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1.
Ohne Zusammenfassung 相似文献
2.
Salal (Gaultheria shallon) is a vigorous evergreen perennial shrub that is native to the west coast of North America, where it can reduce overstorey growth rates and negatively impact regeneration. Since its introduction into the UK almost a century ago it has become an increasing problem in many woodlands, where it completely shades out other understorey vegetation including young trees, preventing forest regeneration. Climate change is likely to favour its future spread in the UK, and in other regions which currently have a similar climate such as Ireland and northwest Europe. Non chemical management is only practical on a small scale, and to date efforts to control this invasive weed with herbicides have been largely ineffective. In our work we found that a single application of 2.69 kg active ingredient (a.i.) ha?1 picloram [as 11.2 l ha?1 Tordon 22 K (240 g l?1 picloram)] diluted in water plus the adjuvant Mixture B NF at 2% of final spray volume, applied between spring and midsummer, killed all treated plants within two growing seasons. Treatment with 3.84 kg a.i. ha?1 triclopyr [as 8 l ha?1 Timbrel (480 g l?1 triclopyr)] diluted in water plus Mixture B NF at 2% of final spray volume, sprayed initially when flower buds are swelling or flushed but vegetative buds are largely dormant (late April in southern Britain), with a repeat application made 4–8 weeks later, was also very effective. If triclopyr or picloram cannot be used, we also found that glyphosate can provide some control, but follow up treatment will be required. In addition, silvicultural practices such as the high density planting of heavily shade bearing species should be adopted to discourage subsequent reinfestation of cleared areas. 相似文献
3.
Susan C. Baker Simon J. Grove Lynne Forster Kevin J. Bonham Dick Bashford 《Forest Ecology and Management》2009
The Warra Silvicultural Systems Trial (SST) in Tasmania, Australia provides a framework for investigating the responses of beetles (Order: Coleoptera) to three alternative systems in lowland wet eucalypt forest: aggregated retention; dispersed retention; and understorey islands retained in clearfelled areas. Beetles from three families known to be sensitive to forest management, the families Carabidae (ground-beetles), Curculionidae (weevils) and Leiodidae (fungus-beetles), were collected with pitfall traps prior to harvest, and in the first and third years post-harvest. The retained aggregates in the aggregated retention system maintained beetle assemblages reasonably typical of mature forests, at least in these early years following harvesting. These aggregates appear to provide a stable habitat, with similar species composition in the first and third years post-harvest. In contrast, the harvested areas of the aggregated retention system contained low numbers of beetle species affiliated with mature forest, as did the understorey islands and the dispersed retention system. Relative to clearfelling, all alternative silvicultural systems appeared to be of some benefit to beetles affiliated with mature forest, but aggregated retention retained far greater numbers of these beetles compared to the other systems in Tasmanian wet eucalypt forest. 相似文献
4.
5.
This paper describes experiments in which nine species of prawns were compared for their suitability for intensive culture in closed systems. The species tested were: Macrobrachium rosenbergii, Penaeus aztecus, P. indicus, P. japonicus, P. monodon, P. occidentalis, P. orientalis, P. schmitti and P. setiferus. Tanks with a bottom area of 0.6 m2 and water depth 20 cm were stocked with juvenile prawns (0.2–0.5 g mean live-weight) of each species at two stocking densities, equivalent to 25 and 166 prawns/m2. Water conditions were maintained at 28±2°C and 28–30‰ (M. rosenbergii was reared in fresh water), and growth and survival were monitored during 16 weeks.Fastest growth was recorded for P. monodon and P. orientalis, which reached mean live-weights of 25.43 g and 22.80 g respectively at the low stocking density and 12.95 g and 14.63 g at the high stocking density. Best survival was recorded for P. monodon, which was considerably better than any of the other species. It was concluded that P. monodon and P. orientalis merit further consideration as candidates for intensive culture. 相似文献
6.
7.
