19366 research outputs found
Sort by
Atmospheric cold plasma pretreatment on germination of guar bean seeds: Effect on germination parameters, bioactive compounds, Antinutritional factors, functional groups, and in vitro protein digestibility
No full textIn this study, atmospheric cold plasma (CP; voltage: 15–25 kV and time: 30–120 s) was applied to guar bean seeds (GBS) and then germinated for 5 days to understand the germination ability based on the germination parameters and chlorophyll content. After that, carbohydrate, protein, bioactive compounds, antinutritional factors, and in vitro protein digestibility of germinated GBS were analyzed. The results showed that CP treatment has significantly (p < 0.05) affected the germination parameters, majorly germination percentage, root length, and chlorophyll content of GBS. The CP-pretreated (20 kV for 90 s) germinated samples (on the fifth day) had maximum germination ability and less antinutritional factors. Similarly, the CP-pretreated germinated samples (15 and 20 kV for 90 s) showed higher in vitro protein digestibility and bioactive compounds than others. Unfortunately, higher applied voltage and duration negatively affected the germination process. From principal component analysis, medium-intensity CP treatment conditions were more effective in accelerating the germination process of GBS
Vineyard management systems influence arbuscular mycorrhizal fungi recruitment by grapevine rootstocks in New Zealand
No full textAims: Arbuscular mycorrhizal fungi (AMF) can perform significant functions within sustainable agricultural ecosystems, including vineyards. Increased AMF diversity can be beneficial in promoting plant growth and increasing resilience to environmental changes. To effectively utilize AMF communities and their benefits in vineyard ecosystems, a better understanding of how management systems influence AMF community composition is needed. Moreover, it is unknown whether AMF communities in organically managed vineyards are distinct from those in conventionally managed vineyards.
Methods and Results: In this study, vineyards were surveyed across the Marlborough region, New Zealand to identify the AMF communities colonizing the roots of different rootstocks grafted with Sauvignon Blanc and Pinot Noir in both conventional and organic systems. The AMF communities were identified based on spores isolated from trap cultures established with the collected grapevine roots, and by next-generation sequencing technologies (Illumina MiSeq). The identified AMF species/genera belonged to Glomeraceae, Entrophosporaceae, and Diversisporaceae. The results revealed a significant difference in AMF community composition between rootstocks and in their interaction with management systems. Conclusions: These outcomes indicated that vineyard management systems influence AMF recruitment by rootstocks and some rootstocks may therefore be more suited to organic systems due to the AMF communities they support. This could provide an increased benefit to organic systems by supporting higher biodiversity
Concurrent and legacy effects of sheep trampling on soil organic carbon stocks in a typical steppe, China
No full textGrazing plays a key role in ecosystem biogeochemistry, particularly soil carbon (C) pools. The non-trophic interactions between herbivores and soil processes through herbivore trampling have recently attracted extensive attention. However, their concurrent and legacy effects on the ecosystem properties and processes are still not clear, due to their effects being hard to separate via field experiments. In this study, we conducted a 2-year simulated-sheep-trampling experiment with four trampling intensity treatments (i.e., T0, T40, T80, and T120 for 0, 40, 80, and 120 hoofprints m¯², respectively) in a typical steppe to explore the concurrent and legacy effects of trampling on grassland ecosystem properties and processing. In 2017 (trampling treatment year), we found that trampling decreased aboveground biomass (AGB) of plant community and community-weighted mean shoot C concentration (CWM C), soil available nitrogen (N) and available phosphorus (P), but did not affect plant species diversity and belowground biomass (BGB). We show that compared with T0, trampling increased soil bulk density (BD) at T80, and decreased soil organic carbon (SOC) stocks. After the cessation of trampling for two years (i.e., in 2019), previous trampling increased plant diversity and BGB, reaching the highest values at T80, but decreased soil available N and available P. Compared with T0, previous trampling significantly increased soil BD at T120, while significantly decreased CWM C at T80 and T120, and reduced SOC stocks at T80. Compared with 2017, the trampling negative legacy effects amplified at T80 but weakened at T40 and T120. We also show that trampling-induced decreases in soil available N, AGB of Fabaceae and CWM C were the main predictors of decreasing SOC stocks in 2017, while previous trampling-induced legacy effects on soil available P, AGB of Poaceae and CWM C contributed to the variations of SOC stocks in 2019. Taken together, short-term trampling with low intensity could maintain most plant functions, while previous trampling with low intensity was beneficial to most plant and soil functions. The results of this study show that T40 caused by sheep managed at a stocking rate of 2.7 sheep ha¯¹ is most suitable for grassland adaptive management in the typical steppe. The ecosystem functions can be maintained under a high stocking rate through the process of providing enough time to rebuild sufficient vegetation cover and restore soil through measures such as regional rotational grazing and seasonal grazing
