Rootstock effects on salt tolerance of irrigated field-grown grapevines (Vitis vinifera L. cv. Sultana).: 1. Yield and vigour inter-relationships

Vegetative growth and yield of grapevines grown in the field on their own roots or grafted to a range of rootstocks were investigated under drip irrigation with water of three salinity levels (0.40, 1.75 and 3.50 dS/m) over a five‐year period. Rootstocks were Ramsey, 1103 Paulsen, J17–69 and 4 hybrids (designated R1, R2, R3 and R4) derived from parentage involving Vitis champini, V. berlandieri and V. vinifera. Of measured yield components (bunches per shoot, bunches per vine, weight per bunch, weight per berry and total yield), only weight per berry was significantly reduced by high salinity (3.50 dS/m) in each year of the trial with the exception of Sultana on 1103 Paulsen and R2 in 1991 and Sultana on Ramsey in 1993. Weights of one‐year‐old pruning wood were also reduced by high salinity in all years for own roots and all rootstocks, with the exception of R2. Mean yield values at each salinity level over the five‐year period of the trial were highest for Sultana on Ramsey, 1103 Paulsen and R2. High salinity had no effect on five‐year mean yields of Sultana on Ramsey, 1103 Paulsen and R2. Yield (five‐year means) of Sultana on Ramsey and R2 at 1.75 dS/m were significantly higher than at 0.40 dS/m by 14.6% and 13.4% respectively. In contrast, 5‐year mean yields of Sultana on J17–69, own roots, R1, R3 and R4 at 3.50 dS/m were reduced by 54, 30, 20, 30 and 30% respectively. Yield of Sultana on J17–69, R1 and R4 rootstocks was reduced by 47, 20 and 24% respectively at 1.75 dS/m. When yield was regressed against bunches per vine and weight per bunch for Sultana on own roots and on Ramsey rootstock, bunches per vine was the main determinant of yield, while weight per berry showed a poor correlation with yield at all salinity levels. Rootstock ranking for salt tolerance based on yield at high salinity was the same as rankings for pruning wood weights at high salinity. The same occurred at medium salinity, demonstrating that vigour imparted by the rootstock was a major factor in Sultana salt tolerance as measured by yield. Mean root weighted soil saturation paste electrical conductivities (RWEC_e) (determined from soil saturation paste salinities and root length densities) were in the range 2.0–2.6 dS/m for the low salinity treatment, increasing to approximately 5.4 dS/m with increasing salinity of irrigation water. Yield reduction for own‐rooted vines for each 1.0 dS/m increase in RWEC_e above 2.6 dS/m was 9.3%.     

Rootstock effects on salt tolerance of irrigated field-grown grapevines (Vitis vinifera L. cv. Sultana) 2. Ion concentrations in leaves and juice

Field vines of cv. Sultana, grown either on their own roots, or grafted to a range of rootstocks, were drip‐irrigated at three salinity levels (0.40, 1.75 and 3.50 dS/m) over a five‐year period. Rootstocks comprised Ramsey, 1103 Paulsen, J17‐69 and 4 hybrids (designated R1, R2, R3 and R4) derived from parentage involving Vitis champini, V. berlandieri and V. vinifera. Concentrations of Cl^‐, Na+, K+, Ca²⁺ and Mg²⁺ were measured in petioles at flowering, and in laminae and grape juice at harvest, in each year of the trial. Vines on all rootstocks accumulated less chloride in either petioles at flowering or in laminae and juice at harvest compared with vines on own roots at all salinity treatments. By inference, all rootstocks behaved as chloride excluders relative to the roots of own‐rooted vines. 1103 Paulsen was the best chloride excluder based on lowest concentrations of accumulated Cl^‐ in petioles, laminae and grape juice at high salinity. Sultana on R3 rootstock at high salinity accumulated more Na+ in both laminae and grape juice (at harvest) than did Sultana on own roots or on any of the other rootstocks. Laminae K+ at harvest time was reduced at high salinity in Sultana on own roots and on all rootstocks. Concentrations of both Cl^‐ and Na+ in petioles at flowering and in laminae and grape juice at harvest showed no significant correlation with either yield (as kg of fresh grapes per vine) or vigour (as measured by fresh weight of one‐year‐old pruning wood per vine) for any salinity treatment. There was however, a strong positive correlation between yield and the subsequent weight of one‐year‐old pruning wood for all salinity treatments. There was also a negative correlation between Na+ concentrations in petioles at flowering and the subsequent weight of one year‐old‐pruning wood from the 0.40 dS/m treatment. Similar negative correlations were found between Na+ concentration in both laminae and grape juice at harvest time, and the subsequent weight of one‐year‐old pruning wood from the 0.40 dS/m treatment (but not from either the 1.75 or 3.50 dS/m treatments). Based on these findings and those from Walker et al. 2002a we conclude that a high innate vigour of a rootstock combined with moderate to high chloride and sodium exclusion ability represents the best combination for salt tolerance in Sultana grapevines as measured by yield at moderate to high salinity.     

