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During austral summer (DJF) 2017/18, the New Zealand region experienced an unprecedented coupled ocean-atmosphere heatwave, covering an area of 4 million km². Regional average air temperature anomalies over land were +2.2 °C, and sea surface temperature anomalies reached +3.7 °C in the eastern Tasman Sea. This paper discusses the event, including atmospheric and oceanic drivers, the role of anthropogenic warming, and terrestrial and marine impacts. The heatwave was associated with very low wind speeds, reducing upper ocean mixing and allowing heat fluxes from the atmosphere to the ocean to cause substantial warming of the stratified surface layers of the Tasman Sea. The event persisted for the entire austral summer resulting in a 3.8 ± 0.6 km³ loss of glacier ice in the Southern Alps (the largest annual loss in records back to 1962), very early Sauvignon Blanc wine-grape maturation in Marlborough, and major species disruption in marine ecosystems. The dominant driver was positive Southern Annular Mode (SAM) conditions, with a smaller contribution from La Niña. The long-term trend towards positive SAM conditions, a result of stratospheric ozone depletion and greenhouse gas increase, is thought to have contributed through association with more frequent anticyclonic 'blocking' conditions in the New Zealand region and a more poleward average latitude for the Southern Ocean storm track. The unprecedented heatwave provides a good analogue for possible mean conditions in the late 21st century. The best match suggests this extreme summer may be typical of average New Zealand summer climate for 2081-2100, under the RCP4.5 or RCP6.0 scenario.

Background and Aims This study investigated: (i) the importance of changing the leaf area: fruit mass ratio (LA : FM) by crop removal and/or shoot trimming on total soluble solids (TSS) concentration and content, pH, titratable acidity (TA) and berry mass; (ii) the extent to which changes in LA : FM ratio altered the synchrony TSS : TA ratio; and (iii) whether the responses were consistent for Pinot Noir and Sauvignon Blanc. Methods and Results Vertical shoot positioned–trained vines were trimmed shortly after fruitset or at veraison to six or 12 main leaves per shoot and crop thinned by removing 0, 50 or 75% of the bunches. TSS and pH, TA and fresh berry mass were measured weekly from pre‐veraison to harvest. TSS concentration accumulation in berries was slowed with shoot trimming and accelerated by crop removal, with crop removal having a greater effect. Trimming shoots at fruitset in combination with no crop removal resulted in the greatest delay in veraison (the start of TSS accumulation) and slowest rate of TSS accumulation. TSS content mirrored TSS concentration for LA : FM manipulations at fruitset but fewer differences were detected for LA : FM changes at veraison. In contrast, TA and pH were largely unaffected. Conclusions Changes to the LA : FM ratio via crop removal or shoot trimming modified berry TSS accumulation but not TA. Such desynchronisation was consistent for both cultivars. Significance of the Study Crop and/or leaf removal represent valuable means to manipulate the time to achieve target fruit TSS concentration and TA. The similar responses of the two cultivars indicate that LA : FM manipulation could potentially have common responses for different cultivars. The desynchronisation of berry components highlights the need to consider each berry component individually and in a dynamic manner by sampling throughout the ripening phase.

Thaumatin-like proteins (TLPs) and chitinases are the two main groups of pathogenesisrelated (PR) proteins found in wine that cause protein haze formation. Previous studies have found that phenolics are also involved in protein haze formation. In this study, Sauvignon Blanc grapes were harvested and processed in two vintages (2011 and 2012) by three different treatments: (1) hand harvesting with whole bunch press (H-WB); (2) hand harvesting with destem/crush and 3 h skin contact (H-DC-3); and (3) machine harvesting with destem/crush and 3 h skin contact (M-DC-3). The juices were collected at three pressure levels (0.4 MPa, 0.8 MPa and 1.6 MPa), some juices were fermented in 750 mL of wine bottles to determine the bentonite requirement for the resulting wines. Results showed juices of M-DC-3 had significantly lower concentration of proteins, including PR proteins, compared to those of H-DC-3, likely due to the greater juice yield of M-DC-3 and interactions between proteins and phenolics. Juices from the 0.8–1.6 MPa pressure and resultant wines had the highest concentration of phenolics but the lowest concentration of TLPs. This supported the view that TLPs are released at low pressure as they are mainly present in grape pulp but additional extraction of phenolics largely present in skin occurs at higher pressing pressure. Wine protein stability tests showed a positive linear correlation between bentonite requirement and the concentration of chitinases, indicating the possibility of predicting bentonite requirement by quantification of chitinases. This study contributes to an improved understanding of extraction of haze-forming PR proteins and phenolics that can influence bentonite requirement for protein stabilization.

