Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2010
Forfattere
Anne Falk ØgaardSammendrag
In catchments with sensitive water bodies it is of interest to improve P retention in the constructed wetlands by including P adsorbing filters in the end of the wetland. Construction of filters at the outlet of pipe drains is also a possible mitigation option. P retention in filters is expected to be a combined effect of retention of soil particles that is too small for sedimentation in the wetland and adsorption of dissolved P. Here, results from a laboratory study of adsorption of phosphate to four different materials of interest for use as filters in constructed wetlands are presented. The filter materials tested were Maxit Filtralite P, Kemira CFH-12, crushed lime stone and coral sand. In Kemira CFH-12, Fe is the active component (ferric hydroxide granules), whereas in the other three Ca is the active component. The laboratory experiment was performed with four different phosphate concentrations in the range from 50 to 500 µg P/L, three different contact times (30 min, 2h and 6h) and with 1 g filter material to 30 ml solution. The ferric hydroxide granules were superior the other filter materials. At 30 min contact time and 500 µg P/L 88 % of P was adsorbed, whereas at 6 h contact time 99 % of P was adsorbed. Crushed lime stone adsorbed less than 20 % of P in the 500 µg P/L solution. Filtralite P and coral sand showed quite similar ability to adsorb P. At 30 min contact time and 500 µg P/L 35-50 % of P was adsorbed, whereas at 6 h contact time 78-90 % of P was adsorbed.
Forfattere
May Bente Brurberg Xiaoren Chen Jahn Davik Håvard Eikemo Inger Martinussen Monica Skogen Yang Hu Abdelhameed Elameen Sonja KlemsdalSammendrag
Phytophthora cactorum causes crown rot in strawberry (Fragaria x ananassa Dutch.), which is characterized by wilting and eventually collapse of the plant. An efficient control measure is the use of resistant cultivars, however most commercial cultivars are susceptible to the disease. The aim of our work is to generate basic knowledge about P. cactorum resistance as well as to develop genetic markers that can be used as tools for development of resistant cultivars. The genetic complexity of the octoploid cultivated strawberry, has led to development of the diploid wild strawberry (F. vesca) as a model system for Fragaria. We have identified suitable parents after screening accessions of diploid Fragaria sp. for resistance [1], and generated a mapping population which we are currently characterizing. In order to study the plant-pathogen interaction in detail we have identified and characterized resistance genes from diploid strawberry and effector genes from P. cactorum using different transcriptional analysis techniques; nucleotide-binding site (NBS)-profiling for resistance genes, and suppression subtractive hybridization (SSH) as well as a designed effector-specific differential display (ESDD) for genes involved in pathogenicity. This work is supported by The Research Council of Norway. [1] Eikemo H, Brurberg MB, Davik J (2010). Resistance to Phytophthora cactorum in diploid Fragaria species. HortScience. 45:193-197.
Sammendrag
Growth, death and N dynamics of leaves, stolons and roots of harvested and unharvested white clover (cv.""Snowy"") were studied in a pot (Sturite et al., 2006) and a combined plot and root window experiment in southeast Norway (Sturite et al., 2007). Leaves of undisturbed plants contained 1.5 g N pot-1 or 6 g N m-2 in late autumn (roughly assuming 4 plants m-2). About 60% of the leaves turned over within the growing season. Thus, in an established, undisturbed white clover stand, leaf turnover would contribute 9 g N m-2 during the growing season. For stolon and root segments tagged during the first growing season, 100% and 91%, respectively, were still present in late autumn. By the end of the second growing season, the corresponding values were 77% and 46%. Thus, dead stolons and roots contributed substantially more to N deposition in the soil in the second than in the first growing season. If taking the turnover of all plant organs into account, the gross N input to the soil-plant system during the two growing seasons would amount to 63 g N m-2. This corresponded to a 2.5-fold increase over the total N in the shoots harvested during the same period.
Forfattere
Siv Lene Gangenes SkarSammendrag
Abstract Quality of vegetables is influenced by many factors during growth. Changeable factors for the farmers are; variety, type of fertilizer, pest treatment methods and to some extent soil type. On the other hand pests (esp. fungi spore infection by air), precipitation, temperature and light conditions are unchangeable factors that can vary largely from year to year. In this presentation the most important pre harvest factors involved in quality changes of vegetables are discussed. Nitrogen tends to be an important factor that affects both yield and physical quality of vegetables as well as dry matter and content of minerals and secondary components. Generally, reduced levels of nitrogen increases dry matter and concentration of essential amino acids, flavour components, sugars, phenolic compounds, but not carotenes. On the other hand, content of nitrate decreases with level of nitrogen fertilisation. However, too little nitrogen restricts growth and can reduce quality of nitrogen demanding crops like Brassica vegetables. Attach by plant pathogens and insects stimulate the plants defence system by producing secondary plant compounds like phytoalexins and antioxidants that could either have positive or negative impact on health. On the other hand, certain pests could produce mycotoxins that contaminate vegetables and make them toxic to humans. Pesticide free cultivation systems can in general increase the probability for higher content of phytoalexins and mycotoxins in vegetables. Organic farming with absence of pesticides and restricted use of nitrogen adapt for an increase in content of the positive health related compounds, while at the same time decreasing the negative related compounds like pesticides and nitrate. Despite this high importance of nitrogen and pest treatment, climate factors that differ between years has shown to highly affect content of secondary compounds and sensory quality of vegetables. On the other hand, variety is a controllable factor that has an overwhelming effect of several quality factors like, sensory quality, colour and content of vitamins, minerals and secondary health related components. This could be utilised to improve quality of vegetables in both organic and conventional systems.