Oil price uncertainty, oil pricing reform, and corporate profitability: The case of China
No full textThis study investigates the impact of oil price uncertainty (OPU) on corporate profitability in China, the world’s largest crude oil consumer. Most importantly, we examine how the Chinese government’s oil price reform affects this relationship. Using the yearly data of Chinese-listed companies, we find that the uncertainty of oil prices negatively affects corporate profitability but positively impacts operating expenses from 2007 to 2020. This finding holds after robust tests, including alternative profitability metrics and endogeneity model. Most interestingly, implementing the 2013 market-oriented oil pricing reform amplifies the adverse impact of OPU on corporate profitability owing to increased operating costs in the post-2013 period. Moreover, the detrimental effect of uncertain oil prices on corporate profitability is less prominent for large-capitalized companies. This research adds to the body of knowledge on the factors affecting corporate profitability by highlighting the volatility effect of oil prices and government pricing mechanisms. The results offer grounds for legislators and corporate managers to consider how to control the uncertainty surrounding oil price matters to ensure stable corporate profitability
Fungal communities associated with myrtle rust infection and their potential as biocontrol agents against the disease
No full textMyrtle rust, caused by Austropuccinia psidii, has spread widely across New Zealand, threatening over 19 native and 17 exotic myrtaceous species. This research aims to investigate fungal communities associated with myrtle rust infection and identify mycoparasite(s) for potential use as biocontrol agents against this pathogen. Symptomatic and asymptomatic leaf samples were collected from ramarama (Lophomyrtus bullata) and pōhutukawa (Metrosideros excelsa) across four sites (Taranaki, Rotorua, Auckland, and Christchurch) for the isolation and identification of the fungal microbiome using metabarcoding. Initial results of the fungal microbiome from plants in Taranaki showed the highest relative abundance of Colletotrichum (28.90%), Simplicillium (25.39%), and Neopestalotiopsis (4.41%) in asymptomatic leaves, while the most common genera in symptomatic leaf samples were Lophiotrema (43.63%), Septobasidium (4.43%), and Conoideocrella (3.1%). Differences in fungal communities between locations and their association with rust infection will be presented. The 201 fungal isolates recovered (148 epiphytes and 53 endophytes) were identified as belonging to 61 fungal genera. Putative mycoparasites from eleven genera (Alternaria, Aureobasidium, Cladosporium, Clonostachys, Colletotrichum, Epicoccum, Myrothecium, Paraconiothyrium, Phlebiopsis, Trichoderma and Sclerostagonospora) were selected for screening for antagonistic activity against A. psidii. Three different in vitro bioassays, including a spore germination test, culture filtrate assay and detached branchlet assay were used to assess each isolate's ability to control myrtle rust. Several isolates capable of inhibiting the germination of A. psidii spores and/or colonizing the pustules have been identified. These isolates are now undergoing further testing for biological control activity against myrtle rust in glasshouse conditions
Relationship between plasma and saliva urea nitrogen concentrations in New Zealand red deer calves (Cervus elaphus)
No full textRed deer (Cervus elaphus), like other ruminants, excrete approximately 70% of the nitrogen they ingest. Developing ways in which to reduce the rate of loss, such as manipulating the diet or selecting for efficiency of growth, requires close monitoring of the plasma urea N (PUN) concentration which, in turn, requires a simple, safe, and reliable method for collecting samples. Saliva is easier to collect than blood, but the relationship between the salivary urea N (SUN) and the PUN is not known for red deer. This was therefore evaluated in two strains of mixed-sex red deer calves (Cervus elaphus): a phenotype with a high seasonality of growth (H, n = 10) and a phenotype with a low seasonality of growth (L, n = 13). Both phenotypes were divided into two groups, which were each offered one of two forage-based diets ad libitum: a medium-quality diverse treatment and a low-quality perennial ryegrass–white clover treatment. Blood and saliva samples for the determination of the PUN and SUN were collected at dawn every four weeks for five months (April to September 2022). There was a strong linear relationship between the PUN and SUN in the pooled sample (R² = 0.65, p 0.75). SUN represents a reliable index of the PUN, and collecting saliva therefore represents a simple and inexpensive alternative to collecting blood samples in studies of nitrogen metabolism in red dee
Pasture growth simulation and sensitivity analysis using APSIM-related models in a tropical silvopastoral system
