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- OPEN ACCESSA novel Brachyspira emerged in 2009 and has since become a production-limiting pathogen of pigs in North America. The name “Brachyspira hampsonii” has been proposed for this novel taxon. “Brachyspira hampsonii” is divided into two phylogenetically distinct clades based on the sequence of the NADH-oxidase (nox) gene, although the clinical disease associated with clades I and II is indistinguishable and phenotypic characteristics that discriminate the clades have not been determined. The objectives of the current study were to enhance the description of the provisional species “B. hampsonii” with biochemical profiles and morphometric data from isolates affecting Canadian swine and to investigate potentially diagnostically informative characteristics for this emerging pathogen. Biochemical profiles of isolates from different commercial swine barns in Western Canada showed that biochemical profiles were insufficient to distinguish “B. hampsonii” clades I and II from each other or from other pathogenic Brachyspira. Hippurate hydrolysis, previously reported as uniformly negative in “B. hampsonii,” was variable among Canadian isolates. Spirochete dimensions and flagella numbers for “B. hampsonii” overlapped with other Brachyspira species. Taken together, these results indicate that nox gene sequencing remains a preferred method for identification and discrimination of “B. hampsonii” from other pig-associated Brachyspira spp.
- OPEN ACCESSBacterial endophytes are thought to enter plants either through pre-existing openings in plant tissues or by creating openings by hydrolyzing major plant cell wall components. A lodgepole endophyte, Paenibacillus polymyxa P2b-2R, consistently formed endophytic colonies when inoculated in diverse plant hosts, viz., lodgepole pine, western red cedar, corn, canola, and tomato. We were interested to know, whether or not this bacterial strain possesses enzymes that can hydrolyze three major plant cell wall components namely cellulose, xylan, and pectin to facilitate entrance into the host plants. Using a BIOLOG assay, we also tested this bacterial strain’s ability to utilize carbon sources that might facilitate its entrance and hence its survival inside host plants. Paenibacillus polymyxa P2b-2R hydrolyzed sodium carboxymethylcellulose, beechwood xylan, and sodium polypectate and utilized 39 of the 95 carbon sources (41%) tested. Of the 39 carbon substrates oxidized by P2b-2R, the “carbohydrates” group represents the largest source of utilizable carbon (23 out of 39). Thus, it can be concluded that P. polymyxa P2b-2R is able to degrade major cell wall components (cellulose, xylan, and pectin) and utilize some of the available carbon substrates, possibly to gain entry and survive inside the plant and form endophytic colonies thereafter.
- OPEN ACCESSA Bt soybean has been recently developed, thus, efficiently regulating the populations of major lepidopteran pests. However, in other cases, these benefits have been reduced or lost because of the rapid evolution of pest resistance to the Bt toxins in transgenic crops. When pest populations are exposed to Bt crops and to refuges (non-Bt plants), the evolution of resistance is governed by the fitness of resistant individuals relative to susceptible individuals for both the presence and absence of Bt toxins. One major ecological concern regarding the biosafety of Bt crops on the environment is their potential effects on non-target organisms, especially predators and parasitoids that play an important role in pest control. This information is important for supporting insect resistance management (IRM) programs and for improving agricultural practices in a crop production system with Bt plants. Before the use of Bt plants for insect pest control in Brazil is adopted, IRM programs should be established to ensure the sustainability of this technology for integrated pest management (IPM). This review presents data on Bt soybean and lepidopteran pests as well as on the importance of natural enemies as a form of biological control, and applications for IPM and IRM.
