添加绿汁发酵液和四蚁酸铵对饲用甜高粱青贮品质的影响

 为探讨绿汁发酵液、四蚁酸铵及绿汁发酵液+四蚁酸铵对“大力士”饲用甜高粱青贮品质的影响,以“大力士”饲用甜高粱全株为青贮原料,设对照、绿汁发酵液、四蚁酸铵和绿汁发酵液+四蚁酸铵4个处理,常温下贮存60 d后取样,测定其发酵品质与化学成分。结果显示：添加绿汁发酵液、四蚁酸铵及绿汁发酵液+四蚁酸铵,均可显著降低“大力士”饲用甜高粱青贮饲料的pH和气体损失率（P＜0.05）,提高干物质回收率、粗蛋白和水溶性碳水化合物含量（P＜0.05）。表明添加绿汁发酵液、四蚁酸铵及绿汁发酵液+四蚁酸铵均可显著改善“大力士”饲用甜高粱的青贮品质。     

苎麻高效脱胶菌T85-260纯培养过程中的胞外酶系研究

本研究采用SDS-PAGE法,系统研究了苎麻脱胶高效菌株T85-260纯培养过程中的胞外酶系,初步得出如下结论能在不同的培养基中组成型产生41种胞外蛋白(含胞外酶或亚基),分子量为10.0KD-120.0KD;可能能分泌分子量分别为60.3KD、49.5KD、33.5KD、29.5KD的4种甘露聚糖酶,分子量为28.6KD的果胶酶,较高浓度的镁离子有利于果胶酶的产生,分子量分别为72.9KD、35.5KD、31.6KD、19.9KD的4种蛋白酶;T85-260嗜好甘露糖.上述酶类需要在苎麻脱胶过程中作进一步的研究.     

月季切花乙烯受体ETR1 cDNA克隆及其序列分析*

 根据乙烯受体基因ETR1 保守区设计引物, 分别以瓶插寿命差异显著的月季切花品种‘德克萨斯’和‘维亚蒂’为材料, 通过RT-PCR 从花瓣中扩增出了797 bp 的cDNA 片段, 它编码265 个氨基酸。测序和序列分析表明,‘德克萨斯’重组质粒中插入片段的核苷酸序列之间完全相同, 命名为pRT-ETR1。而‘维亚蒂’所获得的重组质粒中插入片段的核苷酸和氨基酸序列之间存在差异, 同源性分别为85. 2 %和92. 1 % , 分别命名为pRV-ETR1-V4 和pRV-ETR1-V5。pRV2 ETR12V5 的核苷酸和氨基酸序列与‘德克萨斯’pRT2 ETR1 的同源性均达99 %以上; pRV-ETR1-V4 中的核苷酸和氨基酸序列与‘德克萨斯’pRT-ETR1 的同源性分别为85. 0 %和92. 5 %。上述插入片段与桃、苹果、天竺葵、拟南芥等植物的ETR1相应区域高度同源, 其氨基酸同源性均大于90 %。     

群牛暴发牛泰勒虫病的诊治

牛泰勒虫病在南方地区较为罕见。2001年7月，湖南省衡阳县樟树乡某村牛场所养的93头牛暴发牛泰勒虫病，经笔者诊治及时控制了疫情，现报告如下：     

天农肥育牛用添加剂饲喂肉牛试验

选择年龄２～３岁，体重３００～４００千克的夏洛来杂公牛，西门塔尔杂交牛及黑白花公牛等品种牛共２０头，用天津农学院研制的“天农肥育牛用添加剂”进行了肥育试验，结果表明：试验组牛平均日增重１．２８２千克，对照组牛为１．０１２千克，试验组比对照组牛平均头日增重多０．２７千克，经ｔ经验两组牛日增重差异显著（Ｐ〈０．０５），经济收益比对照组头日净协１．９３元。     

Establishment and production of common sainfoin (Onobrychis viciifolia Scop.) in the UK. 2. Effects of direct sowing and undersowing in spring barley on sainfoin and sainfoin-grass mixtures

