野生草地早熟禾引种驯化抗锈病能力初探

试验对引种驯化的野生草地早熟禾在田间自然感病的抗锈病能力做了初步研究,同时探讨了发病和恢复的时间进程与日温湿指数(TRH)相关性.以期为草坪管理提供理论依据,为野生种质资源评价、开发和新品种选育改良奠定基础.结果表明:发病率、严重度和反应指数在不同材料间存在巨大差异,3个参数变异范围分别为29%～97%、1.61～53.00、2.60～3.90,变异系数分别为37.48%、73.51%和24.51%.根据发病率、严重度、严重度级别、反应指数将供试材料聚为高度感病,中度感病和中度抗病型3类,可知大部分供试草地早熟禾都易感染锈病,感病型材料占66%左右,但亦有33%左右的材料中度抗病,为抗病品种的选育提供资源基础.     

季节和胎次对白牦牛乳中酶活性的影响研究

利用吸光光度法测定了不同季节和胎次的天祝白牦牛乳中酶的活性.结果表明：在5月份,碱性磷酸酶（AKP）和乳酸脱氢酶（LDH）活性显著低于1月份和8月份,酸性磷酸酶（ACP）和黄嘌呤氧化酶（XOD）活性在1月份、5月份和8月份之间不具有差异显著性（P＞0.05）.AKP在第一胎活性最大,第二、三、四和五胎均显著低于第一胎,但此几胎间差异不显著（P＞0.05）;前三胎LDH活力较强,显著高于第四、五胎（P＜0.05）;ACP和XOD不因胎次发生显著变化.说明季节所导致的牧草营养状况与AKP和LDH活性成正相关,但不影响ACP和XOD的活性;AKP第一胎活力最大,之后较平稳,LDH的活性前三胎较强,之后显著下降,胎次的变化不影响体内ACP和XOD的活性,可能是由于ACP和XOD在体内较稳定.     

牛毛色基因的研究进展

综述了近年来国内外牛毛色基因的研究进展,重点介绍了MC1R、agouti基因和牛毛色的相关性研究进展,并简述了黑色素的形成和调控机制,最后对牛毛色形成的调控机制提出了一假设模型.     

笼养绿孔雀繁殖期行为观察

采用扫描取样法对秦皇岛野生动物园40只笼养绿孔雀繁殖期的行为进行了为期58d,325h的观察,结果显示繁殖期各行为所占的比例分别为休息31.31%、取食22.03%、理羽16.37%、游走15.93%、警戒9.79%和繁殖4.59%。方差分析和μ检验表明：天气状况对笼养绿孔雀的休息、取食、理羽和游走行为的时间分配的影响明显,但对繁殖和警戒行为影响不大。     

世界枣业概况及西南枣业发展前景

枣是我国特有果树。枣果风味独特，营养价值又高，用途也广，既可鲜食，又可深加工成多种产品，干制后久贮不腐，耐贮运性强，是传统的重要滋补保健品和中药材。枣树抗旱耐瘠，适应性广，容易栽培，耐粗放管理，投产快，丰产稳产，结果年限长，且是很好的密源水果树，鲜枣经济效益特高。枣树根系发达，是退耕还林、防治水土流失、保持生态平衡、适合山区丘陵发展的理想的经济林。     

番木瓜体胚发生及植株再生研究

研究了外植体类型及培养基的不同激素配比等因素对番木瓜愈伤组织诱导和体胚发生的影响。结果表明,番木瓜的子叶和幼胚两种不同的外植体均能诱导愈伤组织、体胚发生和实现植株再生,但在愈伤组织诱导上存在差异,在MS+2,4-D1.00mg/L+BA0.30mg/L+NAA0.05mg/L培养基上诱导的愈伤组织较好。添加一定浓度的硫酸腺嘌呤(ADS)、水解酪蛋白(CH)可以促进番木瓜体胚发生,在生根培养基上生根后,可移栽成活。     

产气荚膜梭菌α毒素基因工程菌表达产物的免疫原性研究

已构建的能表达产气荚膜梭菌α毒素保护性抗原基因工程菌株Ｅ．ｃｏｌｉＢＬ２１（ＤＥ３）（ｐＸＥＴＡ１）经动物试验证实没有毒性。从ＩＰＴＧ诱导后的工程菌中提取包涵体,再辅以氢氧化铝胶制成抗原,免疫小鼠３０ｄ后,用产气荚膜梭菌强毒株培养上清及培养菌体攻击,结果免疫鼠能抵抗至少２ＬＤ１００的攻击,证明Ｅ．ｃｏｌｉＢＬ２１（ＤＥ３）（ｐＸＥＴＡ１）工程菌株表达产物具有良好的免疫原性。     

The Techniques of Grafted Seedlings in the Thin Shelled Walnut in Akesu District

新疆阿克苏地区薄皮核桃嫁接苗培育技术,分别从采穗圃的建立、芽接砧木选择及处理、嫁接方法及时期和嫁接苗管理等方面提出技术方法.     

Effects of grazing on soil physical properties and soil erodibility in semiarid grassland of the Northern Loess Plateau (China)

Grazing animals provide a livelihood for farmers, but they may also produce adverse environmental effects. We investigated whether grazing leads to deterioration of soil physical properties that subsequently increases topsoil erodibility. We sampled three sites (an ungrazed grassland, a continuously grazed grassland, and a track trampled by stock) on the northern Loess Plateau of China. The bulk density, water content, proportion of stable aggregates, infiltration rate, and resistance to scouring were determined for each soil sample. The results showed that the track had the highest soil bulk density and the lowest soil water content, proportion of stable aggregates, infiltration rate, and ability to resist scouring. The ungrazed plots had the best results for these parameters, in terms of reduced erosion. Soil bulk density and the proportion of stable aggregates differed significantly with depth beneath the track. However, the effect of depth on water content, infiltration rate, and the soil resistance to scouring was not significant at any sampling site. The ability of the soil to resist scouring was negatively correlated with the soil's bulk density and positively correlated with the soil's water content, infiltration rate, and proportion of stable aggregates. Thus, soil physical properties played an important role in determining soil erodibility. Grazing and trampling by livestock therefore appear to cause deterioration of soil physical properties and to increase soil erodibility.