High frequency embryogenic callus induction and plant regeneration from mature caryposis of big bluestem and little bluestem

Big bluestem (Andropogon gerardii Vitman) and little bluestem [Schizachyrium scoparium (Michaux) Nash.] are native to the North America and are important forage grasses and ornamental grasses. Both grasses are proposed as ideal biomass producers for cellulosic ethanol production. To apply genetic transformation, which is an important tool for incorporating desirable agronomic traits into plants to both species, however requires an efficient and reproducible regeneration protocol. We used mature caryopses from big and little bluestem as explants and tested the effect of various combinations of 2, 4-dichlorophenoxyacetic acid (2, 4-D) (1, 2, 3, 4 or 5 mg l⁻¹) and kinetin (KT) (0, 0.1 or 0.2 mg l⁻¹) on embryogenic callus induction with LS as the basal medium. The highest percentage of embryogenic calli induction occurred on medium containing 2, 4-D alone at 2 mg l⁻¹ for ‘Bison’ and on medium containing 4 mg l⁻¹ 2, 4-D alone for ‘Bonilla’ big bluestem. For little bluestem, the highest percentage of embryogenic callus induction occurred on medium containing 3 mg l⁻¹ 2, 4-D plus 0.1 mg l⁻¹ kinetin, suggesting that addition of KT is beneficial. Shoot regeneration took place on LS basal medium without any plant growth regulator for both species, although the addition of KT increased both regeneration frequency and the number of shoots produced per callus. Rooting of shoots reaching about 2 cm long occurred readily with or without α-naphthaleneacetic acid (NAA). Rooted plantlets were all successfully established in the soil.     

落叶松人工林地位指数级导向曲线模型的研究

本文用约1000块样地资抖,系统地研究了黑龙江省落叶松人工林的地位指数级导向曲线模型。通过林业统计分析软件Statistica6.0对各落叶松人工林数据进行拟合、分析比较,结果为：从拟合精度、曲线走向与散点分布趋势、残差分布等综合考虑,舒马切尔曲线函数比较适合落叶松人工林地位指数级导向曲线模型的拟合。     

Seroprevalence of porcine and human influenza A virus antibodies in pigs between 1986 and 1988 in Hassia

1,268 sera collected from slaughtered pigs in Hassia (FRG) from 1986 to 1988 were tested for antibodies against porcine and human influenza A virus strains using the single radial haemolysis test (SRHT). Antibodies against the porcine strains (subtype H1N1) A/Swine/Arnsberg/1/81, A/Swine/Iowa/15/30 and A/New Jersey/7/76 were detected in 411 (32.4%), 318 (25.1%) and 304 (24.0%) of sera, respectively. Up to 1988 a slight increase (10%) in the seroprevalence to A/Swine/Arnsberg/1/81 was noticed, whereas the results obtained with the other strains showed little variation. Antibodies against the human H1N1 strain A/Singapore/6/86 were only found in sera collected 1987 and 1988 in rates of 1.6% and 3.0%. Serological indication of infections with the human H3N2 strains A/Victoria/1/75, A/Hong Kong/1/68 and A/Philippines/2/82 could be shown in 286 (22.6%), 178 (14.4%) and 135 (10.6%) of the serum samples. Within the three year period the rate of sera positive for antibodies against A/Philippines/2/82 increased from 6.5% to 23.0%, whereas no variation in the rates were found using the other H3N2 strains. Antibodies simultaneously against porcine (H1N1) and human (H3N2) virus strains were detected in 9.9% of all sera tested.     

中国独占亚洲饲料市场鳌头

引言：中国饲料需求减缓．一方面源于三聚氰胺事件的影响，另一方面源于大多数国家遭受的经济危机所致。 中国的饲料产量在亚洲独占鳌头．但在2008年，中国饲料受三聚氰胺事件的影响非常大。在婴儿配方奶粉中检测出增加蛋白浓度的“三聚氰胺”而成为对饲料污染源追根究底的导火索．致使其乳业和蛋品业影响较大。     

加入欧盟后波兰饲料业发展回顾

肉价上涨、汇率良好、肉类消费和出口增长、配合饲料和畜禽生产投入不断增加、农业发生全新变化．这是中欧和东欧国家加入欧盟后出现的积极现象。总体来讲，处于该地区的波兰饲料添加剂工业仍处于发展阶段，潜力巨大。     

Veterinary Toxicovigilance: Objectives,Means and Organisation in France

Veterinary Research Communications -     

气候变化对通辽草甸草原草本植物物候期的影响

植物物候期的变化直接反映气候变化,并成为全球变化研究的重点。基于通辽市巴雅尔吐胡硕牧业气象试验站1981-2016年主要植物羊草(Leymus chinensis)、冰草(Agropyron cristatum)、委陵菜(Potentilla chinensis)、车前(Plantago asiatica)物候观测数据和同期气象观测数据,研究了气候变化对草本植物返青期、黄枯期和生长季的影响,结果表明:1)研究区近36年来年均气温上升0.35℃·10 a-1(P0.01),年均降水量减少22.73 mm·10 a-1,气候暖干化特征明显。2)草本植物返青期呈一致性延迟趋势,平均每10年延迟1.16~7.60 d。羊草、车前返青推迟主要受2-3月累计降水量减少的影响,冰草、委陵菜返青推迟主要受2-4月、3-4月累计降水量减少的影响。3)草本植物黄枯期变化趋势不同,羊草、冰草黄枯期延迟主要受夏季、初秋累计降水量影响,委陵菜黄枯期提前主要受夏季、初秋的累计降水量和日照时数共同影响,车前草黄枯期延迟主要受夏季、初秋平均气温影响。4)草本植物生长季长度主要受气温和降水量影响。气候变暖后,研究区夏季、生长季平均气温显著上升,降水量逐渐减少,导致羊草、冰草、委陵菜生长季缩短;而车前对气温反应比较敏感,气温升高有利于车前生长季延长。     

陕西省榆林市某鸡场家禽H7N9流感紧急流行病学调查

2017年5月21日,陕西省榆林市某养殖场的蛋鸡出现异常死亡。经国家参考实验室确诊,该起疫情为H7N9流感疫情。为找出引发疫情的可能原因,采用描述性流行病学方法,描述疫情的三间分布,分析发病的风险因素。调查结果显示:该场饲养规模较大,共有8栋鸡舍,饲养4.5万只蛋鸡;疫情暴发突然,病程仅为5 d;蛋鸡死亡2.2万只,死亡率为48.9%;疫情具有明显的场内传播规律,从靠近鸡场入口的鸡舍逐渐向内蔓延;产蛋高峰期蛋鸡的发病风险是雏鸡的37.458倍,差异显著(P0.05);所分离毒株的HA基因裂解位点有4个氨基酸插入,为变异株;该起疫情可能是通过运输淘汰蛋鸡的车辆、野鸟、饲料和饮水,以及调入雏鸡等途径引入的。疫情发生后,当地政府按照《高致病性禽流感防治技术规范》,发布了封锁令,划定了疫点、疫区和受威胁区;在疫区采取了扑杀、无害化处理、关闭疫区内所有禽类产品交易市场等控制措施。采取以上处置措施后,疫情得以快速有效控制。