Plant and Food Research Ruakura

Hamilton, New Zealand

Plant and Food Research Ruakura

Hamilton, New Zealand
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Judd M.J.,Plant and Food Research Te Puke | Meyer D.H.,Swinburne University of Technology | Meekings J.S.,Plant and Food Research Ruakura | Richardson A.C.,Plant and Food Research Kerikeri | And 2 more authors.
Journal of the Science of Food and Agriculture | Year: 2010

Background: Many deciduous, perennial fruit crops require winter chilling for adequate budbreak and flowering. Recent research has shown that changes in sugar and amino acid profiles are associated with the release of buds from dormancy. This paper uses FTIR spectrometry to provide an alternative mechanism for tracking metabolic changes in themeristems of kiwifruit buds during winter dormancy. The results suggest that the application of multivariate analysis to FTIR spectra has the potential to be a reliable and fast method for detecting structural and compositional changes in fruit crops. Results: Ten wave numbers of the FTIR spectra are used to calculate a bud development function. This function has been validated using data from two seasons and four orchards, and by monitoring the effects of hydrogen cyanamide application, sugar concentrations and soil temperatures on this function. These wave numbers appear to be associated with carbohydrate, pectin and cellulose levels in the meristems. Conclusion: It is expected that this FTIR signature can be used to advance our understanding of the influence of the various environmental and physiological factors on the breaking of bud dormancy and shoot outgrowth, including the optimum timing and concentrations of applications of budbreak regulators, such as hydrogen cyanamide. © 2010 Society of Chemical Industry.

Upreti G.C.,Plant and Food Research Ruakura | Wang Y.,Plant and Food Research Ruakura | Finn A.,Plant and Food Research Ruakura | Sharrock A.,Plant and Food Research Ruakura | And 4 more authors.
BioTechniques | Year: 2012

Traditional colorimetric protein assays such as Biuret, Lowry, and modified Lowry (U-1988) are unsuitable for colored biological samples. Here we describe an improved Lowry protein assay (U-2012), which utilizes stable reagents and offers enhanced sensitivity over the U-1988 assay. U-2012 circumvents interference from colored pigments and other substances (for example sugars) bound to perchloric acid (PCA) precipitated proteins by hydrogen peroxide (H2O2) induced oxidation at 50°C. Unused hydrogen peroxide is neutralized with sodium pyruvate before protein estimation for a stable end color. The U-2012 assay is carried out on the PCA precipitated protein pellet after neutralization (with Na2CO3 plus NaOH), solubilization (in Triton-NaCl), decolorization (by H2O2) and pyruvate treatment. Protein contents in red wine and homogenates of beetroot and blueberry are calculated from standard curves established for various proteins and generated using a rectangular hyperbola with parameters estimated with Microsoft Excel's Solver add-in. The U-2012 protein assay represents an improvement over U-1988 and gives a more accurate estimation of protein content.

Northcott G.,Plant and Food Research Ruakura | Jensen D.,Plant and Food Research Ruakura | Ying L.,Plant and Food Research Ruakura | Fisher P.,Landcare Research
Environmental Toxicology and Chemistry | Year: 2014

The degradation rate of sodium fluoroacetate (SFA) was assessed in a laboratory microcosm study incorporating 3 New Zealand soil types under different temperature (5°C, 10°C, or 20°C) and soil moisture (35% or 60% water holding capacity) conditions using guideline 307 from the Organisation for Economic Co-operation and Development. A combination of nonlabeled and radiolabeled 14C-SFA was added to soil microcosms, with sampling and analysis protocols for soil, soil extracts, and evolved CO2 established using liquid scintillation counting and liquid chromatography-mass spectrometry. Degradation products of SFA and their rates of formation were similar in the 3 soil types. The major degradation pathway for SFA was through microbial degradation to the hydroxyl metabolite, hydroxyacetic acid, and microbial mineralization to CO2, which constituted the major transformation product. Temperature, rather than soil type or moisture content, was the dominant factor affecting the rate of degradation. Soil treatments incubated at 20°C displayed a more rapid loss of 14C-SFA residues than lower temperature treatments. The transformation half-life (DT50) of SFA in the 3 soils increased with decreasing temperature, varying from 6d to 8d at 20°C, 10d to 21d at 10°C, and 22d to 43d at 5°C. © 2014 SETAC.

