“赤霞珠”葡萄转色后不同成熟度指标的变化

研究酿酒葡萄转色后不同成熟度指标的动态变化规律。以“赤霞珠”葡萄为试材,分别测定了技术成熟度和总酚成熟度指标,并进行了浆果感官评价。结果表明：转色后果实物理性状参数和糖含量迅速增加,转色后第4周达到最大值,成熟后期略有下降。果实中总花色苷含量逐渐增加,在转色后第6周达到最高,随后有所降低。浆果中可提取花色苷含量持续增加。细胞成熟指数、种子成熟指数和总酚指数总体上逐渐降低。果皮单宁含量变化较小,种子单宁含量在成熟前期显著降低（P＜0.05）,后期变化较小。不同分子大小聚合色素的含量逐渐增加,转色后第6周时达到最大值。浆果感官评价中各种成熟度的得分逐渐增加,果肉香气成熟度和果皮成熟度得分均在转色后第7周时最高,成熟后期变化较小。     

Deciphering the ability of different grapevine genotypes to accumulate sugar in berries

Background and Aims: To analyse the genetic determinants of berry sugar content in grapevine varieties, a method that combined measurements of total soluble solids (TSS) from berries sampled at a fixed stage after veraison with data on the yield and the leaf area was tested. Methods and Results: Over three seasons, differences in TSS at harvest for Riesling and Gewurztraminer grapes were explained by differences in the veraison dates and in the fruit‐to‐leaf ratios. TSS, yield and leaf area were also evaluated for 120 genotypes, which were progeny from a cross between Riesling and Gewurztraminer. Thermal timescales (degree‐days) proved relevant for describing sugar accumulation in the parent varieties, and when berries were sampled at a fixed heat sum after veraison in the progeny, the genotypic variability of sugar content was considerably reduced compared with the measurements on the same date at the end of the season. A negative relationship between the fruit‐to‐leaf ratio and the sugar content was also detected in the progeny. Conclusions: The evolution of TSS during berry ripening can be described using thermal timescales. Additionally, information on the yield and the leaf area needs to be integrated to analyse the behaviour of genotypes. Significance of the Study: A method to characterize the genotypic effect on fruit sugar accumulation after eliminating the contribution of veraison dates and crop load was proposed.     

The effect of bunch shading on berry development and flavonoid accumulation in Shiraz grapes

Opaque boxes were applied to bunches of Shiraz grapes prior to flowering to determine the effect of sunlight on berry development and accumulation of flavonoids. The boxes were designed to maintain airflow while excluding light and thus to minimise changes in temperature and humidity. There was no significant effect of shading on sugar accumulation and in two of the three seasons studied there was no effect on berry weight. Chlorophyll concentration was much lower in the shaded fruit, which appeared pale yellow until veraison. The fruit coloured normally in the shaded bunches and in two of the three seasons there was no significant change in anthocyanin content. Expression of the gene encoding UDP-glucose flavonoid-3-O-glucosyl transferase (UFGT), a key gene in anthocyanin synthesis, increased after veraison and was similar in both shaded and exposed fruit. Anthocyanin composition was altered in the shaded fruit, which had a greater proportion of the dioxygenated anthocyanins, the glucosides of cyanidin and peonidin. Shading had no significant effect on the levels of condensed tannins in the skin or seeds of ripe fruit. Shading significantly reduced the levels of flavonols in the grape skin. In the exposed fruit, flavonol concentration was highest around flowering then declined as the berries grew, but there was an increase in flavonols per berry during ripening. When the boxes were applied before flowering, shaded fruit had much lower levels of flavonols throughout berry development and at harvest the level of flavonols were less than 10% of that in exposed fruit. A gene encoding flavonol synthase (FLS) was expressed at flowering and during ripening in exposed grapes but its expression was greatly reduced in shaded fruit. The results indicate that shading had little effect on berry development and ripening, including accumulation of anthocyanins and tannins, but significantly decreased flavonol synthesis.     