- OPEN ACCESSContemporary approaches to market-oriented agricultural development focus on increasing production and economic efficiency to improve livelihoods and well-being. For seed system development, this has meant a focus on seed value chains predicated on standardized economic transactions and improved variety seeds. Building formal seed systems requires establishing and strengthening social institutions that reflect the market-oriented values of efficiency and standardization, institutions that often do not currently exist in many local and informal seed systems. This paper describes and analyzes efforts to develop formal seed systems in Sahelian West Africa over the past 10 years, and identifies the impacts for farmers of the social institutions that constitute formal seed systems. Using qualitative and spatial data and analysis, the paper characterizes farmers’ and communities’ experiences with seed access through the newly established formal seed system. The results demonstrate that the social and spatial extents of the formal and informal seed systems are extended and integrated through social institutions that reflect values inherent in both systems. The impacts of current market-oriented agricultural development projects are, therefore, more than in the past, in part because the social institutions associated with them are less singular in their vision for productive and economic efficiency.
- OPEN ACCESSThis paper addresses how available resources, food security, technology, and culture are shaping the choices rural Malian women are making to ensure the health, energy, and well-being of their families. This research contributed to evaluating an eight-year research project (An Be Jigi) targeting improved nutrition. The study, performed over four months, used semi-structured interviews of 120 women in six villages in Mali to assess the identified issues with qualitative and quantitative approaches. This paper describes the history of the An Be Jigi project, whole-grain processing techniques, and group cooking for knowledge sharing with rural women for improved nutrition. Interviews revealed substantial adoption of whole-grain processing techniques and women’s appreciation of the nutritional benefits of those techniques. The women engaged in group cooking (cuisines collectives) appreciated the activities and mentioned multiple benefits from using them. Women identified access to mills, and to some extent the social stigma of laziness and poverty associated with whole-grain food, as limiting factors of adoption. This study of women’s practices and perceptions regarding use of whole grain tells a story of changing consumption habits being shaped by culture, technology, knowledge, and available resources. Malian women are agents of change and care in their adoption of new techniques and recipes for the improved nutrition of young children and households.
- OPEN ACCESSBiochar is gaining attention as an organic soil amendment that can increase plant yields and improve soil fertility. We studied the effect of biochar on the growth of fowl mannagrass (Glyceria striata (Lam.) Hitchc.) (Poaceae), propagated in a greenhouse for future re-introduction into restored wetlands. Three different application rates (10%, 50%, and 75% biochar volume/substrate volume (v/v)) of nutrient-charged (i.e., nutrients added) and uncharged biochar were tested with and without a commercial arbuscular mycorrhizal fungal (AMF) inoculant. Aboveground biomass (shoot mass), belowground biomass (root mass), and shoot height of 166 G. striata samples were recorded after 92 d of growth. Using generalized linear models our data indicated a 50% (v/v) application rate of nutrient-charged biochar without AMF produces a significantly greater growth response (4.4× greater shoot height and 85× greater shoot mass compared with 0% biochar (AMF negative) control). We propose that the increased G. striata growth may be due to changes in pH, and (or) increased nutrient availability due to the addition of biochar. We recommend an application rate of 50% biochar (v/v) charged with nutrients as an advantageous amendment for propagating G. striata.
- OPEN ACCESS
- James M.C. Jones,
- Elizabeth A. Webb,
- Michael D.J. Lynch,
- Trevor C. Charles,
- Pedro M. Antunes, and
- Frédérique C. Guinel
Carbonatites are unusual alkaline rocks with diverse compositions. Although previous work has characterized the effects these rocks have on soils and plants, little is known about their impacts on local ecosystems. Using a deposit within the Great Lakes–St. Lawrence forest in northern Ontario, Canada, we investigated the effect of a carbonatite on soil chemistry and on the structure of plant and soil microbial communities. This was done using a vegetation survey conducted above and around the deposit, with corresponding soil samples collected for determining soil nutrient composition and for assessing microbial community structure using 16S/ITS Illumina Mi-Seq sequencing. In some soils above the deposit a soil chemical signature of the carbonatite was found, with the most important effect