乌骨绵羊和黑色素的研究进展

黑色素在生物体内起着重要的作用,本文从黑色素的分类、生物合成机制、分析方法、结构、理化性质和功能、分布、沉积等方面进行了阐述,并对新近在云南发现的乌骨绵羊乌质性状形成相关的黑色素的生成的基因进行了描述。     

茶多酚对朗德鹅产肝性能和血清脂类成分的影响

采用单因素试验设计方案。将14周龄、体重相近的健康公朗德鹅150只随机分成5组,每组30只,每只一个重复。对照组饲喂基础日粮,试验组在基础日粮基础上分别添加40、80、160、320mg/kg茶多酚,以研究茶多酚对朗德鹅产肝性能和血清脂类成分的影响。试验结果表明,1)160mg/kg添加组肥肝重、肝屠比,与对照组和320mg/kg添加组均差异显著(P<0.05),肝体比与对照组和320mg/kg添加组差异均显著(P<0.01)。2)320mg/kg添加组血清甘油三酯含量(TG)与对照组和其他试验组差异均显著(P<0.05);320mg/kg添加组血清总胆固醇含量(TC)与对照组差异均显著(P<0.05),与其他试验组差异不显著(P>0.05);高密度脂蛋白胆固醇(HDL-C)和低密度脂蛋白胆固醇(LDL-C)各组差异均不显著(P>0.05)。试验结论:在玉米型日粮添加40￣160mg/kg均能提高朗德鹅产肝性能,添加160mg/kg茶多酚朗德鹅产肝性能最佳,添加320mg/kg茶多酚能显著降低血清TG和TC含量。     

Reclassification of an isolate of Guignardia citricarpa from New Zealand as Guignardia mangiferae by sequence analysis

Citrus black spot was recorded as present in New Zealand in international databases on the basis of one isolate (ICMP 8336) identified by morphological features as Guignardia citricarpa . This isolate was from a soft rot, not a typical symptom of citrus black spot, on a Seminole tangerine fruit grown in the northern region of New Zealand. Sequence analysis of the internal transcribed spacer (ITS) region (ITS1, 5·8S and ITS2) showed that this isolate was 99% identical to the ITS region of G. mangiferae , a closely related saprotroph. Despite climatic conditions being suitable for this disease, citrus black spot symptoms have never been seen on citrus fruits grown in New Zealand. Thus the absence of symptoms on citrus in New Zealand is probably because G. citricarpa is not present. On the basis of these results, the record of citrus black spot occurring in New Zealand should be re-examined.     

Potential Inoculum Sources of Phaeomoniella chlamydospora in South African Grapevine Nurseries

Petri disease of grapevine is primarily caused by Phaeomoniella chlamydospora. This pathogen affects mostly young grapevines, but is also implicated in esca disease of older grapevines. Little is known about the disease cycle of this fungus. Infected propagation material was identified as a major means of dissemination of the pathogen. Recently, the pathogen was also detected from soil in South Africa and airborne conidia have been found in vineyards. The aim of this study was to use a molecular detection technique to test different samples collected from nurseries in South Africa at different nursery stages for the presence of P. chlamydospora. A one-tube nested-PCR technique was optimised for detecting P. chlamydospora in DNA extracted from soil, water, callusing medium and grapevine wood. The one-tube nested-PCR was sensitive enough to detect as little as 1 fg of P. chlamydospora genomic DNA from water and 10 fg from wood, callusing medium and soil. PCR analyses of the different nursery samples revealed the presence of several putative 360 bp P. chlamydospora specific bands. Subsequent sequence analyses and/or restriction enzyme digestions of all 360 bp PCR bands confirmed that all bands were P. chlamydospora specific, except for five bands obtained from callusing media and one from water. Phaeomoniella chlamydospora was positively detected in 25% of rootstock cane sections collected from mother blocks, 42% of rootstock cuttings and 16% of scion cuttings collected during grafting, 40% of water samples collected after pre-storage hydration, 67% of water samples collected during grafting, 8% of callusing medium samples and 17% of soil samples collected from mother blocks. These media can therefore be considered as possible inoculum sources of the pathogen during the nursery stages.     