Accumulation of potassium and calcium by ripening berries on field vines of Vitis vinifera (L) cv. Shiraz

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 subsequent to veraison, followed by a cessation of phloem flow into berries during later stages of ripening. We address this issue in this present paper, and show a continuing increase in berry content of both potassium and calcium throughout ripening. We measured changes in berry fresh weight and berry content of potassium (phloem mobile) and calcium (phloem immobile) in fruit on field vines sampled from set to harvest. Berry fresh weight reached a plateau between 81 and 95 days after flowering, then declined to 75% of maximum fresh weight by 115 days. Dry weight maximum occurred 14 days after the onset of the fresh weight plateau. Potassium accumulation was slow pre-veraison, increased 3.5-fold post-veraison, and continued during berry shrinkage. Calcium content per berry also showed a linear increase throughout fruit enlargement and ripening phases. Assuming both potassium and calcium were entering berries via vascular conduits, our results imply a continuing connection between parent grapevine and ripening berries. Moreover, an abrupt change (increase) in the ratio of potassium/calcium content per berry subsequent to veraison implies that phloem inflow has increased relative to xylem inflow during post-veraison enlargement.     

赤霞珠葡萄生长发育过程中内源激素的变化及其与果实成熟的关系

为研究赤霞珠葡萄果实发育过程中不同组织(果皮、果肉和种子)内源激素的含量变化及其与果实成熟的关系,用高效液相色谱-质谱联用技术测定果实发育过程中果皮、果肉以及种子中脱落酸(abscisic acid,ABA)、生长素(indole acetic acid,IAA)、赤霉素(gibberellin A_3,GA_3)、茉莉酸(jasmonic acid,JA)和水杨酸(salicylic acid,SA)的含量。结果发现,在葡萄果实生长发育过程中,葡萄果皮和果皮中ABA含量呈双S型变化,花后20 d左右,ABA含量较高,随着果实膨大开始下降,随后开始上升,至转色中期达到最大值,随着果实的成熟缓慢下降;果皮、果肉和种子中GA_3含量均是从果实膨大期开始上升,膨大后期下降,随后在转色初期又开始上升,随后下降;JA含量的变化与GA_3类似;果皮和果肉中IAA含量首先略微下降,在果实快速生长期迅速上升,并达到峰值,随着果实进入转色期,含量逐渐下降并保持稳定,果实膨大期之前,种子中IAA含量较高,随着果实膨大降低,并维持在较低水平,SA含量的变化与IAA类似。结论:ABA、GA_3、JA含量与赤霞珠果实成熟有关,IAA、GA_3、SA、JA含量与赤霞珠果实生长有关。     

Rootstock and salinity effects on rates of berry maturation, ion accumulation and colour development in Shiraz grapes

Shiraz grapevines on either their own roots, or on the rootstocks Ramsey, 1103 Paulsen, 140 Ruggeri or 101–14, were grown at two separate sites within the Murray‐Darling viticultural region with similar irrigation regimes but with an irrigation water salinity of either 0.43 dS/m (low salinity site) or 2.3 dS/m (high salinity site). Rootstock effects on grape berry development, ion concentrations, soluble solids and acidity were followed during one season. Wines were also made and compared using spectral analysis and sensory evaluation. Rootstock effects that were common across both sites were (1) a close relationship between K+and soluble solids accumulation in developing grape berries which commenced at the onset of veraison and was indicative of a link between K+and sucrose transport in the phloem, and (2), higher wine K+, pH and colour hue for all rootstocks with one exception, namely 101–14 at high salinity where 101–14 responded similarly to own roots. Juice K+, pH and loss of K+from juice during winemaking were highest for grapes from the high salinity site. Mean berry weight was smaller and the range in berry size across rootstocks was narrower at the saline site. The narrower range in berry sizes may have contributed to fewer rootstock effects on wine spectral characteristics at high salinity. There was no effect of rootstock on CO₂ assimilation rate or stomatal conductance at either site, although intrinsic leaf‐based water‐use efficiency measured as A/g was 50% higher at the saline site. All treatments exhibited berry shrivel at maturity, but the extent was smaller at high salinity. Slower development of berry colour during veraison was observed on some rootstocks, for example 101–14, and while unrelated to canopy size per se, a higher leaf‐to‐fruit ratio for 101–14 may have been a factor. Slower berry colour development during veraison had no bearing on the colour density of wine made from the harvested grapes.     

