Geographical, altitude and agro-ecological differentiation of isozyme and hordein genotypes of landrace barleys from Ethiopia: implications to germplasm conservation   总被引：1，自引：0，他引：1  

Abebe Demissie  Åsmund Bjørnstad 《Genetic Resources and Crop Evolution》1997,44(1):43-55

An analysis of the variability of genes encoding six isozyme systems (15 loci) and two storage proteins (2 loci) in landrace barley from Ethiopia is reported. The materials consisted of populations collected from sites as low as 1650 and as high as 3750 meters, covering a wide range of agro-ecological conditions and geographical areas. Of the 17 loci 7 were polymorphic and 10 monomorphic when the 95% criterion of polymorphism was applied. Despite the disproportionate monomorphic loci, polymorphism was detected in all populations when this criterion is used. The populations were found to possess fairly low mean number of alleles per locus (A = 1.5), low mean value of expected heterozygosity (H = 0.134) and a fairly high mean percentage of polymorphic loci (P = 35.3%). The mean F_ST= 0.474 for the populations is typical of inbreeding species. The result indicated that allelic richness is concentrated in altitude class 3 (2500–3000 m) followed by altitude class 1 (<2000 m). Altitude class 2 (2000–2500) holds an intermediate place though it is the highest in terms of expected heterozygosity (H = 0.245). Higher genetic diversity is concentrated in some geographical regions such as Shewa, Arsi, Bale compared to others (Welo, Gamu Gofa, Gojam). Genetic differentiation among the agro-ecological zones was more profound than both among the altitudes and among regions. Correlation analysis between phenotypic diversity (Shannon-Weaver diversity index) and expected heterozygosity (H) for isozyme/hordein loci revealed non significant associations except with respect to agro-ecological zones. In general, it was detected that sites in highland areas in central and northern regions may be more desirable for in situ conservation than sites in peripheral regions in terms of isozyme/hordein diversity and current rate of varietal replacement.  相似文献   

Postmortem proteome changes of porcine muscle related to tenderness   总被引：12，自引：0，他引：12  

Lametsch R  Karlsson A  Rosenvold K  Andersen HJ  Roepstorff P  Bendixen E 《Journal of agricultural and food chemistry》2003,51(24):6992-6997

Proteome analysis was used to investigate the relation between changes in postmortem proteome of porcine muscle and tenderness development. Muscle samples were taken at slaughter and 72 h postmortem, and the registered changes in the proteome were related to Warner-Bratzler shear force. One hundred and three protein spots were found to change significantly (P < 0.01) over time, and of these the 27 most pronounced changes were identified. Eleven out of the 27 changes were fragments of actin. Other identified myofibril proteins or fragments included myosin heavy chain, titin, myosin light chain I, myosin light II, CapZ, and cofilin. Correlation analysis revealed significant correlations between three of the identified actin fragments and the myosin heavy chain fragment to shear force. Moreover, myosin light chain II and triose phosphate isomerase I were also found to correlate significantly to shear force. The results clearly demonstrate that postmortem degradation of actin and myosin heavy chain is related to meat tenderness.  相似文献   

Crustacean Communities in Canada and Norway: Comparison of Species along A pH Gradient     

Bjørn Walseng  Ann Kristin L. Schartau 《Water, air, and soil pollution》2001,130(1-4):1319-1324

Increased pH in acid lakes changes the crustacean fauna from communities dominated by acid-tolerant species to communities dominated by more acid-sensitive species. Studies from Canada (Killarney) and southeastern Norway (Østfold county) have demonstrated that planktonic and littoral crustaceans can be used as indicators of such recoveries. In both places the cladocerans Alona rustica and Acantholeberis curvirostris were found in acidic lakes, whereas Alona costata and the copepod Eucyclops macrurus were found in near neutral lakes. The calanoids Diaptomus minutus in North America and Eudiaptomus gracilis in Europe, both dominate in acidic water, and may ecologically be equivalent species. Sometimes the same species occur at different pH in the two continents. Bosmina longirostris and Alonella excisa may serve as examples, but a pertinent question is whether or not they are really the same species.  相似文献   

Changes in fruitbody production of mycorrhizal and litter decomposing macromycetes in heavy metal polluted coniferous forests in North Sweden     

Åke Rühling  Bengt Söderström 《Water, air, and soil pollution》1990,49(3-4):375-387

Basidiomycete fruitbodies growing in coniferous forests along a complex heavy metal pollution gradient in north Sweden were identified and counted over a 4 yr period. The dominant metals in the humus layer were As, Cd, Cu, Pb, and Zn. Pb occurred at the highest levels in a range of 80 to 8500 μg g^?1 dry wt. Both the number of fruitbodies and the number of fruiting species decreased strongly with increasing pollution level. A few species appeared to sustain the metal loads. Many of these were ectomycorrhizal fungi. The relationship between fruitbody frequencies and plant species composition were also studied statistically although no obvious relations were found. Metal content of the fruitbodies of six species were also analyzed and their bioaccumulation calculated. Amanita muscaria accumulated Cd efficiently.  相似文献   

Metal uptake in plants from a birch forest area near a copper smelter in Norway     

Else Marie Løbersli  Eiliv Steinnes 《Water, air, and soil pollution》1988,37(1-2):25-39

Uptake of Ca, Mg, K, Mn, Fe, Al, Rb, Ph, Cu, Zn, and Cd in vascular plants from a birch forest area near a Cu smelter in northern Norway was investigated. The primary objective was to study metal uptake in plants growing in a strong local acidification gradient. Decreased levels of Mn, Mg, and Ca found in Betula pubescens, Vaccinum myrtillus, and Deschampsia flexuosa near the smelter corresponded to a decrease in base saturation of the soil. This suggests that appreciable soil acidification has taken place. The level of Rb in Vaccinum myrtillus and Sorbus aucuparia increased significantly towards the smelter, probably due to the higher soil acidity. Elevated levels of Cu, Zn, Ph, and Cd in surface soil were found with values up to 2500 mg kg^?1 Cu within 1 km from the smelter. These concentrations decreased significantly with distance, but metal contamination was detectable up to 27 km from the smelter along the prevailing wind direction. A corresponding decrease was detected for Cu in the four plant species analyzed. Elevated levels of Zn, Ph, Fe, and Al were found in some, but not all, species.  相似文献   

Transport of volatile chlorinated hydrocarbons in unsaturated aggregated media     

Thomas Gimmi  Hannes Flühler  BjØrn Studer  Anders Rasmuson 《Water, air, and soil pollution》1993,68(1-2):291-305

Transport of volatile hydrocarbons in soils is largely controlled by interactions of vapours with the liquid and solid phase. Sorption on solids of gaseous or dissolved compounds may be important. Since the contact time between a chemical and a specific sorption site can be rather short, kinetic or mass-transfer resistance effects may be relevant. An existing mathematical model describing advection and diffusion in the gas phase and diffusional transport from the gaseous phase into an intra-aggregate water phase is modified to include linear kinetic sorption on gas-solid and water-solid interfaces. The model accounts for kinetic mass transfer between all three phases in a soil. The solution of the Laplace-transformed equations is inverted numerically. We performed transient column experiments with 1,1,2-Trichloroethane, Trichloroethylene, and Tetrachloroethylene using air-dry solid and water-saturated porous glass beads. The breakthrough curves were calculated based on independently estimated parameters. The model calculations agree well with experimental data. The different transport behaviour of the three compounds in our system primarily depends on Henry's constants.  相似文献   

Organic acids in root exudates from Picea abies seedlings influenced by mycorrhiza and aluminum     

Toril Drabløs Eldhuset  Berit Swensen  Torild Wickstrøm  Gro Wollebæk 《植物养料与土壤学杂志》2007,170(5):645-648

Organic acid anions exuded from roots of Picea abies (Norway spruce) seedlings grown on glass beads in the presence and absence of mycorrhiza (Laccaria bicolor) and aluminum (Al) at pH 3.9 were measured. We wanted to test if the roots exuded more organic acid anions when exposed to Al and if mycorrhization influenced the exudation. Oxalate was exuded in far higher amounts than any other organic acid anion, with a maximum rate of 1.7 nmol (mg root DW)^–1 d^–1. Mycorrhizal roots exuded significantly more oxalate than nonmycorrhizal roots. The presence of Al did not enhance oxalate exudation. We conclude that the oxalate exuded constitutively by Picea abies/Laccaria bicolor may lead to rhizosphere oxalate concentrations that are relevant for Al resistance.  相似文献   

Investigation of packaging systems for shelled walnuts based on oxygen absorbers     

Jensen PN  Sørensen G  Brockhoff P  Bertelsen G 《Journal of agricultural and food chemistry》2003,51(17):4941-4947

Storage of nuts at a high oxygen concentration results in rancid nuts whereas storage at a low oxygen concentration results in fine-tasting nuts. During a 13 month experiment, packaging of walnuts with an oxygen absorber was compared to packaging in nitrogen or atmospheric air. At the same time, the effects of oxygen permeability of the packaging material and storage temperature (11 and 21 degrees C) were investigated by determination of hexanal and rancid taste of the walnuts. The optimal storage condition for walnuts is at 11 degrees C or lower, eventually combined with an oxygen absorber. However, without chilled storage and use of an oxygen absorber, it is possible to obtain an acceptable quality of walnuts with a packaging material having a very low oxygen permeability (e.g., laminate with EVOH) combined with nitrogen flushing. The results also revealed that the development of hexanal during time can be described by a second-order polynomial regression model.  相似文献   

Chaotic or deterministic development of nematode populations in pine forest humus incubated in the laboratory     

Björn Sohlenius 《Biology and Fertility of Soils》1993,16(4):263-268

Humus material from an old stand of Scots pine and from an open area clearcut 13–15 years ago was incubated in the laboratory. The incubations were started in different years and the differences in nematode faunal development between the years were compared with site characteristics. In all incubations there was an increase in total nematode abundance. The total number and diversity of nematodes were higher in humus from the forest than from the clearing. The results indicated that biotic control mechanisms were much weaker in the humus from the clearcut area, where a strong dominance of Acrobeloides nanus occurred in most incubations. The differences in faunal development between years were rather large. A certain pattern of unpredictability indicated that the nematode fauna was a rather labile component of the community of soil organisms in a pine forest soil.  相似文献   

Bacterial dynamics during decomposition of alder litter     

A. Kjøller  S. Struwe  K. Vestberg 《Soil biology & biochemistry》1985,17(4):463-468

Different groups of aerobic and anaerobic bacteria were enumerated in decomposing alder litter (Alnus glutinosa) and the underlying soil. Unspecific media with soil extract were used for total counts and media with single carbon compounds or different nitrogen compounds for specific functional groups.The numbers of aerobic, amylolytic and proteolytic bacteria were high after litter fall and decreased towards the end of decomposition. The fluctuations in the anaerobic groups of organisms were mainly influenced by moisture. The numbers of denitrifiers in the soil were highest during decomposition of litter in the winter, while the numbers of ammonifiers in litter were always high.  相似文献