19366 research outputs found
Sort by
Species prevalence and plant traits discriminate between herbicide resistant and susceptible weeds
No full textBACKGROUND: Herbicide resistant weeds pose one of the most significant global challenges to sustainable food and fiber production. Plant traits are assumed to play a significant role in determining whether a weed is likely to evolve herbicide resistance but there have been few quantitative assessments to date. There is therefore an urgent need to investigate both the demographic and evolutionary characteristics of weeds to predict which weed species are likely to evolve herbicide resistance. Here, the discriminatory power of multiple plant traits was examined by comparing herbicide resistant and herbicide susceptible weeds in the United States.
RESULTS: Despite the taxonomic and agronomic similarity of herbicide resistant and susceptible weeds in the United States, differences between these groups were captured by a relatively small set of explanatory variables. Herbicide resistant weeds were found across more states than susceptible species and this suggests widespread weeds also happen to be more problematic in crops and therefore specifically targeted for weed control. In terms of traits, herbicide resistant species were more likely to be outcrossing, have unisexual flowers and be wind pollinated as well as have larger chromosome numbers and seed size than herbicide susceptible weeds.
CONCLUSIONS: A trait-based approach to understanding herbicide resistance confirms many assumptions as to the genetic attributes that make a weed more likely to evolve herbicide resistance. Scope therefore exists to build better risk assessment tools to identify future herbicide resistance hazards by incorporating plant traits, environmental tolerances, and evidence of herbicide resistance elsewhere in the world
Sooty mould populations on kiwifruit: post harvest and seasonal variation : A thesis submitted in partial fulfilment of the requirements for the Degree of Master at Lincoln University
No full textSooty mould is a universal term used to describe the complex of superficial, Ascomycota fungi that grow upon the honeydew exudates of sap-sucking insects. These organisms form an extensive network of dense, black mycelia on the surfaces of affected leaves, fruit and other plant material. Scolypopa australis (passionvine hopper) are Hemiptera that feed from the petiole of kiwifruit and subsequently excrete copious amounts of honeydew onto fruit surfaces. In the 2018/19 kiwifruit season, S. australis was responsible for $44 million in economic loss due to sooty mould. This study identified the fungal organisms constituting sooty mould on green-fleshed Actinidia chinensis var. deliciosa ‘Hayward’ and A. chinensis var. chinensis ‘Zesy002’ (informally referred to as Gold3) during cool storage and on ‘Zesy002’ throughout a single, growing season.
‘Hayward’ and ‘Zesy002’ fruit with sooty mould symptoms were harvested from the Plant and Food Research orchards in June 2021. Fruit were assessed at three sampling periods throughout six months in cool storage (1°C). Isolations were taken from the flesh, lenticel and skin tissue on non-sooty mould and sooty mould areas of the same fruit, followed by incubation (20°C) on ½ strength potato dextrose agar for seven days, with a 12 h photoperiod. Sub-culturing and morphological identification on representative morphotypes was conducted, followed by amplification of the ITS region of rDNA, with primer pairs ITS1-F/ITS4. Amplified PCR products were then SANGER sequenced and the consensus contig analysed using NCBI BLAST®. This study identified a total of 42 morphotypes within 17 fungal genera. There was no difference in fungal communities recovered from non-sooty mould and sooty mould areas of fruit surfaces. The number of isolates recovered from non-sooty mould and sooty mould areas decreased over time in cool storage however, the diversity of genera increased. No difference was observed between the fungal communities recovered from ‘Hayward’ and ‘Zesy002’. Fungi were also recovered from all tissue types. The most frequently recovered isolates belonged to Cladosporium, Epicoccum, Alternaria, Phoma, Diaporthe and Pestalotiopsis genera, with the greatest diversity of morphotypes within the Alternaria genus.
The sooty mould communities on ‘Zesy002’ were also analysed throughout a growing season from a Bay of Plenty orchard in December 2021, January 2022 and February 2022. An artificial honeydew solution was applied weekly to 24 fruit and sampled after four weeks of applications. Fruit with naturally infected sooty mould growth were also sampled. Subsequent sooty mould growth on the shoulder of fruit was analysed using the previous chapter’s methodology. This study identified a total of 52 morphotypes and 17 fungal genera. A greater number of isolates were recovered from sooty mould areas however, a similar fungal diversity was recovered between areas. The number of isolates recovered from non-sooty mould and sooty mould areas increased throughout the growing season however the fungal diversity remained similar. Fungi were recovered from all tissue types. The most frequently recovered fungi belonged to the genus Phoma followed by isolates from Cladosporium, Pestalotiopsis, Epicoccum, Didymella and Fusarium genera with the greatest diversity of morphotypes within the Fusarium genus. A greater number of isolates were recovered from fruit directly adjacent to a source of S. australis, compared to spatially removed. Only four naturally infected sooty mould fruit were observed in the orchard, therefore comprehensive analyses’ were not conducted. A total of 19 morphotypes and 12 genera were identified from these fruit, with no difference in fungal diversity between non-sooty mould and sooty mould areas. The Aureobasidium genus was only isolated from ‘Zesy002’ with naturally infected sooty mould, compared to the artificially applied honeydew.
