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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2010

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Abstract

The effects of postflowering temperature on the fruit chemical composition of Glen Ample raspberries were studied under controlled environment conditions. The berry weight decreased significantly with increasing temperature (12, 18, and 24 degrees C) and with progress of the harvest period. Because the moisture content increased in parallel with the berry weight, the antioxidant capacity (AOC) and the concentration of a range of bioactive compounds decreased with decreasing temperature and progress of the harvest season when expressed on a fresh weight basis in the conventional way. Under those circumstances, dry weight units are therefore preferable. However, despite the dilution effect of large berries, the concentration of ascorbic acid (vitamin C) increased with decreasing temperature, even on a fresh weight basis. Berry AOC was closely correlated with total phenolic concentration (r = 0.958), predominantly anthocyanins and ellagitannins. While a total of 10 anthocyanins were detected, cyanidin-3-sophoroside and cyanidin-3-(2(G)-glucosylrutinoside)-rutinoside accounted for 73% of the total, the former decreasing and the latter increasing with increasing growth temperature. By far, the most prevalent ellagitannins were lambertianin C and sanguiin H-6, both of which increased significantly with increasing temperature. It is concluded that the growth temperature has significant and contrasting effects on the concentration of a range of potentially bioactive compounds in raspberry.

Abstract

Red raspberry (Rubus idaeus L.) is an economically important small fruit species, rich in antioxidants and other phytochemicals (Rao and Snyder, 2010). Most research in the area of screening the antioxidant activity in dietary plants have mainly been focused on variation among species and cultivars and effects of postharvest handling and storage (e.g. Kalt et al., 2002). Little is known about the impact of environmental factors such as temperature and light conditions. The use of plastic tunnels for out-of-season production of red raspberries has expanded production in Norway. This involves a change in climate environment which might influence the chemical composition of the fruits. Here we present the results of an investigation of temperature on fruit quality of red raspberry (Remberg et al., 2010).

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Abstract

A collection of four clonal isolates of Podosphaera aphanis was heterothallic and was composed of two mutually exclusive mating types. Cleistothecial initials approximate to 20 to 30 mu m in diameter were observed within 7 to 14 days after pairing of compatible isolates and developed into morphologically mature ascocarps within 4 weeks after initiation on both potted plants maintained in isolation and in field plantings in New York State and southern Norway. Ascospores progressed through a lengthy maturation process over winter, during which (i) the conspicuous epiplasm of the ascus was absorbed; (ii) the osmotic potential of the ascospore cytoplasm increased, resulting in bursting of prematurely freed spores in water; and, finally, (iii) resulting in the development of physiologically mature, germinable, and infectious ascospores. Release of overwintered ascospores from field collections was coincident with renewed plant growth in spring. Overwintered cleistothecia readily dehisced when wetted and released ascospores onto glass slides, detached strawberry leaves, and leaves of potted plants. Plant material exposed to discharged ascospores developed macroscopically visible mildew colonies within 7 to 10 days while noninoculated controls remained mildew free. Scanning electron and light microscopy revealed that cleistothecia of P. aphanis were enmeshed within a dense mat of hyphae on the persistent leaves of field-grown strawberry plants and were highly resistant to removal by rain while these leaves remained alive. In contrast, morphologically mature cleistothecia on leaves of nine deciduous perennial plant species were readily detached by simulated rain and seemed adapted for passive dispersal by rain to other substrates. Contrary to many previous reports, cleistothecia appear to be a functional source of primary inoculum for strawberry powdery mildew. Furthermore, they differ substantially from cleistothecia of powdery mildews of many deciduous perennial plants in their propensity to remain attached to the persistent leaves of their host during the intercrop period.

Abstract

The water quality in the western part of Lake Vansjø in south eastern Norway is classified as very poor due to excessive growth of blue green algae. It has been shown that phosphorus (P) losses are high from a subcatchment where potatoes and vegetables are grown on 25 % of the agricultural area. The water quality of the lake is of great concern because it is the drinking water reservoir of 60.000 inhabitants and an important recreation area for people living in the area. An integrated project funded by the government was started in 2008 in order to improve the water quality of the lake. Within this project, the public agricultural management, agricultural advisors, farmers and the Norwegian Institute for Agricultural and Environmental Research (Bioforsk) collaborate to attain the target of improved water quality. The farmers are encouraged to sign a contract where they will receive a financial support for covering extra costs for committing to a set of restrictions and mitigation options aiming at reduced P losses. Vegetable- and potato fields give large challenges when aiming at reduced P losses. A large part of the research activity is therefore related to possible mitigation options on these fields, e.g. effect of reduced P fertilization on yields and quality of bulb onion (Allium cepa), carrots (Daucus carota) and white cabbage (Brassica oleracea var. capitata alba), and evaluation of catch crops as a mitigation option for reduced soil erosion from these fields. Development of constructed wetlands to include filters that adsorb P and measurement of P losses through tile drains are also included in the project.