南疆灌区冬小麦/夏玉米改良模式增产潜力与机理分析     

章建新  赵明  图尔贡  卡地尔亚 《干旱地区农业研究》2013,31(6):15-21

田间试验系统地比较了新冬20/沈玉2002不同套种模式（“522模式”与“952模式”）及“521模式”下保麦10号/蠡玉35、保麦10号/登海3672、新冬20/蠡玉35的产量、叶面积指数、光合势及干物质积累等性状的差异。结果表明,“522模式”新冬20/沈玉2002周年产量（17 838.2 kg·hm^-2）较“952模式”(16 550.9 kg·hm^-2)增产7.8%,其中,冬小麦增产18.4%。“521模式”保麦10号/蠡玉35、保麦10号/登海3672、新冬20/蠡玉35周年产量为19 905.0～20 751.0 kg·hm^-2,其中,冬小麦产量为9 740～10 275 kg·hm^-2、夏玉米产量为9 630～10 211.0 kg·hm^-2;冬小麦孕穗期和开花期叶面积指数分别为6.0、5.0左右,返青至成熟的总光合势290.2～324.3×10⁴·m²·d·hm^-2;夏玉米生育期111 d,大喇叭口期至吐丝后20 d的叶面积指数均保持在4左右,生育期间总光合势233.1～257.5×10⁴·m²·d·hm^-2,冬小麦和玉米总光合势为523.3～581.8×10⁴·m²·d·hm^-2;总干物质量38 569.1～40 487.0 kg·hm^-2;冬小麦产量的边际效应为85.7%～112.9%。“521模式”比“952模式”大幅度增产,是小麦行数和边行数及边际产量增大的结果,并将夏玉米播期提至麦收前15 d左右,延长玉米生育期（达110 d左右）,优化株行配置使玉米增产显著,实现全年超高产。“521模式”同时充分利用了冬小麦边际补偿效应和玉米时间补偿效应,较“952模式”易获得周年超高产。并对超高产栽培技术进行了讨论。  相似文献   

Preliminary Studies on Cryopreservation of Common Tench (Tinca tinca) Embryos (Work in Progress)     

KA El-Battawy  O Linhart 《Reproduction in domestic animals》2009,44(4):718-723

Vitrification could provide a promising tool for the cryopreservation of fish embryos. However, to achieve cryopreservation using vitrification, chilling sensitivity and cryoprotectants toxicity were determined using tench embryos at four developmental stages (11, 17, 23 and 29 h). Embryos treated with alcalase (2 ml/998 ml, 2 min at 22°C) were exposed to chilling with/without warming. Other embryos were exposed to methanol and glycerol at the concentration of 10% and 20% for periods of 20 min. At last, embryos were incubated at special incubator cages where hatching rates were counted. Regarding chilling sensitivity and exposure to chilling followed by warming, the hatching rates of embryos decreased significantly (p < 0.001) after exposure to 0°C at all developmental stages except the 29-h stage compared with the controls. The embryo stage most sensitive to chilling was 11-h stage. The 29-h stage exhibited the least sensitivity to low temperature while 17-h and 23-h stages were intermediate in their sensitivity to chilling. The toxicity of methanol increased significantly (p < 0.001) with developmental stage for 11, 17 and 23-h stages. The highest hatching rates of tench embryos were obtained with 29-h embryos using various concentrations of methanol. The hatching rates of tench embryos exposed to glycerol concentrations were approximately similar to those embryos exposed to methanol concentrations except for 11-h embryos that showed no hatching. Unfortunately, we could not obtain living embryos in any of the conditions examined after vitrification. In conclusion, it was quite difficult to vitrify the tench embryos during this study using various vitrifying solutions and the method reported by Chen & Tian (2005) and further studies are needed to achieve successful cryopreservation.  相似文献   

Trichostrongylus axei infection as a cause of deaths and loss of weight in sheep     

KA ABBOTT  IJ MCFARLAND 《Australian veterinary journal》1991,68(11):368-369

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Effects of intake and forage level on site and extent of digestion of plant cell wall monomeric components by sheep     

