Bruno Holzapfel

• Researcher at New South Wales Department of Primary Industries

Fire damage can significantly impact fruit productivity in orchards. However, the effects of nonlethal fire injuries on the reproductive development of apple trees remain poorly understood. To investigate these effects, we implemented three treatments: trunk girdling to simulate fire injury to xylem, defoliation of a third of the canopy (simulated...

Minirhizotron tubes were installed to monitor root growth dynamics of mature Shiraz grapevines in a rootstock trial established in the hot climate Riverina region of New South Wales, Australia. The vertical root distribution and seasonal root growth dynamics of Shiraz on own-roots and Shiraz grafted on the rootstocks Ramsey, 140 Ruggeri and Schwarz...

Minirhizotron tubes were installed to monitor root growth dynamics of mature Shiraz grapevines in a rootstock trial established in the hot climate Riverina region of New South Wales, Australia. The vertical root distribution and seasonal root growth dynamics of Shiraz on own-roots and Shiraz grafted on the rootstocks Ramsey, 140 Ruggeri and Schwarz...

Sunburn is a physiological disorder that reduces grape quality and vineyard yield. It is the result of excessive sunlight and high temperatures. As climate change continues to increase air temperatures, reports of sunburn damage in vineyards worldwide are becoming more frequent. Grapes produce secondary metabolites (carotenoids, polyphenols and aro...

Understanding the adaptive response of grapevines and berries to abiotic stresses may be key to alleviate increasing climate variability. In Australia, a large proportion of vineyard is planted in already warm and hot regions [1], which, with more frequent heatwaves, could be exposed to abnormally high temperatures in the early stages of the growin...

Auxin-type herbicides are widely used to control broad-leafed weeds in cereal crop fields and pastures. Vapour drift, however, can spread several kilometres and therefore reach nearby vineyards. When grapevines are exposed to these chemicals, the active constituents induce phytotoxic effects including injury to foliage and impairment of reproductiv...

Variability in fruit quality greatly impedes the profitability of an orchard. Modelling can help find the causes of quality variability. However, studies suggest that the common assimilate pool model is inadequate in terms of describing variability in organ biomass. The aim of the current study was to compare the performances of the common assimila...

Background and Aims In response to global heating, accurate climate data are required to calculate climatic indices for long-term decisions about vineyard management, vineyard site selection, varieties planted and to predict phenological development. The availability of spatially interpolated climate data has the potential to make viticultural clim...

Background and Aims Tissue nutrient concentration is useful for determining vine nutritional status and managing vineyard nutrition. Current Australian guidelines are based on the analysis of petioles at flowering and leaf blades at veraison, sampled adjacent to the basal inflorescence and bunch. The comparative value of these two tissue types and...

budbreak; chilling; correlative inhibition; dormancy; abscisic acid; cytokinins

Sunburn is a physiological disorder that affects the visual and organoleptic properties of grapes. The appearance of brown and necrotic spots severely affects the commercial value of the fruit, and in extreme cases, significantly decreases yield. Depending on the severity of the damage and the driving factors, sunburn on grapes can be classified as...

Background: Elucidating the effect of source-sink relations on berry composition is of interest for wine grape production as it represents a mechanistic link between yield, photosynthetic capacity and wine quality. However, the specific effects of carbohydrate supply on berry composition are difficult to study in isolation as leaf area or crop adj...

Climate models predict an increase in the frequency and duration of heatwaves with an increase in intensity already strongly evident worldwide. The aim of this work was to evaluate the effect of two heatwave-related parameters (intensity and duration) during berry ripening and identify a threshold for berry survival and flavonoid accumulation. A Do...

Vine nutrition is a key element of vineyard management. Nutrient disorders affect vine growth, crop yield, berry composition, and wine quality. Each vineyard may have a unique combination of soil type, vine age, canopy architecture, cultivar and rootstock. Therefore nutritional requirements vary between vineyards and even locations within a vineyar...

Heatwaves are expected to become more frequent, reach higher maximum temperatures, last longer and occur earlier during the grape growing season. Such heat events during berry development are already known to dramatically reduce berry growth and quality by affecting berry size and primary metabolites (e.g. sugars, organic acids, and amino acids). I...

