Mette Thomsen

Research Scientist

(+47) 406 22 631
mette.thomsen@nibio.no

Place
Apelsvoll

Visiting address
Nylinna 226, 2849 Kapp

Abstract

The maturity stage of carrot and the temperature strategy during storage are essential factors in maintaining storage quality during long-term storage. The aim of the study was to examine the effect of maturity and storage strategy on storage quality in different cultivars of carrot (Daucus carota subsp. sativus). Two cultivars, ‘Nominator’ and ‘Romance’, harvested at three different maturity levels were stored with different temperature strategies in small-scale experimental stores. The different maturity levels were obtained by different sowing dates. The study was conducted over 2 years and storage seasons in 2019-2020 and 2020-2021. The carrots were stored with three different temperature strategies with stable temperature at 0, 2 or 0°C interrupted with intervals of 2 weeks with 4°C in February and in March. After six-months storage we found that weight loss was higher (7.8%) after storage when the temperature was not stable during storage (fluctuations up to 4°C in February and March) than at stable temperatures at 0 or 2°C. The number of healthy roots after storage was highest in the most mature carrots (91%) while there were less healthy roots in the least mature roots (85%) (P<0.05). Diseases detected after storage were gray mold (Botrytis cinerea), liquorice rot (Mycocentrospora acerina), tip rot, crater rot (Fibularhizoctonia carotae), Fusarium rot (Fusarium spp.) and cavity spot (Pythium spp.). There was significantly more liquorice rot in Nominator (1.9%) than in Romance (0.6%). There was more tip rot in the least mature carrots (3.3%) compared to the other two maturity levels (1.3 and 1.5%).

Abstract

Temperature and humidity were measured in 28 vegetable stores and corelated to quality of stored vegetable through two storage seasons. The vegetables swede, carrot and celeriac were grown at one site within each of the four regions in Norway ROG, MID, INN and OSL, respectively. After harvesting, the vegetables were weighed and visually assessed for any injuries or diseases and stored in different stores within the same region as grown. Four bags dug down in four storage bins in each store. Temperature and humidity were logged in each bag as well as on the top of each bin and on wall of the storage. In general, we found significant differences in the storage quality between the different storages as well as between regions. Correlating data on quality with temperature data shows for carrot a tendency to an increase in the proportion of fresh roots and reduction in incidence of tip-rot by an increased average temperature during the first two weeks of storage. This corresponds to results from tested various wound healing treatments. An increase in accumulated temperature during the storage period showed a tendency to increase the emergence of tip-rot and reduce the proportion of fresh roots. For celeriac, the effect of temperature varied between years, possibly due to a large difference in quality in the two test years, and it was difficult to draw any conclusion. In swede, the results suggest that a decrease in temperature in the first two weeks of storage increased the risk of the symptom shown as black veins in the phloem. Nutrient status was found to be a possibly predisposing factor for reduced storage quality in celeriac. Balance of boron (B) to calcium (Ca) and zinc (Zn) were studied in two sites. Highest incidence of brown spots and lowest proportion of fresh roots following storage was found in celeriac with the lowest Ca/B ratio in leaves, lowest content of Zn in the leaves and roots and lowest soil pH.

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Abstract

There is an increased interest in identifying beneficial compounds of plant origin that can be added to animal diets to improve animal performance and have a health-promoting effect. In the present study, nine herb species of the Norwegian wild flora or which can be cultivated in Norway were selected for phytogenic evaluation (hops, maral root, mint, oregano, purslane, rosemary, roseroot, sweet wormwood, yarrow). Dried herbs were sequentially extracted with dichloromethane (DCM), ethanol (EtOH) and finally water (H2O) by ultrasound-assisted extraction (UAE). The UAE protocol was found to be more rational than conventional Soxhlet with respect to DCM extraction. Total extraction yield was found to be highest for oregano (Origanum vulgare) with 34.4 g 100−1 g dry matter (DM). H2O-extracts gave the highest yields of the three solvents, with up to 25 g 100−1 g DM for purslane (Portulaca oleracea ssp. sativa) and mint (Mentha piperita). EtOH- and H2O-extracts were the most efficient extracts with respect to free radical scavenging capacity (ABTS (=2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), and oregano, mint, hops (Humulus lupulus) and maral root-leaves (Leuzea carthamoides) were found to be the most efficient antioxidant sources. Hops (EtOH-extract) contained α- and β-acids, xanthohumols, chlorogenic acid and the hitherto unreported 3-O-glucosides of kaempferol and quercetin. Maral root-leaves contained among other compounds hexosides of the 6-hydroxy- and 6-methoxy-kaempferol and -quercetin, whereas roseroot (Rosea rhodiola) revealed contents of rosavin, rhodiosin and rhodionin. Sweet wormwood (Artemisia annua) contained chlorogenic acid and several derivatives thereof, scopoletin and poly-methylated flavones (eupatin, casticin, chrysoplenetin). Antimicrobial potential of different plant extracts was demonstrated against Gram-positive and Gram-negative bacteria using the indicator organisms Staphylococcus aureus, and Escherichia coli, and the Atlantic salmon bacterial pathogens Moritella viscosa, Tenacibaculum finnmarkense and Aliivibrio wodanis. DCM extracts possessed the highest activities. Data demonstrate the potential ability of herb extracts as natural antimicrobials. However, future safety studies should be performed to elucidate any compromising effect on fish health.

