Influence of water and nitrogen deficit on fruit ripening and aroma potential of Vitis vinifera L cv Sauvignon blanc in field conditions

S‐Cysteine conjugate precursors of three volatile thiols were monitored in Vitis vinifera L cv Sauvignon blanc grapes during fruit ripening to assess the influence of vine water and nitrogen status on the grape aroma potential in field conditions. Four dry farmed plots were studied in the Pessac‐Léognan and Graves appellations (Bordeaux area) in 1998, which was a very dry vintage, and in 1999, when regular summer rainfall occurred. Soil water‐holding capacity ranged from very low to high. Soil total nitrogen content was related to soil organic matter content, which was highly variable on the four plots. Vine vigour was enhanced by both high water and nitrogen status. Major compounds in grapes depended mainly on vine water status. Water deficit‐stressed vines produced small berries with low sugar and low total acidity. Grape aroma potential was highest in vines under mild water deficit and moderate nitrogen supply. Severe water deficit stress seemed to limit aroma potential, as did nitrogen deficiency. Consequences for site selection and irrigation management for Sauvignon blanc are discussed. Copyright © 2004 Society of Chemical Industry     

Development of inflorescence primordia in Vitis vinifera L. cv. Chardonnay from hot and cool climates

Background and Aims: The purpose of this study was to gain a quantitative understanding of environmental effects on the formation of yield potential; it is critical that the timing of anlagen initiation and differentiation in latent buds is defined for economically important Vitis vinifera L. cultivars in a range of environments. Methods and Results: This study combined scanning electron microscopy with light microscopy to compare the timing and extent of inflorescence primordia (IP) initiation and differentiation (branching) in primary latent buds of Chardonnay vines grown in a hot (mean January temperature (MJT) 22.3°C) and a cool (MJT 18.1°C) climate. Initiation of anlagen (uncommitted primordia) in dormant buds at node 4 commenced 4 weeks after budburst (BB) in the hot climate and 6 weeks after BB in the cool climate. Subsequent differentiation of anlagen was first observed 6 and 9 weeks after BB in the hot and cool climate, respectively. Conclusions: The extent of IP differentiation varied with climate, with hot climate buds at modified Eichorn and Lorenz scale (E‐L) ( Coombe 1995 ) stage 33 being more advanced, larger and exhibiting more widespread secondary branching than cool climate buds. Significance of the Study: This research provides new insights into the timing and extent of reproductive development in Australia's most important white grape cultivar, Chardonnay, thereby having implications for strategic management and forecasting potential yield.     

Direct measurement of hydraulic properties in developing berries of Vitis vinifera L. cv Shiraz and Chardonnay

Berries of Vitis vinifera L. cv Shiraz can undergo weight loss during later stages of ripening. Existing published views on how weight loss occurs are based on changes in capacity of the vascular system to import water during development (McCarthy and Coombe, Australian Journal of Grape and Wine Research, 5, 17–21, 1999). One important element of these views is the proposed cessation of water flow through the xylem after veraison. We have now measured the water flow into berries of Shiraz and Chardonnay as they develop using the pressure probe and the high pressure flow meter (HPFM). The pressure probe connected to the pedicel of individual berries provided measurements of single berry hydraulic conductance. By systematic excision of tissue segments of the berry and pedicel we determined where in the pathway hydraulic conductance changed during development. The HPFM was used on whole bunches showing that berries (including pedicels) represent parallel high hydraulic resistances and that the hydraulic resistance of the bunch axis was rather small. The hydraulic conductance per berry could be determined from excision experiments. There was close agreement between the pressure probe and HPFM measurements. Both showed a ten‐fold reduction in hydraulic conductance of whole berries from veraison to full ripeness. Shiraz had hydraulic conductances that were 2‐ to 5‐fold higher than those for Chardonnay. Shiraz maintained a higher hydraulic conductance past 90 days after flowering than Chardonnay. The decrease in hydraulic conductance occurred in both the distal and proximal parts of the berry for both varieties. The pressure probe also provided measurements of the xylem pressure that non‐transpiring berries could develop. These pressures were –0.2 to –0.1 MPa until veraison and increased to zero when the juice osmotic potential reached about –3 MPa in Chardonnay and –4 MPa in Shiraz. The results suggest values of the reflection coefficient of the osmotic barrier around the xylem vessels of about 0.1–0.2 at veraison decreasing to 0 at harvest. It is suggested that in addition to changes in xylem anatomy, aquaporins in berry membranes may play a role in regulating hydraulic conductance. Water movement from the berry back to the parent vine via the xylem (backflow) may be an important component of berry weight loss in Shiraz, particularly if the phloem ceases functioning at high osmotic potentials near maximum weight. Backflow could account for a weight loss of 43 mg per day in Shiraz berries for a relatively small gradient of 0.1 MPa.     

不同灌溉量对设施红地球葡萄生理特性及品质的影响

为实行节水灌溉和提高红地球葡萄的质量和产量,在高寒干旱地区设施栽培条件下各生长期设置了不同灌溉量试验.结果表明,与传统漫灌方式(对照)相比,果实成熟时各处理中的叶片生理指标和果实品质表现不同,其中处理4的叶绿素含量、单粒重、穗重和可溶性固形物含量相对最高,与对照相比分别增长了20.63%、16.61%、16.62%～,48.92%;脯氨酸、丙二醛含量、SOD、POD、CAT活性相对最低,与对照相比降低了42.11%、36.09%、21.11%、49.76%和39.44%.     

Canopy microclimate and berry composition: The effect of bunch exposure on the phenolic composition of Vitis vinifera L cv. Shiraz grape berries

Studies on the effect of light exposure on specific phenolic compounds of berries from Shiraz vines grown in a hot climate are reported. Berries that had developed on bunches receiving high levels of ambient light generally had the highest relative levels of quercetin-3-glucoside and a lower proportion of their malvidin anthocyanins as the coumarate derivative, compared to berries that had developed on bunches in shaded canopy conditions. The response of total anthocyanin levels to treatment conditions was variable and depended on the degree of bunch shading and the resultant berry temperature. It appears that a high degree of bunch exposure in hot climates is not conducive to optimal anthocyanin accumulation in berries. The interactive effects of light and temperature on berry phenolic content and concentration are discussed.     

Scion photosynthesis and leaf gas exchange in Vitis vinifera L. cv. Shiraz: Mediation of rootstock effects via xylem sap ABA

Limited water resources are placing pressure on the wine grape industry to improve vineyard water use efficiency by continuing improvements in vineyard management. One way to improve vineyard water use efficiency is to improve transpiration efficiency, and judicious use of scion-rootstock combination can play a role. Accordingly, this paper examines the influence of rootstocks on the water use physiology of a common scion variety (Shiraz) and assesses the importance of variation in xylem sap abscisic acid (ABA) as an indicator of relative water use efficiency of different scion-rootstock combinations. Shiraz scions (clone BVRC12) grafted to seven rootstock varieties (along with an ungrafted control), were observed over two consecutive seasons in a field trial located in Adelaide, South Australia. Those two seasons (2001/02 and 2002/03) offered sharp contrasts with respect to soil and atmospheric water stress. Rootstock genotype had a significant impact on scion gas exchange, water status, canopy growth and yield in both seasons. Those impacts were associated with an inverse relationship between xylem sap ABA and stomatal conductance. We suggest that strategic analysis of xylem sap ABA may provide a marker for comparative water-use physiology of different stock-scion combinations, while recognising that irrigation pre-history, and associated degree of vine water stress, will be a further source of variation in grapevine water use.