Five crossbred beef steers (329 kg) were used in a 5 x 5 Latin square experiment with 14-d periods to determine the effects of supplementation with high-nitrogen (N) feeds alone or mixed with tallow on sites of digestion with a basal diet of bermudagrass hay. Hay was 1.93% nitrogen, 75% neutral detergent fibre and fed at 1.83% of body weight (dry matter; DM). Supplements were basal (B; 105 g DM): 81.8% dried molasses product (DMP) and 18.2% calcium carbonate (CC); soybean meal (S; 942 g DM): 88.0% soybean meal, 9.8% DMP and 2.2% CC; S mixed with 9.8% tallow (SF; 1041 g DM); corn gluten and blood meals (CB; 662 g DM): 62.5% corn gluten meal, 20.8% blood meal, 13.6% DMP and 3.0% CC; CB mixed with 13.2% tallow (CBF; 757 g DM). Total N intake was 117, 185, 187, 174 and 172 g/d, and duodenal N flow was 121, 148, 143, 162 and 169 g/d for B, S, SF, CB and CBF, respectively, being lower for B than for other treatments and higher for supplements with the corn gluten and blood meal mix than for soybean meal (P less than 0.05). Duodenal microbial N flow was 39, 51, 49, 38 and 45 g/d for B, S, SF, CB and CBF, respectively, being greater (P less than 0.05) for supplements with soybean meal than with corn gluten and blood meals. Duodenal flow of feed N was greater (P less than 0.05) with than without high-N feeds and for supplemental corn gluten and blood meals than for soybean meal (78, 90, 86, 117 and 116 g/d for B, S, SF, CB and CBF, respectively). In conclusion, mixing of tallow and high-N feeds did not affect the extent of ruminal N disappearance, and soybean meal supplementation increased duodenal N flow less than did supplementation with corn gluten and blood meals. Increased duodenal N flow with soybean meal was associated with about equal elevations of ruminal outflow of microbial and feed N, whereas the corn gluten-blood meal mix affected the intestinal protein supply by increasing ruminal escape of feed protein. 相似文献
8.
Associations of simple sequence repeats with quantitative trait variation including biotic and abiotic stress tolerance in Hordeum spontaneum 总被引:1,自引:0,他引:1
A total of 33 simple sequence repeats (SSRs) was analyzed in 52 genotypes of Hordeum spontaneum originally collected from two different soil types (Terra rossa and Basalt) at Tabigha in Israel. Data on the performance of developmental, morphological, and yield‐related traits under well‐watered control and water‐stress conditions were available from previous experimentation, and powdery mildew susceptibility was scored. Regression analyses based on SSR allele class differences were performed. Highly significant associations were detected at the SSR loci Bmac181 (on chromosome 4H) and Bmac316 (6H) for water ‐stress tolerance and powdery mildew resistance, respectively. The study shows that association mapping using SSRs and genetically diverse germplasm provides an effective means of relating genotypes to complex quantitative phenotypes. 相似文献
9.
Brian P. Forster 《Euphytica》2001,120(3):317-328
A review of research at the Scottish Crop Research Institute (SCRI) on the effects of semi-dwarfing genes on salt tolerance
in barley is given. Work began in1993 with the fortuitous and unexpected result that the cultivar ‘Golden Promise’ showed
considerable tolerance to salt. Golden Promise is a gamma-ray induced semi-dwarf mutant of the cultivar ‘Maythorpe’. The parent
and mutant cultivars are presumed to be isogenic, but show significant differences in their responses to salt stress. The
positive and pleiotropic effects of the mutant gene, commonly known as GPert were found to be effective in a number of genetic backgrounds. Earlier, in 1991 Frackowiak showed that the GPert mutation was allelic to the ari-e mutants in barley. The ari-emutants were salt tested and found to show the same positive responses to salt stress as Golden Promise. This supported the
allelism tests, and consequently the GPert symbol was changed to ari-e.GP. The semi-dwarf mutant sdw1 (also known as denso) and the erectoides semi-dwarf mutant,ert-k
32 were also tested for their effects on tolerance to salt, but did not show any positive effects. Salt tolerance was therefore
not a general phenomenon of semi-dwarf stature but specific to mutations at the Ari-e locus in these lines. Genetic markers (RAPDs, AFLPs and SSRs) have been used for fingerprinting, genetic mapping, and QTL
analysis. The markers have helped 1) confirm the isogenic relationship between Maythorpe and Golden Promise, 2)clarify the
confusion over the pedigree of Golden Promise, and 3) genetically map the ari-e.GPlocus and examine its pleiotropic effects.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
10.
The use of bulked leaf samples from individual plants for amplified fragment length polymorphism (AFLP) analysis was evaluated
as a tool for assessment of genetic diversity in white clover (Trifolium repens L.). Bulking of leaf samples produced slightly simpler AFLP profiles compared to the combined profiles of individual plants
from the same cultivar. Approximately 90% of bands which were present in individual plants were present in bulked samples
of the same cultivar. The majority of those absent were rare bands, shared by less than 25% of individual plants. Replicate
bulk samples gave almost identical banding patterns, demonstrating the robustness of the bulked AFLP technique. Cluster analysis
of AFLP data derived from individual plants resulted in a phenogram similar to that produced from data derived from bulked
samples of the same plants. AFLP analysis of bulked samples detected significant amounts of genetic variability among 52 cultivars
and accessions with genetic similarity values ranging from 0.42 to 0.92. However, cluster analysis of AFLP data only partially
reflected the geographic origin of cultivars and accessions and was not congruent with cluster analysis based on variation
for morphophysiological characters. Bulked AFLP analysis provides a powerful tool for rapid assessment of genetic variability
in white clover and may also be used for cultivar identification.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献