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.
2018
Authors
Jorunn BørveAbstract
No abstract has been registered
Abstract
Modified atmosphere packaging (MAP) may inhibit undesirable quality changes of fruit and vegetables. The aim of this experiment was to evaluate the effect of MAP on selected quality parameters for sweet cherries (Prunus avium L.) stored at simulated distribution chain temperatures. ‘Lapins’ sweet cherries with maturity grade 4-5 and 6-7 were packaged in macroperforated polyethylene “carry bags” (control) and in trays wrapped in a laser perforated film giving passive modified atmosphere (MAP). After packaging, the cherries were stored at 4°C for 5 days and thereafter for 3 days at 4°C (chill) or 20°C (retail) simulating storage at chill or room temperature in the grocery stores. Headspace gas atmosphere in the MA packages, fruit quality, weight loss and amount of fungal fruit decay and other decays were recorded after 1, 5 and 8 days of storage. The gas atmosphere in MA packages was approximately 18% O2 and 4% CO2 at 4°C and between 6-9% O2 and 12-14% CO2 at 20°C. The weight loss was negligible in the MA packages at both storage conditions, whereas the cherries in carry bags showed a weight loss from 1 to 4%. The stem colour was significantly browner in the carry bags compared to the MA packages after 8 days of retail storage. Fungal decay was below 0.5% for both maturity grades stored at chill conditions for 8 days. At retail conditions, 4 and 6% decay was detected for maturity grade 4-5 in MA-packages and carry bags, respectively. For maturity grade 6- 7, the MA-packages had 9% decay and the carry bags 7%. The overall picture was that MA packaging for sweet cherries better maintained the fruit quality than the carry bags during the storage period of 8 days at two simulated retail conditions.
Authors
Guro BrodalAbstract
No abstract has been registered
Abstract
Different seed lots of Pinus spp. cultivated within South Africa were screened for the presence or absence of seed-borne fungi according to modified ISTA (International Seed Testing Association) prescribed protocols. Numerous (454 isolates) fungi were successfully isolated, purified and stored using agar slants and cryopreservation. Sydowia polyspora was isolated from six different seed lots from three Pinus species (P. greggii (South), P. elliottii and P. taeda) and was morphologically and molecularly identified. Koch’s postulates was fulfilled by inoculating one year old seedlings (wounded and unwounded) with a spore suspension (107 ml-1) obtained from 30 day old pure cultures grown on PDA. Inoculated and uninoculated control seedlings were incubated in a greenhouse at 220C until symptom development. Sydowia polyspora was re-isolated from symptomatic needles with both wounded and unwounded needles showing characteristic symptoms. No symptoms were apparent on the control seedlings. To the best of our knowledge, this is the first report of the fungus being isolated and recorded within the country. Further investigations will look at the prevalence, pathogenicity and characterization of the fungus within South Africa.
Abstract
The Svalbard Global Seed Vault was opened in 2008. The aim was to secure genetic diversity of crop plants important to future food production. The Seed Vault has the capacity to store 4.5 million seed samples, each containing on average 500 seeds sealed in airtight aluminum bags. By the end of 2016, the Vault had approximately 880,000 accessions representing more than 5000 plant species. The samples, originating from 71 gene banks and research institutes from all across the world, include major food crops such as wheat, rice, barley, sorghum, maize, legumes and forage crops, and vegetables. The seed samples are duplicates (backups) of seed stored in national, regional and international gene banks. Deposits can only be made by following a depositor agreement and the seed samples in the Vault remain the property of the depositing gene bank. The Vault is situated in permafrost at -3 to -4°C, but artificial cooling maintains a temperature of -18°C inside the Vault. Management of the Vault is secured through an agreement between the Norwegian Ministry of Agriculture and Food, the Crop Trust and the Nordic Genetic Resource Centre (NordGen). Secure storage of gene bank seeds in Svalbard was initiated during the 1980s, when the Nordic Gene Bank placed a collection of seed duplicates in an abandoned coal mine outside Longyearbyen in Svalbard. In addition to the secure storage of the base collection, a study of the longevity (germination and seed health) in long-term storage (100 years) in permafrost was started in 1986. A total of 42 seed samples of 16 common agricultural and horticultural Nordic species were included in the study. A set of sub-samples has been taken out for analyses every two and a half years during the first 20 years, and are taken out every five years for the next 80 years.
Abstract
In temperate forests, red wood ants (Formica aquilonia) are considered ecosystem engineers affecting ecosystem properties and functions. Possible effects of F. aquilonia ants on species communities of invertebrates and plants were studied in the pine-dominated Geitaknottane forest reserve, Norway. Species richness of carabids, lichens and epiphytes (tree-living lichens and bryophytes) was negatively affected by ant mound density. Species of all groups, except for lichens and snails, were affected either positively or negatively by ant presence. Food availability and interference competition are plausible explanations of decreased species richness and negative species associations in carabids; while collecting, foraging and changed chemical environment may explain decreased species richness in lichens and epiphytes. Thirteen out of 15 plant and invertebrate species were weakly associated with ant mound density. Associations of only two species (Carabus violaceus and Drusilla canaliculata) were negative, while Pella humeralis and Agroeca proxima were associated positively and very strongly with ant mounds. Positive associations with ants of those invertebrates may be a response to excessive abundance of food and chemical mimicry.
