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Thiagarajan A.,Dalhousie University | Thiagarajan A.,Laval University | Lada R.,Dalhousie University | Pepin S.,Laval University | And 3 more authors.
Trees - Structure and Function | Year: 2012

To fulfill the US Thanksgiving and Christmas tree markets, balsam fir (Abies balsamea (L.) Mill.) is generally harvested before the cold season, anecdotally leading to premature needle senescence. Accordingly, we tested the hypothesis that LT exposure before harvest induces specific hormonal changes and delays postharvest senescence and/or abscission in balsam fir. Two hundred and six seedlings exposed to two temperature treatments for 48 h, LT at 5 °C and controls at 22 °C were severed off roots and monitored for their postharvest needle senescence. Root and shoot (needles and buds) tissues were examined for major endogenous hormone metabolites. LT increased shoot ABA (2,007 ng g -1 DW) by 2.5× and decreased GA 44 (9.84 ng g -1 DW) by 3.5× over those in roots. LT did not alter cytokinins, auxins or any root hormonal concentration. With auxins, only IAA, IAA-Asp, IAA-Leu and IAA-Glu were detected and the concentrations of IAA and IAA-Asp in shoots were lower than those found in roots. Among cytokinins, shoot c-ZR (58.95 ng g -1 DW) and t-ZR (4.17 ng g -1 DW) were 3× higher than those in roots. Apart from GA 44, GA 9 (136.76 ng g -1 DW) was abundant in shoots. The PBL and PNL were 46 and 1.2 %, irrespective of treatments. LT seedlings held needles 11 days longer than the controls (122 days). In balsam fir, short-term LT exposure augmented ABA and decreased GA 44 levels in shoots and delayed postharvest needle senescence. © 2012 Her Majesty the Queen in Right of Canada.


Amon-Armah F.,Dalhousie University | Yiridoe E.K.,Dalhousie University | Jamieson R.,Dalhousie University | Hebb D.,Atlantic Food and Horticulture Research Center
Agroecology and Sustainable Food Systems | Year: 2015

Alternative mathematical functional forms commonly applied in modelling crop and pollution production response to nitrogen (N) fertilizer use were investigated. Data were generated using soil and water assessment tool modeling, and explicitly accounted for rotation effects on regression parameters. The Mitscherlich–Baule model best represented potato, carrot, and alfalfa yield response, while the quadratic model best described corn, winter wheat, and barley yield response to N fertilization. The quadratic functional form also best represented nitrate-N leaching response to N fertilization for most crops. Maximum economic rates of N fertilization for crops were sensitive to residual N effects of previous crops. © ,Taylor & Francis Group, LLC.


Beni L.H.,Food Research and Development Center | Villeneuve S.,Food Research and Development Center | Leblanc D.I.,Atlantic Food and Horticulture Research Center | Delaquis P.,Agriculture and Agri Food Canada
Transactions in GIS | Year: 2011

A Geographical Information System (GIS)-based approach was developed for the identification of vulnerabilities and the measurement of risks associated with contamination of food systems with biological agents. In this research work, a tight integration of ArcGIS with the Arena simulation tool has been implemented. Arena was used to simulate and track contamination in a food distribution network and transmit the time dependent information to GIS. ArcGIS was employed to provide the primary user interface, process network data, and visualize the results. In addition, the GIS, through its powerful capabilities to process spatial data, could allow decision- makers to quickly determine the potential impact of a contamination event, at any stage, as a function of both time and geography. Two contamination scenarios along the farm-to-fork chain were examined to show the geographic zone and the proportion of the population affected by the contamination. A constraint Voronoi data structure was developed to define influence zones (these were color coded according to a dynamic risk index), to identify those areas that are at greatest immediate risk as time progresses, and to estimate the population affected by these contamination events. This approach thus appears to have general application to many GIS-based risk assessment problems. © 2011 Crown in the right of Canada.


