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.
2020
Abstract
No abstract has been registered
Authors
Anita Smailagic Petar Ristivojevic Ivica Dimkic Tamara Pavlovic Dragana Dabic´ Zagorac Sonja Veljovic Milica Fotiric´ Akšic Mekjell Meland Maja NaticAbstract
The main focus of this study is to assess radical scavenging and antimicrobial activities of the 11 wood extracts: oak (Quercus petraea (Matt.) Liebl., Q. robur L., and Q. cerris L.), mulberry (Morus alba L.), myrobalan plum (Prunus cerasifera Ehrh.), black locust (Robinia pseudoacacia L.), and wild cherry (Prunus avium L.). High-performance thin-layer chromatography (HPTLC) provided initial phenolic screening and revealed different chemical patterns among investigated wood extracts. To identify individual compounds with radical scavenging activity DPPH-HPTLC, assay was applied. Gallic acid, ferulic and/or caffeic acids were identified as the compounds with the highest contribution of total radical scavenging activity. Principal component analysis was applied on the data set obtained from HPTLC chromatogram to classify samples based on chemical fingerprints: Quercus spp. formed separate clusters from the other wood samples. The wood extracts were evaluated for their antimicrobial activity against eight representative human and opportunistic pathogens. The lowest minimum inhibitory concentration (MIC) was recorded against Staphylococcus aureus for black locust, cherry and mulberry wood extracts. This work provided simple, low-cost and high-throughput screening of phenolic compounds and assessments of the radical scavenging properties of selected individual metabolites from natural matrix that contributed to scavenge free radicals.
Abstract
The aim of this study was to evaluate the thinning efficacy of metamitron (Brevis®) as fruitlet thinner compared to ammonium thiosulphate (ATS) and ethephon (Cerone) as flower thinning agents to ‘Rubinstep’ apple. The thinning efficacy of the flower thinning agents was compared to different timings (8-10 and 12-14 mm fruitlet diameters) and dosages (165 and 330 ppm) of the fruitlet thinner metamitron at the experimental farm at Nibio Ullensvang, western Norway (60°19’8.03”N; 6°39’14.31”E) in 2018. Untreated trees and trees manually thinned after June drop were used as reference treatments. Fruit set, yield data and fruit quality parameters for each treatment were recorded. None of the chemical thinning treatments resulted in a significant reduction in the final number of fruits and yield tree-1. Crop load of the untreated trees was almost twice the target crop load of the hand-thinned trees. Ammonium thiosulphate (ATS) was the only chemical thinning treatment that significantly increased fruit weight above the untreated trees, but to a lesser extent than achieved by hand thinning. Qualitative traits of ‘Rubinstep’ apples (ground and over colour, firmness, starch index and soluble solid contents were not correlated with the fruit set. Return bloom of the untreated trees was 50% of the bloom of the previous year. The ammonium thiosulphate-treated trees showed a significant higher percentage return bloom of 122%. Return bloom in all other treatments did not differ significantly from the untreated controls. However, the average values showed a clear trend of a decrease in return bloom in metamitron-treated trees in comparison with the untreated and hand-thinned trees. The exceptionally high levels of solar radiation in May 2018 and the excellent pollination conditions resulting in very high seed numbers fruit-1 are likely the reasons for the lack of thinning efficacy of Brevis®.
Abstract
Norwegian pear production is low due to climatic limitations, a lack of well-adapted cultivars and suitable pollinizers. However, nowadays it is increasing as a result of newly introduced and bred pear cultivars. Since cross pollination is necessary for high yields and good fruit quality, the aim of this investigation was to find the most suitable pollinizers for the pear cultivars “Ingeborg” (“Conference” × “Bonne Louise”) and “Celina” (“Colorée de Juillet” × “Williams”). Self-pollination of “Ingeborg” and “Celina”, together with “Conference”, “Belle Lucrative”, “Anna”, “Clara Frijs”, “Herzogin Elsa”, “Kristina” and “Fritjof” as potential pollinizers, were studied in this experiment during the 2017 and 2018 seasons in Norway. The success rate of each pollinizer was tested under field conditions, while the monitoring of pollen tube growth was done using the fluorescence microscopy method. All reproductive parameters (pollen germination, number of pollen tubes in the upper part of the style, pollen tube number in the locule of the ovary, number of fertilized ovules, initial fruit set, and final fruit set) in all crossing combinations were higher in 2018 due to much warmer weather. Based on the flowering overlap and success rate of each individual pollinizer and fruit set, the cultivars “Anna” and “Clara Frijs” can be suggested as pollinizers for the cultivar “Ingeborg”, while “Fritjof”, “Anna”, “Kristina” and “Herzogin Elsa” for the cultivar “Celina”. An even distribution of two compatible pollinizers having overlapping flowering times with the main commercial pear cultivar is a general recommendation for commercial pear production.