Abstract
Ophiostoma spp. (Ophiostomatales, Ascomycota) are well-known fungi associated with bark and ambrosia beetles (Curculionidae: Scolytinae, Platypodinae). Fungi in the Ophiostomatales include serious tree pathogens as well as agents of timber blue-stain. Although these fungi have been extensively studied in the northern hemisphere, very little is known regarding their occurrence on hardwoods in Europe. The aims of the present study were to identify and characterize new Ophiostoma spp. associated with bark and ambrosia beetles infesting hardwoods in Norway and Poland, and to resolve phylogenetic relationships of Ophiostoma spp. related to the Norwegian and Polish isolates, using multigene phylogenetic analyses. Results obtained from five gene regions (ITS, LSU, b-tubulin, calmodulin, translation elongation factor 1-a) revealed four new Ophiostoma spp. These include Ophiostoma hylesinum sp. nov., O. signatum sp. nov., and O. villosum sp. nov. that phylogenetically are positioned within the Ophiostoma ulmi complex. The other new species, Ophiostoma pseudokarelicum sp. nov. reside along with Ophiostoma karelicum in a discrete, well-supported phylogenetic group in Ophiostoma s. stricto. The results of this study clearly show that the diversity and ecology of Ophiostoma spp. on hardwoods in Europe is poorly understood and that further studies are required to enrich our knowledge about these fungi.
Authors
Robert Jankowiak Agnieszka Ostafińska Truls Aas Halvor Solheim Piotr Bilański Riikka Linnakoski Georg HausnerAbstract
Species of Leptographium are characterized by mononematous or synnematous conidiophores and are commonly associated with different arthropods. Some of them also produce a sexual state characterised by globose ascomata with elongated necks. Compared to investigations on coniferous trees, the occurrence of Leptographium species on hardwood trees has been poorly studied in Europe. During a survey of ophiostomatoid fungi on various hardwood tree species in Norway and Poland, three unusual species, which fit in the broader morphological description of Leptographium spp., were found in association with Trypodendron domesticum, Trypodendron signatum and Dryocoetes alni, and from wounds on a variety of hardwoods. Phylogenetic analyses of sequence data for six different loci (ITS1–5.8 S–ITS2, ITS2-LSU, ACT, b-tubulin, CAL, and TEF-1a) showed that these Leptographium species are phylogenetically closely related to the species of the Grosmannia olivacea complex. The first species forms a well-supported lineage that includes Ophiostoma brevicolle, while the two other new taxa resided in a separate lineage; possibly affiliated with Grosmannia francke-grosmanniae. All the new species produce perithecia with necks terminating in ostiolar hyphae and orange-section shaped ascospores with cucullate, gelatinous sheaths. These species also produce dark olivaceous mononematous asexual states in culture. In addition, two of the newly described species have a second type of conidiophore with a short and non-pigmented stipe. The new Leptographium species can be easily distinguished from each other by their appearance and growth in culture. Based on novel morphological characters and distinct DNA sequences, these fungi were recognised as new taxa for which the names Leptographium tardum sp. nov., Leptographium vulnerum sp. nov., and Leptographium flavum sp. nov. are provided.
Abstract
Blue and yellow sticky traps equipped with blue light emitting diodes (LEDs) were evaluated for their attractiveness to the western flower thrips (Frankliniella occidentalis Pergande) and compared to similar traps without light in two greenhouses with commercial production of either mixed herbs or Alstroemeria cut flowers. Blue traps were more attractive to F. occidentalis than the yellow traps in both crops, regardless of whether they were equipped with light or not. In herbs, the blue light equipped traps caught 1.7 to 2.5 times more thrips compared to blue traps without light, and 1.7 to 3.0 times more thrips than yellow traps with light. Blue light on both blue and yellow traps increased thrips catches in one out of two experiments in Alstroemeria. The blue light equipped traps caught 3.4 and 4.0 times more thrips than blue traps without light in coloured and white Alstroemeria cultivars, respectively, whereas yellow light equipped traps increased thrips catches 4.5 times compared to yellow traps without light in both coloured and white cultivars. The yellow light equipped traps caught, however, only equal to or only slightly more thrips than blue traps without light, and caught fewer thrips than the light equipped blue traps. The relative trapping efficiency of the different combinations of trap colour and light varied with experiment, crop and Alstroemeria cultivars. This suggests that factors other than merely the addition of light influenced the thrips' phototactic response to the traps. Such factors could be differences in the relative strength of the competition between attractive signals from traps and plants between the two crops and Alstroemeria cultivars, thrips density, seasonal lighting conditions or different pest management strategies and other operational procedures in the greenhouses. The light from the traps did not increase the thrips population on the plants below the traps. The implications of the results for thrips control and suggestions for further studies are discussed.
Authors
A. Pérez-Sierra V. Rafiei C. Olivares H. Rees S. van der Linde N. Keča K. Schwanda Venche Talgø B. B. LandaAbstract
No abstract has been registered