Thiagarajan A.,Dalhousie University | Thiagarajan A.,Laval University | Lada R.,Dalhousie University | Pepin S.,Laval University | And 3 more authors.
Journal of Plant Growth Regulation | Year: 2013

Seasonal changes in the concentration of abscisic acid (ABA) in current-year needles of two different genotypes (AB-NSD-004 and AB-NSD-184) were monitored in branches collected from 20-year-old balsam fir (Abies balsamea L. (Mill.)) trees over a period of 11 months. A significant genotype × harvesting time interaction was observed for endogenous ABA levels and postharvest needle retention duration (NRD). A consistent pattern of seasonal variation in ABA concentration was observed in both genotypes, with the highest amount of ABA (7,887 ng g-1 DW) accumulating in April and May. The highest levels of ABA coincided with the lowest postharvest NRD regardless of genotype. Nevertheless, genotypes differed in their ABA concentrations. Branches of genotype AB-NSD-184 sampled during August exhibited 170 days of NRD whereas those collected in May and June registered the lowest NRD of around 40 days. There was a significant negative correlation (P < 0.05) between endogenous ABA concentrations and postharvest NRD in genotype AB-NSD-184. Also, an inverse relationship was observed between the average daily photoperiod and the postharvest NRD (R 2 = 0.35; P = 0.000) in the same genotype. Together with average daily temperature, the R 2 value for this correlation reached the highest (0.75; P ≤ 0.00). Genotypes differed in their physiological responses to environmental cues and thus differed in their postharvest qualities. Average daily photoperiod and maximum daily temperature are strongly linked to the postharvest NRD through modulating endogenous ABA concentration. © 2013 Her Majesty the Queen in Rights of Canada.


Amon-Armah F.,Dalhousie University | Yiridoe E.K.,Dalhousie University | Ahmad N.H.M.,Dalhousie University | Hebb D.,Atlantic Food and Horticulture Research Center | And 3 more authors.
Environmental Management | Year: 2013

Government priorities on provincial Nutrient Management Planning (NMP) programs include improving the program effectiveness for environmental quality protection, and promoting more widespread adoption. Understanding the effect of NMP on both crop yield and key water-quality parameters in agricultural watersheds requires a comprehensive evaluation that takes into consideration important NMP attributes and location-specific farming conditions. This study applied the Soil and Water Assessment Tool (SWAT) to investigate the effects of crop and rotation sequence, tillage type, and nutrient N application rate on crop yield and the associated groundwater NO3 --N leaching and sediment loss. The SWAT model was applied to the Thomas Brook Watershed, located in the most intensively managed agricultural region of Nova Scotia, Canada. Cropping systems evaluated included seven fertilizer application rates and two tillage systems (i.e., conventional tillage and no-till). The analysis reflected cropping systems commonly managed by farmers in the Annapolis Valley region, including grain corn-based and potato-based cropping systems, and a vegetable-horticulture system. ANOVA models were developed and used to assess the effects of crop management choices on crop yield and two water-quality parameters (i.e., NO3 --N leaching and sediment loading). Results suggest that existing recommended N-fertilizer rate can be reduced by 10-25 %, for grain crop production, to significantly lower NO3 --N leaching (P > 0.05) while optimizing the crop yield. The analysis identified the nutrient N rates in combination with specific crops and rotation systems that can be used to manage NO3 --N leaching while balancing impacts on crop yields within the watershed. © 2013 Springer Science+Business Media New York.


Kelly J.A.,Acadia University | Avery T.S.,Acadia University | Stewart D.T.,Acadia University | Cutler C.G.,Dalhousie University | And 3 more authors.
Canadian Entomologist | Year: 2013

Cucullia umbratica Linnaeus (Lepidoptera: Noctuidae), Agnippe prunifoliella Chambers (Lepidoptera: Gelechiidae), and Bryotropha plantariella Tengstrom (Lepidoptera: Gelechiidae), were significant bycatch in pheromone-based trapping systems for red-striped fireworm, Aroga trialbamaculella Chambers (Lepidoptera: Gelechiidae), in Nova Scotia, Canada. Cucullia umbratica is a European introduced species and a new macrolepidopteran recorded in continental Canada. The only previous record of this moth in North America was from the Magdalen Islands (Québec, Canada). Potential attractants for B. plantariella, A. prunifoliella, and C. umbratica are a result of this bycatch investigation. Copyright © 2013 Entomological Society of Canada.