Rootstock effects on salt tolerance of irrigated field-grown grapevines (Vitis vinifera L. cv. Sultana). 3. Fresh fruit composition and dried grape quality

Field‐grown vines of cv. Sultana on either their own roots or grafted to a range of rootstocks, were drip‐irrigated at one of three salinity levels (0.40, 1.75 and 3.50 dS/m) over a five year period. Rootstocks were Ramsey, 1103 Paulsen, J17‐69 and 4 hybrids (designated R1, R2, R3 and R4) derived from parentage involving Vitis champini, V. berlandieri and V. vinifera. Grape juice total soluble solids, titratable acidity and pH were measured at harvest, while colour of dried fruit was measured before and after processing and again after six months storage. Damage index (an indicator of skin damage) was measured post‐processing; sugar crystal formation in dried grapes and dried grape compaction were measured post‐storage. There was a strong salinity x rootstock interaction for grape juice soluble solids concentration, soluble solids yield (the product of soluble solids concentration and fruit yield) and pH, but not for titratable acidity when analysed on the basis of 5 year means. Small increases (< 5%) in juice soluble solids concentration were recorded at medium salinity (1.75 dS/m) for the low vigour genotypes, Sultana on own‐roots and on J17‐69 rootstock, based on the 5 year means and Fisher's protected (interaction) LSDs. Moderate increases (< 10%) also occurred in years of low crop load e.g. 1993 at high salinity for the high vigour rootstock R2 and in 1995 at medium salinity for Sultana on own roots and at high salinity for Sultana on R1 rootstock. By contrast, decreases in soluble solids concentration occurred with increasing salinity for the high vigour rootstocks (Ramsey, 1103 Paulsen and R2) in years of high crop load e.g. 1992. Small (< 2%) increases in grape juice pH were recorded at high salinity for Sultana on R3 rootstock and moderate increases (< 7%) in grape juice titratable acidity were recorded at high salinity for Sultana on own roots and Sultana on J17‐69, R1, R2 and R4 rootstocks. Dried grapes from all treatments achieved a light amber colour (quality grade termed 5 crown light) and were generally of high quality. Sultanas from own‐rooted grapevines were redder (higher ‘a‐value’) than sultanas from 1103 Paulsen and Ramsey when assessed as unprocessed fruit, after processing (both years) and after 6 weeks storage. While soluble solids yields per vine were 23–31% lower at high salinity for Sultana on own roots and on R1, R3 and R4 rootstocks, they were unaffected by high salinity for Ramsey, 1103 Paulsen and R2 rootstocks. Moreover, soluble solids yields for Sultana on Ramsey, 1103 Paulsen and R2 rootstocks were 1.4 to 2.5‐fold higher than for Sultana on the other rootstocks at high salinity. This study has shown that over a 5 year period rootstocks such as Ramsey, 1103 Paulsen and R2 grafted with Sultana were tolerant of salinity, producing dried grapes of generally high quality.     

Yield-salinity relationships of different grapevine (Vitis vinifera L.) scion-rootstock combinations