A background diversity of fungi are present on the surfaces of ‘Zesy002’ and ‘Hayward’ fruit, irrespective of honeydew association. The sooty mould complex also constitutes organisms that are both epiphytic and endophytic in nature. Future studies should investigate the fungal microbiome of kiwifruit and whether these organisms could develop into pathogens. Furthermore, assessing fungal communities from a greater number of orchards, including organically grown fruit should be conducted and compared to the current study. Control must focus on reducing S. australis populations and developing a method that prevents fungal infection during fruit development
Modelling of the dielectric resonator and metal strip based negative-refractive-index lens
No full textTwo modelling methods of an experimental 3 GHz negative-refractive-index lens comprising an array of dielectric resonators and metal strips are compared. One model approach represents all constituent elements, whilst the other uses a continuous media approach. Both models display focusing properties and frequency dependent behavior similar to that observed in the experimental data
Introduction
No full textAotearoa New Zealand remains touted as an incredibly successful sporting nation despite its small population and arguably geographically remote location. Yet as the Introduction details, a range of challenges for sport and recreation lurk beneath the surface. Through providing an overview of the various chapters in the book, the Introduction outlines how Aotearoa New Zealand has a range of “legacy” issues, particularly in relation to race, ethnicity and gender, while being shaped by forms of tradition, myth, ritual and nostalgia, which many sports are needing to work through. Though there have been a range of government interventions through policies, these have largely been hampered by the strength of Aotearoa New Zealand’s neoliberal orientation. Collectively, the Introduction and the book as a whole metaphorically and symbolically criss-cross the New Zealand sport terrain to unearth some of these issues and tensions, both large and small, that undergird the contemporary sporting landscape
Attitude formation towards green products evidence in Indonesia: Integrating environment, culture, and religion
No full textThis study integrates three attitudinal drivers of green consumption attitudes, namely environmental responsibility, cultural responsibility, and religious responsibility. The data was gathered through a questionnaire distributed to 565 respondents of 3 different faiths; Muslims, Christians, and Hindus, who are reportedly consumers of green plastic products in Indonesia. To test the proposed hypotheses, the data was analysed using partial least square modelling. The findings reveal religiosity as playing a key role in influencing green product attitudes, as well as strengthening environmental concerns and environmental knowledge. Further, the data analysis shows insignificant variation of the model relationships across the religious groups
The effect of feeding a mix of condensed and hydrolyzable tannins to heifers on rumen fermentation patterns, blood urea nitrogen, and amino acid profile
No full textThe objective of this pilot study was to begin to evaluate the effect of feeding a mix of condensed and hydrolyzable tannins to heifers on rumen fermentation patterns, blood urea nitrogen (BUN), and amino acid profile. Four growing Holstein-Friesian × Jersey heifers with a mean live weight of 319.5 ± 8.38 kg and a mean body condition score of 4 ± 0.17 out of 10 were used in a cross-over design. Heifers were either orally administered the mixed tannin treatment at 0.15% of daily DMI or a control dose of water whilst consuming perennial ryegrass baleage and soybean meal for 12 days in a cross-over trial. Administration of mixed tannins reduced non-glucogenic volatile fatty acid (VFA) production by 2%, the acetate to propionate (A:P) ratio by 13%, and the relative abundances of specific methanogenic archaea – i.e., Methanobrevibacter and Methanosarcina. The tannin treatment also reduced BUN concentration by 12% in comparison with the control dose of water, which indicates associated reductions in daily urinary nitrogen excretion and therefore environmental impact. The effects of ingestion of mixed tannins on rumen function in this study would be expected to result in a reduction of both methane and urinary nitrogen excretion and thereby reducing the environmental impact of heifers consuming conventional feeds
In vitro digestion characteristics of cereal protein concentrates as assessed using a pepsin-pancreatin digestion model
No full textAn alkaline extraction method has been used in many studies to extract total protein from cereal samples. Wheat bran protein concentrate (WBPC), oat bran protein concentrate (OBPC), and barley protein concentrate (BPC) were prepared by alkaline extraction and isoelectric precipitation to study their functional and nutritional properties. The three protein concentrates were hydrolysed by an in vitro pepsin-pancreatin digestion model. Their digestibility (%) and degree of hydrolysis (DH%) were evaluated, and SDS-PAGE electrophoresis was used to illustrate the protein and peptides patterns. The change of the particle sizes and the release of the essential amino acids was followed during the digestion process. The in vitro digestibility of WBPC, OBPC and BPC was 87.4%, 96.1% and 76.9%, respectively. The DH% of protein concentrates were between 50 and 60%. The change of the particle size distribution values Dv(50) was assumed to be related to protein aggregations during the digestion. The protein fractions were identified and the degradation during the digestion and were analysed by SDS-PAGE; the gels of WBPC and OBPC digestion showed virtually complete degradation whereas the intensive bands of undigested protein were presented for BPC. The generation of the free amino acids and short chain peptides were significantly higher at the end of the intestinal digestion compared to the stages of before and after gastric digestion. Higher content of the deficient amino acids such as lysine and threonine were found comparing to the level of deficient amino acids in cereal grains but does not meet the daily recommended intake
Ultrasonication as an emerging technology for processing of animal derived foods: A focus on in vitro protein digestibility
No full textBackground: Animal products are sources of highly bioavailable proteins and make a significant contribution to human nutrition and wellbeing. Ultrasonication can induce favourable non-thermal effects in food matrices and this has led to a recent increase in its use in the food industry and related research. In addition to prospective improved quality and sensory attributes of animal products, ultrasonication offers opportunities to improve the digestibility of these foods. However, this beneficial effect of the technology has not been reviewed.