Sunburn damage commonly appears as browning of the berry surface when these are directly exposed to sunlight in combination with high temperatures and ultraviolet radiation. Factors such as variety, berry developmental stage, ambient temperature, water availability and viticultural practices (i.e. defoliation) modulate the intensity of symptoms. Le...

Grapegrowers can be informed to upcoming heatwaves thanks to the Heatwave Service for Australia provided by the Bureau Of Meteorology. They also have tools to prepare for heatwaves with a number of mitigation options available. These include hydrocooling, canopy management, sunscreen or even shade cloth to reduce direct bunch exposure to sunlight d...

Context and purpose of the study-Vine balance is a concept describing the relationship between carbon assimilation (usually estimated using a measure of vine vigour, e.g. pruning weight) and its utilisation for fruit production (usually estimated using harvest yield). Manipulating vine balance through leaf area or crop load adjustments affects the...

Flavonoids, including flavonols, tannins and anthocyanins, are important contributors to grape and wine quality, and their biosynthesis is strongly influenced by bunch microclimate. While the synergistic effect of light and temperature on flavonoids has been extensively examined in relation to bunch exposure, studies targeting the sole effect of hi...

Aim: The nutrient reserves in the grapevine perennial structure perform a critical role in supplying the grapevine with nutrients when demand cannot be sustained by root uptake. The seasonal changes in these reserves largely depend on the developmental stage and the associated growth requirements. These stored reserves are, in turn, influenced by e...

Fine roots can grow more rapidly at certain points during the day depending on species and environmental conditions. The grapevine is a large perennial that has an extensive below-ground structural system; however its diurnal root growth pattern has received little attention. The aim of this study was to characterize the diurnal fine root growth dy...

Aim: The aim of the study was to test the effect of a single heat event (HE), and the additive effects of repeated HEs at whole-vine level, on Shiraz berry composition, including detailed tannins. Methods and results: In a UV-transparent glasshouse, a system was developed to individually heat the above-ground parts of well-irrigated potted Shiraz v...

Background and Aims Spring drift of herbicides can have devastating consequences on grapevines. The impact of 2,4‐dichlorophenoxyacetic acid (2,4‐D), dichloro‐2‐methoxybenzoic acid (Dicamba), 2‐methyl‐4‐chlorophenoxyacetic acid (MCPA) and glyphosate exposure on reproductive and vegetative development was investigated. Methods and Results Simulated...

Climate change scenarios predict an increase in average temperatures and in the frequency, intensity and length of extreme temperature events in many wine regions around the world. In already warm and hot regions, such changes may compromise grape growing and the production of high quality wine as high temperature has been found to critically affec...

Petiole nutrient concentrations are widely used to assess the nutritional status of grapevines. Nitrogen (N) allocation to ripening berries contributes to the juice yeast assimilable N (YAN) concentration. In addition to supplying the ripening berries with assimilates, leaves can contribute as N source towards berry N accumulation during maturation...

Leaves are an important contributor toward berry sugar and nitrogen (N) accumulation, and leaf area therefore affects fruit composition during grapevine (Vitis vinifera) berry ripening. The aim of this study was to investigate the impact of leaf presence on key berry quality attributes in conjunction with the accumulation of primary berry metabolit...

Some plant species demonstrate a pronounced 24 h rhythm in fine root growth but the endogenous and exogenous factors that regulate these diel cycles are unclear. Photoperiod and temperature are known to interact with diel patterns in shoot growth but it is uncertain how these environmental factors are interrelated with below-ground growth. In this...

Rapid advances in analytical and statistical techniques provide increased opportunities for studies of complex biological systems. However, experiments need to be designed around crucial requirements, such as background samples and similar handling of control and treatments [1], and be built around strong experimental designs. As a demonstration of...

Grapevine (Vitis vinifera) roots and leaves represent major carbohydrate and nitrogen (N) sources, either as recent assimilates, or mobilized from labile or storage pools. This study examined the response of root and leaf primary metabolism following defoliation treatments applied to fruiting vines during ripening. The objective was to link alterat...

The grapevine inflorescence is a determinate panicle and as buds emerge, shoot, flower and rachis development occur simultaneously. The growth and architecture of the rachis is determined by genetic and environmental factors but here we examined the role of flower and leaf number as well as hormones on its elongation and vascular development. The c...

Grapevine ( Vitis vinifera ) berries are sugar and nitrogen (N) sinks between veraison and fruit maturity. Limited photoassimilation, often caused by water constraints, induces reserve total nonstructural carbohydrate (TNC) remobilization, contributing to berry sugar accumulation, while fruit N accumulation can be affected by vine water supply. Alt...

Insufficient leaf photoassimilation could allow mobilized carbohydrate reserves to contribute to berry sugar accumulation. However, the extent of this contribution during rapid and slow berry sugar accumulation is undefined. The potential effect of leaf-to-fruit ratio and water availability on carbohydrate reserve distribution in potted Tempranillo...

The rachis, the structural framework of the grapevine (Vitis vinifera L.) inflorescence (and subsequent bunch), consists of a main axis and one or more orders of lateral branches with the flower-bearing pedicels at their fine tips. The rachis is crucial both for support, and transport from the shoot. Earlier suggestions that the flowers per se affe...

Targeted manipulation of vine balance

Effect of carbohydrate supply on berry sugar/anthocyanin accumulation

Vine balance is a concept describing the relationship between carbon assimilation (usually estimated using a measure of canopy size, such as pruning weight) and utilisation of the resulting carbohydrates for fruit production (usually estimated using harvest yield). Manipulating vine balance through leaf area or crop load adjustments affects the pro...

Amino acids are essential to grape berry and seed development and they are transferred to the reproductive structures through the phloem and xylem from various locations within the plant. The diurnal and seasonal dynamics of xylem and phloem amino acid composition in the leaf petiole and bunch rachis of field-grown Cabernet Sauvignon are described...

In warm climate regions of Australia grapevines may retain leaves for up to four months after harvest. However, a dry postharvest period may reduce root growth, nutrient uptake and the replenishment of carbohydrate reserves. This can impact on canopy function in the current season as well as canopy development and berry ripening in the following se...

The carbohydrate reserve pool of the perennial structure of grapevines is determined by internal requirements for growth and the production of assimilates. In addition, the processes of depletion and replenishment of reserves during the growing season are altered by the vineyard environment and by viticultural practices. The mobilisation and storag...

Vineyard management requires the maintenance of the leaf area per unit weight of fruit necessary for growing grapes without detrimental effects on fruit composition. Leaf removal and bunch thinning experiments have previously shown some effects on berry composition. Several berry compositional parameters (e.g. berry weight, sugar concentration and...

Carbohydrates are accumulated within the perennial structure of grapevines when their production exceeds the requirements of reproduction and growth. The period between harvest and leaf-fall (the post-harvest period) is a key period for carbohydrate accumulation in relatively warmer grape-growing regions. The level of carbohydrate reserves availabl...

The carbohydrate reserve pool of the perennial structure of grapevines is determined by internal requirements for growth and the production of assimilates. In addition, the processes of depletion and replenishment of reserves during the growing season are altered by the vineyard environment and by viticultural practices. The mobilisation and storag...

This paper presents the results from the first season of trials conducted in 2013-14 at three field sites in Australia, representing three different winegrape growing regions: Langhorne Creek (South Australia), Sunraysia (Victoria) and Hilltops (New South Wales), to determine whether vine balance manipulation directly affect fruit and wine composit...

Berry water loss during late ripening is a cultivar dependent-trait and is accentuated in wine grape varieties such as 'Shiraz'. 'Shiraz' berry development was monitored in twelve vineyards over two seasons to characterise the extent of weight loss that can occur within a grape growing region. From veraison onwards, berry fresh mass was greatest in...

The amount and timing of nitrogen (N) application to a vineyard is critical for must yeast assimilable nitrogen (YAN) concentrations. YAN concentrations and amino acid profiles are important for the fermentation process and wine composition. Commonly, N is applied at flowering to optimize leaf functioning or after harvest to enhance vine productivi...

