Eine neue Lehrmitteltafel des Forstzoologischen Institutes Hann. Münden     

Frhr. v. Arnold Vietinghoff-Riesch 《Journal of pest science》1953,26(4):59-59

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Organogenesis and embryogenesis in mature zygotic embryos of Picea sitchensis     

Arnold SV  Woodward S 《Tree physiology》1988,4(3):291-300

Differentiation of adventitious buds and somatic embryos from mature zygotic embryos of Picea sitchensis (Bong.) Carr. is described. Adventitious buds were formed on embryos pulse-treated with 250 microM benzyladenine for 2 h and cultured on medium lacking growth regulators. Buds were initiated at different frequencies and sites depending on when the BA-pulsed embryos were transferred to fresh culture medium. Embryogenic callus was formed when the zygotic embryos were cultured on medium containing 10 microM 2,4-dichlorophenoxyacetic acid and 5 microM benzyladenine. Although 50% of the embryos gave rise to embryogenic callus, only 20% of the callus continued to proliferate after subculture. Proliferation of new somatic embryos occurred from both the embryonic region and the suspensor region on previously formed somatic embryos. The pattern for development of adventitious buds and somatic embryos in Picea sitchensis is compared to that in Picea abies under similar culture conditions.  相似文献   

Wasserhaushalt,Stoffeintrag, Stoffaustrag und biologische Studien im Naturpark Schönbuch bei Tübingen     

U. Ammer  G. Einsele  W. Arnold  O. Klee  R. Agerer  G. Agster  U. Babel  J. Behringer  W. Böcking  F. -H. Evers  W. Fleck  H. Günzl  K. -F. Hofmann  H. Janz  J. Körner  I. Kottke  V. Kracht  A. Krebs  K. Kunzweiler  W. -D. Langbein  H. -U. Moosmauer  S. Müller  E. Nickel  S. Pfeiffer  R. Rausch  H. Schmidt-Witte  O. Schwarz  R. Stegmayer 《European Journal of Forest Research》1983,102(1):282-324

Ohne Zusammenfassung (Prof. Agerer seit 1982 am Institut für Systematische Botanik, München). (Weilimdorf) (zuvor t?tig bei der FVA Stuttgart, siehe oben) (Hohenheim)  相似文献   

Global genotype by environment trends in growth traits for Eucalyptus dunnii     

Bird  Michael G.  Hardner  Craig M.  Dieters  Mark  Heberling  Mónica  Montouto  Cristian  Arnold  Roger J.  Ruiz  Federico  Schapovaloff  Juan  Gore  Peter L. 《New Forests》2022,53(1):101-123

New Forests - Eucalyptus dunnii Maiden (Dunn’s white gum) is a fast-growing tall tree with a restricted natural distribution in south-east Australia and favorable wood properties for pulp...  相似文献   

The evolution of the prevalence of classical scrapie in sheep in Great Britain using surveillance data between 2005 and 2012     

Mark Arnold  Angel Ortiz-Pelaez 《Preventive veterinary medicine》2014

After the decline of the Bovine Spongiform Encephalopathy (BSE) epidemic in Great Britain (GB), scrapie remains the most prevalent animal Transmissible Spongiform Encephalopathy (TSE) present in GB. A number of control measures have been implemented for classical scrapie, and since 2005 there has been a large reduction in the number of observed cases. The objective of this study is to estimate two measures of disease frequency using up to date surveillance data collected during and after the implementation of different control measures established since 2004, and breeding for resistance schemes that ran from 2001 until 2009. This would enable an assessment of the effectiveness of both the breeding for resistance programme and the compulsory eradication measures in reducing the prevalence of scrapie in GB. Evaluation of the sensitivity of the rapid post-mortem test for scrapie indicated that it detected scrapie in the last 25% of the incubation period. A back-calculation model was developed to estimate the prevalence of infection at animal and flock-level. The results of the model indicated a mean drop of infection prevalence of 31% each year, leading to a 90% drop in infection prevalence between 2005, with an estimate of 5737 infected sheep in GB in 2012.  相似文献   

Effects of moderate exercise on semen parameters and serum LH and cortisol concentrations in stallions     

R.K. Gordon  J.D. Mawyer  C.A. Cavinder  D.H. Sigler  T.L. Blanchard  C.C. Love  S.P. Brinsko  C.E. Arnold  S. Teague  M.M. Vogelsang 《Journal of Equine Veterinary Science》2014

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Histological examination of final oocyte maturation and atresia in wild and domesticated Penaeus monodon (Fabricius) broodstock     

Sílvio Peixoto  Greg Coman  Stuart Arnold  Peter Crocos  & Nigel Preston 《Aquaculture Research》2005,36(7):666-673

Oocyte maturation and gonadosomatic index (GSI) of eyestalk ablated Penaeus monodon females collected from the wild and from two first‐generation domesticated lines were assessed. Frequency and diameter of the different oocytes, and the intensity of oocyte atresia, were compared among groups through histological assessments of the sections of the middle ovarian lobe. Digitized images from ovary sections were used to record the frequency and diameter of different oocyte types. Spawning performance of the three groups were expressed in terms of the percentage of females that spawned at least once (productive females), time from eyestalk ablation to first spawning (latency period) and the number of spawnings per female stocked. Final ovarian maturation was attained in all groups, as indicated by the presence of mature oocytes with cortical rods (cortical oocytes), dark‐green ovarian colour and high GSI values (5.83–6.86%). However, domesticated groups presented significant larger immature oocyte types (previtellogenic and yolky oocytes) and smaller cortical oocytes compared with wild females, indicating a reduced vitellogenic activity during final oocyte maturation. Additionally, the frequency of atresia was comparatively higher for both domesticated groups, which could be related to their inferior spawning performance. The implications of these results on the reproductive potential and development of domesticated P. monodon are discussed.  相似文献   