The dry matter (DM) yield and herbage quality of swards of sainfoin ( Onobrychis viciifolia ), meadow fescue ( Festuca pratensis ,) and tetraploid perennial ryegrass ( Lolium perenne ) grown in monocultures and in four sainfoin:grass mixtures (0·33 sainfoin:0·66 meadow fescue, 0·66 sainfoin:0·33 meadow fescue, 0·33 sainfoin:0·66 perennial ryegrass and 0·66 sainfoin:0·33 perennial ryegrass), established by direct sowing or undersowing in spring barley, were investigated over 3 years in a field experiment in the UK. Direct sowing produced a mean yield across all species and mixtures of 1·8 t DM ha⁻¹ in the establishment year, whereas undersowing produced no measurable yield except for that of the spring barley. Undersowing reduced the yields of sainfoin and sainfoin-grass mixtures in the first full-harvest year but not in the second. The annual yield of a monoculture of sainfoin was 7·53 t DM ha⁻¹ and that of sainfoin-grass mixtures was 8·33 t DM ha⁻¹ averaged over 3 years. Both sainfoin and the sainfoin-grass mixtures had higher annual DM yields than the grass monocultures. The mixture of 0·66 sainfoin:0·33 meadow fescue gave the highest mean annual yield (9·07 t DM ha⁻¹) over the 3 years. There was a higher proportion of sainfoin maintained in mixtures with perennial ryegrass than with meadow fescue. The proportion of sainfoin in sainfoin–meadow fescue mixtures declined from 0·62 in the first year to 0·32 in the third year, whereas the proportion in sainfoin–perennial ryegrass increased from 0·48 in the first year to 0·67 in the second year and remained stable in the third year.     

70%噻虫嗪种子处理可分散粉剂和10%吡虫啉可湿性粉剂拌种对马铃薯甲虫的防效

利用药剂拌种处理马铃薯种薯后播种的方法,研究比较了2种新烟碱类杀虫剂对马铃薯甲虫的活性和防治效果。结果表明,按药剂有效成分18 g/100 kg种薯拌种,70%噻虫嗪种子处理可分散粉剂拌种出苗后60 d对马铃薯甲虫幼虫的生物活性和防效较高,卵块孵化率较低,死亡率在61.1%以上,防效达57.3%,孵化率为36%,这有利于降低马铃薯甲虫种群数量,减轻为害。而10%吡虫啉可湿性粉剂拌种出苗后60d对马铃薯甲虫幼虫生物活性和防效较低,卵块孵化率较高,死亡率在12.5%以下,防效为37.1%,孵化率为64.6%,对马铃薯甲虫的控制效果较差。     

异色瓢虫对菜缢管蚜、禾谷缢管蚜和白杨毛蚜捕食的作用

异色瓢虫是一种重要的捕食性天敌,可捕食多种蚜虫,在生物防治中具有很大应用前景。研究了异色瓢虫对3种蚜虫(即菜缢管蚜、禾谷缢管蚜和白杨毛蚜)的捕食功能反应。结果表明:异色瓢虫对3种蚜虫的日捕食量中,其中四龄幼虫最大,成虫和三龄幼虫次之,1、2龄幼虫最小。捕食者对猎物的功能反应均属于Holling-Ⅱ型方程。     

多污染源混合废水对鱼类呼吸的影响

鸭绿江发源于长白山天池,流长795公里,经丹东一新义州入黄海,是中朝两国的界河。丹东市区段的鸭绿江,近年由于工业的迅猛发展而带来了江水的严重污染,致使鱼类大幅度减产。 水工作的目的是探索鸭绿江下游鱼类种群、数量变动的主要原因,为恢复鸭绿江下游渔业生产提供     

Effect of mSOF and G1.1/G2.2 Media on the Developmental Competence of SCNT‐Derived Bovine Embryos

The objective of this study was to compare the effect of two culture media: modified synthetic oviductal fluid (mSOF) and G1.2/G2.2, on the developmental competence of bovine somatic cell–cloned embryos. Cloned embryos were produced by transferring adult skin fibroblasts into enucleated MII oocytes. After activation, the reconstructed embryos were randomly allotted to either mSOF or G1.2/G2.2 for culture (the embryos were transferred from G1.2 to G2.2 on days 3 of culture). The development competence of cloned embryos in these two culture systems was compared in terms of cleavage rate, blastocyst formation rate and apoptosis cell number in day 7 blastocyts. To investigate the in vivo developmental competence of cloned embryos in the two culture systems, a total of 87 and 104 blastocysts derived from mSOF and G1.2/G2.2 medium groups were transferred individually to recipient Angus cows, respectively. No differences were observed in terms of cleavage rate, day 7 blastocyst rate and blastocyst cell number between these two culture systems. However, the day 6 blastocyst formation rate was significantly higher in G1.2/G2.2 than that in mSOF. In addition, blastocysts cultured in mSOF have a higher percentage of apoptotic blastomeres compared to those in G1.2/G2.2 (8.5 ± 1.2 vs 16.8 ± 1.5, p < 0.05). Although difference in pregnancy rate was not observed 40 days after embryo transfer, significantly higher pregnancy rate was observed in G1.2/G2.2 group after 90 days of embryo transfer (12.4% vs 37.5%, p < 0.05). Moreover, calving rate was significantly improved in G1.2/G2.2 group compared to mSOF group (27.9% vs 6.7%, p < 0.05). In conclusion, our results indicate that G1.2/G2.2 can improve developmental competence of bovine SCNT embryos both in vitro and in vivo, which is more suitable for culture of bovine SCNT embryos than mSOF medium.