The relationship between the expression of abscisic acid biosynthesis genes, accumulation of abscisic acid and the promotion of Vitis vinifera L. berry ripening by abscisic acid

Background and Aims:  Grapevines ( Vitis vinifera L.) are considered to have non-climacteric fruit, but the trigger initiating ripening (veraison) is poorly understood. This study aimed to further investigate the role of abscisic acid (ABA) during berry ripening.
Methods and Results:  In field-grown grapes over three seasons, free ABA levels increased at veraison then subsequently declined to low levels. Bound ABA increased as the free ABA level decreased after 10–11 weeks post-flowering (wpf), but ABA must also be degraded and/or exported. The absence of a large pool of bound ABA before veraison makes it unlikely that the increase in free ABA is due to the mobilization of conjugated ABA. The expression pattern of genes crucial for ABA synthesis, zeaxanthin epoxidase and two 9-cis-epoxycartenoid dioxygenases (NCEDs) indicates that berries may have the potential to synthesize ABA in situ . However, the expression profile of these genes did not correlate well with ABA levels indicating that ABA accumulation is under more complex control. The application of (+)-ABA advanced ripening as measured by colour formation, berry size increase and to a lesser extent sugar accumulation and altered the expression of one of the NCED genes.
Conclusions:  The changes in berry ABA levels around the time of veraison, which influence the timing of ripening, are under complex developmental control.
Significance of the Study:  The improved understanding of the control of berry ripening is vital to attempts to successfully manipulate this process.     

Exclusion of sunlight from Shiraz grapes alters wine colour, tannin and sensory properties

The aim of this study was to determine how changes in grape composition brought about by artificial shading (sunlight exclusion) influence wine properties including colour, flavonoid composition and sensory attributes. Prior to flowering, bunches of Shiraz grapes were enclosed in boxes designed to eliminate light without altering bunch temperature and humidity. This artificial bunch shading had little effect on berry ripening and accumulation of sugar but at harvest the shaded bunches had smaller berries and higher seed weight, juice pH and titratable acidity. The amount of anthocyanins in the fruit was not changed significantly but anthocyanin composition in the shaded berries was shifted towards dioxygenated anthocyanins (the glucosides of cyanidin and peonidin derivatives). Shaded fruit had increased seed tannins and decreased skin tannins but the largest relative change in flavonoids was a marked decrease in flavonols in the shaded fruit, similar to previous studies. Wines made from shaded fruit had lower wine colour density, total phenolics, anthocyanins and tannins when the wine was bottled and after ageing for up to three years. Analysis of potential flavour compounds following acid hydrolysis indicated that the wines made from shaded fruit had decreased levels of glycosides of β-damascenone and 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN). Sensory analysis of the wines indicated no significant difference in aroma attributes but the wines made from shaded fruit were rated lower for astringency, fruit flavour and flavour persistence in-mouth sensory attributes. The results indicate that extreme shading of Shiraz fruit can decrease wine colour, anthocyanins and tannins as well as altering sensory attributes.     

Fruit composition and ripening of Pinot Noir (Vitis vinifera L.) in relation to leaf area

Fruit development from pea size to maturity was investigated in grape berries on fruit-bearing cuttings subjected to a range of leaf removal treatments. Pot-grown vines were trained as a single shoot, with four basal leaves retained. From this point four treatments were applied: 100% leaves retained (control); 66% leaves retained; 33% leaves retained; 0% leaves retained. Leaves were removed as they appeared. The fruit of all treatments passed through veraison, accumulated water, coloured and displayed the typical double sigmoid change in volume, but the onset of growth and colour development associated with ripening was delayed by up to 25 days when leaves were removed. Berry dry weight, sugar content and soluble solids were more affected by leaf removal than berry volume or fresh weight. Bunches from the 0% leaf retained treatment formed seed, but increased very little in dry weight or soluble solids during the course of sampling. This indicates that seed growth and development are independent of sugar accumulation in pericarp tissues.     