The grape and wine industry is commercially attractive because it includes a significant value adding chain. Its structure, size and competitiveness however make it a complex industry. The skills required to produce wine usually distinguish between those associated with the production of the fruit and those associated with processing it. This chapt...

We determined the effectiveness of attenuated total reflectance Fourier transform infrared spectroscopy as a rapid and low-cost method for measuring the concentration of nutrients in grapevine petioles. Attenuated total reflectance Fourier transform infrared spectra were recorded for 392 dried and ground petiole samples collected from Chardonnay, S...

Root-zone warming of trees can result in an increase in biomass production but the mechanisms for this increase may differ between evergreen and deciduous species. The leaf gas exchange, carbohydrate and nitrogen (N) partitioning of two Australian evergreens, Acacia saligna and Eucalyptus cladocalyx, were compared to the deciduous Populus deltoides...

Nitrogen supply and rootstock have important consequences for the composition and quantity of nitrogenous compounds in the must, both of which impact on fermentation rate and wine quality. In the Sunraysia district (SE Australia), musts prepared from 'Shiraz' grapes from vines grafted onto three rootstocks and supplied with five different nitrogen...

The overwintering carbohydrate reserve status of grapevines has been linked to fruiting responses in the following season, providing a possible avenue for yield management through manipulation of reserve accumulation. Conducted across four consecutive seasons, this study examined the extent to which carbohydrate reserve accumulation could be altere...

In cultivated grapevines (Vitis vinifera L.), suboptimal photoassimilatory conditions during flowering can lead to inflorescence necrosis and shedding of flowers and young ovaries and, consequently, poor fruit set. However, before this study it was not known whether carbohydrate reserves augment fruit set when concurrent photoassimilation is limite...

Root sugar accumulation was studied in two grapevine varieties contrasting in tolerance to water stress. During a 10-day water withholding treatment, the drought-tolerant variety, Grenache, sustained less negative predawn and midday leaf water potentials as well as root water potential compared with the sensitive variety, Semillon. Grenache vines a...

Remote optical imaging can rapidly acquire information describing spatial variability in vineyard block performance. Canopy characteristics were derived from very high spatial resolution (0.25m) optical imagery of a Cabernet Sauvignon vineyard acquired at various canopy growth stages. Within-season changes to correlation coefficients between vineya...

Introduction Carbohydrate Reserves Accumulation of Carbohydrate Reserves Photoassimilation and Storage Processes Mobilization and Utilization of Carbohydrate Reserves Viticultural Management of Carbohydrate Reserves Summary and Conclusions Literature Cited

The response of grapevine carbohydrate reserves and seasonal growth and development to defruiting at the onset of ripening or complete defoliation at commercial harvest was examined at four sites in two hot, inland regions of New South Wales, Australia. Early defruiting over two consecutive seasons increased total nonstructural carbohydrates (TNC)...

Background and Aims: Water and nutrients exported from vineyards through surface and subsurface pathways have the potential to adversely affect water quality downstream. This project aimed to improve the scientific understanding of the pathways and quantity of Nitrogen (N) leaking from Australian vineyards. Methods and Results: Seasonal water balan...

Potted Shiraz grapevines, in a glasshouse, were exposed to two different soil temperatures (13$,^circ$C and 23$,^circ$C) to evaluate the effects on vegetative growth and floral development from dormancy to anthesis. Soil temperature had no effect on the time of budbreak, anthesis, or the number of flowers per inflorescence. At anthesis total biomas...

Sugars play an important role in grapevine flowering. This complex process from inflorescence initiation to fruit maturity takes two growing seasons. Currently, most of the available data concern the involvement of sugars as energy sources during the formation of reproductive structures from initiation of inflorescen-ces during the summer of the fi...

Ripening berries of Vitis vinifera (L) cv. Shiraz can show pre-harvest weight loss at sub-optimal sugar content (shrinkage). This later-age decline in berry weight implies that water loss from mature berries has begun to exceed water inflow from the parent grapevine. Such decrease in net inflow has been attributed to a cessation of xylem flow subse...

Bunchstem tissue from three Cabernet Sauvignon vineyards during three years were analysed for ammonium ion and abscisic acid to test whether their levels correlated with the incidence of the disorder bunchstem necrosis (BSN, Stiellähme). Levels of free ammonium ion, known to be toxic to plant tissue when excessive, were found to be low, considerabl...

Chardonnay grapes from a rootstock trial in the Murray Valley region of South Australia were sampled for two seasons and concentrations of free amino acids in grape extract (‘juice’) were determined. The lowest concentrations of free assimilable amino-N were measured in Chardonnay grapes from vines on 140 Ruggeri and 101–14 rootstocks, and the high...

Carbon isotope discrimination (Δ) is used to determine differences in apparent transpiration efficiency amongst genotypes of many C3 plant species. In this present study the possible influence of certain commercially-available rootstocks on apparent transpiration efficiency in grapevines was investigated. Variation in Δ was studied for Shiraz and e...

The incidence of grapevine bunchstem necrosis (BSN) in cv. Cabernet Sauvignon was assessed in three South Australian regions during three years. The percentage of bunches affected varied widely—from nil to 26%-between years and regions. At the site with most BSN, high incidence was related to lower temperatures during 20 days before flowering and n...

Sugars play an important role in grapevine flowering. This complex process from inflorescence initiation to fruit maturity takes two growing seasons. Currently, most of the available data concern the involvement of sugars as energy sources during the formation of reproductive structures from initiation of inflorescences during the summer of the fir...

Yeast cells have a minimum N requirement to ferment a must through to dryness, so that grape N content (hence must N) becomes critical in meeting that prerequisite. Viticultural practices aimed at meeting that N requirement are of special relevance because interactions between rootstock and vineyard nitrogen supply strongly influence scion mineral...

Trials were established in four Semillon hot-climate vineyards to determine the importance of the postharvest period for vines grown under different cropping levels and management practices. Two sites were chosen in high-yielding, furrow-irrigated vineyards in the Riverina region, and two in lower-yielding, drip-irrigated vineyards in the neighbori...

The effects of vineyard nitrogen (N) application timing and irrigation strategy on fruit quality and amino-N (proline and arginine) composition of Vitis vinifera 'Shiraz' were investigated. Three irrigation treatments (PRD, RDI and standard practice (STD) were factorialised with three nitrogen (N) applications (bloom to veraison, post-harvest, and...

The emergence of precision agriculture technologies and an increasing demand for higher quality grape products has led to a growing interest in the practice of precision viticulture; monitoring and managing spatial variations in productivity-related variables within single vineyards. Potentially, one of the most powerful tools in precision viticult...

Anatomical studies on the movement of a xylem tracer dye were combined with functional studies on changes in grape berry volume during final stages of berry ripening to gauge xylem effectiveness. Movement of a xylem tracer dye into pre-veraison fruit was compared with movement into post-veraison fruit by feeding a solution of acid fuchsin to excise...

Xylem sap glutamine and nitrate contents were determined in three different grafting combinations with three grapevine rootstocks. Glutamine (2.6–38.5 µg N/ml) and nitrate (0.21–10.25 µg N/ml) levels differed between rootstocks in the own-rooted and reciprocal combination; the conventional combination had much lower levels and insignificant differe...

Nitrogen is frequently the most limiting plant nutrient for grape production in the warm irrigated regions of inland Australia. Consequently, must N levels are often insufficient to sustain a fermentation through to dryness without supplementation with exogenous N. A novel N supply strategy was trialled on drip-irrigated Shiraz vines growing on thr...

Wick-feeding of chemicals into grape bunches in the field successfully induced bunchstem necrosis (BSN) and hastened or delayed berry ripening. Evidence is presented that ammonium ion has a specific effect in delaying ripening. The most potent inducer of BSN was the amine agmatine; this compound, and the auxin benzothiazol-2-oxyacetic acid (BTOA),...

Management of water and nitrogen is variable in the Riverina (NSW, Australia), being one of the major reasons yield and berry composition differ between Shiraz vineyards in this wine region. Both inputs can have a major impact on yield, canopy size and berry composition. Large canopies produced by excessive water and N supply result in shading of g...