Abstract
No abstract has been registered
Abstract
BACKGROUND Low growth temperatures and the special light qualities of midnight sun in northern Scandinavia, have both been shown to improve eating quality of swede root bulbs. To study the combined effect of these factors on root development and sensory‐related compounds, plants were grown in phytotron under different 24 h supplemental light‐emitting diode (LED) light colours, at constant 15 °C, or reduced end‐of‐season temperature at 9 °C. RESULTS Far‐red LED (740 nm) light induced longer leaves and produced more roundly shaped bulbs, than the other light quality treatments. At constant 15 °C, supplemental light of far‐red LED also produced a stronger purple crown skin colour than the other LED treatments. This difference between light quality treatments disappeared at 9 °C, as all bulb crowns developed a purple colour. There were no significant effects of LED‐supplements on sugar concentrations, while the reduced temperature on average did increase concentrations of d‐fructose and d‐glucose. Total glucosinolate concentrations were not different among treatments, although the most abundant glucosinolate, progoitrin, on average was present in highest concentration under LEDs containing far‐red light, and in lower concentration at 9 °C compared to 15 °C. CONCLUSION The light quality of 24 h photoperiods in combination with temperature appears primarily important for growth and morphological traits in swede root bulbs. Influence of light quality and low temperature on appearance and sensory‐related compounds may be utilized in marketing of root vegetables with special quality related to growth conditions of high latitude origin. © 2020 Society of Chemical Industry
Authors
Pia Heltoft Thomsen Bjarni Hannesson Karin Normann Per Sørensen Tania Gneist Michelle DaCosta Eric Watkins Karin Juul Hesselsøe Trygve S. Aamlid Tatsiana Espevig Trond Olav Pettersen Wendy Marie Waalen Jan TangsveenAbstract
No abstract has been registered
Authors
Jiangsan Zhao Dmitry Kechasov Boris Rewald Gernot Bodner Michel Verheul Nicholas Clarke Jihong Liu ClarkeAbstract
Hyperspectral imaging has many applications. However, the high device costs and low hyperspectral image resolution are major obstacles limiting its wider application in agriculture and other fields. Hyperspectral image reconstruction from a single RGB image fully addresses these two problems. The robust HSCNN-R model with mean relative absolute error loss function and evaluated by the Mean Relative Absolute Error metric was selected through permutation tests from models with combinations of loss functions and evaluation metrics, using tomato as a case study. Hyperspectral images were subsequently reconstructed from single tomato RGB images taken by a smartphone camera. The reconstructed images were used to predict tomato quality properties such as the ratio of soluble solid content to total titratable acidity and normalized anthocyanin index. Both predicted parameters showed very good agreement with corresponding “ground truth” values and high significance in an F test. This study showed the suitability of hyperspectral image reconstruction from single RGB images for fruit quality control purposes, underpinning the potential of the technology—recovering hyperspectral properties in high resolution—for real-world, real time monitoring applications in agriculture any beyond.
Abstract
The major part of Norwegian apples is marketed within 3-4 months after harvest. ‘Summerred’ is a popular medium early cultivar in Norway, however, it is known to soften quickly during storage and marketing. Storing apples in low temperature and low oxygen atmosphere will slow down the ripening and the fruit will keep green and firm. Delayed cooling has been reported to reduce susceptibility to develop physiological disorders like scald. The experiment included different strategies in delaying cooling (5 days at 7°C) and allowing the apples to reach 1 kPa oxygen storage after an intermediate period (5 days) at 3 kPa oxygen. The main focus was on changes in firmness, degreening, scald and fruit rots. The apples were stored for 3, 6 or 9 weeks in 1 or 4°C and analyzed for standard fruit quality factors (color, firmness, IAD-index, starch, soluble solids content and titratable acidity) as the samples were removed from low temperature and low oxygen storage and after a week at 20°C in regular atmosphere (shelf life). Physiological disorders and fruit rots were registered. In these experiments the fruit quality changes were greater (poorer quality) in apples kept at 7°C for 5 days before storage at 1 or 4°C compared to apples stored immediately at low temperature. The intermediate storage in 3 kPa oxygen tended to make the apples keep firmer during storage. The stepwise reduction in oxygen content reduced the negative effect of delayed cooling. Delayed cooling slowed the starch degradation. The incidences of soft scald and fruit rots were low, and the effects of delayed cooling and/or delayed low oxygen storage were weak.
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.