Abstract

Horticultural production systems are under pressure to find environmentally friendly growing media. Peat is currently the most popular substrate for fresh potted herbs production; however, this raw material is not sustainable due to the large amount of greenhouse gases released during its harvesting. Therefore, the goal of the study was to test the performance of various commercial wood fiber products and compare them with peat and coir in an ebb-and-flow production system with basil (Ocimum basilicum L. 'Marian'). Basil plants were grown in three different pot sizes (6, 9 and 12 cm in diameter) and under various fertigation regimes (EC 1, 2 and 3). Height and biomass of the plants were recorded when the best performing plants reached the commercial stage. The tallest plants and greatest biomass were produced in peat and coir, however, the results confirm that wood fiber can be a promising substrate alternative. Further research is needed to study, among others topics, how to modify some properties of wood fibers to fulfil their potential as a replacement for non-sustainable growing media in production of herbs in pots.

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Abstract

Even though plants represent an essential part of our lives offering exploitational, supporting and cultural services, we know very little about the biology of the rarest and most threatened plant species, and even less about their conservation status. Rapid changes in the environment and climate, today more pronounced than ever, affect their fitness and distribution causing rapid species declines, sometimes even before they had been discovered. Despite the high goals set by conservationists to protect native plants from further degradation and extinction, the initiatives for the conservation of threatened species in Europe are scattered and have not yielded the desired results. The main aim of this Action is to improve plant conservation in Europe through the establishment of a network of scientists and other stakeholders who deal with different aspects of plant conservation, from plant taxonomy, ecology, conservation genetics, conservation physiology and reproductive biology to protected area's managers, not forgetting social scientists, who are crucial when dealing with the general public. in situ plant conservation, ex situ plant conservation, conservation genetics, red lists of threatened plant species, citizen science

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Abstract

Several factors may define storability in root crops. In the following paper, preliminary results are presented from two experiments performed to test factors affecting storage quality of carrot. The study have focused on 1) soil loosening/soil compaction and 2) different cultivars of carrot and root age considered by the length of the growing period. The results so far indicate that the soil compaction had few effects on storability of carrot, but did seem to negatively affect the length of the carrot. Soil loosening reduced the occurrence of liquorice rot caused by Mycocentrospora acerina. Large differences were found in storability between the ten tested carrot cultivars and length of growing period tended to be negatively correlated to storability. We conclude that a number of precautions in carrot production may increase storability and thus economic performance.

Abstract

After harvest, vegetables go from storing assimilates to break down of assimilates and it is of crucial importance to slow down this process. Controlling the pre-storage period may contribute to maintain high quality in root vegetables during long-term storage. The aim of this 2-years study was to investigate the effect of seven different pre-storage strategies (direct to 0°C vs. down 1°C per day vs. 0.2°C temperature reduction per day and wound healing at 10°C with low/high humidity) on root storability in four cultivars of carrot (Daucus carota subsp. sativus) stored in 2016/2017/2018, swede (Brassica napus) in 2017/2018 and celeriac (Apium graveolens var. rapaceum) in 2017/2018. Mass loss and disease incidences were determined during and after long-term storage (6-7 month) in small-scale stores. Wound healing with low humidity resulted in larger mass loss than the other preharvest strategies in carrot and celeriac. In carrot, slow temperature reduction (0.2°C per day) also resulted in larger mass loss than the other strategies. Significantly higher numbers of infected roots, dominated by licorice rot (Mycocentrospora acerina), tip rot and gray mold (Botrytis cinerea), occurred in carrots stored at 0°C immediately compared to roots with a period of wound healing and slow temperature decline. In celeriac, the incidence of gray mold (Botrytis cinerea) and licorice rot (Mycocentrospora acerina) were significantly reduced with wound healing at low humidity. Storage quality of swede was not affected by pre-storage strategies. This study shows that prestorage strategies affect mass loss and disease incidence in celeriac and carrot during and after long-term storage.