Background and Aims The extent to which the carbohydrate source-sink ratio influences the time of veraison of different Vitis viniferaL. cultivars was studied for Sauvignon Blanc and Pinot Noir. The aims were to: (i) determine how changing the leaf area: fruit mass (LA:FM) ratio shortly after fruitset alters the timing of veraison; (ii) establish the relative importance of adjusting the vine yield or the leaf area on the timing of veraison; and (iii) evaluate the relative effect on the timing of veraison, leaf area and yield parameters of the two cultivars at similar LA:FM ratios. Methods and Results Four cane, vertical shoot positioned trained vines were trimmed shortly after fruitset to retain six or 12 leaves per shoot and thinned by removing 0, 50 or 75% of the bunches. The timing of veraison was assessed by colour change for Pinot Noir, berry softness for Sauvignon Blanc and the day at which a mean of 8 degrees Brix was reached for both cultivars. Manipulating leaf area had a greater effect on the date of veraison than crop removal, which had no effect, except when vines were trimmed to six leaves. Sauvignon Blanc was always later than Pinot Noir for the time to reach 8 degrees Brix at all LA:FM ratio manipulations. Conclusions Restricting potential carbohydrate sources post-flowering delayed veraison, while removing crop had less influence. Significance of the Study Reduced leaf area can delay the time of veraison, which could counter the earlier timing that could occur from climate change or warmer than average seasons. Conversely, increased leaf area could enable target soluble solids to be achieved in cooler seasons.

Background and Aims: Inflorescence morphology, flower formation and subsequent fruit development of grapevines are influenced by genetic, environmental and cultural practices. While the effect of temperature on inflorescence primordia number per bud is documented, its effect during dormancy and budburst (BB) on floral development is less clear. In our study, winter dormant buds were passively heated for different periods of time from mid‐winter (July) to BB (October). Methods and Results: Individual canes were heated pre‐BB for different periods in polyethylene tunnels. Heating during winter dormancy had no effect on the number or position of inflorescences on the shoot, or on the type of structure occurring at the outer arm position of the inflorescence. Heating buds for either July or August to BB advanced the date of BB and the start date of flowering by 12–14 and 14 days, respectively, compared with that of the unheated Control treatment. There was a significant (P < 0.05) negative correlation between the mean temperature 12 days pre‐BB and flower number per shoot. The time between 50% flowering and the fruit TSS reaching 14°Brix was not influenced by winter heating or the date of flowering; the difference in this time interval, however, between the inner and outer arm components increased as shoot node number increased. Conclusions: Flower number per inflorescence had the greatest influence on the proportion of fruitset. The date of flowering of the outer arm was later at higher inflorescence positions on the shoot and later than that of the inner arm. Likewise, the outer arms of bunches higher up the shoot took longer from flowering to accumulate a fruit TSS of 14°Brix. Significance of the Study: Much of the within‐vine variability in berry composition at harvest can be attributed to the position of bunches on the shoot and the presence of an outer arm. The outer arm on apical bunches took significantly longer to progress from flowering to a fruit TSS of 14°Brix, suggesting that removal would significantly reduce within‐vine fruit variability.

A new model for grapevines (Vitis vinifera) is the first perennial fruit crop model using the Agricultural Production System sIMulator (APSIM) Next Generation framework. Modules for phenology, light interception, carbohydrate allocation, yield formation and berry composition were adapted or added into APSIM Next Generation to represent the nature of fruit-bearing vines. The simulated grapevine phenological cycle starts with the dormancy phase triggered by a critical photoperiod in autumn, and then goes through the subsequent phenophases sequentially and finally returns to dormancy for a new cycle. The canopy microclimate module within APSIM Next Generation was extended to allow for row crop light interception. The carbohydrate arbitrator was enhanced to consider both sink strength and sink priority to reflect carbohydrate reserve as a concurrent competing sink. Weather conditions and source-sink ratio at critical developmental stages were used to determine potential grapevine yield components, e.g. bunch number, berry number and berry fresh weight. The model was calibrated and tested extensively using four detailed data sets. The model captured the variations in the timing of measured budburst, flowering and véraison over 15 seasons across New Zealand for five different varieties. The calculated seasonal dynamics of light interception by the row and alley were consistent with field observations. The model also reproduced the dynamics of dry matter and carbohydrate reserve of different organs, and the wide variation in yield components caused by seasonal weather conditions and pruning regimes. The modelling framework developed in this work can also be used for other perennial fruit crops.

Background and Aims Inflorescence primordia (IP) development starts in the buds of leaf axils approximately 12months before flowering. Primordia initiation progresses acropetally as the shoot develops, although little is known about the timing of initiation at different node positions up the developing shoot. Girdling and/or leaf removal treatments were used to investigate the timing of development and structure of grapevine inflorescences at different positions along the shoot. Methods and Results Individual shoots were either girdled at their base shortly after fruitset or left intact. Leaves were then removed from those shoots on four occasions from the time of girdling to natural leaf fall in the autumn. Dormant latent buds from treatment shoots (shoot node positions one to ten) were grown as single-node cuttings (SNCs) in a glasshouse, and the inflorescence number per SNC and their architecture were scored on developing shoots. Girdling fully leafed shoots increased the proportion of SNC basal inflorescences with an outer arm but had no effect on the number of inflorescences per SNC. Girdled shoots that had their leaves removed at 0 or 4weeks post-fruitset had a decrease in inflorescence number per SNC and outer arm development from nodes six and eight, respectively. Conclusions Inflorescence initiation before node positions six and eight was complete by the time girdling and leaf removal treatments were applied, and initiation at nodes six and eight occurred at 0 and 4weeks post-fruitset. The development of the apical IP and the outer arm of the basal IP appears to occur at the same time. Significance of the Study This study presents novel information regarding the timing of IP initiation at different positions along the developing shoot, including the initiation and development of the outer arm. Also, the formation of an outer arm is shown to be sensitive to girdling and/or leaf removal.

Background and Aims Inflorescence numbers per shoot and their size vary between seasons and may, within a season, be affected by pruning systems, bud position along a cane and the size of the cane. A grapevine inflorescence typically has a main rachis and a tendril, which may or may not have flowers (an outer arm). The aim of this study was to identify the effect of these factors during inflorescence primordia (IP) initiation on the resulting number of inflorescences per shoot and their architecture. Methods and Results Two-cane, four-cane and spur-pruned Sauvignon Blanc vines were used to investigate changes in inflorescence number, distribution and architecture over two growing seasons. The pruning system had no effect on the inflorescence number per shoot (fruitfulness), inflorescence architecture or distribution at a given cane node number. There were differences in inflorescence number and structure between the seasons, likely associated with air temperatures during primordia initiation. A warmer initiation period was associated with an increase in the occurrence of flowers on the outer arm and lower positions of the basal inflorescences (shoot bud position). An increase in cane cross-sectional area correlated to an increase in fruitfulness and an increase in the average occurrence of an outer arm with flowers along a cane. Conclusions Inflorescence number, the position of the basal inflorescence on the developing shoot and the development of the outer arm are affected by the bud position of the shoot along a cane, the cross-sectional area of the cane and the season. Our results suggest that initiation of IP may occur at the same time for all bud positions along a shoot, so long as they are free from inhibiting factors. Significance of the Study Cane selection can be used to modify inflorescence number and architecture and thus the potential yield of grapevines. [PUBLICATION ABSTRACT]

BACKGROUND AND AIMS: Protein instability has long been a technical issue in white wine production. The aims of this study were: to examine the variability of wine proteins from a single cultivar within a defined wine region over two vintages; and to investigate the correlation of the content of the total and individual proteins and protein haze with the bentonite dosage required for heat stability. METHODS AND RESULTS: Proteins in Sauvignon Blanc juices and wines from five selected Marlborough, New Zealand, vineyards with two pruning/training regimes (two‐ and four‐cane vertical shoot positioned) were studied over two consecutive vintages. Proteins were quantified and characterised by Coomassie Brilliant Blue assay, sodium dodecyl sulfate polyacrylamide gel electrophoresis and sodium dodecyl sulfate capillary gel electrophoresis (SDS‐CGE). The bentonite requirement for wine protein stability was determined by bentonite fining coupled with a hot/cold test. One vineyard consistently showed the lowest protein concentration and bentonite requirement regardless of pruning treatment and vintage, whereas others varied with pruning treatment and/or vineyard site and/or vintage. Two prevalent juice protein peaks at 22 and 28 kDa in SDS‐CGE corresponded to two main wine protein peaks at 22 and 26 kDa, respectively. The 26 kDa fraction was reduced and became heterogeneous after fermentation, while the 22 kDa fraction remained unaffected. There was a good correlation between bentonite requirement and the 26 kDa fraction (R² = 0.78). CONCLUSION: The depletion of 26 kDa fraction in wine determined by SDS‐CGE was a good indicator for protein stability by bentonite fining. SIGNIFICANCE OF THE STUDY: These results suggest that the method of protein quantification may have a strong influence on the utility of protein concentration measurement to predict the bentonite requirement of wine.

Anaerobic (anoxic) solution cultures were used to investigate the effect of a restricted oxygen supply to roots on the development of symptoms of waterlogging damage in young wheat plants, especially effects on growth and nutrient uptake by the shoots. Anaerobic conditions produced by bubbling solutions with oxygen-free nitrogen gas caused premature senescence of the lower leaves, slowed shoot fresh weight accumulation, and arrested the growth of the seminal roots. However the shoot dry weight initially increased above that of the aerobic controls. Nutrient accumulation by the shoot was severely inhibited by anoxia, the uptake of nitrate, phosphate, and potassium being more affected than that of calcium and magnesium. The calculated concentrations in the xylem stream of all these ions (except nitrate) were equal to, or less than, those in the external solution, suggesting that the slow but continuous accumulation of nutrients in the shoot could have occurred passively by the mass flow of solution across damaged roots in response to transpiration. Aerenchymatous nodal roots extended into the anoxic solutions to a maximum length of 12 cm but there were few produced, and the size of the root system remained small and may have limited shoot growth. Inclusion of carbon dioxide (10 kPa partial pressure) in the nitrogen gas stream had little additional effect on plants to that caused by anoxia alone. All the responses of wheat to the anaerobic solutions were similar to those observed previously in waterlogged soil, indicating that many of the early symptoms of waterlogging damage to wheat can be caused simply by the direct effects of inadequate oxygen supply to the roots. The results are discussed in relation to current views of the mechanisms contributing to waterlogging damage to plants.