Walton E.F.,Plant and Food Research Mt Albert | Boldingh H.L.,Plant and Food Research Ruakura | McLaren G.F.,Plant and Food Research Clyde | Williams M.H.,Plant and Food Research Mt Albert | Jackman R.,Plant and Food Research Mt Albert
Postharvest Biology and Technology | Year: 2010

The carbohydrate dynamics of cut peony (Paeonia lactiflora Pall. 'Sarah Bernhardt') stems were examined during vase life of fresh-cut stems, while in storage at 0°C and during their vase life after storage. During flower opening of fresh-cut stems, the rate of starch hydrolysis in the flower buds was more rapid than in those still attached to the plant, and once the flowers had opened, the total sugar concentrations of the flowers, leaves and stems were lower than in those still attached to the plant. Quantification of the sugar content of fresh-cut stems during flower opening and those still attached to the plant, suggests that an additional 3.2. g of sugars are translocated into attached stems during flower opening, which equates to nearly 42% of an open flower. However, reserves in fresh stems were still sufficient to provide a total vase life of 14. d, only 2. d less than stems still attached to the plant. During the first 4 weeks of cool-storage, starch reserves in the flower buds were almost completely hydrolysed, contributing to similar hexose concentrations but much higher sucrose concentrations than in fresh-cut stems. Flower opening was more rapid but the subsequent vase life was only 9. d, shorter than that for fresh-cut stems. Much of that difference could be attributed to the faster opening of buds (2. d cf. 5. d), which is likely to have been the result of the starch having already been hydrolysed during storage. Together, these results indicate that cut peony stems have sufficient carbohydrate reserves to drive flower opening and still have an acceptable vase life even after 8 weeks of storage. © 2010 Elsevier B.V.

Mondet F.,University of Otago | Goodwin M.,Plant and Food Research Ruakura | Mercer A.,University of Otago
Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology | Year: 2011

The parasitic mite Varroa destructor is responsible for heavy losses in honey bee colonies and represents a major threat to the beekeeping industry. Essential oils offer an attractive alternative to the use of synthetic chemicals for the control of varroa. Amongst them, thymol appears to be particularly promising. However, treatments using thymol as their active substance, such as the gel formulation Apiguard ®, are suspected to have adverse effects on honey bee colonies. In this study, laboratory assays are used to investigate the effects of Apiguard ® exposure on honey bee behaviour. Our results reveal that honey bee responses to this anti-varroa treatment change with honey bee age. While 2-day-old bees respond neutrally to Apiguard ®, older bees generally avoid the Apiguard ® gel. Responses of forager bees were particularly striking. Foragers appear to be repelled by Apiguard ®. Touching their antennae with Apiguard ® induces robust fanning behaviour. Our data suggest, however, that forager bees exposed to Apiguard ® in the hive can become habituated to this treatment. These results offer interesting new perspectives on the effects of Apiguard ® on honey bee behaviour and serve to highlight age-related changes in honey bee responses to gustatory, as well as olfactory cues. © 2011 Springer-Verlag.

Parkar S.G.,The New Zealand Institute for Plant and Food Research Ltd | Parkar S.G.,Plant and Food Research Ruakura | Rosendale D.,The New Zealand Institute for Plant and Food Research Ltd | Paturi G.,The New Zealand Institute for Plant and Food Research Ltd | And 6 more authors.
Plant Foods for Human Nutrition | Year: 2012

We examined the effects of whole kiwifruit on gut microbiota using an in vitro batch model of gastric-ileal digestion and colonic fermentation. Faecal fermentations of gold and green kiwifruit, inulin and water (control) digests were performed for up to 48 h. As compared to the control, gold and green kiwifruit increased Bifidobacterium spp. by 0. 9 and 0. 8 log10 cfu/ml, respectively (P < 0.001), and the Bacteroides-Prevotella-Porphyromonas group by 0.4 and 0.5 log10 cfu/ml, respectively. Inulin only had a bifidogenic effect (+0.4 log10 cfu/ml). This was accompanied with increases in microbial glycosidases, especially those with substrate specificities relating to the breakdown of kiwifruit oligosaccharides, and with increased generation of short chain fatty acids. The microbial metabolic activity was sustained for up to 48 h, which we attribute to the complexity of the carbohydrate substrate provided by whole kiwifruit. Kiwifruit fermenta supernatant was also separately shown to affect the in vitro proliferation of Bifidobacterium longum, and its adhesion to Caco-2 intestinal epithelial cells. Collectively, these data suggest that whole kiwifruit may modulate human gut microbial composition and metabolism to produce metabolites conducive to increased bifidobacteria-host association. © 2012 Springer Science+Business Media, Inc.

Horswell J.,Institute of Environmental Science and Research ESR Ltd | Prosser J.A.,Institute of Environmental Science and Research ESR Ltd | Siggins A.,Institute of Environmental Science and Research ESR Ltd | van Schaik A.,Institute of Environmental Science and Research ESR Ltd | And 4 more authors.
Soil Biology and Biochemistry | Year: 2014

Little is known about the environmental fate and effect of low levels of co-contaminants that are commonly present in wastes such as biosolids. Lysimeters were established using soils contaminated with Cu or Zn and augmented with triclosan. Triclosan degraded rapidly in the soils, with methyl-triclosan being the major degradation product. However, as metal concentration increased, transformation and biodegradation of triclosan decreased. For some soil health indicators (e.g. sulphatase enzyme), results suggested that general toxicity was increased when metals and triclosan were both present. These preliminary results suggest that co-contaminants can result in a combined effect that is potentially greater than the sum of the individual effects, with additional impacts on the rate and extent of contaminant degradation. © 2014 Elsevier Ltd.

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