Forfattere
Marie E. Olsson Karl-Erik Gustavsson Ingunn M. VågenSammendrag
Effects of heat treatment and storage on quercetin and isorhamnetin content, major and minor components of isorhamnetin and quercetin glucosides and aglycone, were investigated in onion (Allium cepa L.). The sweet onion ‘Recorra" and red onions ‘Hyred" and ‘Red Baron" were cultivated in the south part of Norway, and thereafter stored for eight months. The onions were either not field dried, but stored directly, or field dried and then stored, or field dried and then heat treated before storage. Neither storage nor heat treatment caused any major differences in total flavonol content in the investigated sweet onion as well as in the red onion cultivars. The two major quercetin glucosides differed in their changes in content during storage; quercetin-4¢-glucoside did not show any consistent changes during storage in the two red cultivars, independent of treatment, whereas quercetin-3,4¢-diglucoside increased significantly by 30 or 51 % respectively during storage in ‘Hyred" and ‘Red Baron" in the 24h heat treated onions. Isorhamnetin-4"-glucoside, which might possibly be of special interest from a human health point of view, was present at 2-3 times higher amount in the sweet onion cultivar than in the two red cultivars. Some of the quercetin glucosides present at lower concentrations, isorhamnetin-3,4"-diglucoside, quercetin-3,7,4"-triglucoside, and quercetin-7,4"-diglucoside increased during storage in all treatments in both ‘Hyred" and ‘Red Baron", though sometimes a decrease was found at the end of storage.
Forfattere
David M Gadoury Arne Stensvand Robert C. Seem Catherine Heidenreich Maria Herrero Mary Jean Welser Andrew Dobson Håvard Eikemo Belachew AsalfSammendrag
Cleistothecia on leaves of deciduous perennials are often dispersed before leaf fall to other substrates. In contrast, strawberry leaves remain attached during winter, and cleistothecia of Podosphaera macularis remained attached to these leaves. Release of overwintered ascospores was coincident with renewed plant growth, and pathogenicity of ascospores was confirmed. Upper and lower surfaces of emergent leaves were similarly susceptible, but upper surfaces were obscured by folding in emergent leaves. Emergent leaves exposed to airborne inoculum developed severe infection of the lower surface, but not the obscured upper surface. Emergent leaves acquired ontogenic resistance during unfolding, and the upper leaf surface thereby escaped infection. We found no evidence that the pathogen survives winters in New York, USA or Norway within crown tissue. Plants stripped of infected leaves remained mildew-free when forced after overwintering, while mildew colonies commonly developed on emergent leaves of plants not stripped of mildewed leaves. Unsprayed plots established using mildew-free plants either remained asymptomatic or developed only traces of powdery mildew during one growing season, even when located within 100 to 150 meters of severely diseased plots. In summary, our results suggest the following: (i) sanitation, use of disease-free plants, and eradicative treatments could contribute greatly to management of strawberry powdery mildew; (ii) cleistothecia represent a functional source of primary inoculum; and (iii) the common observation of higher mildew severity on lower leaf surfaces may reflect escape of the upper epidermis due to the combined effect of leaf folding and rapid acquisition of ontogenic resistance.
Sammendrag
In Norway, Nordmann fir (Abies nordmanniana) and subalpine fir (A. lasiocarpa) are the dominant Christmas tree species, and noble fir (A. procera) the dominant bough plant species. Several fungal shoot and foliage diseases may reduce their marketability. To determine if fungi found to cause diseases on fir in Norway might be seed borne, samples from twelve seed lots, including five Nordmann fir (from Austria, Georgia and Russia), four subalpine fir (from Canada and Norway) and three noble fir seed lots (from Norway) have been tested using agar plate methods (PDA and WA). The most important finding was that Sydowia polyspora was present on seed from all firs from all countries. Recently, it has been demonstrated in Norway that this fungus is the biotic cause of cause current season needle necrosis (CSNN), which is considered a major disease in the Christmas tree and bough production both in Europe and USA. Sirococcus conigenus, causing shoot blight of several conifer species, was found in a Norwegian A. procera seed lot (31% infected seeds), which to our knowledge is the first report of this pathogen on noble fir seed. Caloscypha fulgens, the seed or cold fungus, was recorded at low levels on subalpine fir from Canada. In addition 20 fungal genera and an unidentified fungus were recorded. Species within some of these genera are known pathogens in nurseries and production fields.