Three data sets derived from 5– or 6‐year field experiments at Merbein (Victoria), Dareton (New South Wales) and Loxton (South Australia) were used to assess the relationship between yield of own‐rooted or grafted grapevines and electrical conductivity of the saturated soil paste extract (ECe). This involved a non‐linear least squares fit method to determine the threshold of ECe at which yield begins to decline and the slope of the yield reduction with increasing ECe above that threshold. Threshold and slope are the two key parameters in this piece wise linear model of grapevine response to salinity. The soil ECe values were integrated to take account of both spatial and temporal variation in soil salinity within the profile. The ECe threshold for own‐rooted Sultana at Merbein in the Sunraysia region was found to be 2.3 0.2 dS/m and the slope of yield reduction above the threshold was 8.9 1.2 % per 1 dS/m increase in soil ECe. At Dareton, a similar threshold of 2.1 0.3 dS/m was found for own‐rooted Sultana, however the higher slope of the yield reduction (15.0 2.0 %) relative to the same vines at Merbein may have been related to the higher sodium adsorption ratio (SAR) in irrigation water and its impacts on soil physical properties, especially in that part of the vineyard with a heavier soil type. The rootstock Ramsey resulted in a threshold of 3.3 0.2 dS/m and slope of 5.7 0.4% with the scion Colombard at Loxton, indicating a more tolerant combination of scion‐rootstock to salinity. The rootstocks 1103 Paulsen and R2 with Sultana as scion were the most salt tolerant, with no discernible yield reduction until ECe exceeded about 4 dS/m. Of four other rootstocks with Sultana as scion, compared with own‐rooted Sultana, J17–69, and R4 had similar threshold values (2.3 0.2 and 2.5 0.2 dS/m) and slopes of yield reduction (10.1 1.9 % and 8.0 0.5 %, respectively), while R1 had a similar threshold of 1.8 0.2 dS/m but a lower slope of yield reduction (4.3 0.9 %) than Sultana on own roots and R3, J17–69, R1 and R4 rootstocks. Comparatively, R3 rootstock responded differently by way of a higher threshold of 3.0 0.2 dS/m than own‐rooted Sultana and J17–69 and R1 rootstocks and a higher slope of yield reduction of 12.4 1.0 % relative to Sultana on own roots and R4 and R1 rootstocks. Based on our long‐term studies of yield‐salinity relationships on contrasting sites, the pre‐eminence of certain rootstocks in conferring tolerance to soil salinity has been confirmed. Ramsey, 1103 Paulsen, and a new hybrid designated here as R3 were generally outstanding, with Ramsey varying only slightly in its comparative effectiveness when grafted to different scion varieties. An overall interaction between scion variety and rootstock genotype was thus evident in the form of yield‐salinity relationships.     

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.     

Impact of rootstock on yield and ion concentrations in petioles,juice and wine of Shiraz and Chardonnay in different viticultural environments with different irrigation water salinity

Background and Aims: Within-site comparisons were made of rootstock effects on yield, and chloride and sodium concentrations in petioles, juice and wine of Shiraz and Chardonnay vines at sites with irrigation water salinities (EC_iw) ranging from low (0.4 dS/m) to moderate-high (1.8 to 3.3 dS/m). It also compared consistency of yield performance of the various rootstocks with both scions over 8 years at one site with an EC_iw of 2.1 dS/m. Methods and Results: Chardonnay and Shiraz on own roots and on Ramsey, 1103 Paulsen, 140 Ruggeri, K51-40, Schwarzmann, 101-14, Rupestris St. George and 1202 Couderc were compared. Ramsey resulted in better yields relative to most of the other rootstocks at three of the four sites for each scion. Exceptions were the low salinity site where Schwarzmann was best with Chardonnay, and Padthaway where 140 Ruggeri was best with Shiraz. Chardonnay wine chloride concentrations were similar to grape juice chloride concentrations, but Shiraz wine chloride concentrations were on average 1.7-fold higher than grape juice chloride. Conclusions: Shiraz on own roots, K51-40 and 1202C rootstocks carry some risk of accumulating unacceptable levels of chloride in grape juice and wine when the salinity of the irrigation water is at moderate to high levels. Rootstocks K51-40 (with Chardonnay and Shiraz) and potentially 101-14 (with Shiraz) should be avoided in situations of long term irrigation with moderate to high salinity water. Significance of the Study: The study identifies rootstocks with acceptable yields and grape juice chloride concentrations for potential use in regions affected by salinity.     

Effect of reduced irrigation on growth,yield, ripening rates and water relations of Chardonnay vines grafted to five rootstocks