L D Bourquin  K A Garleb  N R Merchen  G C Fahey 《Journal of animal science》1990,68(8):2479-2495

The objective of this experiment was to study the effects of level of intake and proportion of forage in the diet on site and extent of digestion of plant cell wall monomeric components (phenolics, neutral sugars) by sheep. Four Suffolk wethers (65 kg) with ruminal and duodenal cannulas were fed diets containing 75% (75A) or 25% (25A) alfalfa hay at two levels of intake, 1,700 (high intake, HI) or 1,100 (low intake, LI) g DM/d in a 4 X 4 latin-square design with a 2 X 2 factorial arrangement of treatments. The remainder of the diet consisted primarily of ground corn. Wethers had lower (P less than .05) total tract NDF and ADF digestibilities when fed 75A or at HI. An intake X forage level interaction (P less than .05) was noted for non-core lignin ferulic acid (FA) total tract disappearance, with wethers at LI having the highest, 25A-HI having the lowest, and 75A-HI having an intermediate FA disappearance. Wethers fed at LI had higher (P less than .05) total tract disappearance of non-core lignin p-coumaric acid (PCA). Wethers fed 75A had greater (P less than .05) total tract disappearances of core lignin vanillic acid (VA) and vanillin (VAN). Total tract digestibilities of the neutral monosaccharides glucose (GLC), xylose (XYL), arabinose (ARA) and galactose (GAL) were greater (P less than .05) for LI vs HI treatments. Wethers consuming 75A had greater (P less than .05) total tract ARA and GAL digestibilities, whereas wethers fed 25A had greater (P less than .05) total tract digestibilities of GLC and mannose (MAN). Diet composition and level of intake appear to influence site and extent of digestion of cell wall monomeric components.  相似文献   

Peripheral blood lymphocyte subsets in fleece rot-resistant and -susceptible sheep     

KA McCOLL  RP GOGOLEWSKI  JC CHIN 《Australian veterinary journal》1997,75(6):421-423

Objective To compare haematological values and lymphocyte phenotypes in the peripheral blood of fleece rot-resistant and -susceptible sheep.
Procedure Experiments were conducted on 2- and 3-year-old Merino rams, flock 1 (17 rams) and flock 2 (32 rams), respectively. Within each flock, individual rams were classified as fleece rot-resistant or -susceptible, based on established criteria. Total and differential white cell counts, and indirect fluorescent antibody tests specific for B cells and T cells were performed on all sheep. The concentration of various subsets of circulating lymphocytes was then determined in each sheep.
Results There were no significant differences between fleece rot-resistant and -susceptible sheep from either flock in the mean total or differential white cell counts. However, fleece rot-resistant rams in flock 1 did have a significantly higher concentration of circulating SBU-T1⁺ cells than fleece rot-susceptible rams from the same flock. No such difference was noted in the rams from flock 2. While all rams in flock 1 were free of clinical fleece rot, 24 rams in flock 2 (comprising all 17 fleece rot-susceptible and 7 of 15 fleece rot-resistant animals) had clinical signs of the disease. Fleece rot-free rams in this flock (irrespective of their classification as fleece rot-resistant or -susceptible) had significantly higher concentrations of circulating SBU-T1⁺ cells compared with fleece rot-affected animals. They also had significantly higher concentrations of circulating B cells, and total lymphocytes.
Conclusions An examination of peripheral blood lymphocyte subsets in fleece rot-resistant and -susceptible sheep revealed a possible association between resistance to fleece rot and the concentration of circulating SBU-T1⁺ cells.  相似文献   

Stratospheric Mean Ages and Transport Rates from Observations of Carbon Dioxide and Nitrous Oxide     

KA Boering  SC Wofsy  BC Daube  HR Schneider  M Loewenstein  JR Podolske  TJ Conway 《Science (New York, N.Y.)》1996,274(5291):1340-1343