Sammendrag
Colletotrichum acutatum causes bitter rot (often named anthracnose) in cherry and apple. It is the most important fruit decay in sour cherry in Norway and may give severe losses also in sweet cherry and apple. We have found the fungus in all fruit and berry crops grown commercially in the country and on many ornamentals and a few weeds. Single spore isolates frequently developed the ascigerous stage of the fungus (Glomerella acutata) in culture, but it was not detected on apple or cherry plant material. If still attached to the tree, fruits and fruit stalks of sour cherry infected the previous year produced conidial inoculum throughout the entire following season. Also newly infected sour cherry flowers produced conidial inoculum until harvest. Up to 80% of the fruit spurs on sweet cherry had buds infected with C. acutatum in spring. Apple buds also contained the fungus, but to a much lower extent. More than 90% of the sweet cherry leaves could be infected with C. acutatum around harvest in heavily infected orchards. Symptoms on leaves never appeared in the orchards. We also found such asymptomatic leaf infections in apples. Most of the inoculum seemed to be present on the fruit trees themselves. However, initial inoculum in newly established, disease free plantings may be introduced from older fruit trees, ornamentals and weeds in or in close vicinity to the orchards.
Forfattere
Dag-Ragnar Blystad Karen Rae Bone May Bente Brurberg Erling Fløistad Roar Moe Arild Sletten D. L. Davies Carl Jonas Jorge Spetz Sonja KlemsdalSammendrag
We have beendoing research on two phytoplasma diseases relevant for Norwegian plantproduction. Theoccurrence of Apple proliferation phytoplasma in NorwayOurinstitute was made aware of suspicious symptoms in 1996. A few trees of apple‘Summerred’ in Gvarv, Telmark County, had symptoms looking like appleproliferation. This case initiated a survey. The first samples were analyzed inEngland. Later we have done the PCR-diagnosis in our own lab.During asurvey carried out from 1996 to 1998, Apple proliferation was found in 14orchards: 1 experimental orchard inTelemark County, 4 orchards in Vestfold County, 4 orchards in Hordaland Countyand 5 orchards in the County of Sogn og Fjordane.Appleproliferation has later also been found at other locations. From this we canconclude that this quarantine disease is found in almost all importantfruit-producing districts. It is important to follow the situation to stopfurther spread of this disease. All infected trees have been eradicated.Theamount and distribution of Poinsettia branch-inducing phytoplasma in poinsettiaFree-branchingpoinsettias (Euphorbia pulcherrima) were first introduced during the sixties throughthe Norwegian cultivar ‘Annette Hegg’. The identity of the “branching agent”,was proven to be a phytoplasma, termed Poinsettia branch-inducing phytoplasma(PoiBI) (Lee et al. Int. Journal of Syst. Bacteriology 48,1153-1169.1998).Without phytoplasma, poinsettias grow tall, and produce very few branches.We havestudied the relative amount and distribution of PoiBI in poinsettia and howthis relates to branching in different cultivars grown under different lightlevels and temperatures using a quantitative PCR assay (TaqMan). Results fromthis work were presented.
Forfattere
Christian Linder Janet Allen Catherine Baroffio Agata Broniarek-Niemiec Victorio Brookes Jerry Cross Cathy Eckert Rudolf Faby Bruno Gobin Alberto Grassi Adrian Harris Barbara Labanowska Emilie Lascaux Carlo Malavolta Vincent Michel Slobodan Milenkovic Thilda Nilsson Paivi Parikka Klaus Paaske Jean-Jacques Pommier Daniel Prodorutti Lene Sigsgaard Arne Stensvand Christer Torneus Nina Trandem Tuomo Tuovinen Gabor VetekSammendrag
The usage of plant protection products and biocontrol agents in soft fruit production has always been an important subject for the IOBC/WPRS Working Group "Integrated Protection of Fruit Crops" Study Group "Soft Fruits". The usage of pesticides and biological control methods varies considerably between countries and it is very difficult to get a good overview on the range of products that are applied or in development in soft fruits. In order to share and facilitate the flow of information, the Study Group "Soft Fruit" initiated a survey on the availability and usage of active ingredients and biocontrol agents in the different European countries in 2007. First, the most important pests and diseases in strawberry and raspberry production were identified. Then members of the different countries listed available products on the domestic market and indicated their usage in the field. So far 15 countries have contributed to the survey. The received data are accessible on the website http://www.any3.ch/IOBC/Softpest/index.html