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Abstract

Transnational cooperation is a common strategy for addressing research and development (R&D) issues resulting from similar challenges that cut across administrative borders. Value chains for food and drinks are complex, and transdisciplinary work is recognised as a method for solving complex issues. The Northern Cereals project ran from 2015 to 2018, and its goal was to increase cereal production and the value of grain products in four regions in the Northern Periphery programme area. The project included both R&D, but the main emphasis was on development, and was carried out by transdisciplinary cooperation between R&D partners and small and medium-sized enterprises (SMEs). By reviewing the project’s methods, outcomes and composition, we discuss if a framework of transnational and transdisciplinary cooperation can help to develop the value chain from local barley to beer. We found that transnational cooperation was achieved successfully, that stakeholder involvement was crucial, but that academic disciplines such as marketing and innovation could have been included. In addition, we recognised that much work remains to further increase cereal production and the use of local grain in the Northern Periphery region, but believe that this project has laid a good foundation for further progress.

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Abstract

Rhodiola rosea L. (roseroot) is an adaptogen plant belonging to the Crassulaceae family. The broad spectrum of biological activity of R. rosea is attributed to its major phenyletanes and phenylpropanoids: rosavin, salidroside, rosin, cinnamyl alcohol, and tyrosol. In this study, we compared the content of phenyletanes and phenylpropanoids in rhizomes of R. rosea from the Norwegian germplasm collection collected in 2004 and in 2017. In general, the content of these bioactive compounds in 2017 was significantly higher than that observed in 2004. The freeze-drying method increased the concentration of all phenyletanes and phenylpropanoids in rhizomes compared with conventional drying at 70 °C. As far as we know, the content of salidroside (51.0 mg g−1) observed in this study is the highest ever detected in Rhodiola spp. Long-term vegetative propagation and high genetic diversity of R. rosea together with the freeze-drying method may have led to the high content of the bioactive compounds observed in the current study.

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Abstract

After harvesting, the Norwegian root vegetables are normally stored at refrigerated temperatures for 5 to 7 months. During this period, up to 30% of the products are lost. The goal is to reduce the diseases, the product loss and energy consumption, in addition to increase shelf-life and storage period. Twenty-eight commercial root vegetable cold-stores were instrumented to measure air temperature, relative humidity and product temperature. The study was done over two years. The cold-stores were located in four different regions of Norway. The three focus-products carrot, swede and celeriac were harvested from one field in each region in open wire nets. The nets were placed in the various cold-stores in the respective regions and put in the wooden bins together with the producer's own products. The quality and yield of the products were determined and correlated to the storage condition. The various storage condition negatively affects the respiration and quality of the root vegetables, storage-life, and influence on the cooling capacity of the refrigeration systems.

Abstract

Rhodiola rosea is a perennial flowering plant with a long history as a medicine plant. The plant contain a range of bioactive compounds including salidroside, rosavin, rosarian and rosin. Some of the compounds are characterized as adaptogens, meaning they can increase the body’s resistance to various stressors. An increased demand for better pharmaceuticals has stimulated the development of new methods for agricultural as well as in vitro cultivation of medicinal plants. A new technology, called rhizosecretion of biologically active chemicals, can provide a continuous supply of biologically active compounds over the lifetime of plants. The plants will then be grown under controlled conditions. In order to increase the production of bioactive compounds in Rhodiola rosea under these conditions it is therefore hypothesized that the biosynthesis can be upregulated by growing it under specific temperature and light quality treatments. An experiment with different light and temperature regimes was established for optimal accumulation of biologically active compounds. Four different clones of Rhodiola rosea were grown under three different light conditions (red, blue and white) combined with two different temperatures (9 and 18 °C) for three weeks. The gene expression of Tyrosine decarboxylase (TyrDC), found to have a key role in the biosynthesis of salidroside, were investigated. In addition, the content of various bioactive compounds were quantified before and after treatment. The results indicate that use if high producing clones is most important for high production and that there is a short-term upregulation during blue light treatment. During the three-week treatment, there was no significant effect of the temperature treatments.

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Abstract

Preliminary results on aroma profiles (GC-MS) related to storage conditions (temperature, time and packaging atmosphere) are presented. The vegetables used in the experiments were rutabaga, carrot and turnip, which were peeled and cut before packaging, and stored at two different temperatures. O2 and CO2 concentrations in the packaging atmosphere were measured during the storage period to calculate the respiration rates of the produce. Cubed carrot showed a higher respiration rate than cubed turnip and rutabaga. Samples for analysis of volatiles were taken after 0 and 7 or 10 days. This type of analysis could be used as a complement to sensory analysis.

Abstract

Rhodiola rosea is a well-known herbal medicinal plant, valued for highly active secondary metabolites. It is growing wild in most parts of Norway and mountainous areas in a number of countries. Some of the most important metabolites are believed to be salidroside, cinnamyl alcohol, glycosides (rosine, rosavine, rosarine), flavonoids (rhodionin, rhodiosin,rhodiolin) and terpenes (Galambosi 1999). In Norway, germplasm collections of R. rosea are maintained by NIBIO; at Apelsvoll in southern Norway, consisting of 97 different clones. The ranges in content of secondary metabolites in the collection are for rosavin 2.90-85.95 mg g-1, salidroside 0.03-12.85 mg g-1, rosin 0.08-4.75 mg g-1, tyrosol 0.04-2.15 mg g-1 and cinnamyl alcohol 0.02-1.18 mg g-1. Clones selected from the collection has throughout been studied for different aspects affecting plant growth and production of secondary metabolites. We have looked into cultivation requirements of the plant like water requirement, effects of nutrient levels (N and K) and soil types. Postharvest treatment from washing, cutting,drying and differences in the plant parts. Finally we will in this presentation also present results on requirements for dormancy release and the clonal differences and also how use of primers may affect production of secondary metabolites.

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Abstract

Swede is known as a healthy vegetable with a high content of vitamin C. However, very few studies have worked with the aim to evaluate how varieties, soil type and fertilizer interact and affect quality in swede. In the present study two varieties of swedes (‘Vige’ and ‘Vigod’) were grown on peat, loam and sand, with three levels of K (0, 120, 240 kg ha-1) and N fertilizer (0, 80, 160 kg ha-1). Low to moderate levels of N gave highest saleable yield, highest content of vitamin C and lowest content of nitrate. Peat soil gave highest saleable yield, lowest soluble solids and vitamin C and highest nitrate content. Soluble solids and vitamin C were negatively correlated with total root yield. Sandy soil gave lowest saleable yield, sweetest taste and lowest nitrate content. Contents of total, aliphatic, indole and individual glucosinolates, on dry matter basis, were highest on peat. N fertilization increased the content of most glucosinolates, whereas K affected glucobrassicin at the highest N level. Progoitrin was lowest in roots grown on sand, and was affected by N level and variety on sand and loam soils. Consumers preferred ‘Vigod’, which had the highest intensity of sweetness, although ‘Vige’ had more vitamin C and less nitrate.

Abstract

Optimization of produce quality and storage conditions to reduce loss during long-term storage of root vegetables in Norway (OPTIROOT, 2016-2019) Authors: Thomsen, M.G., Indergaard, E., Asalf, B., Heltoft, P., Wold, A.B., Nordskog, B., Guren, G, Dyste, J. & Larsen, H. Author’s affiliation: Key words: carrot, swede, celeriac, storage technology, diseases, physiological disorder, packaging, nutrition Reducing yield loss along the supply chains is important for resource sustainability in vegetable production. Norwegian root vegetables are typically stored 6 to 8 months before consumption, often resulting in 20-30% loss post harvest. In OptiRoot 26 producers, refrigeration-technology companies, sensor developer, grower’s organisation, agricultural advisory service, and four research institutes are cooperating and conducting research to improve storage quality of carrot, swede and celeriac. The research focuses on: i) Fertilizer/Boron deficiency affects the storage quality of root vegetables and amount, methods of application, and timing of boron are studied in swede and celeriac. ii) Interaction between storage conditions/functions and produce quality of the root vegetables through mapping of technical features of 27 storages. The storage conditions recorded are relative humidity, air movement, temperature in boxes and storages, and physical features of storages. In addition, the physiological and health status of the produces are assessed one week before harvest, postharvest and post-storage. The prevalence of fungal diseases or disorders varied from region to region and between storages. iii) Effects of pre-storage wound healing are tested using seven different temperature strategies (direct to 0° C vs. down 0.2° C per day vs. 1° C per day) and low/high humidity in carrot (2016/17/18), celeriac and swede (2017/18/19). Preliminary results show that wound healing reduced loss due to fungal infections in carrot iv) CO2 concentration, temperature and relative humidity were recorded over time inside carrot storage bin liners with different numbers of perforations. An initial screening indicated a positive correlation between number of holes and number of fresh roots. As a post storage method, coating of swede with chitosan oligomers will be tested to inhibit growth of post-harvest pathogens. In conclusion, OptiRoot have gained good progress and promising preliminary results by connecting data on biology and technology for reduction of loss during long-term storage.

