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Vine Water Status (vine + water_status)
Selected AbstractsInfluence of water and nitrogen deficit on fruit ripening and aroma potential of Vitis vinifera L cv Sauvignon blanc in field conditionsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 1 2005Catherine Peyrot des Gachons Abstract 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 [source] Effect of irrigation and variety on oxygen (,18O) and carbon (,13C) stable isotope composition of grapes cultivated in a warm climateAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2 2010S. GÓMEZ-ALONSO Abstract Background and Aims:, ,13C values from Vitis vinifera leaves, whole grape, seed, pulp, skin and/or grape must sugars have been investigated as an integrated marker of vine water status or intrinsic water-use efficiency during berry growth and across region of origin, vintage and variety. The use of 18O/16O isotopic ratio as a marker of water addition, vintage and geographical origin has also been studied. This paper examines the effect of irrigation and grapevine variety on ,18O and ,13C of grape must from eight varieties, all cultivated in the same vineyard to reduce the effects from other variables. Methods and Results:, Stable isotope compositions of grape must water and sugar were determined by isotope ratio mass spectrometry. The result of the study showed statistically significant effects of irrigation and vine variety on both ,18O and ,13C. The effect of vintage on ,18O was only significant for non-irrigated vines. Conclusion:, This research highlights the effect of variety and irrigation on ,13C and ,18O of grape. Significance of the Study:, This is the first report to demonstrate that the varietal effect on ,13C and ,18O of grape is not due only to differences in the vegetative cycle of each variety. It further suggests that water exhibits a lower isotopic discrimination in the indigenous Spanish varieties studied than in non-indigenous varieties. [source] Identification and significance of sources of spatial variation in grapevine water statusAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 1 2010J.A. TAYLOR Abstract Background and Aims:, Water stress in grapevines is directly linked to grape quality. Differential vine water management should therefore be strongly linked to the water stress in the vine. To do this, an understanding of the dominant drivers and indicators of vine water status are needed from a sub-block to whole vineyard level. This understanding will help generate effective vine water status models for variable rate irrigation systems. Methods and Results:, A vineyard in the south of France was sampled for pre-dawn leaf water potential (,PD) at several dates during the growing season for two consecutive years. Sampling was stratified by soil types and relative within-block vegetative expression. A recursive partitioning analysis identified that cultivar had a dominant effect at low water stress, while vegetative expression and then soil unit effects became dominant as water restriction increased. Variance in ,PD was calculated at difference scales (plant, site, block and vineyard) and Smith's heterogeneity law was used to evaluate the scalar nature of ,PD variance. Spatial heterogeneity increased as the season and water restriction increased. Conclusion:, Variance in ,PD changed temporally through a season and the dominant drivers/indicators also changed. The opportunity to spatially manage water stress (irrigation) increased as water restriction increased. Significance of the Study:, Managing vine water stress helps optimise production and a ,PD model would be a useful addition to a viticulture decision support system. This study identified how the variance in ,PD evolved during a season and the best ancillary indicators of ,PD for spatial and temporal modelling. [source] Berry size and vine water deficits as factors in winegrape composition: Anthocyanins and tanninsAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2 2004GASPAR ROBY Abstract Soluble solids, seed tannin, skin tannin, and skin anthocyanin were measured in fruit from Cabernet Sauvignon vines that had experienced either High, Control or Low water status during ripening. Berries from each treatment were segregated into 6 size categories at harvest in order to test independently for relationships due to size compared with those due to water deficits. Berry content of all solutes increased approximately in proportion to the increase in berry size. Deviations from proportionality caused Brix and anthocyanin concentration (mg per unit berry fresh mass) to decrease, and the concentration of skin tannin to remain unchanged or decrease slightly with increasing berry size. The concentration of seed tannin did not decrease and appeared to increase with berry size in multiple-seeded berries. In comparison with skin tannin or anthocyanin content, seed tannin content varied more with berry size and less with vine water status. In addition to decreasing berry size, water deficits increased the amount of skin tannin and anthocyanin per berry and the concentrations of skin tannin and anthocyanins, but did not significantly affect the content or concentration of seed tannin. The results show that there are effects of vine water status on fruit composition that arise independently of the resultant differences in fruit size. The effect of vine water status on the concentration of skin tannin and anthocyanin was greater than the effect of fruit size on those same variables. However, the increases in skin tannin and anthocyanin that accompanied water deficits appear to result more from differential growth sensitivity of inner mesocarp and exocarp than direct effects on phenolic biosynthesis. [source] | ||||||||||