being an increase in soil pH compared with the non-deposit soils. Both plants and microorganisms responded to the altered soil chemistry: the plant communities present in carbonatite-impacted soils were dominated by ruderal species, and although differences in microbial communities across the surveyed areas were not obvious, the abundances of specific bacteria and fungi were reduced in response to the carbonatite. Overall, the deposit seems to have created microenvironments of relatively basic soil in an otherwise acidic forest soil. This study demonstrates for the first time how carbonatites can alter ecosystems in situ. - OPEN ACCESSThis research explores the potential hydroponic systems have for contributing to climate mitigation in fodder agriculture. Using British Columbia (BC) and Alberta as case studies, the study compares greenhouse gas (GHG) emissions and carbon sequestration potential of hydroponically grown sprouted barley fodder to conventional barley grain fodder. GHG emissions were examined through scenarios that assumed Alberta to be the main barley producer, while exploring different situations of BC and Alberta as consumers, distributed/centralized hydroponic systems, and renewable/nonrenewable energy. Carbon sequestration opportunities were examined through scenarios that explored the land sparing potential of transitioning from conventional to hydroponic barley and shifts from tillage to no-tillage practices. Sensitivity analyses were done to examine how changes in hydroponic seed-to-fodder output and energy consumption affect the systems’ climate mitigation potential. The results indicated that incorporating hydroponic systems into barley production has the potential to reduce GHG emissions, given seed-to-fodder output and energy consumption are maintained at certain levels and the systems are powered by renewable energy. Results also showed that hydroponic farming can provide greater carbon sequestration opportunities than simply shifting to no-tillage farming. The research indicates that hydroponic fodder farming could contribute to climate mitigation objectives if complemented with effective energy and land use policies.
- OPEN ACCESS
- OPEN ACCESSSalt marshes are ecosystems of significant ecological importance for coastal stability and fundamental roles in marine ecosystems. Salt marshes are declining due to anthropogenic and natural causes including sea level rise. Coastal restoration efforts have increased worldwide, but many fail in long-term coastal stability. We used a naturally occurring arbuscular mycorrhizal fungus (AMF) to test whether survival and early growth of the salt marsh grass Sporobolus pumilus (formerly Spartina patens) improved under simulated salt marsh conditions. Using a tidal mesocosm bench, we grew inoculated plants with varying AMF treatments under simulated tidal regimes to determine if AMF could aid in establishment of healthy Sporobolus communities. Rhizome-derived S. pumilus had greater survival and grew faster than seed-derived plants. Plants inoculated with propagated AMF consistently outperformed both sterile and native sediment controls in terms of plant survival and growth. Use of rhizome-derived Sporobolus inoculated with propagated Funneliformis geosporum showed the most promise in producing successful plant populations for salt marsh restoration. This may be due to plant life stage and improved plant nutrient status, allowing rhizome-derived plants to grow more quickly than seed-derived plants. Using these plants in future large-scale restoration may increase re-establishment of salt marsh ecosystems.
- OPEN ACCESSLarge-scale monitoring is used to track population trends for many ecologically and economically important wildlife species. Often, population monitoring involves professional staff travelling to collect data (i.e., conventional monitoring) or in efforts to reduce monitoring costs, by engaging volunteers (i.e., community science). Although many studies have discussed the advantages and disadvantages of conventional vs. community science monitoring, few have made direct, quantitative comparisons between these two approaches. We compared data quality and financial costs between contemporaneous and overlapping conventional and community science programs for monitoring a major forest pest, the spruce budworm (Choristoneura fumiferanae Clem.). Although community science trapping sites were clumped around urban areas, abundance estimates from the programs were strongly spatially correlated. However, annual program expenditures were nearly four times lower in the community science versus the conventional program. We modelled a hypothetical hybrid model of the two programs, which provided full spatial coverage and potentially the same data, but at half the cost of the conventional program and with the added opportunity for public engagement. Our study provides a unique quantitative analysis of merits and costs of conventional versus community science monitoring. Our study offers insights on how to assess wildlife monitoring programs where multiple approaches exist.