Is weight loss in ripening grape berries cv. Shiraz caused by impeded phloem transport?

Berry shrinkage in ripening grapes cv. Shiraz is systemic within a given grapevine and coincident between grapevines in any given season. In this present study on weight loss in ripening berries, ripening curves of non-solutes per berry (largely water) were similar to curves for berry weight (as a function of time). Both sets of curves were equivalent with respect to timing of maximum weights and subsequent rates of weight loss. However, curves of solutes per berry (largely sugar) increased steeply up to the time of maximum berry weight, then slowed and plateau-ed. We suggest that phloem sap is the sole source for water and solutes that enter grape berries subsequent to veraison, and accumulate until maximum berry weight. We further suggest that phloem flow becomes impeded at maximum berry weight.
As berry ripening proceeds, continuation of berry transpiration leads to berry shrinkage and a concentration of solutes; i.e. any increase in juice Brix depends on shrinkage. One implication is that assimilates enter a berry up to the onset of shrinkage, whereafter accumulation of non-anthocyanin glycosides (including glycosides of flavour compounds) depends upon their synthesis in situ.     

Dynamics of grape berry growth and physiology of ripening

Data from two experiments on development of grape berries is re-examined with emphasis on partitioning of berry weight into non-solutes per berry (largely water) and solutes per berry (largely sugar), using weight times juice °Brix. This approach is based on the thought that, since xylem flow is blocked after veraison, time curves of solutes per berry indicate the activity of phloem transport into the berry during ripening growth. Experiment 1: Measurements of Muscat Gordo Blanco berries from inflorescences with a spread of flowering times showed typical double-sigmoid volume/time curves but with divergent rates and amounts of volume increase. Despite this divergence, °Brix curves after veraison were almost coincident because, in each case, the rate of increase in solutes per berry was proportional to that of berry volume. These results indicate that sugar and water increments after veraison are linked and depend on the same source, namely, phloem sap. Experiment 2: An irrigation experiment on cv. Shiraz also showed divergent berry weight curves between treatments and years but with the difference that all berries shrank after a maximum berry weight was attained at 91 days after flowering (at about 20 °Brix). At this point, the curves of solutes per berry slowed then plateaued, indicating that inflow of phloem sap had become impeded. Prior to shrinkage these berries accumulated primary metabolites (mainly phloem sugar) but, during shrinkage, when berries were apparently isolated from vascular transport, non-anthocyanin glycosides accumulated. These results have implications for the study of berry flavour buildup and berry composition, and also for the understanding of sink competition within the vine, fresh and dried yield, and juice °Brix levels.     

Influence of shriveling on berry composition and antioxidant activity of Cabernet Sauvignon grapes from Shanxi vineyards

BACKGROUND: Berry shrivel (BS), a berry development disorder, appears soon after veraison. It occurs worldwide and affects the quality of grape berries and wine. However, it had not been reported in China until recently. This study aimed to investigate the changes in berry composition and antioxidant activity of Cabernet Sauvignon grapes from Xiangning Valley, Shanxi Province, China, during BS. RESULTS: Shrinkage contributed to an increase in the concentration of basic grape ingredients such as sugar and acid. An appropriate degree of shrinkage was apparently helpful in improving the phenolic content and increasing the antioxidant activity, but the berries that continued to shrivel showed a low antioxidant activity. Further, the results indicated distinct differences between the berries harvested from the southern side of the canopy and those harvested from the northern side, presumably due to variations in sunlight exposure. CONCLUSION: Moderate BS was beneficial since it increased berry quality and antioxidant activity of Cabernet Sauvignon grapes from Shanxi vineyards. Copyright © 2011 Society of Chemical Industry     