Background and Aims: In the first decade of the 21st century, drought within the Murray–Darling Basin has reduced the amount of water available for irrigation. We investigated whether the response of vines to reduced irrigation was modified by rootstock. Methods and Results: Reduced irrigation (5 versus 8 ML/(ha·year)) was applied to Chardonnay vines grafted to five rootstocks (Ramsey, 140 Ruggeri, 1103 Paulsen, 110 Richter and K51‐40) for four seasons. It decreased the yield from 29.3 to 26.7 kg/vine, and increased the irrigation water use index (IWUI) from 4.7 to 6.6 t/(ha·ML), but gains in this index declined as the trial progressed. The values of mid‐afternoon leaf water potential were not affected by reduced irrigation, but leaf CO₂ assimilation declined from 13.1 to 11.7 µmol/(m²·s). These effects were independent of rootstock. Reduced irrigation did not increase soil salinity (ECe) or vine tissue Na and Cl concentrations. Vines on Ramsey and 1103 Paulsen rootstocks had higher yields, 32.2 and 30.0 kg/vine, respectively, and the highest IWUIs, 5.9 and 5.5 t/(ha·ML). In two of the three seasons, reducing irrigation did not affect the rates of ripening (°Brix/growing degree days) excepting vines on 1103 Paulsen. Ripening rates varied by 1.5‐fold between seasons. Conclusion: The yield and growth responses of Chardonnay vines to a 35% reduction in irrigation were not modified by rootstock. Significance of the Study: Reducing irrigation did not lead to a build‐up of soil salts. The response of vines to reduced irrigation on rootstocks rated as having good drought tolerance was the same as that for vines on a rootstock rated as having poor drought tolerance.     

Transpiration efficiency and carbon-isotope discrimination of grapevines grown under well-watered conditions in either glasshouse or vineyard

This paper describes variation in transpiration efficiency ‘W’ (where W = dry matter produced/water transpired) among grapevine genotypes grown under well‐watered conditions in either a glasshouse or a vineyard. Nineteen genotypes were grown in a glasshouse where growth and transpiration were measured. W ranged from 2.5 to 3.4 g dm/kg H₂O transpired. Carbon‐isotope discrimination (Δ) of laminae dry matter ranged from 20.8 to 22.7%o and there was a negative relationship (R²= 0.58) between W and Δ. A large proportion of variation in W could be attributed to variation in stomatal conductance. Genotypic variation in photosynthetic capacity was also an important component of variation in W. In a second experiment, lamina Δ was measured for mature field‐grown Shiraz and Chardonnay, grown either on their own roots or grafted to five different rootstocks, and maintained at three sites under well‐watered conditions. At all sites and regardless of rootstock, the laminae of Chardonnay had Δ values 1 to 2%o lower than Shiraz. There was also a 1 to 2%o variation among the sites. Rootstock variety affected Δ values inconsistently and by a maximum of 0.5%o. Leaf gas exchange measurements were performed at a single site on sun‐exposed leaves of Chardonnay and Shiraz on either their own roots or 1103 Paulsen, a moderate to high vigour rootstock. There was no significant effect of rootstock on leaf gas exchange and photosynthetic rates did not differ between scion varieties. However, Chardonnay had a 20% lower stomatal conductance and a 1.4‐fold higher ratio of CO₂assimilation/H₂O transpiration (A/T) indicating a potentially higher W, at a leaf level, for Chardonnay compared with Shiraz. We conclude that photosynthetic capacity was also higher for Chardonnay. Δ values, predicted from the C_i/C_a ratio calculated from leaf gas exchange measurements, did not differ significantly from measured values for laminae Δ. This similarity for Δ, in conjunction with the fact that the lower Δ of Chardonnay was reflected in a higher A/T ratio, suggests that Δ may be a reliable predictor of comparative W under vineyard conditions.     

Light and temperature effects on shoot fruitfulness in Vitis vinifera L. cv. Sultana: Influence of trellis type and grafting

Fruit bud initiation in Sultana is more sensitive to climatic factors than fruit bud initiation in other cultivars. This paper considers historical findings regarding the influence of light and temperature on fruit bud initiation and fruitfulness in view of modern Sultana vineyard management practices.
Past results were reviewed and confirmed by experiments in which variability in vine size and structure was introduced by grafting and modifications of trellis design. Ramsey-grafted vines were consistently less fruitful than own-rooted Sultana, possibly because of a more shaded canopy interior due to greater vegetative growth of vines grafted to Ramsey rootstock. Carbohydrate reserves of node and internode tissue in late winter between node 2 and 18 followed a similar trend along the cane as fruitfulness in the following spring.     