- OPEN ACCESSFor cities to grow their urban forest canopy the formula appears rather straightforward: the right trees, plus the right conditions, plus the right care equals success. These simplified “tree chain of custody” steps, however, represent activities within a complex value-chain in Canada. Given that there is heightened demand for urban tree planting as natural climate solutions become the norm, how can we prepare the value-chain to meet these demands? To answer this question, we outline the pathways by which trees presently go from nurseries into urban and peri-urban areas. Delineating the actors, roles, and present barriers to success exposes the complexity of the process and relationships in the value-chain, as there are distinct phases with multiple actor groups involved who influence, and are influenced, by one another. We explore the issues that pose prominent challenges to, as well as opportunities for, the value-chain. Emergent themes include communication, forecasting demand and timing, underpricing and undervaluing tree establishment, lack of awareness on the importance of soils, juvenile tree health, species selection, and gaps in evidence-based decision support tools. The touchstones of science and innovation, collaboration, and knowledge mobilization are pertinent for the value-chain in Canada to draw upon to navigate the future.
- OPEN ACCESS
- Isadora Louise Alves da Costa Ribeiro Quintans,
- Juliana Alves da Costa Ribeiro Souza, and
- Michael K Deyholos
Fusarium oxysporum f. sp. lini and Septoria linicola are causes of fusarium wilt and pasmo in flax (Linum usitatissimum). Members of a third fungal genus, Alternaria spp., have also been found in fiber and linseed varieties of flax, and are a source of post-harvest spoilage and mycotoxins in a wide range of crops. We performed a microdilution assay and calculated the median effective concentration (EC50) to compare the potency of cyclolinopeptides (CLPs), two polyamines (spermidine and spermine), and the fungicide carbendazimin in the control of three fungi that have potential pathogenic activity (F. oxysporum, S. linicola, and Alternaria spp), of which the first two are particulary significant causes of disease in flax. For carbendazim, all EC50 values were <0.6 μg/mL. The observed EC50 ranged from 111 to 340 μg/mL for a mixture of six unique CLPs, 109 to 778 μg/mL for spermine, and 21 to 272 μg/mL for spermidine. Spermidine was most effective against Alternaria sp., with an EC50 of 21 μg/mL. The results presented here showed that polyamines and CLPs possess limited antifungal activities against several fungi, with spermidines the most effective naturally occurring compound tested. Our findings do not support the hypothesis that CLPs act as potent antifungals against the three species of pathogens tested. - OPEN ACCESSAcademic scientists face an unpredictable path from plant biology research to real-life application. Fundamental studies of γ-aminobutyrate and carotenoid metabolism, control of Botrytis infection, and the uptake and distribution of mineral nutrients illustrate that most academic research in plant biology could lead to innovative solutions for food, agriculture, and the environment. The time to application depends on various factors such as the fundamental nature of the scientific questions, the development of enabling technologies, the research priorities of funding agencies, the existence of competitive research, the willingness of researchers to become engaged in commercial activities, and ultimately the insight and creativity of the researchers. Applied research is likely to be adopted more rapidly by industry than basic research, so academic scientists engaged in basic research are less likely to participate in science commercialization. It is argued that the merit of Discovery Grant applications to the Natural Sciences and Engineering Research Council (NSERC) of Canada should not be evaluated for their potential impact on policy and (or) technology. Matching industry funds in Canada rarely support the search for knowledge. Therefore, NSERC Discovery Grants should fund basic research in its entirety.
- OPEN ACCESS
- P. Burgess,
- G.S. Betini,
- A. Cholewka,
- J.R. deWaard,
- S. deWaard,
- C. Griswold,
- P.D.N. Hebert,
- A. MacDougall,
- K.S. McCann,
- J. McGroarty,
- E. Miller,
- K. Perez,
- S. Ratnasingham,
- C. Reisiger,
- D. Steinke,
- E. Wright,
- E. Zakharov, and
- J.M. Fryxell
We used Malaise traps to sample arthropod community composition at biweekly intervals across an agroecosystem landscape in southern Ontario, Canada, to evaluate the relative impact of site spacing, seasonal timing, weather conditions, local plant community attributes, and agricultural extent across the local landscape on spatial and temporal variation in arthropod community composition. The 15 field sites sampled spanned a wide gradient of agricultural extent that in isolation had a strong impact on spatial variation in arthropod community composition. DNA metabarcoding of the samples identified >10 000 different arthropod biodiversity index numbers. Local variation in plant community composition and canopy cover best explained variation in arthropod community dissimilarity. Weather variables followed closely in explanatory power, driven primarily by seasonal variation in temperature. Significant effects of time remained after accounting for environmental variables, with little independent effect of spatial distance. The proportion of agricultural land at the landscape scale had little detectable effect after controlling for the influence of the other environmental variables. Our results suggest that plant community composition, cover, weather conditions, and seasonality structured the arthropod community to considerable degree. - OPEN ACCESSExpanding local rice production to meet consumer demand is a priority action under the Government of Ghana’s Planting for Food and Jobs initiative. While studies on yield-enhancing interventions abound, fewer studies focus on food safety issues (e.g., the potential toxic element status of the production ecosystems). This study was, therefore, conducted to bridge the knowledge gap. Chemical analyses were conducted on water, soil, and rice grain samples from different production ecosystems in the Northern and Upper East regions of Ghana. Statistical analysis of the data showed that soil and rice grain arsenic concentrations were significantly higher (P < 0.001) in the Upper East region. In the Northern region, mean cadmium concentration in rice grains from the irrigated lowland fields (0.023±0.003 mg/kg) was significantly higher than in grains from the rainfed fields. All recorded concentrations of rice grain arsenic, cadmium, and lead were, however, within permissible limits, indicating a low risk of dietary exposure. The observed differences in concentrations within and between regions suggest that soil texture and other geogenic factors could influence the potential toxic element status of the rice production ecosystems. Regular monitoring is, therefore, recommended to maintain the safety of Ghana’s locally produced rice for human consumption.
- OPEN ACCESSPlant structures that enclose trapped air are morphologically and taxonomically diverse. They range from pubescence (trichomes) on various parts of plants to flowers, inflorescences, stems, culms (above-ground jointed stems of grasses), petioles, peduncles, scapes, fruits, bracts, leaves, galls, algal pneumatocysts, moss sporophytes, lichen podetia, and fungal fruiting bodies. Despite being familiar, such structures have not been studied systematically until recently when their complex thermodynamic functionality as microgreenhouses has been recognized. We propose the term “heliocaminiform” (Greco-Latin origin for “sun-room”) provides an umbrella term that describes form and function. Almost all the hollow structures we have examined have elevated internal temperatures of several degrees C above the surrounding air in sunshine, but those are abolished under cloud or at night. The potential importance for the additional heat is presumed to be in growth, maturation, reproduction, sexual function, and overall fitness of the plants. There seem to be no experimental studies on those effects even though they may help explain aspects of plants’ responses to climate change and to phenological mismatches with symbionts (mutualists and herbivores) as ecologically co-dependent partners. Our review and observations opens a remarkably new and hitherto surprisingly neglected avenue in botany which we hope others will explore.
- OPEN ACCESSThe prairies and savannahs historically found in the Mixedwood Plains Ecozone have been largely converted into farmland, the dominant present-day land cover. Consequently, many species native to these grasslands have shifted to inhabiting suitable agricultural lands. More recently, agricultural intensification has led to the conversion of pastures and hay fields to annual crops, further removing habitat suitable for the persistence of grassland species. We quantified the shift from pasture and forage to annual crops as well as the dynamics among agricultural lands and other land covers in the Mixedwood Plains Ecozone, predicting biodiversity implications by providing a case study on Eastern Meadowlark (Sturnella magna (Linnaeus, 1758)). The total agricultural land area changed little over the study period, but area of pasture and forage decreased while row crop area increased. The loss of agricultural lands to urbanization was partly offset by the conversion of forests and wetlands; however, the farmland gained was of lesser agricultural quality than the farmland lost. Declines in Eastern Meadowlark abundance correlated significantly with carrying capacity loss, suggesting that habitat availability is a limiting factor for this species. We highlight the importance of land management policies to minimize the impacts of land conversion on biodiversity and agricultural production.