不同脐橙品种离体茎段培养及茎尖微芽嫁接条件的优化

筛选‘赣南早’、‘纽荷尔’和‘晚棱’脐橙品种离体茎段培养及微芽嫁接优化条件,为柑橘无病化苗木繁育提供技术支撑。对不同季节‘赣南早’、‘纽荷尔’和‘晚棱’脐橙品种离体茎段进行不同浓度NaClO、H2O2和HgCl2消毒,筛选脐橙离体茎段最佳采集季节及最适消毒方式,开展诱导不定芽及不同季节田间茎尖微芽嫁接优化条件研究。‘赣南早’、‘纽荷尔’和‘晚棱’脐橙茎段最佳消毒方式是75% C2H6O消毒30 s后1% HgCl2消毒6 min,污染率低至30%、18.33%和15%;‘赣南早’和‘纽荷尔’脐橙茎段最适采集季节为夏季,‘晚棱’脐橙茎段最适采集季节为秋季。‘赣南早’、‘纽荷尔’和‘晚棱’脐橙茎段诱导的不定芽其微芽嫁接萌发率显著高于田间芽嫁接苗萌发率,最高为46.67%、41.67%、38.33%。以诱导不定芽为接穗进行微芽嫁接可提高嫁接苗萌发率,同时解决田间因季节无芽、少芽的问题。     

牙买加:茎尖嫁接控制柑桔黄龙病

由于柑桔黄龙病开始入侵牙买加柑桔园,牙买加农业部正积极采取措施控制柑桔黄龙病。农业部宣布,将在联合国粮农组织(FAO)的技术合作项目的帮助下,提供茎尖嫁接技术培训,由来自古巴的技术顾问提供技术支持。茎尖嫁接技术是一项在实验室进行的技术操作方法,已被证明是获得无病毒柑桔苗木的重要方法。研究人员将对当地7个地方品种进行茎尖嫁接,如果成功,这些将作为母本树向当地的柑桔产业提供接穗。与此同时,业界还对保护栽培的植物进行检测,以确保无病毒,     

桑树茎尖嫁接技术研究

在无菌条件下将桑籽接种至含ＭＳ无机盐与０．２％凝胶剂（Ｇｅｌｒｉｔｅ）的培养基上，于２６℃每日１６ｈ、１０００１ｘ照明下培养；２周后以激素处理茎切段，转培于蛭石培养基，１０～１２ｄ苗茎围度达８ｍｍ时，以长２ｃｍ的切段为砧木，以７０７等桑品种的１～２ｍｍ茎尖作接穗，嫁接成活率达７５％～８０％。增大砧木苗基的围度是取得桑树茎尖嫁接成功的关键。     

桑枝条双面削嫁接桑树的关键技术研究

对桑枝条双面削嫁接技术接稳的不同捆扎方式、不同插入方式、不同成熟度接穗的桑枝条嫁接桑树的成活率及生长势进行了调查.结果表明：桑枝条双面削嫁接时,桑芽上部枝条顶端捆扎的嫁接成活率达95％以上,不捆扎的嫁接成活率降低10％以上.接穗芽的鳞片颜色50％达到接穗品种固有色、髓部明显、枝（芽）没有损伤及没有病虫害的枝条作为接穗,嫁接成活率达100％;如接穗芽完全未变色、芽的鳞片颜色全为绿色时,嫁接成活率仅有35.63％.桑枝条单面削嫁接,如接穗插入方法不当,嫁接成活率降低30％,即使嫁接成活生长势也弱.综合不同试验、不同处理方式比较结果认为：选择适熟接穗,采用桑枝条双面削嫁接,接穗保存适当水分,接穗宽斜削面正对袋口皮层,保持削面平整、清洁,嫁接捆扎严实,在芽基部的叶痕下捆扎薄膜,芽体及叶痕露出,嫁接成活率可达95％以上.     

