A5018655714- Plant Water Relations and Carbon Dynamics
- Horticultural and Viticultural Research
- Plant Physiology and Cultivation Studies
- Tree-ring climate responses
- Plant and animal studies
- Postharvest Quality and Shelf Life Management
- Ecology and Vegetation Dynamics Studies
- Plant nutrient uptake and metabolism
- Plant responses to water stress
- Plant Surface Properties and Treatments
- Tree Root and Stability Studies
- Plant-Derived Bioactive Compounds
- Plant Pathogens and Fungal Diseases
- Plant Parasitism and Resistance
- Fern and Epiphyte Biology
- Agronomic Practices and Intercropping Systems
- Forest ecology and management
- Photosynthetic Processes and Mechanisms
- Peatlands and Wetlands Ecology
- Bee Products Chemical Analysis
- Species Distribution and Climate Change
- Coastal wetland ecosystem dynamics
- Mycorrhizal Fungi and Plant Interactions
- Light effects on plants
- Plant responses to elevated CO2
University of Waikato
2015-2024
Plant & Food Research
2002-2013
AgResearch
2002-2007
Hawaii Agriculture Research Center
1999-2001
University of Edinburgh
1998-1999
University of Auckland
1995
The empirical calibration of Granier-type heat dissipation sap flow probes that relate temperature difference (ΔT) to velocity (v) was reevaluated in stems three tropical tree species. original confirmed when the entire heated probe contact with conducting xylem, but mean v underestimated part nonconducting xylem or bark. Analysis effects nonuniform profiles on estimates showed errors increased as and proportion wood increased. If half a 20-mm is sapwood 0.15 mm s−1 other wood, then for...
Robust thermal dissipation sensors of variable length (3 to 30 cm) were developed overcome limitations the measurement radial profiles sap flow in large-diameter tropical trees with deep sapwood. The effective measuring custom-made was reduced 1 cm at tip a thermally nonconducting shaft, thereby minimizing influence nonuniform flux density across Sap measured different depths and circumferential positions trunks four Parque Natural Metropolitano canopy crane site, Panama City, Republic...
Summary A central goal of functional ecology is to determine how independent traits are selectively filtered by environmental conditions improve our understanding the mechanisms community assembly. Soil fertility clearly influences composition, but it unclear which plant most strongly associated with gradients increasing nutrient limitation. We hypothesized that leaf economic and stem tissue density would be soil given their direct relationship resource acquisition use. In contrast, we...
Tomato, melon, grape, peach, and strawberry primarily accumulate soluble sugars during fruit development. In contrast, kiwifruit (Actinidia Lindl. spp.) banana store a large amount of starch that is released as only after the has reached maturity. By integrating metabolites measured by gas chromatography–mass spectrometry, enzyme activities robot-based platform, transcript data sets development Actinidia deliciosa genotypes contrasting in concentration size, this study identified metabolic...
Stomatal regulation is crucial for forest species performance and survival on drought-prone sites. We investigated the of root shoot hydraulics in three Pinus radiata clones exposed to drought stress its coordination with stomatal conductance (gs ) leaf water potential (Ψleaf ). All experienced a substantial decrease root-specific hydraulic (Kroot-r response stress, but leaf-specific (Kshoot-l did not change any clones. The reduction Kroot-r caused whole-plant (Kplant-l Among clones, larger...
Summary Hydraulic failure explains much of the increased rates drought‐induced tree mortality around world, underlining importance understanding how species distributions are shaped by their vulnerability to embolism. Here we determined which physiological traits explain climatic limits among temperate rainforest trees in a region where chronic water limitation is uncommon. We quantified variation stem embolism and leaf turgor loss point 55 New Zealand tested were most strongly related...
We have measured photosynthesis at the cellular, tissue, and whole leaf levels to understand role of anthocyanin pigments on patterns light utilization. Profiles chlorophyll fluorescence through sections red green leaves Quintinia serrata showed that anthocyanins in mesophyll restricted absorption uppermost palisade mesophyll. The distribution was further when were also present upper epidermis. Mesophyll cells located beneath a cyanic light-filter assumed characteristic photosynthetic...
There are still large uncertainties in peatland methane flux dynamics and insufficient understanding of how biogeochemical processes scale to ecosystems. New Zealand bogs differ from Northern Hemisphere ombrotrophic systems climatic setting, hydrology, dominant vegetation, offering an opportunity evaluate our knowledge biogeochemistry gained primarily northern fens. We report eddy covariance fluxes a raised bog over 2.5 years. Annual total 2012 was 29.1 g CH4 m−2 yr−1, whereas during year...
Summary Explanations of leaf size variation commonly focus on water availability, yet also varies with latitude and elevation in environments where is not strongly limiting. We provide the first conclusive test a prediction energy balance theory that may explain this pattern: large leaves are more vulnerable to night‐time chilling, because their thick boundary layers impede convective exchange surrounding air. Seedlings 15 New Zealand evergreens spanning 12‐fold width were exposed clear...
Asexual Epichloё endophytes colonise agricultural forage grasses in a relationship which is mutually beneficial and provides the host plant with protection against herbivorous insects. The endophyte strain AR37 (Epichloё festucae var. lolii) produces epoxy-janthitrem alkaloids only known to provide ryegrass resistance porina larvae (Wiseana cervinata (Walker)), major pasture pest cooler areas of New Zealand. This study examined effect temperature on concentrations epoxy-janthitrems...
We compared the effects of nitrogen fertilization on shoot hydraulic architecture and leaf photosynthetic properties Eucalyptus grandis Hill ex Maiden trees in Hawaii. It was hypothesized that water transport capacity would adjust to nutrient availability, with specific conductivity (kl) increasing fertilized coordination higher per unit area. Trees were grown from seedlings field for 10 months at four rates (N) between 0 336 kg ha−1. Leaf potentials, kl measured before whole shoots...
ABSTRACT Previous reports suggest that in some plant species the refilling of embolized xylem vessels can occur while negative pressure exists xylem. The aim this experiment was to use non‐destructive nuclear magnetic resonance imaging (MRI) study dynamics cavitation and embolism repair in‐vivo . Serial 1 H‐MRI used monitor contents stems two dicotyledonous ( Actinidia deliciosa chinensis , kiwifruit) one monocotyledonous Ripogonum scandens supplejack) woody liana. configuration horizontal...
Whole‐plant hydraulic conductance, shoot growth, and leaf photosynthetic properties were measured on kiwifruit vines with four clonal rootstocks to examine the relationship between plant conductance stomatal (gs) test hypothesis that reduced can provide an explanation for reductions in vigour caused by rootstocks. The selected from species of Actinidia grafted chinensis var. 'Hort16A' (yellow kiwifruit) as scion. Total area scion least vigorous rootstock, A. kolomikta, was 25% most vigorous,...
The external heat ratio method is described for measurement of low rates sap flow in both directions through stems and other plant organs, including fruit pedicels, with diameters up to 5 mm flows less than 2 g h(-1). Calibration was empirical, pulse velocity (v(h)) compared gravimetric measurements flow. In the four stem types tested (Actinidia sp. Schefflera arboricola petioles, Pittosporum crassifolium Fagus sylvatica stems), v(h) linearly correlated (v(s)) a v(s) approximately 0.007 cm...
Indirect evidence suggests that water supply to fleshy fruits during the final stages of development occurs through phloem, with xylem providing little water, or acting as a pathway for loss back plant. This inference was tested by examining balance and vascular functioning ripening kiwifruit berries (Actinidia chinensis var. 'Hort16A') exhibiting pre-harvest 'shrivel' disorder in California, normal New Zealand. Dye labelling mass experiments indicated phloem were both functional contributed...
Abstract Higher calcium (Ca) concentration in several fleshy fruit including kiwifruit is a pre‐requisite for lower incidence of Ca‐related diseases and improved nutritional value. This review examines the internal external factors operating along soil‐to‐fruit pathway that are involved uptake partitioning Ca vines. After brief description growth dynamic nutrient accumulation during development, considers role soil availability, root elongation, mass flow apoplast, transpiration, competition...