Managing ochratoxin A risk in the grape-wine food chain

The main source of ochratoxin A (OTA) in the wine food chain is the infection of grapes by "black aspergilli" in the field. OTA-producing black aspergilli include principally Aspergillus carbonarius, followed by A. niger and possibly A. tubingensis. They are opportunistic fungi that develop particularly on damaged berries at ripening, although they may occur and form OTA on grapes from veraison to harvest. Climatic conditions (high humidity and temperature) and geographical location are important factors favouring OTA accumulation in grape berries. The severity of aspergillus rot is influenced by excessive irrigation and rainfall prior to harvest, which causes berry splitting. In addition, berry wounds caused by insect attack provide preferential entries for black aspergilli. High OTA levels occur in grapes severely damaged by the grape moth, Lobesia botrana, particularly in Mediterranean areas. Some grape varieties display greater susceptibility to aspergillus rot due to intrinsic genetic characteristics and bunch conformation (i.e. compact>sparse). Control measures for toxigenic mycoflora in the vineyards must consider these critical control points. Proper fungicidal and insecticidal treatments can reduce OTA contamination. Nevertheless, knowledge about the fate of OTA and its distribution in wine and winery by-products is important to manage OTA risk in contaminated stock. In our wine-making experiments, only 4% of the OTA present in grapes remained in the wine--the majority is retained in pressed grape pomaces. OTA concentration remained unchanged in wine after a 1-year aging as well as in all liquid fractions collected during vinification (i.e. must, free run wine, and wine after first and second decantation). Activated carbon can reduce OTA levels in wine but negatively affects wine quality.     

Vascular function in berries of Vitis vinifera (L) cv. Shiraz

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 excised shoots with bunches still attached, and then sectioning fruit for photo-microscopy. Those comparisons confirmed published studies showing an apparent blockage to dye movement along major vessels within the brush tissue of post-veraison fruit. However, our functional approach yielded a different impression of vascular activity. A continuation of xylem transport in ripening fruit was inferred from comparisons of berry volume where pedicels were either girdled (phloem interrupted, but xylem intact) or excised (both phloem and xylem interrupted). Volume changes in manipulated berries were compared with immediately adjacent intact control berries within the same bunch. Control fruit lost volume subsequent to 78 days after flowering (DAF) while manipulated fruit lost volume from the first day of treatment at 67 DAF. By harvest time at 95 DAF, both control fruit and girdled fruit had fallen to 91% and excised fruit to 46% of maximum volumes recorded around 78 DAF. Berry volume loss in girdled fruit was further enhanced by deficit irrigation. We conclude that xylem flow into those Shiraz berries must have continued beyond veraison despite dye evidence of a vessel blockage within the brush region of analogous post-veraison fruit.     

Effects of manipulated grape berry transpiration on post-veraison sugar accumulation

A series of experiments were conducted on container-grown Pinot Noir and Sangiovese grapevines ( Vitis vinifera L.) to investigate whether changes in berry water loss at veraison influence the pattern of sugar accumulation. Berry transpiration was induced to vary either by changing the vapour pressure deficit (VPD) around bunches through temperature or relative humidity (RH) manipulations, or by applying drying-accelerating emulsion or a hydrophobic coating (vaseline) over the berry skin. In all the experiments, every berry of every bunch was rated prior to treatment as to softness and colour intensity. Transpiration rates were derived either from measurements of attached bunches using a custom-built open gas-exchange system or from weight loss calculated for single excised berries. Berry development and ripening were monitored throughout each experiment as deformability, fresh weight, and sugar concentration and content. Berries either did not respond to VPD-enhancement or showed reduced water loss when bunches were subjected to high temperature. Low berry transpiration in the latter treatment led to lower sugar content per berry up to harvest, and berry transpiration and net sugar intake were linearly correlated up to 0.20–0.25 mmol/m².s. A similar correlation was found also in the coating experiment within the first five days after treatments. When berry transpiration was restricted by applying vaseline, sugar accumulation was retarded. Low values of VPD, induced by raising the RH around the bunches, lowered sugar concentration but not sugar content per berry. The present study provides preliminary evidence that sugar accumulation in grapevine berries responds to changes in the evaporative demand around the bunch at veraison.     

