2022
Forfattere
Dragana Skocajic U Gasic D Dabic Zagorac Marija Nesica Z Tesic Mekjell Meland Milica Fotiric-AksicSammendrag
Compatibility and synchrony between specialized tissues of the pistil, female gametophytes and male gametophytes, are necessary for successful pollination, fertilization, and fruit set in angiosperms. The aim of the present work was to study the development and viability of embryo sacs, as well as fertilization success, in relation to the fruit set of the cultivars ‘Mallard’, ‘Edda’, ‘Jubileum’, and ‘Reeves’, under specific Norwegian climatic conditions. Emasculated, unpollinated, and open-pollinated flowers were collected at the beginning of flowering, and on the 3rd, 6th, 9th, and 12th days after flowering, from all four plum cultivars over two years (2018/2019). Ovaries were dehydrated, embedded in paraffin wax, sectioned, stained, and observed under a light microscope. Results showed the existence of synchronization between successive phases in the development of the embryo sac and individual phases of flowering. All plum cultivars had higher percentages of viable embryo sacs, fertilized embryo sacs, and fruit set in 2018 than in 2019. These differences may be related to the very low temperatures during the post-full-flowering period in 2019, and to the low adaptation of some studied cultivars to unfavorable conditions. In our study, the cultivar ‘Jubileum’ showed the highest percentage of viable embryo sacs, fertilized embryo sacs, and fruit set compared to other cultivars, i.e., the best low-temperature adaptation.
Forfattere
Miyuru GunathilakeSammendrag
Det er ikke registrert sammendrag
Sammendrag
Understanding the mechanisms of ecological community dynamics and how they could be affected by environmental changes is important. Population dynamic models have well known ecological parameters that describe key characteristics of species such as the effect of environmental noise and demographic variance on the dynamics, the long-term growth rate, and strength of density regulation. These parameters are also central for detecting and understanding changes in communities of species; however, incorporating such vital parameters into models of community dynamics is challenging. In this paper, we demonstrate how generalized linear mixed models specified as intercept-only models with different random effects can be used to fit dynamic species abundance distributions. Each random effect has an ecologically meaningful interpretation either describing general and species-specific responses to environmental stochasticity in time or space, or variation in growth rate and carrying capacity among species. We use simulations to show that the accuracy of the estimation depends on the strength of density regulation in discrete population dynamics. The estimation of different covariance and population dynamic parameters, with corresponding statistical uncertainties, is demonstrated for case studies of fish and bat communities. We find that species heterogeneity is the main factor of spatial and temporal community similarity for both case studies.
Redaktører
Randi HesjedalSammendrag
Det er ikke registrert sammendrag
Sammendrag
Using decades of satellite observations, Finnish and Norwegian scientists calculated the warming effect caused by changes in the snow and ice cover of the Arctic and Antarctic regions.
Forfattere
Mari Røken Kristin Forfang Yngvild Wasteson Anita Haug Haaland Hans Geir Eiken Snorre Hagen Ane Mohn BjellandSammendrag
Aims To investigate and compare antimicrobial resistance genes (ARGs) in faeces from cohabiting dogs and owners. Methods and Results DNA from faecal samples from 35 dogs and 35 owners was screened for the presence of 34 clinically relevant ARGs using high throughput qPCR. In total, 24 and 25 different ARGs were present in the dog and owner groups, respectively. The households had a mean of 9.9 ARGs present, with dogs and owners sharing on average 3.3 ARGs. ARGs were shared significantly more in households with dogs over 6 years old (3.5, interquartile range 2.75–5.0) than in households with younger dogs (2.5, interquartile range 2.0–3.0) (p = 0.02). Dogs possessed significantly more mecA and aminoglycoside resistance genes than owners. Conclusions Dogs and owners can act as reservoirs for a broad range of ARGs belonging to several antimicrobial resistance classes. A modest proportion of the same resistance genes were present in both dogs and owners simultaneously, indicating that ARG transmission between the dog and human gut is of minor concern in the absence of antimicrobial selection. Significance and Impact of the Study This study provides insight into the common dog and human gut resistomes, contributing to an improved knowledge base in risk assessments regarding ARG transmission between dogs and humans.
Sammendrag
Aldersfri bonitering er en metode for estimering av bonitet uten bruk av alder på skogen. Metoden er utviklet ved NIBIO i seinere år, og omtalt i tidligere publikasjoner. Vi går her videre i arbeidet med å kvalitetssikre metoden, og vurderer hvilken potensiell anvendelse den kan ha i skogbruket. Samlet sett viser resultatene at aldersfri bonitet har et potensial for å brukes i skogbruk i Norge. Det kan brukes for det første som et alternativ til konvensjonell bonitering i skogbruksplanlegging og på det landsdekkende skogressurskartet SR16, og for det andre som et supplement til konvensjonell bonitet på Landsskogtakseringens felt for å overvåke endringer forårsaket av klimaendringer. I det første tilfellet er fordelen at metoden ikke krever alder som input. En generell fordel er at metoden kan fange opp endringer i bonitet som skyldes endringer i vekstvilkår grunnet for eksempel klimaendringer, og dermed i større grad enn konvensjonell bonitet representere dagens bonitet. Metoden har også den fordelen at den er velegnet for bruk med fjernmåling, og resultatene viser at både enkelttre- og areal-baserte metoder fungerer, og at både laserskanning og stereo flybilder kan brukes.
Forfattere
Darius Kviklys Jonas Viškelis Mindaugas Liaudanskas Valdimaras Janulis Kristina Laužikė Giedrė Samuolienė Nobertas Uselis Juozas LanauskasSammendrag
Modern apple orchard systems should guarantee homogeneity of fruit internal and external qualities and fruit maturity parameters. However, when orchards reach productive age, a variation of these parameters takes place and mostly it is related to uneven light distribution within the tree canopy. The aim of the study was to evaluate the canopy position’s effect on fruit internal and external quality parameters. This is the first study where all the main fruit quality and maturation parameters were evaluated on the same trees and were related to the light conditions and photosynthetic parameters. Four fruit positions were tested: top of the apple tree, lower inside part of the canopy, and east and west sides of the apple tree. Fruit quality variability was significant for fruit size, blush, colour indices, total sugar content, dry matter concentration, accumulation of secondary metabolites and radical scavenging activity. Fruit position in the canopy did not affect flesh firmness and fruit maturity parameters such as the starch index, Streif index and respiration rate. At the Lithuanian geographical location (55°60′ N), significantly, the highest fruit quality was achieved at the top of the apple tree. The tendency was established that apple fruits from the west side of the canopy have better fruit quality than from the east side and it could be related to better light conditions at the west side of the tree. Inside the canopy, fruits were distinguished only by the higher accumulation of triterpenic compounds and higher content of malic acid. Light is a main factor of fruit quality variation, thus all orchard management practices, including narrow two-dimensional tree canopies and reflecting ground covers which improve light penetration through the tree canopy, should be applied.
Forfattere
Erling MeisingsetSammendrag
Det er ikke registrert sammendrag
Forfattere
Ingrid TengeSammendrag
Det er ikke registrert sammendrag