Exserohilum turcicum. Conserved domain analysis showed that the typical domains VWA, Ku78 and Ku-PK-bind are usually present in Ku70/80 proteins in eukaryotes and are also present in St Ku80. Phylogenetic analysis indicated that St Ku80 is most closely related to Ku80(XP_001802136.1) from Parastagonospora nodorum, followed by Ku80(AGF90044.1) from Monascus ruber. Furthermore, the gene knockout mutants ΔSt KU80-1 and ΔSt KU80-2 were obtained. These mutants displayed longer septas, thinner cell walls, smaller amounts of substances on cell wall surfaces, and more mitochondria per cell than the wild-type(WT) strain but similar HT-toxin activity. The mutants did not produce conidia and mature appressoria. On the other hand, the mutants were highly sensitive to H_2O_2, but not to ultraviolet radiation. In summary, the St KU80 plays devious roles in regulating the development of E. turcicum. 相似文献