Scope and approach: The present paper reviews the application of ultrasonication in processing of animal derived foods and examines the effect of ultrasonication on the digestibility of different animal derived food matrices. The underlying mechanisms and optimized conditions for improved protein digestibility of different animal derived food matrices have been critically evaluated and discussed in detail. The review focuses on papers published in the last five years to provide the latest concepts and views on the ultrasonication process.
Key findings and conclusions: This green and eco-friendly technology has a wide range of applications in the area of animal derived foods. It has been used to accelerate processes such as filtration, extraction, marination, proteolysis, fermentation, decontamination and drying. It can also improve the functional, sensorial and nutritional properties of animal protein-based foods. Ultrasonication can alter the sensorial, especially textural, and other quality attributes of dairy, egg and meat products by affecting the chemical reactions and processes involved in their processing, such as oxidation, Maillard reaction, proteolysis, esterification and production of volatile flavour compounds. It can also modify food structure. There has been recent interest in the application of ultrasonication to improve the digestibility of various animal protein-based foods. Almost all the papers analysed in this review reported a positive impact of ultrasonication on the digestibility of animal proteins. The main mechanisms responsible are related to altered protein structure and changes in the microstructure of food matrices, which improve the digestibility of the animal proteins by making active hydrolytic sites available for digestive enzymes. This technology can be used to develop novel animal protein-based foods with improved digestibility. Future studies should validate this effect in animal models and possibly in human trials
Energy and crop price cycles before and after the global financial crisis: A new approach
No full textUsing the newly developed Hamilton filter, we decompose prices of three primary energy sources (crude oil, coal and natural gas) and five significant crops (corn, palm oil, rice, soybean and wheat) to isolate their cyclical components. Then, we apply time-difference analyses to study their co-movement. Analysing 15 energy price–crop price pairs over two periods, 1990–2009 and 2010–2020, we find that the correlations between coal and crop prices have weakened significantly during the 2010s, while correlations of crude oil and natural gas prices with crop prices have strengthened. Until 2009, crude oil and natural gas prices led crop prices, whereas during the 2010s they lagged crop prices. We conclude that the global financial crisis marked a pivotal shift in the associations between energy and crop prices. The results underscore the importance of examining the associations between specific crop and energy prices rather than aggregated indices; furthermore, using crude oil as a proxy for energy prices is not suitable—an aggregated approach that presumes the predominance of one energy source apropos different crops may yield incorrect results
Antimicrobial activity of tofu whey and steam blanching pea water for enhancement of shelf-life of 3D printed mashed potatoes
No full textUsing naturally-occurring antimicrobials against the resistance of foodborne pathogens towards antibiotics and chemicals, as well as their insensitivity is a promising research field. Water extracts of legumes have been proven to inhibit microbial development due to the presence of phenolic compounds, protein-derived peptides, saponins and defensin. This study examined the antimicrobial effects of two types of legume water, such as tofu whey (TW) and steam blanching pea water (SBPW), by adding into three-dimensional (3D) printed mashed potato. Composition, moulding, microbial growth assessment and the inhibition zone analysis were conducted. TW and SBPW contained 4 g/100 ml of solid matter, consisting of protein, soluble carbohydrates, minerals and saponins. Results have shown decreased microbial spoilage and enhanced Lactobacillus growth of mashed potato formulated with legume water. Limited inhibition zone (1 mm) was present on TW saponin extract against Staphylococcus aureus and Lactobacillus spp. TW and SBPW addition to 3D printed mashed potatoes encouraged the development of probiotic bacteria, which can be applied to extend shelf-life of food products as well as to develop fermented foods