No full textSilvopastoral systems integrate trees, pastures, and animals aiming for sustainable livestock production. The APSIM model has been used to simulate silvopastoral systems but the estimates of light transmission through the tree canopies, belowground water competition, and their effects on pasture production, have not been well adjusted. Thus, we improved the simulation of pasture growth within a silvopastoral system by integrating the APSIM-Tropical Pasture and APSIM-Slurps models and calibrated the coupled models to simulate light transmission through the trees along with water competition among species. Observed data was obtained from a silvopastoral system established in São Carlos, SP, Brazil, during two experimental periods that went from Dec-2014 until May-2016 and from Apr-2018 until May-2019. The calibration of the combination of the models was considered overall accurate. The APSIM-Slurp model simulated well (R² = 0.64, NSE = 0.60) the radiation interception by trees. The APSIM-Tropical Pasture model showed a good performance to simulate pasture (R² = 0.90 and NSE = 0.72), leaf (R² = 0.82 and NSE = 0.44), and stem (R² = 0.82 NSE = 0.75) biomass and an acceptable performance for pasture LAI (R² = 0.76 and NSE = 0.58). With that, a multifactorial simulation was performed to test the sensitivity of pasture production as a function of levels of nitrogen, tree leaf area index (LAI), tree root water extraction coefficient, post grazing residual biomass, and season of the year, using 39 years of weather data from the same location of the field experiment as input. The sensitivity analysis showed that the combination of the models was sensitive to variations of the factors with the greatest sensitivity occurring for the tree LAI. The assembling of APSIM-Tropical Pasture and APSIM-Slurp models well simulated pasture production in a silvopastoral system with different managements, indicating the potential of its use as a decision-making tool for silvopastoral systems´ design
Nitrogen and Nod factor signaling determine Lotus japonicus root exudate composition and bacterial assembly
No full textSymbiosis with soil-dwelling bacteria that fix atmospheric nitrogen allows legume plants to grow in nitrogen-depleted soil. Symbiosis impacts the assembly of root microbiota, but it is unknown how the interaction between the legume host and rhizobia impacts the remaining microbiota and whether it depends on nitrogen nutrition. Here, we use plant and bacterial mutants to address the role of Nod factor signaling on Lotus japonicus root microbiota assembly. We find that Nod factors are produced by symbionts to activate Nod factor signaling in the host and that this modulates the root exudate profile and the assembly of a symbiotic root microbiota. Lotus plants with different symbiotic abilities, grown in unfertilized or nitrate-supplemented soils, display three nitrogen-dependent nutritional states: starved, symbiotic, or inorganic. We find that root and rhizosphere microbiomes associated with these states differ in composition and connectivity, demonstrating that symbiosis and inorganic nitrogen impact the legume root microbiota differently. Finally, we demonstrate that selected bacterial genera characterizing state-dependent microbiomes have a high level of accurate predictio
Effects of retained node numbers on berry maturity and yield components of cane-pruned Sauvignon blanc
No full textCane pruning is used in most New Zealand Sauvignon blanc vineyards to manage yield, vine balance (relationship between vegetative growth and fruit growth) and fruit primary and secondary metabolites. The source–sink ratio (TLA/FM—total leaf area to fruit mass or ELA/FM—exposed leaf area to fruit mass), the fruit mass to pruning mass (FM/PM), the fruit mass to cane mass (FM/CM) and fruit composition provide an assessment of the vine performance and balance. The interpretation of these metrics (i.e., TLA/FM, ELA/FM, FM/PM, FM/CM) requires their comparison with known optimal ranges specific to cultivars, locations and growing conditions. More often, such context-and cultivar-specific optimal ranges do not exist, thus warranting research to investigate them. To understand the influence of retained node numbers on the vegetative and fruit development of Sauvignon blanc, grapevines were pruned across three vineyard sites (two in Marlborough—Site 1 and 2, and one in Waipara— Site 3) over two growing seasons, retaining 10, 20, 30, 40 and 50 nodes on one to four canes (each cane carrying ten nodes, with 50-node vines carrying on average 12.5 nodes on each of the four canes). The accumulation of soluble solids (TSS) generally increased at lower node numbers and vine yields, reflecting an increase in ELA/FM, with 50-node vines having the least TSS concentration at harvest. The average berry mass, titrable acidity (TA) and pH were unaffected by node numbers over the two seasons. A low source–sink ratio induced by high node numbers not only reduced the vine capacity to ripen the current crop but also reduced the following season’s bunch number per shoot (from 1.8 to 1.6 bunches per shoot; p < 0.05), average bunch mass (from 82.0 ± 6 g to 67.7 ± 3 g; p < 0.01) and bunch mass per shoot (from 153.5 ± 15 g to 106.7 ± 9 g; p < 0.05). When compared to 50-node vines, 10-node vines had a two-fold increase in the average cane mass (from 30.1 ± 3.9 g to 69.2 ± 8.7 g; p < 0.001) and average old cane mass (from 82.4 ± 6.9 g to 163.8 ± 21 g; p < 0.001). The ELA/FM and TLA/FM required for optimal TSS accumulation were 0.75 m² kg-1 and 2.0 m² kg-1, respectively, across all sites. A source–sink ratio above these values resulted in high average cane mass and average old cane mass (an indication of excess vigour), while lower values indicated reduced vigour and slowed TSS accumulation. This research provides useful optimal ranges to compare and interpret vine balance metrics measured at those sites
Towards a tika political science: Restoring balance, reflecting our context
No full textThis article is a rejoinder to Annie Te One and Maria Bargh’s article published in The Australian Journal of Indigenous Education in 2023, “Towards a Fairer and More Tika Political Science and Politics: Are Political Science Programs Equipping Students Adequately for Aotearoa Realities?” (vol. 52, no. 2)