Contribution of the natural biota associated with substrates to the nutritional requirements of the post-larval shrimp, Penaeus esculentus (Haswell), inhigh-density rearing systems     

Michele A Burford  Melony J Sellars  Stuart J Arnold  Sandy J Keys  Peter J Crocos  & Nigel P Preston 《Aquaculture Research》2004,35(5):508-515

The contribution of epiphytes associated with physical substrates to the nutritional requirements of post‐larval shrimp, Penaeus esculentus Haswell, was determined in high‐density rearing systems (3000, 6000 and 11 000 m^?3). Stable isotope signatures of epiphytes on polyethylene mesh substrate, AquaMats? and tank walls were compared with shrimp signatures. Two methods were used: the determination of carbon and nitrogen natural abundance ratios; and ¹⁵N‐nitrogen enrichment ratios after the addition of ¹⁵N‐ammonium to tanks. Using the natural abundance technique and a simple mixing model, epiphytes were found to contribute substantially to the carbon requirements of post‐larval shrimp (39–53%). This was despite the addition of formulated feed at satiation levels. There was no indication of a reduced contribution of carbon from epiphytes to shrimp nutrition at higher shrimp densities. The lack of a difference in the ¹⁵N/¹⁴N ratios of the two food sources meant that mixing models could not be used to calculate the contribution of nitrogen from epiphytes vs. artificial feed to shrimp nutrition. Using the ¹⁵N‐nitrogenenrichment method, the amount of nitrogen contributed by epiphytes to shrimp nutrition over 24 h could be determined. This method showed that nitrogen from epiphytes was assimilated by shrimp. ¹⁵N‐enrichment methods provided a more accurate alternative to natural abundance techniques, particularly when the stable isotope signals ofthe food sources are similar. This experiment hasshown the benefits in providing substrates for P.esculentus in high‐density rearing systems to provide an additional food source for shrimp.  相似文献   

Spectral sensitivity in the photodegradation of fir wood (Abies alba Mill.) surfaces: colour changes in natural weathering     

Vjekoslav Živković  Martin Arnold  Kristijan Radmanović  Klaus Richter  Hrvoje Turkulin 《Wood Science and Technology》2014,48(2):239-252

Activation spectra of wood under natural irradiation were investigated in detail in this work. The main purpose was to study colour changes on the wood surface over time and into the depth during natural light exposure and thus to further contribute to the optimization of surface-protecting treatments. In a natural weathering test, three 80-μm-thick strips of fir wood forming the surface layer of a wood composite were exposed to light under a series of glass cut-off filters. Samples were withdrawn at intervals and tested for colour changes. Identification of the most detrimental wavebands of light causing photodegradation was performed based on recorded colour changes. With chronological development of exposure, the colour changes shifted ever deeper into the surface and further into the visible region of the spectrum. A relatively narrow waveband from 360 to 435 nm was identified in the activation spectra to be the most active band, causing the greatest proportion of recorded colour changes. However, also visible light of wavelengths up to 515 nm significantly contributed to colour changes of the surface layers.  相似文献   

Growth, Survival and Reproductive Performance of Domesticated Australian Stocks of the Giant Tiger Prawn, Penaeus monodon, Reared in Tanks and Raceways   总被引：1，自引：0，他引：1  

Greg I  Coman  Peter I  Crocos  Stuart J.  Arnold  Sandy I.  Keys Nigel P.  Preston Brian  Murphy 《Journal of the World Aquaculture Society》2005,36(4):464-479

The growth, survival and reproductive performance of domesticated Australian stocks of the giant tiger shrimp Penaeus monodon were evaluated in trials conducted in 1997 and 2003. The 1997 trials assessed the performance of first generation progeny of wild broodstock from the northeast coast of Australia and fourth generation progeny of pond‐reared broodstock, which also originated from northeast coast wild stocks. In these trials, growth and survival of the shrimp were assessed when reared for 17 mo in tanks. Reproductive performance of the shrimp was assessed at 14.5 mo and 17 mo. The 2003 trials assessed the performance of first generation progeny of wild broodstock from the Gulf of Carpentaria (north coast of Australia). In these trials, growth and survival of shrimp were assessed when reared for 14 mo in tanks and raceways. Reproductive performance of the shrimp was assessed at 11 mo, 12 mo, and 15 mo. Growth and reproductive performance of the stocks varied between trials, families, ages and rearing systems. The most pronounced differences in growth and reproductive performance were between the 1997 and 2003 trials. At 11 mo of age, the average wet weight of the shrimp in the 2003 trials (females 117.1 ± 5.8 g; males 87.9 ± 7.6 g) was 200% greater than the average wet weight of shrimp in the 1997 trials (females 55.2 ± 6.8 g; males 41.2 ± 3.4 g). The reproductive performance of the shrimp was also higher in the 2003 trials in terms of the percentage of spawnings hatching (52.0% in 1997; 77.1% in 2003) and mean hatch rate (21.5% in 1997; 31.6% in 2003). Differences in the growth and reproductive performance of the tank‐reared stocks between years were indicative of significant improvements in the rearing environment, diet and husbandry techniques. Variation in the reproductive performance between families was consistent across rearing environments and at different ages and suggests the potential to improve reproductive performance through genetic selection. Notably, this study identified hatch rates of nauplii from the spawned eggs as a key area for future improvement of domesticated stocks reared in tanks and raceways. Future efforts to improve the growth and reproductive performance of domesticated P. monodon could benefit from integrating incremental improvements to husbandry with genetic selection.  相似文献