Agronomic effects from the control of Agropyron repens in barley by pre-harvest application of glyphosate     

B. W. SHEPPARD  M. C. RICHARDS  J. A. PASCAL 《Weed Research》1984,24(1):9-16

Pre-harvest application of glyphosate in barley at 1·44 and 0·72 kg ha^?1 was compared with post-harvest application at 1·44 kg ha^?1 at six sites in south-east Scotland, three sprayed in 1980 and three in 1981. Both levels of pre-harvest application gave consistent 95–99% control of A. repens compared with 0–76% control from post-harvest application. Yields of crops grown in 1981 were significantly increased after all the 1980 pre-harvest treatments and after one post-harvest treatment. No significant depressions in grain germination were recorded from the lower rate of pre-harvest application but one significant depression was recorded from the higher rate. Combine harvesting throughput at a given grain loss level was significantly improved by pre-harvest application and moisture content of grain at harvest was significantly reduced by up to 2·5%. Wheeling losses from pre-harvest spraying ranged from 1 to 5%. Crop yield increases in the year after spraying compensated for herbicide and application costs plus any yield losses through tractor wheelings.  相似文献   

Seasonal Changes in the Frost Hardiness of Provenances of Picea sitchensis in Scotland   总被引：6，自引：0，他引：6  

CANNELL  M.G.R.; SHEPPARD  L.J. 《Forestry》1982,55(2):137-153

Changes in the natural level of frost hardiness of shoots offour provenances of Picea sitchensis were monitored over twogrowing seasons by detaching shoots from 7 to 10-year-old treesgrowing in a nursery in Scotland, and subjecting them to freezingtemperatures under conditions which simulated night frosts. Six seasonal phases of frost hardiness were identified (Fig.3).

1. During each autumn, killing temperatures (the level of hardiness)decreased from –5°C to below –20°C, beginningseveral weeks after shoot elongation ceased. Alaskan provenanceshardened in September, apparently in response to shorteningday lengths alone, whereas an Oregon provenance did not hardenuntil November, after repeated frosts. Queen Charlotte Islandsprovenances were intermediate.
2. From November to March allprovenances were hardy to below –20°C,which is adequateto prevent direct freezing injury at mostplantation sites.
3. In March-April, several weeks before bud-burst, old shootsdehardenedto killing temperatures of about –10°Cin responseto warm temperatures, and southerly provenancesdid so beforenortherly ones.
4. During bud-burst the newly-emergingshoots were hardy to only–3°C to –5°C untilthey were about 3.5 cmlong. All provenances burst bud at thesame time and were equallyfrost susceptible at this time.
5. DuringMay-July the elongating shoots fluctuated in hardinessbetween–5°C and –10°C apparently in responsetofluctuating ambient temperatures.
6. In August 1980 there wasa period of late summer dehardeningto killing temperaturesof about –3°C.

Seasonal changes in hardiness are discussed in relation to changesin shoot growth and environmental factors. The main opportunitiesfor selecting frost hardy genotypes seem to be in the rate ofautumn hardening, the time of pre-bud burst dehardening, andthe time of bud-burst.  相似文献   

Can an integrated management approach provide a basis for long-term prevention of weed dominance in Australian pasture systems?   总被引：2，自引：0，他引：2  

R K HUWER  D T BRIESE  P M DOWLING†  D R KEMP‡  W M LONSDALE  D L MICHALK†  M J NEAVE  A W SHEPPARD  & T L WOODBURN§ 《Weed Research》2005,45(3):175-192

Broad-leaved weeds in pasture, such as Carduus nutans, Onopordum spp. and Echium plantagineum are a major problem for graziers in southern Australia. Previous attempts to combat these weeds with a single technique have only resulted in short-term success. An approach to long-term control, combining biological control with different grazing and herbicide strategies, was evaluated in an integrated weed management (IWM) programme, in south-eastern Australia. This IWM study was one of the few that has focused on biological control agents. During the field trials, the impacts of grazing and herbicide treatments on the weed and biological control agents, as well as on pasture composition, were monitored. This paper concentrates on the part of the study that focuses on the role and importance of pasture composition as part of weed management. The main pasture components were monitored using botanal , a sampling technique for estimating species composition and pasture yield in the field. IWM is a long-term ecological approach and after 3 years, major trends were just becoming apparent. This study shows that pasture composition can be manipulated to increase productivity and sustainability. It demonstrates that broad-leaved weeds can be reduced when high level pasture background management and chemical control are combined.  相似文献   

THE HEALING OF SEGMENTAL BONE DEFECTS, INDUCED BY RECOMBINANT HUMAN BONE MORPHOGENETIC PROTEIN (rhBMP-2): A RADIOGRAPHIC, HISTOLOGICAL, AND BIOMECHANICAL STUDY IN RATS     

AW Yasko  JM Lane  EJ Fellinger  V. Rosen  JM Wozney  EA Wang 《Veterinary surgery : VS》1993,22(1):10-10

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Function and anatomy of plant siRNA pools derived from hairpin transgenes     

Bess L Chau  Kevin AW Lee 《Plant methods》2007,3(1):13-14

Background  

RNA interference results in specific gene silencing by small-interfering RNAs (siRNAs). Synthetic siRNAs provide a powerful tool for manipulating gene expression but high cost suggests that novel siRNA production methods are desirable. Strong evolutionary conservation of siRNA structure suggested that siRNAs will retain cross-species function and that transgenic plants expressing heterologous siRNAs might serve as useful siRNA bioreactors. Here we report a detailed evaluation of the above proposition and present evidence regarding structural features of siRNAs extracted from plants.  相似文献   

Vets at War.     