单芽腹接在板栗高接换种上的应用

在有些地区,推广的板栗高接换种嫁接技术为插皮枝接。这种嫁接方法的优点是砧穗接合部愈合快、包合完整,接穗留两个芽以上,成冠快。但是存在着接穗用量大,嫁接时间短,嫁接速度慢,捆绑费工等缺点。笔者从1994年开始使用单芽腹接法在闽西地区的新罗、上杭、长汀、连城及宁化等地高接2～10年生的实生板栗树6万多株,200多hm~2,每株接3～12个芽。 采用此法高接换种有如下优点:接穗贮藏方法简单,只需用地膜捆扎包装,不需封蜡;接穗用量少,一个接口只需一个芽;嫁接速度快,接穗的削取一气呵成,绑扎时只需用薄膜带封紧接穗即可;扶绑容易、省工,扶绑时可将接口上10cm左右的残桩作支柱,不必重新立支架;成活率高,嫁接部位在截口处     

桑树冬季芽穗双面削嫁接技术试验与应用

为找到一种嫁接速度快、成活率高、成本低、适合川渝地区在冬季农闲时进行大规模良桑改造的嫁接技术和方法,进行了冬季芽穗双面削嫁接技术与冬季简易芽接技术的对比试验。试验结果显示,冬季芽穗双面削嫁接技术操作简单,易学易做,接穗成活率在95%以上,比冬季简易芽接技术的效率提高1倍以上,接穗成活率提高25个百分点,嫁接成本减少三分之二,达到了提高接穗成活率和工作效率,降低技术难度和嫁接成本的技术和经济目的。冬季芽穗双面削嫁接技术是适合于川渝地区冬季桑树嫁接改良的快速、高效、低成本的新方法。     

板栗多芽枝接效果好

板栗多芽枝接 ,实际就是整穗全芽嫁接。在接穗充足 ,嫁接量不太大的情况下 ,不论是高接换种还是就地嫁接成园 ,采用此法均能取得良好效果。一是成活率高 ,平均达 97%以上。二是多芽同时萌发 ,成枝多 ,一般抽生 3～ 5个壮枝 ,有利于树形培养。三是接穗生长快 ,生长量大 ,有利于切口愈合。据观察 ,截面直径 5～ 6ｃｍ的砧木接两根接穗 ,接后80天左右可形成完全愈伤组织 ,将砧穗融为一体。四是抗风折能力强。因接穗是头年发育枝 ,木质化程度高 ,所以抗风折能力远远高于芽接未木质化新梢。五是便于防风支撑。木质化接穗长 ,方便绑缚防风支架。1…     

枇杷切接技术

我们在多年的实践中发现 ,枇杷接穗湿软 ,水分多 ,不利于萌芽 ,影响嫁接成活。但如果接穗适当失水 ,受到一定的水分胁迫 ,可明显减缓树体生长和芽的萌发 ,促进砧木与接穗的愈合 ,提高嫁接成活率。一旦愈合 ,芽便以一种短期的、超常速度的生长 ,使总生长量不受影响。由此 ,我们逐渐摸索出一套高嫁接成活率的嫁接技术。1　嫁接时间一般在春、秋两季。春季最好在梅雨过后 ,此时温暖无雨 ,是嫁接良机。嫁接过早恰逢梅雨 ,土壤潮湿 ,影响成活率。秋季嫁接最好在连绵阴雨来临前半个月完成 ,此时秋高气爽 ,易成活。也可在冬季嫁接 ,一般在“冬至”…     

果桑"大十"的芽接技术

由于果桑“大十”品种冬季休眠期短,脱苞期早(一般桑品种在早春气温上升到12℃以上时冬芽膨大萌发,而果桑“大十”在5℃以上都可以生长活动)故果桑的袋接法、硬枝扦插和条枝扦插的成活率都不高,在生产上缺少推广价值;另外,由于果桑的休眠期短,果桑接穗要提早剪取,接穗与插条需贮藏二个多月,因贮藏接穗条件的限制,往往造成接穗发芽和烂芽,影响嫁接成活率。因此,为了提高果桑嫁接的成活率,对果桑“大十”进行夏季芽接试验。     

银杏实生树嫁接技术

1998年10月上旬采取以下方法,对1100株3年生实生银杏树进行嫁接,成活率达95％。l嫁接部位嫁接高度在5（）左右,每株选2－3个方位,嫁接2－3个芽,每芽间距10－15cm。2嫁接技术接穗来自力一功年生丰产、稳产,核大优质的良种株,取树冠顶部、中上部芽眼饱满、具有效芽6－8个、径粗约0．6cm的充实枝条。接或剪下后去叶,用湿毛巾包好,置前处备用。采用芽片胶接法,削芽时左手拿接穗,基部向外,芽眼向里,在芽眼下方Icm处下刀,刀口向内与接穗呈45”,然后在芽眼上方0．5～1cm处刀口向外与接穗呈领”切一刀深达木质部,削好后平放于湿毛…     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein