Effects of storage conditions on dormancy and vigor of Picea abies seeds   总被引：1，自引：0，他引：1  

Leinonen  Kari 《New Forests》1998,16(3):231-249

The dormancy and vigor of Picea abies seeds were studied after five months of storage at 25 and 75% relative humidity (RH) and 5 and 12 °C. Dormancy was evaluated by studying germination response to light and moist chilling at 12 and 21 °C. Dormancy causing germination reduction in the dark was induced in seeds during storage at 25% RH (5–6% moisture content, MC) in darkness. The dormancy was greater when seeds were germinated at 12 than at 21 °C and after storage at 12 than at 5 °C. The effective dormancy relief by light indicates that germination was under phytochrome control. Moist chilling could partly replace light. According to accelerated aging and leachate conductivity tests, dry seeds could be stored at 12 °C for five months without affecting their vigor. After storage at 75% RH (11% MC) and 5 °C, the seeds germinated slowly and incompletely. The decreased germination response to light indicates that other processes than those mediated directly by phytochrome restricted germination of these seeds. The positive germination response to moist chilling suggested that secondary dormancy was induced in the seeds. However, vigor tests gave some evidence of simultaneous decrease of vigor. Storage at 75% RH and 12 °C decreased germination nearly to 0%. Germination of seeds stored at 75% RH could be stimulated by a short accelerated aging period.  相似文献   

Swimming depth and thermal history of individual Atlantic salmon (Salmo salar L.) in production cages under different ambient temperature conditions     

David Johansson  Kari Ruohonen  Jon-Erik Juell  Frode Oppedal 《Aquaculture (Amsterdam, Netherlands)》2009,290(3-4):296-303

Salmon production cages at sites with a pronounced thermal stratification give individual fish an opportunity to choose their thermal environment. The behavioural responses of individual salmon to such stratification, however, are poorly documented. Information about spatial distributions and temperature experience of individual Atlantic salmon (initial weight 1.5 kg) was gathered over a period of 4 months (mid-August to early-December) using data storage tags. Fish were stocked at normal or high densities in triplicate 2000 m³ production cages at 5.6–14.5 (ND) or 15.7–32.1 (HD) kg m^− 3, and valid data were collected for 12 ND and 11 HD salmon. There were large inter- and intra-individual variations in swimming depth, with indications that the salmon performed behavioural thermoregulation in an attempt to maintain body temperature within the range of 8–20 °C. Stocking density influenced the average swimming depth and body temperature, indicating competition for preferred thermal space in periods of unfavourably high temperature (towards 20 °C) in large parts of the cage volume. Analysis of temporal behavioural patterns demonstrated a higher variability during day than night and that 60 to 70% of the individuals displayed cyclic diel patterns in either swimming depth or body temperature in at least one out of three sub-periods. The results are discussed in relation to bio-energetic and thermal stress theory and possible consequences for growth variation in salmon cages. Generally, this study suggests that individual swimming depth and body temperature is in part a response to available temperature interacting with stocking density and time of day, while some individual variation cannot be ascribed to the measured variables.  相似文献   

Economic and policy considerations regarding hydropower and migratory fish          下载免费PDF全文

Emmi Nieminen  Kari Hyytiäinen  Marko Lindroos 《Fish and Fisheries》2017,18(1):54-78

Environmental standards have rarely been applied for promoting the joint production of hydropower and migratory fish. The objective of this study was to review existing research results on the effectiveness and costs of alternative measures improving fish migration, which are necessary for the development of environmental standards. The ranking of alternative measures indicates that cost‐effective combinations of measures are case‐specific and highly dependent on measure design, implementation and maintenance. In addition to tailored ex ante cost‐effectiveness analyses, other preconditions for cost savings include effective and affordable monitoring and enforcement, and cooperation among power companies that share water‐use rights within a river basin as well as among other stakeholders, such as the local community, fishermen and recreational users.  相似文献   

Pathogenicity and genetic variation of Phytophthora cactorum from silver birch and strawberry     

Arja Lilja  Reijo Karjalainen  Päivi Parikka  Kari Kammiovirta  Heikki Nuorteva 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(6):529-535

Phytophthora cactorum strains isolated from necrotic stem lesions on Betula pendula seedlings or from Fragaria ananassa plants suffering from crown rot were pathogenic to their host plants. Only isolates from birch caused clear lesions on non-wounded bark of birch. P. cactorum isolates from birch were not detrimental to strawberry. Random Amplified Polymorphic DNA (RAPD) analysis revealed variation within P. cactorum, isolates from silver birch having different banding patterns than those from strawberry. UPGMA analysis clustered isolates from silver birch and strawberry plants into separate groups. The data show that the recent outbreak in Finland of P. cactorum in birch could not be caused by the import of strawberry plants affected by crown rot.  相似文献   

Inheritance of recurrent exertional rhabdomyolysis in thoroughbreds     

Dranchak PK  Valberg SJ  Onan GW  Gallant EM  MacLeay JM  McKenzie EC  De La Corte FD  Ekenstedt K  Mickelson JR 《Journal of the American Veterinary Medical Association》2005,227(5):762-767

OBJECTIVE: To develop a diagnostic test for recurrent exertional rhabdomyolysis (RER) in Thoroughbreds that relied on in vitro contracture of muscle biopsy specimens and determine whether the inheritance pattern of RER diagnosed on the basis of this contracture test was consistent with an autosomal dominant trait. DESIGN: Clinical trial. ANIMALS: 8 adult horses with RER and 16 control adult horses for development of the contracture test; 23 foals for inheritance of RER. PROCEDURE: External intercostal muscle biopsy specimens from the 24 adult horses were tested for contracture in response to halothane and caffeine, and criteria for a positive test result were determined. These criteria were then applied to results for the 23 foals to determine whether they had RER. Simple segregation analysis was performed to determine whether results were consistent with a dominant pattern of inheritance. RESULTS: Results of the contracture test were positive for 5 of the 12 colts and 4 of the 11 fillies. Results of segregation analysis were consistent with an auto-. somal dominant pattern of inheritance. Two sires with RER produced colts with RER, supporting the hypothesis that RER had an autosomal, rather than an X-linked, inheritance pattern. In addition, in 1 instance, an unaffected colt was produced by 2 affected parents, which was not consistent with a recessive mode of inheritance. CONCLUSIONS AND CLINICAL RELEVANCE: Although the expression of the RER trait is influenced by sex, temperament, and diet, among other factors, results from the in vitro muscle contracture test and this breeding trial suggest that RER in Thoroughbreds can be modeled as a genetic trait with an autosomal dominant pattern of inheritance.  相似文献   

Rangeland Ecology and Management,Volume 71, Issue 3: Relationships Between Cattle and Biodiversity in a Multi-use Landscape Revealed by the Kenya Long-Term Exclosure Experiment (KLEE)     

Truman P. Young  Lauren M. Porensky  Corinna Riginos  Kari E. Veblen  Wilfred O. Odadi  Duncan M. Kimuyu  Grace K. Charles  Hillary S. Young 《Herpetological Monographs》2018,40(3):95-97

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Water uptake through sweet cherry (Prunus avium L.) fruit pedicels: Influence of fruit surface water status and intact fruit skin     

Kari Louise Hovland  Lars Sekse 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(2):91-96

A modified potometer consisting of a water-filled glass tube mounted in parallel with a metric scale and connected to a fruit was used to study water uptake into detached fruits of sweet cherry. Results describing quantities of imported water from some introductory studies were in the same range as in previously published studies conducted with alternative methods. Water uptake was measured in fruits of four cultivars kept in air of approximately 50±5% RH followed by immersion in water 1–2 h into the experimental period. This caused a significant decrease in water uptake. However, the fruits continued to accumulate water at a reduced rate. When the fruits were dried, the water uptake immediately increased to the same level as before the immersion in water. The fruit skin of two cultivars was exposed to normal air after being ruptured with four shallow cuts to simulate cuticular fractures or shallow cracks. These two treatments did not give statistically different water uptake through the pedicel, although there was a tendency to an increased rate of water uptake in fruits with ruptured fruit skin.  相似文献   

What is your diagnosis? Hypophosphatemic rickets as a consequence of hypovitaminosis D     

McClanahan SL  Wilson JH  Anderson KL 《Journal of the American Veterinary Medical Association》2006,229(4):499-500

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Pressurised hot water extraction ofn-alkanes and polyaromatic hydrocarbons in soil and sediment from the oil shale industry district in estonia     

Juhani Kronholm  Johannes Kettunen  Kari Hartonen  Marja-Liisa Riekkola 《Journal of Soils and Sediments》2004,4(2):107-114

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Impact of liming on utilization of 59Fe‐chelates by lettuce (Lactuca sativa L.)     

Kari Ylivainio  Antti Jaakkola  Reijo Aksela 《植物养料与土壤学杂志》2006,169(4):523-528

A pot experiment was conducted to determine the utilization of iron (Fe) by lettuce (Lactuca sativa L. cv. Australian gelber). Iron was applied as ⁵⁹Fe in inorganic and chelated form, particularly biodegradable chelate, ⁵⁹Fe‐EDDS. Two stereoisomeric forms of ethylenediaminedisuccinate: [S,S]‐EDDS and a mixture of EDDS containing 25% [S,S]‐EDDS, 25% [R,R]‐EDDS, and 50% [S/R]/[R/S]‐EDDS, ethylenediaminetetraaceticacid (EDTA) and ethylenediimino bis(2‐hydroxyphenyl)acetic acid (EDDHA) were used as ligands. Lettuce was grown in unlimed and limed quartz sand with nitrate as the sole source of nitrogen. Liming decreased lettuce yields but had no effect on Fe concentrations, indicating that Fe concentrations were a poor indicator of Fe bioavailability within the plant. In unlimed sand, utilization of ⁵⁹Fe from all ⁵⁹Fe‐chelates was on the same level (2.8%–3.6%). In limed sand, only ⁵⁹Fe‐EDDHA maintained the ⁵⁹Fe utilization on a level (3%) comparable to that in unlimed sand. Although the utilization of ⁵⁹Fe from the other chelates decreased to 0.6%–1.1% after liming, Fe concentrations were not affected due to the increased uptake of indigenous Fe. The most biodegradable form of EDDS, namely ⁵⁹Fe‐EDDS(S,S), provided ⁵⁹Fe for lettuce as efficiently as the mixture of ⁵⁹Fe‐EDDS stereoisomers and the ⁵⁹Fe‐EDTA. Utilization of ⁵⁹Fe in inorganic form was 0.5% and 0.03% in unlimed and limed sand, respectively. This study shows that biodegradable ligands are able to serve as chelators to sustain Fe availability in calcareous environments. They may be of use especially in drip irrigation, where ligand accumulations may pose a threat to groundwater quality.  相似文献