Measurements of stratospheric carbon dioxide (CO2) and nitrous oxide (N2O) concentrations were analyzed to investigate stratospheric transport rates. Temporal variations in tropospheric CO2 were observed to propagate into the stratosphere, showing that tropospheric air enters the lower tropical stratosphere continuously, ascends, and is transported rapidly (in less than 1 month) to both hemispheres. The mean age A of stratospheric air determined from CO2 data is approximately 5 years in the mid-stratosphere. The mean age is mathematically equivalent to a conserved tracer analogous to exhaust from stratospheric aircraft. Comparison of values for A from models and observations indicates that current model simulations likely underestimate pollutant concentrations from proposed stratospheric aircraft by 25 to 100 percent.  相似文献   

美国黑核桃嫁接育苗技术研究     

宋锋惠  史彦江  丛桂枝  张海群  卡德尔 《西南林学院学报》2004,24(4):15-17

利用新疆已有的丰富核桃资源，高接黑核桃优良无性系，在南北疆建立黑核桃无性系种子园或采穗圃，通过自己采收种子播种育苗，可有效地降低黑核桃苗木生产成本，提高苗木质量，加快黑核桃良种苗木的繁育速度，实现黑核桃良种在新疆的推广、发展。  相似文献   

Sodium, potassium and calcium concentrations in varieties of Dactylis glomerata     

V. MÍKA 《Grass and Forage Science》1982,37(4):321-325

Twelve varieties of cocksfoot, Dactylis glomerata L., were analysed for three mineral elements (Na, K, Ca) and their dry matter (DM) yields were measured in pot and field trials. Among these characteristics there were strong varietal differences in Na concentration, whereas in other cases the varietal differences were less significant. The concentrations of individual mineral elements were, in most cases, independent of yield and of one another.
Parent plants and their clonal derivatives were highly correlated in Na and Ca concentration as well as in DM yield. Tiller size or position on the parental plant had no significant effects on the mineral concentrations or DM yields of clones derived from separated tillers.
Within varieties continuous variation was observed for Na concentration and the range of variation increased with increasing mean Na concentration. When plants were grown under different experimental conditions there was a high repeatability in Na concentration within varieties over cuts and years. This result was taken as an indication of a strong genetic basis for Na concentration. The results obtained in this study show that it is possible to develop grass varieties of defined potential Na concentration.  相似文献   

Concurrent avian malaria and avipox virus infection in translocated South Island saddlebacks (Philesturnus carunculatus carunculatus)     

MR Alley  KA Hale  W Cash  HJ Ha  L Howe 《New Zealand veterinary journal》2013,61(4):218-223

Abstract

CASE HISTORY: Outbreaks of mortality in South Island saddlebacks (Philesturnus carunculatus carunculatus) that had been translocated to two offshore islands in the Marlborough Sounds of New Zealand were investigated during the summer of 2002 and 2007. Both outbreaks were associated with a severe decrease in numbers of saddlebacks of up to 60% of approximately 200 birds.

CLINICAL AND PATHOLOGICAL FINDINGS: Many of the surviving birds were in poor condition, and had skin lesions on the legs and head. Necropsy showed pale liver and lungs, and a swollen spleen. Histopathology revealed schizonts resembling Plasmodium spp. within the cytoplasm of many hepatocytes and splenic histiocytes. The skin lesions consisted of epithelial proliferations containing numerous Bollinger bodies typical of avipox virus (APV) infection. Two different APV were isolated, using PCR, from two different birds exhibiting skin lesions. Each isolate had 100% sequence homology with APV members from either Clade A or Clade B. In addition, PCR analysis revealed that the Plasmodium elongatum present in infected birdsbelonged to a strain that was endemic in the population of North Island saddlebacks (Philesturnus carunculatus rufusater).

DIAGNOSIS: Concurrent infections with Plasmodium spp. haemoparasites and APV were identified as the likely cause of death in the birds examined.