不同营养水平补饲对湘东黑山羊肥育羔羊生产性能的影响

采用80只3~4月龄的湘东黑山羊羔羊,研究3种不同营养水平补饲对肥育羔羊日增重、经济效益的影响。分别在冬、春两个季节进行为期2个月的补饲。试验按完全随机单因子设计,每个季节设4个处理,即3个精料补饲组与1个对照组,每个处理10头湘东黑山羊。参考NRC(1981)的山羊饲养标准设计补充饲料配方,每个季节的3个补饲试验组饲粮的精粗比分别按30∶70、40∶60、50∶50确定,平均补饲量依次按100、200、300g/(d.只)。结果表明冬季补饲试验1、2、3组平均日增重分别为62.75、80.00和85.92g,分别比对照组提高42.06%、81.12%、94.52%,差异显著(P<0.05)或极显著(P<0.01)。春季补饲试验1、2、3组平均日增重分别为85.33、93.50和100.83g,分别比对照组提高38.00%、51.22%、63.08%,差异均为极显著(P<0.01)。从季节对补饲效果来看,冬季的高精料补饲与低精料补饲(精粗比=30∶70)差异显著;春季的精料补饲量对增重影响不大。冬季补饲以精粗料比40∶60为好,春季以30∶70为好。冬季补饲使试验1、2、3组比对照组增加利润分别为5.14、9.23、4.49元/只;春季补饲使试验1、2、3组比对照组增加利润分别为8.97、5.98、2.35元/只。经济效益比较好的补饲量是,冬季187.5g/d,春季154.1g/d。     

茶树新品系福选9号的观察研究

为观察鉴定茶树新品系福选9号在重庆市巴南区的适应性及表现,以福鼎大白茶为对照品种,于2002-2004年进行了品比试验。结果表明,福选9号表现出如下特性:(1)春芽萌动特早,较对照提早11～13d,春茶产量较高。(2)育芽能力强,生长势旺盛,秋梢休止期较对照晚5～7d,全年生育期较对照长16～20d,平均单产高20.5%。(3)抗逆性强,耐寒性和抗旱性与对照相当,抗病虫性稍强。(4)发芽整齐度高,适宜机械化作业。(5)制绿茶品质优良,适制性强。     

美国白蛾生物学上的几个重要特性

本文对青岛市美国白蛾Hyphandria cunez种群的几个重要生物学特性进行了调查，获得了如下有意义的结果。（1）在生态光周期范围内，该虫显示了一个典型的长日照型昆虫，临界日长为14h 30min。然而在全光条件下，有41.2％的个体滞育；在全暗条件下则有83．7％的个体发育。（2）第1代蛹在自然条件下羽化的结果表明，部分个体的蛹期显著延长，呈现了夏季滞育。（3）滞育蛹置于25℃，LD16：8下滞育能够解除，但死亡率极高。（4）雄虫前翅黑斑的出现是由光周期控制的，只有在短日照下诱导的滞育蛹，滞育解除后羽化出来的雄虫才会出现黑斑。     

进境美国苹果果实中黑斑病病原的初步鉴定

从美国进境苹果中截获的链格孢Alternaria sp．，经分离纯化后，得到菌株（MP1），通过观察其产孢表型、孢子的形态特征以及接种试验后的病果症状，初步确定为苹果黑斑病菌Alternaria mali Roberts。     

北方紫竹盆景制作技术

综述了紫竹的地域分布、生态习性、现赏价值,重点从母竹的选择和挖掘方法、上盆技术、盆景的养护管理措施等3个方面研究总结了紫竹盆景制作的关键技术,比较分析了紫竹盆景最适宜的租摆场所和所表达的意境.     

"黑土型"退化草地人工植被施肥试验研究

采用四因素二次通用回归旋转设计,以产草量为标准对“黑土型”退化草地上人工植被的施肥时间和氮磷钾的用量进行2年定位试验,建立牧草产量函数模型。结果表明,单因素增产效应为施肥当年:氮肥>磷肥>钾肥>施肥时间;第2年:氮肥>磷肥>施肥时间>钾肥。确定“黑土型”退化草地上人工植被的施肥组合方案为施肥时间在分蘖~7月上旬、N:75~130 kg/hm2、P2O5:50.0~112.5 kg/hm2、少施或不施钾肥,可取得较高的产量和经济效益。同时,为获得较高牧草产量,以每2年施肥1次为好。