Effects of partial rootzone drying on yield, ripening and berry ABA in potted Tempranillo grapevines with split roots

Our objective was to investigate whether grape berry growth and colour development is associated with variation in abscisic acid (ABA) levels during ripening under an irrigation regime of partial rootzone drying (PRD). The study was carried out using container‐grown Tempranillo grapevines (established as fruit‐bearing cuttings) with a split root system (occupying two contiguous pots) and grown under controlled conditions. Three irrigation treatments were imposed – a control (well watered), and two forms of deficit irrigation, viz. partial rootzone drying (PRD), and sustained deficit irrigation (SDI). Under SDI, a given volume of irrigation water was applied uniformly and simultaneously to both sides of the split roots of each vine. Under the PRD regime, the same total volume of irrigation was applied, but as separate allocations to each side of the split root system in turn, and alternating on a 10‐day cycle. Because both deficit treatments received the same total amount of irrigation water (about 50% of the volume applied to controls), we were able to distinguish between the effects of deficit irrigation per se, versus any specific impact PRD might be having on vine performance. Outcomes were as follows. Compared to well‐watered control vines, yield per plant, and weight per bunch were both reduced significantly under SDI, but were sustained close to control values under the PRD regime. SDI and PRD thus differed significantly in their respective impacts on vine performance, and comparing just these two forms of deficit irrigation, PRD resulted in greater yield, higher bunch weight, bigger leaf area and increased berry weight compared with the SDI treatment. Moreover, PRD also induced greater accumulation of skin anthocyanins at harvest, compared to SDI. Berry ABA concentration increased continuously throughout veraison, achieving a maximum at the end of this period. The increase of berry ABA concentration was earlier and faster in PRD than in SDI, which exhibited only a slight increase in berry ABA by the end of veraison. These distinctive responses to PRD compared to SDI imply that the alternating wet‐dry cycles of PRD, rather than simply a deficit irrigation, as in SDI, had a distinctive effect on growth, ripening and berry composition. Our data imply that these different responses might be related to ABA physiology, and especially to ABA levels in berries during ripening.     

陕西合阳地区白色酿酒葡萄果实品质调研

以白色酿酒葡萄品种‘霞多丽’‘爱格丽’‘雷司令’‘小芒森’和‘贵人香’为试材,在陕西省合阳县气候条件下探讨葡萄成熟过程中浆果的还原糖、总酸的变化趋势,并测定成熟果实的可溶性固形物、果皮中总酚和单宁含量。结果表明‘爱格丽’在8月中、下旬成熟;‘雷司令’‘贵人香’和‘霞多丽’在9月上旬成熟;‘小芒森’在9月中旬成熟。成熟时‘小芒森’的含糖量最高,‘爱格丽’次之,‘雷司令’较低;含酸量‘小芒森’最高,‘霞多丽’最低,5个品种的糖酸比均大于20。‘贵人香’和‘霞多丽’的总酚和单宁含量较高。综合来看,‘爱格丽’与‘小芒森’可作为合阳地区白色酿酒葡萄的主推品种,‘贵人香’与‘霞多丽’为次要栽植品种,研究结果将为合阳地区酿酒葡萄的种植示范和推广提供参考和依据。     

Effects of ethephon, methanol, ethanol and girdling treatments on berry maturity and colour development in Cardinal table grapes

To hasten berry maturity and improve skin colour, the early-season table grape variety Cardinal was treated (post veraison) with a bunch + foliar spray using either 240 or 480 mg/L ethephon, as well as with 30% methanol, 30% ethanol (v/v); or by girdling. Treatment effects were evaluated in a randomised experimental design, with 10 replications of one plant per plot, down a single row. Ethephon at 480 mg/L applied twice, on July 2 when 5% of the berries showed colouring and on July 9 when 20% of the berries developed partial colour, increased total soluble solids, °Brix/titratable acidity and skin colour. Girdling, methanol and ethanol also increased total soluble solids and berry colouration and caused faster ripening. Ethephon at 480 mg/L was generally the most effective means of hastening ripening and improving colour.