Thiagarajan A.,Dalhousie University | Thiagarajan A.,Laval University | Lada R.,Dalhousie University | Pepin S.,Laval University | And 3 more authors.
Scandinavian Journal of Forest Research | Year: 2015

Low temperature (LT) exposure has been shown to delay postharvest needle abscission and senescence (NAS) in balsam fir and changes in vapor pressure deficit (VPD) are expected to alter these processes. Two and half year-old seedlings were exposed to a LT of 5°C for 15 days while the control (CT) group was maintained at 22°C. Seedlings were then exposed to four different VPD (0.22, 0.87, 1.3 and 1.86 kPa) and observed for relative water content (RWC), xylem pressure potential (XPP), membrane injury index (MII), stem capacitance (SC) and NAS. An interactive effect of LT and VPD was observed in RWC, XPP, MII and NAS. Low VPD (0.22 and 0.87 kPa) resulted in less negative XPP, lower electrolyte leakage, higher SC and ultimately higher NAS than those at high VPD. Maximum NAS was recorded at 0.22 kPa. At 1.86 kPa, LT had 5× lower RWC (13%), 3× more negative XPP (−1.1 MPa), 1.8× higher membrane damage and 35% lower NAS (47 days) than CT. The SC declined with an increase in VPD with no effect of LT. The XPP and RWC of LT seedlings showed a positive relationship with NAS with R2 values of 0.54 and 0.59, respectively. LT offered no benefits to NAS at high VPD environments. © 2015 Taylor & Francis


Cliff M.A.,Agriculture and Agri Food Canada | Fan L.,Atlantic Food and Horticulture Research Center | Sanford K.,Atlantic Food and Horticulture Research Center | Stanich K.,Agriculture and Agri Food Canada | And 2 more authors.
Journal of Dairy Science | Year: 2013

This research explored the sensory characteristics and consumer acceptance of novel probiotic unsweetened yogurts. Yogurts were made with 4 carrot juice levels (8, 16, 24, and 32%), 2 firmness levels (regular, 45. g/L milk solids; firm, 90. g/L milk solids), and 2 starter cultures (C1, C2). The sensory profile characterized the color intensity (before and after stirring), carrot flavor, sourness, and 7 texture/mouth-feel attributes (astringency, chalkiness, mouth-coating, thickness, smoothness, creaminess, and graininess). The influence of carrot juice level and firmness level were evaluated using ANOVA, polynomial contrasts, and principal component analysis. Mean scores and standard errors were calculated. Consumer acceptance panels in Wolfville, Nova Scotia (n = 56), and in Vancouver, British Columbia (Asian n = 72, non-Asian n = 72), evaluated the hedonic responses to the C1 and C2 formulations, respectively. We observed increases in color intensity, carrot flavor, creaminess, mouth-coating, and chalkiness with increasing carrot juice levels, as well as increases in color intensity, carrot flavor, creaminess, mouth-coating, thickness, and astringency with increasing milk solids concentrations of the C1 and C2 yogurts. Mean hedonic scores for color, appearance, and texture/mouth-feel were greater than hedonic scores for aroma, flavor/taste, and overall liking. This research identified the sensory qualities that need further development and demonstrated the importance of early-stage consumer acceptance research for directing new product development. © 2013 American Dairy Science Association.


