| 1. |
- George, T. S., et al.
(författare)
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Organic phosphorus in the terrestrial environment : a perspective on the state of the art and future priorities
- 2018
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Ingår i: Plant and Soil. - : Springer Netherlands. - 0032-079X .- 1573-5036. ; 427:1-2, s. 191-208
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Tidskriftsartikel (refereegranskat)abstract
- Background: The dynamics of phosphorus (P) in the environment is important for regulating nutrient cycles in natural and managed ecosystems and an integral part in assessing biological resilience against environmental change. Organic P (P-o) compounds play key roles in biological and ecosystems function in the terrestrial environment being critical to cell function, growth and reproduction.Scope: We asked a group of experts to consider the global issues associated with P-o in the terrestrial environment, methodological strengths and weaknesses, benefits to be gained from understanding the P-o cycle, and to set priorities for P-o research.Conclusions: We identified seven key opportunities for P-o research including: the need for integrated, quality controlled and functionally based methodologies; assessment of stoichiometry with other elements in organic matter; understanding the dynamics of P-o in natural and managed systems; the role of microorganisms in controlling P-o cycles; the implications of nanoparticles in the environment and the need for better modelling and communication of the research. Each priority is discussed and a statement of intent for the P-o research community is made that highlights there are key contributions to be made toward understanding biogeochemical cycles, dynamics and function of natural ecosystems and the management of agricultural systems.
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| 2. |
- Hudson, Lawrence N., et al.
(författare)
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The PREDICTS database : a global database of how local terrestrial biodiversity responds to human impacts
- 2014
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 4:24, s. 4701-4735
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Tidskriftsartikel (refereegranskat)abstract
- Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species' threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project - and avert - future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups - including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems - ). We make site-level summary data available alongside this article. The full database will be publicly available in 2015.
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| 3. |
- Landhausser, S. M., et al.
(författare)
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Standardized protocols and procedures can precisely and accurately quantify non-structural carbohydrates
- 2018
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Ingår i: Tree Physiology. - : Oxford University Press (OUP). - 0829-318X .- 1758-4469. ; 38:12, s. 1764-1778
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Tidskriftsartikel (refereegranskat)abstract
- Non-structural carbohydrates (NSCs), the stored products of photosynthesis, building blocks for growth and fuel for respiration, are central to plant metabolism, but their measurement is challenging. Differences in methods and procedures among laboratories can cause results to vary widely, limiting our ability to integrate and generalize patterns in plant carbon balance among studies. A recent assessment found that NSC concentrations measured for a common set of samples can vary by an order of magnitude, but sources for this variability were unclear. We measured a common set of nine plant material types, and two synthetic samples with known NSC concentrations, using a common protocol for sugar extraction and starch digestion, and three different sugar quantification methods (ion chromatography, enzyme, acid) in six laboratories. We also tested how sample handling, extraction solvent and centralizing parts of the procedure in one laboratory affected results. Non-structural carbohydrate concentrations measured for synthetic samples were within about 11.5% of known values for all three methods. However, differences among quantification methods were the largest source of variation in NSC measurements for natural plant samples because the three methods quantify different NSCs. The enzyme method quantified only glucose, fructose and sucrose, with ion chromatography we additionally quantified galactose, while the acid method quantified a large range of mono- and oligosaccharides. For some natural samples, sugars quantified with the acid method were two to five times higher than with other methods, demonstrating that trees allocate carbon to a range of sugar molecules. Sample handling had little effect on measurements, while ethanol sugar extraction improved accuracy over water extraction. Our results demonstrate that reasonable accuracy of NSC measurements can be achieved when different methods are used, as long as protocols are robust and standardized. Thus, we provide detailed protocols for the extraction, digestion and quantification of NSCs in plant samples, which should improve the comparability of NSC measurements among laboratories.
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| 4. |
- Adusei-Fosu, Kwasi, et al.
(författare)
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Evaluating the efficacy of potential fungicide-adjuvant combinations for control of myrtle rust in New Zealand
- 2021
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Ingår i: Journal of Plant Diseases and Protection. - : Springer. - 1861-3829 .- 1861-3837. ; 128, s. 1501-1515
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Tidskriftsartikel (refereegranskat)abstract
- Myrtle rust is a serious fungal disease caused by Austropuccinia psidii affecting a number of Myrtaceae species in New Zealand and elsewhere. Control with fungicides or biologicals provides a mechanism to reduce the build-up of inoculum in the short-term while other strategies are being developed or deployed for long-term management. This study evaluated the efficacy of fungicides for control of myrtle rust under controlled conditions and identified adjuvants that would promote spreading of fungicidal active ingredients across the leaf surface. The spread of fungicide on detached M. excelsa leaves was assessed by applying three different adjuvants in combination with seven fungicides. Subsequently, M. excelsa plants were treated with three fungicides/mixes, (azoxystrobin + epoxiconazole, triademinol or a natural tea-extract) at a single rate followed by inoculation with A. psidii urediniospores on day 0, 7, 14 or 21 days after spraying. The response to infection in M. excelsa plants based on different inoculation timings at days 0, 7 and 21 significantly differed among fungicide treatments. The fungicide azoxystrobin + epoxiconazole was the most effective with infections significantly lower on the adaxial leaf surface than abaxial, despite good surface coverage of fungicide being achieved on both leaf surfaces. There were significant differences among fungicides based on the proportion of infected leaves on M. excelsa plants. Day 21 post-spray inoculation indicated a significant interaction between inoculation time and fungicide on leaf disease ratings. However, this was not the case at either 28 or 35 days post-inoculation. This research contributes to fungicide options for myrtle rust control in New Zealand.