CONCLUSIONS AND CLINICAL RELEVANCE: Although the Plasmodium spp. identified is thought to be endemic to saddlebacks in New Zealand, the affected birds were likely to be immunocompromised by concurrent APV infection or through lack of genetic diversity. Both the introduced mosquito Culex quinquefasicatus and the native mosquito Culex pervigilans are likely vectors for both these diseases, and the provision of water supplies less favourable to mosquito-breeding is recommended.  相似文献   

New Zealand veterinarians — demography,remuneration and vacancies     

R Jackson  KA Goodwin  NR Perkins  J Roddick 《New Zealand veterinary journal》2013,61(4):180-188

AIMS: To determine levels of remuneration for veterinarians in New Zealand, to examine associations between putative explanatory factors and gross annual remuneration, and to quantify the type and prevalence of vacant positions.

METHODS: A postal survey to 486 identifiable clinical practices and 53 identifiable organisations that employ veterinarians was used to gather data for the 2-month period of December 2001 to January 2002.

RESULTS: Data were produced for 972 veterinarians (367 females and 605 males) working in 325 clinical practices, and 299 veterinarians (88 females and 211 males) employed by 32 organisations.

Median levels of gross annual remuneration for assistants, partners/shareholders and sole owners working ≥ days per week in clinical practice were NZ$60,000, $90,000 and $75,000, respectively, and for veterinarians in organisations, irrespective of number of days per week worked, was $68,000. Pay rates increased linearly as the number of years since graduation increased for all clinicians and with increasing age for veterinarians in organisations. Full-time assistants were likely to be paid more if the practice was rural rather than urban in location, if they were males, and if administrative duties were part of the job.

The same factors, except for sex, were significant for remuneration for owners and partners/shareholders working full-time. Their remuneration tended to be higher if the practice was involved with either dairy or deer work but decreased as the number of animal species serviced increased and if they worked >5 days per week. Part-time female veterinarians were generally paid more than male counterparts.

Male veterinarians working in organisations were generally paid about 8% more than their female colleagues. Veterinarians in organisations involved with administration at a head office were generally better paid than those without administrative duties. Pay rates were, on the whole, better in private organisations than in universities, state-owned enterprises, government-operated and other types of organisations

About 50% of all services provided by clinical practices were directed to small animals, 27% to dairy cattle and about 10%, 6% and 3% to horses, sheep and beef cattle, and deer, respectively. About 31% of veterinarians worked solely with small animals but most had multiple species workloads.

Of the 325 respondent practices, 98 reported vacancies for 119 veterinarians, of which 79 were full-time, 27 part-time and 12 locum positions. Of the 32 respondent organisations, seven reported vacancies for 16 mostly full-time positions. Farmer-owned co-operative practices were less likely than privately-owned practices to have full-time vacant positions. The only factor identified as influencing part-time vacancies in clinical practices was hourly pay rate. Vacancies occurred randomly across practices, irrespective of location, and there was no indication of greater demand for services for any particular species. The odds of a vacancy in organisations was lower for state-owned enterprises and private organisations than for government organisations (odds ratios (OR)=0.14 and 0.18, respectively).

CONCLUSIONS: Relatively more females than males worked part-time and 23% of all assistants in clinical practice worked part-time. Sex made a significant difference to gross remuneration for full-time assistants in clinical practice and for veterinarians employed by private or government organisations. In both situations, males were generally better paid than females. Female part-time assistants and partners/shareholders or sole owners in clinical practice were generally better rewarded than their male counterparts. Sex had no effect on remuneration levels for owners/partners working full-time in clinical practices.

The study confirmed a serious shortage of veterinarians in New Zealand. The probability of a vacancy occurring in farmer-owned co-operative (‘club’) practices was lower than in private practices. Vacancies were distributed randomly among rural, urban and rural/urban practices with no evidence of rural practices being more severely affected than urban or rural/urban practices.  相似文献