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Abstract

Although grass dominates most agricultural systems in the North Atlantic region (NAR), spring barley is the most important cereal and is used for animal feed and food and drink products. Recent changes in climate have resulted in warmer conditions across the NAR which have major implications for crop production. In this paper, we investigate the thermal requirement of spring barley in the region and use the results to examine the effects of recent trends in temperature and rainfall on barley cultivation, based on 11 regional meteorological sites. At these sites, between 1975 and 2015, we found significant warming trends for several months of the cropping season and significant trends for increases in the cropping season degree days (CSDD). In recent years, this has resulted in an increased proportion of years when the estimated minimum thermal requirement for barley has been met at sites above about 60°N. However, annual variations in CSDD are large and years still occur at these sites where this is insufficient. While warming could potentially allow an earlier start and later end to the cropping season, it is likely that high rainfall at maritime sites, and low rainfall at continental sites, will limit the ability of growers to benefit from this. Warming is considered to have been one of the main factors contributing to the large expansion of the area of barley cultivated in Iceland since the 1990s.

Abstract

In the present study we evaluated the effect of phenological stage at harvest and drying temperature on the content of secondary metabolites in six year old cultivatedclones of Rhodiola rosea. The experimental work was performed in cooperation between MTT in Finland and Bioforsk in Norway. In spite of the differences in growing season, we found similar development in biomassproduction and content of secondary metabolites in the two field experiments.During the period with intensive shoot growth the dry weight of the rootdecreased until budding / full flowering followed by an increase towards thelast harvest after wilting. The % dry matter followed the same development. The content of total rosavins in the dry rhizomes was highest at flowering at both sitesand the average content for spring was 24 % respectively 21% higher than inautumn in Finland and Norway (P=0,002). In Finland the average content of salidroside in spring of the dry rhizomewas 68 % higher than in autumn. While in Norway there were no differences insalidroside content at the different phenological stages (P = 0,097), lowvariation in the content of cinnamic alcohol at both sites was observed, but atendency to a small increase after flowering. The content of total rosavins was significantly higher at drying temperatures at or below 50˚C (P

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Abstract

Six clones of Rhodiola rosea, obtained from plants originating from widely different areas in Norway, were investigated for their in vitro inhibitory potential on CYP3A4-mediated metabolism and P-gp efflux transport activity. Presumed active constituents in the ethanol extracts of the different clones were quantified. C-DNA baculovirus expressed CYP3A4 and Caco-2 cells were used for inhibitory assays, and as positive control inhibitors ketoconazole and verapamilwere applied, respectively. A validated HPLC methodology was used to quantify the formation of 6-β-OH-testosterone and scintillation counting was used to quantify the transport of 3H-digoxin in Caco-2 cells. All clones showed potent inhibition of CYP3A4 and P-gp activities, with IC50 values ranging from 1.7 to 3.1 μg/mL and from 16.7 to 51.7 μg/ mL, respectively, being below that reported for other herbs and some known classic drug inhibitors, such as St. John’s wort and fluoxetine. Rhodiola rosea might thus be a candidate for clinically relevant drug interactions. The concentration of presumed biologically active constituents in the different clones varied considerably, but this variationwas not related to the clones’ inhibitory potential on CYP3A4 or P-gp activities. Other constituents might thus be responsible for the observed inhibitory properties. The place of origin seemed to be of minor importance for CYP3A4 or P-gp inhibition.