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| 5. |
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| 6. |
- Richardson, Gisela, et al.
(författare)
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The function of alpha-crystalline emulsifiers on expanding foam surfaces
- 2004
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Ingår i: Food Hydrocolloids. - : Elsevier BV. - 0268-005X. ; 18:4, s. 655-663
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Tidskriftsartikel (refereegranskat)abstract
- The expanding capacity and the stabilizing function of an alpha-crystalline emulsifier on the bubble surfaces during and after expansion of a sugar foam were examined by volume measurements, confocal laser scanning microscopy (CLSM), freeze-etching and transmission electron microscopy (TEM) and oscillatory theological measurements. 0.2-10% (w/w) emulsifier, either a polyglycerol ester mixed with monoglycerides (PGE/MG) in alpha-gel form or sodium oleate in micellar form, was mixed into a 65% sucrose solution in a specially designed vessel at a pressure of 1-5 bar. The foam produced was expanded to ambient pressure before measurements were made. The total volume of the foam was shown to increase proportionally to the expansion with both emulsifiers. With PGE/MG, small bubbles were produced (1-4 mum). With oleate, the bubbles became much larger (5-25 mum) and more coalescence could be observed. The storage modulus of the foam was shown to depend on the bubble sizes, the volume fraction of air and also the emulsifier. The foam stabilized with PGE/MG was stiff at a high concentration of emulsifier, while the micelle forming emulsifier remained more liquid-like. A possible explanation was that the alpha-crystalline PGE/MG emulsifier formed aggregates and caused an attractive bridging interaction between the bubbles, which resulted in a higher storage modulus. The micellar oleate did not cause any bubble bridging. (C) 2003 Elsevier Ltd. All rights reserved.
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| 7. |
- Richardson, G., et al.
(författare)
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Wheat starch gelatinization : The effects of sucrose, emulsifier and the physical state of the emulsifier
- 2003
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Ingår i: Starke (Weinheim). - 0038-9056 .- 1521-379X. ; 55:42067, s. 150-161
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Tidskriftsartikel (refereegranskat)abstract
- The effect of emulsifier and/or sucrose on the swelling of an 8% wheat starch dispersion was evaluated by microscopy. Visual observations of smeared starch pastes under the light microscope, image analysis of the starch granule sizes and viscosity measurements of the starch paste during heating were combined to explain the effects of the added ingredients. Sucrose (12 or 24%, w/w) was shown to delay the swelling of the granules at least up to 50°C. Above this temperature, the leakage of amylose and granule fragmentation were delayed, but the swelling itself seemed to be accelerated. The polyglycerol ester emulsifier (PGE/MG) at concentrations of 0.5 and 4.0% hindered amylose leakage completely up to 90°C, followed by a sudden granule rupture. The size of the granules increased up to about 70°C, but not above this temperature. The monoglyceride (MG) emulsifier in ?-form already had a restrictive effect on the swelling at low temperatures, while the same emulsifier in ?-form did not restrict the swelling until higher temperatures were reached. The emulsifier itself converted into the lamellar state at between 55 and 70°C, irrespective of the initial form, but the final viscosity was higher in the paste with MG in ?-form. Thus, the initial physical state of the emulsifier was shown to have an influence on the final properties of the gel. © 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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| 8. |
- Richardson, James E., et al.
(författare)
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The influence of tectonics, sea-level changes and dispersal on migration and diversification of Isonandreae (Sapotaceae)
- 2014
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Ingår i: Botanical journal of the Linnean Society. - : Wiley-Blackwell. - 0024-4074 .- 1095-8339. ; 174:1, s. 130-140
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Tidskriftsartikel (refereegranskat)abstract
- Internal transcribed spacer (ITS) ribosomal DNA sequence data were generated for 80 of the c. 200 species of Isonandreae and were added to data from African and Neotropical representatives in subfamily Sapotoideae and outgroups in Sapotaceae. Bayesian dating and ancestral area reconstruction indicated that Isonandreae are derived from within an African grade. Multiple Australasian species or lineages are derived from Sundanian lineages in South-East Asia with stem ages originating from the late Oligocene. Sri Lankan and Indian lineages are also derived from Sundanian lineages. Our results are consistent with migration from Africa into Sundania followed by numerous over-water dispersal events across Wallace's Line into Australasia and migration from Sundania to the Indian subcontinent. Pleistocene speciation indicates that sea-level changes during that epoch could have been responsible for some species diversification in Sundania.
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| 9. |
- Siefert, Andrew, et al.
(författare)
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A global meta-analysis of the relative extent of intraspecific trait variation in plant communities
- 2015
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 18:12, s. 1406-1419
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Forskningsöversikt (refereegranskat)abstract
- Recent studies have shown that accounting for intraspecific trait variation (ITV) may better address major questions in community ecology. However, a general picture of the relative extent of ITV compared to interspecific trait variation in plant communities is still missing. Here, we conducted a meta-analysis of the relative extent of ITV within and among plant communities worldwide, using a data set encompassing 629 communities (plots) and 36 functional traits. Overall, ITV accounted for 25% of the total trait variation within communities and 32% of the total trait variation among communities on average. The relative extent of ITV tended to be greater for whole-plant (e.g. plant height) vs. organ-level traits and for leaf chemical (e.g. leaf N and P concentration) vs. leaf morphological (e.g. leaf area and thickness) traits. The relative amount of ITV decreased with increasing species richness and spatial extent, but did not vary with plant growth form or climate. These results highlight global patterns in the relative importance of ITV in plant communities, providing practical guidelines for when researchers should include ITV in trait-based community and ecosystem studies.
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