Elkins R.B.,University of California Cooperative Extension | Castagnoli S.,Oregon State University | Embree C.,Atlantic Food and Horticulture Research Center | Parra-Quezada R.,Instituto Nacional Of Investigaciones Forestales Agricolas Y Pecuarias | And 3 more authors.
Acta Horticulturae | Year: 2011

Nine single cultivar replicated trials located in six locations in the states of California, New York, and Washington in the US, Nova Scotia, Canada, and Chihuahua, Mexico were established in 2004 and 2005 as part of the "NC-140 Improving Economic and Environmental Sustainability in Tree-Fruit Production Through Changes in Rootstock Use" project. Rootstocks were grafted to 'Bartlett' ('Williams') in four locations, 'Golden Russet Bosc' in three locations, and 'Concorde' and 'Taylors Gold Comice' in two locations. 'Bartlett' tree spacing ranged from 1.5×3.0 to 2.7×4.6 m, 'GR Bosc' from 1.5×3.0 to 1.8×3.7 m, and 'Concorde' and 'Taylors Gold Comice' was 2.4×4.8 m. Training systems included central leader, vertical trellis and slender spindle. 'Bartlett' was grafted onto 708-36, BM 2000, Horner-4, Fox 11, OH×F 87, Pyrodwarf, and Pyro 2-33 in all four locations. The same rootstocks were included for 'Golden Russet Bosc', however, only Horner 4 and Pyrodwarf were included in all three locations; 'Concorde' and 'Taylors Gold Comice' were grafted to Pyrodwarf, OH×F 87 and OH×F 97. OH×F 69 and 'Winter Nelis' were each included in one 'Bartlett' trial and one 'Golden Russet Bosc' trial also included BU-3. Percent tree survival, trunk cross sectional area (TCSA), fruit yield, number of flower clusters, number of fruit, and number of root suckers were measured and percent set, yield efficiency and average fruit weight were calculated. Percent tree survival and reasons for mortality varied by location and included fire blight and poor vigor. Production data are preliminary, however several trends are notable. Generally, for 'Bartlett', trees on Horner-4 exhibited the largest TCSA but trees on Pyro 2-33, Pyrodwarf, and OH×F 87 performed the best overall across four locations. For 'Golden Russet Bosc', there was no statistical difference between Horner-4 and Pyrodwarf; while trees on Horner-4 generally had the largest TCSA in two of the three trials, OH×F 87 appears to induce better yields and yield efficiency. Cumulative yield efficiencies were equal for 'Concorde' and 'Taylors Gold Comice' on all rootstocks. There was no clear trend in number of suckers, but BM 2000 and Pyrodwarf had the most in some locations. For all rootstock cultivars, fruit weight trends were unclear due to limited data. Formal data collection and reporting will continue through 2014.


PubMed | Atlantic Food and Horticulture Research Center, Metropolitan Autonomous University, University of Montréal and University of Ottawa
Type: Journal Article | Journal: BMC complementary and alternative medicine | Year: 2017

Obesity and Type 2 diabetes have reached epidemic status worldwide. Wild lowbush blueberry (Vaccinium angustifolium Aiton) is a plant of the North American Aboriginal traditional pharmacopeia with antidiabetic potential, especially when it is fermented with Serratia vaccinii.A phytochemical fractionation scheme was used to identify potential bioactive compounds as confirmed by HPLC retention times and UV-Vis spectra. 3T3-L1 cells were differentiated for 7days with either Normal Blueberry Extract (NBE), Fermented Blueberry Extract (FBE/F1), seven fractions and four pure compounds. Triglyceride content was measured. Examination of selected intracellular signalling components (p-Akt, p-AMPK) and transcriptional factors (SREBP-1c and PPAR) was carried out by Western blot analysis.The inhibitory effect of FBE/F1 on adipocyte triglyceride accumulation was attributed to total phenolic (F2) and chlorogenic acid enriched (F3-2) fractions that both inhibited by 75%. Pure compounds catechol (CAT) and chlorogenic acid (CA) also inhibited adipogenesis by 70%. Treatment with NBE, F1, F3-2, CAT and CA decreased p-AKT, whereas p-AMPK tended to increase with F1. The expression of SREBP1-c was not significantly modulated. In contrast, PPAR decreased in all experimental groups that inhibited adipogenesis.These results demonstrate that fermented blueberry extract contains compounds with anti-adipogenic activity, which can serve to standardize nutraceutical preparations from fermented blueberry juice and to develop novel compounds with anti-obesity properties.

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