AW English 《Australian veterinary journal》2006,84(5):162-162

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Effects of fertilization and incubation factors on the quality and yield of scallop, Pecten fumatus Reeve, larvae     

M P Heasman  W A O'Connor  AW Frazer 《Aquaculture Research》1996,27(7):505-513

Variable quality and yield (percentage development from eggs) D-veligers of the scallop, Pecten fumatus Reeve, prompted assessment of fertilization and incubation protocols. Various sperm to egg ratios were tested on eggs suspended in sea water at different densities. Ratios of 1000:1 led to the highest D-veliger yield when eggs were incubated in suspension at one per millilitre. With increasing egg densities, the addition of 1000 sperm per egg led to increasing average numbers of sperm visible at the periphery of each egg, indicating that fewer sperm were necessary for fertilization at higher egg densities. The time period and temperature over which released gametes were stored before fertilization were also found to significantly affect D-veliger yield. Decreasing gamete storage temperature from 26 to 14^oC increased D-veliger yield, as did a reduction in the gamete storage period from 6 to 1 h. The incubation of embryos at densities in the 5-50 ml^-1 range did not affect D-veliger yield. A significant increase in total bacterial counts in the culture water occurred with increasing embryo stocking densities. However, presumptive Vibrionaceae counts did not increase significantly with increasing embryo stocking densities. In a comparison of the viability of self- and cross-fertilized embryos and larvae, fewer self-fertilized embryos developed to D-veliger stage; however, percentage survival, although highly variable, did not differ significantly in subsequent larval rearing. Cross-fertilized larvae had attained a significantly larger size by day 7.  相似文献   

Causes of perinatal mortality in farmed fallow deer (Dama dama)     

AW ENGLISH  RC MULLEY† 《Australian veterinary journal》1992,69(8):191-193

The causes of perinatal mortality in farmed fallow deer in the Camden region of New South Wales were determined between 1982 and 1987. The results of 144 necropsies on fawns showed that ante-parturient and parturient deaths occurred in 33 (22.9%) of cases, with post-parturient deaths accounting for 99 (69.8%), and undiagnosed causes the remaining 12 (8.3%). The most common cause of post-parturient death (43.1%) was exposure/starvation of fawns that had birthweights lower than the average for surviving fawns on these same farms (3.01 kg and 4.12 kg, respectively). These results provide good evidence of the correlation between low birthweight and perinatal mortality in fallow deer on Australian deer farms.  相似文献   

Ecological scale and seasonal heterogeneity in the spatial behaviors of giant pandas   总被引：1，自引：0，他引：1  

Zejun ZHANG  James K. SHEPPARD  Ronald R. SWAISGOOD  Guan WANG  Yonggang NIE  Wei WEI  Naxun ZHAO  Fuwen WEI 《Integrative zoology》2014,9(1):46-60

We report on the first study to track the spatial behaviors of wild giant pandas (Ailuropoda melanoleuca) using high‐resolution global positioning system (GPS) telemetry. Between 2008 and 2009, 4 pandas (2 male and 2 female) were tracked in Foping Reserve, China for an average of 305 days (± 54.8 SE). Panda home ranges were larger than those of previous very high frequency tracking studies, with a bimodal distribution of space‐use and distinct winter and summer centers of activity. Home range sizes were larger in winter than in summer, although there was considerable individual variability. All tracked pandas exhibited individualistic, unoriented and multiphasic movement paths, with a high level of tortuosity within seasonal core habitats and directed, linear, large‐scale movements between habitats. Pandas moved from low elevation winter habitats to high elevation (>2000 m) summer habitats in May, when temperatures averaged 17.5 °C (± 0.3 SE), and these large‐scale movements took <1 month to complete. The peak in panda mean elevation occurred in Jul, after which they began slow, large‐scale movements back to winter habitats that were completed in Nov. An adult female panda made 2 longdistance movements during the mating season. Pandas remain close to rivers and streams during winter, possibly reflecting the elevated water requirements to digest their high‐fiber food. Panda movement path tortuosity and first‐passage‐time as a function of spatial scale indicated a mean peak in habitat search effort and patch use of approximately 700 m. Despite a high degree of spatial overlap between panda home ranges, particularly in winter, we detected neither avoidance nor attraction behavior between conspecifics.  相似文献   

Coral record of equatorial sea-surface temperatures during the penultimate deglaciation at huon peninsula     

MT McCulloch  AW Tudhope  TM Esat  GE Mortimer  J Chappell  B Pillans  AR Chivas  A Omura 《Science (New York, N.Y.)》1999,283(5399):202-204

Uplifted coral terraces at Huon Peninsula, Papua New Guinea, preserve a record of sea level, sea-surface temperature, and salinity from the penultimate deglaciation. Remnants have been found of a shallow-water reef that formed during a pause, similar to the Younger Dryas, in the penultimate deglaciation at 130,000 +/- 2000 years ago, when sea level was 60 to 80 meters lower than it is today. Porites coral, which grew during this period, has oxygen isotopic values and strontium/calcium ratios that indicate that sea-surface temperatures were much cooler (22 degrees +/- 2 degreesC) than either Last Interglacial or present-day tropical temperatures (29 degrees +/- 1 degreesC). These observations provide further evidence for a major cooling of the equatorial western Pacific followed by an extremely rapid rise in sea level during the latter stages of Termination II.  相似文献