A diminished capacity for chloride exclusion by grapevine rootstocks following long-term saline irrigation in an inland versus a coastal region of Australia

Shiraz and Chardonnay grapevines that had been initially assessed for Cl^‐ exclusion in the 1996 and 1997 harvest seasons at both Merbein (inland region of Victoria) and at Padthaway (sub‐coastal region of South Australia), were re‐evaluated in 2003 and 2004 at those same two locations. Both scion varieties were grown either on their own roots or were grafted to one of the following rootstocks: Ramsey, 1103 Paulsen, 140 Ruggeri, K51‐40, Schwarzmann, 101‐14, Rupestris St George and 1202 Couderc. Both sites had been irrigated with saline water since 1994. The salinity of irrigation water at Merbein was approximately 2.1 dS/m; at Padthaway irrigation salinity varied between approximately 1.6 dS/m and 2.5 dS/m during the survey period. Changes in the Cl^‐‐excluding ability of all rootstock/scion combinations between 1996, 1997 and 2003, 2004 were based upon analysis of Cl^‐ concentrations in grape juice and in laminae at harvest, as well as Electrical Conductivity (EC), pH and Sodium Adsorption Ratio (SAR) of the 1:5 soil:water extract. Taking juice Cl^‐ as indicative of rootstock effectiveness for Cl^‐ exclusion, and considering data from Merbein, our analyses demonstrated that overall means for Shiraz juice Cl^‐ increased from around 190 to 427 mg/L over the survey period (7 years). In Chardonnay grapevines at Merbein, overall mean concentrations of Cl^‐ in juice increased from around 70 to around 225 mg/L over 7 years. Significant differences between rootstocks were evident, with some rootstocks at Merbein showing a diminished capacity for Cl^‐ exclusion in 2003 and 2004. By contrast, in Padthaway there was no consistent deterioration in Cl^‐‐excluding capacity by rootstocks supporting either Shiraz or Chardonnay as scions. In 2004 there were significant differences between grapevines at Merbein and Padthaway in the concentration of Cl^‐ accumulated, even though the mean soil EC_1:5 after harvest for 0–90 cm depth was the same at both sites, namely 0.4 dS/m. Containment of grapevine salinity at Padthaway (relative to Merbein) between 1996/97 and 2003/04 was most likely due to factors such as a lower volume of saline irrigation, double the rainfall and 27% lower pan evaporation.     

Effects of applied water amounts at various fractions of evapotranspiration (ETc) on leaf gas exchange of Thompson Seedless grapevines

Aims: To determine the effects of applied water amounts at various fractions (0.2, 0.6, 1.0 and 1.4) of grapevine evapotranspiration on leaf gas exchange of Thompson Seedless grapevines. Methods and Results: Midday stomatal conductance (g_s) decreased linearly as leaf water potential (Ψ_l) and soil water content decreased. Leaf net CO₂ assimilation rate only decreased once midday Ψ_l values were less than ?1.0 MPa and when ～50% of the soil water content at field capacity had been depleted. The mean seasonal midday A/g_s ratio (intrinsic water use efficiency) was greatest for the 0.2 irrigation treatment and decreased as applied water amounts increased. Diurnal A and g_s for vines irrigated at the 0.6 level or greater reached a maximum prior to midday remained constant thereafter before decreasing late in the afternoon, while those for vines that received less water decreased subsequent to the first measurement of the day. Conclusions: A and g_s responded differently to vine and soil water statuses under the conditions of this study. There was no midday depression in either A or g_s for vines irrigated at full evapotranspiration. Significance of the Study: The values of Ψ_l, A and g_s reported here would serve as criteria to indicate that vines were well watered.     

Modeling Respiration Rate of Strawberry (cv. San Andreas) for Modified Atmosphere Packaging Design

A model for strawberry (Fragaria × ananassa cv. San Andreas) respiration rate was determined as a function of O₂ and CO₂ concentrations and temperature. Strawberries were enclosed in containers under different gaseous compositions (0–24% O₂ and 0–15% CO₂) and temperatures (10, 19, 23°C). Respiration rate was determined as O₂ consumption and CO₂ production. Respiration rate data was fitted to Michaelis-Menten models, with temperature dependence according to Arrhenius type equation. Non–linear regression was applied to calculate model parameters. No CO₂ inhibition was verified, so a simple Michaelis–Menten model was selected (R² = 0.91).     

Reduced irrigation and rootstock effects on vegetative growth,yield and its components,and leaf physiological responses of Shiraz

Background and Aims: The study investigated whether rootstocks can modify grapevine responses to reduced irrigation. Methods and Results: Drip-irrigated Shiraz vines on eight rootstocks were subjected to industry standard and 30% reduced irrigation regimes over four seasons. Reducing irrigation decreased pruning weights and yield, but did not consistently affect irrigation water use index (IWUI). It increased leaf Δ¹³C. Reduced irrigation and elevated vapour pressure deficit (VPD) were associated with decreases in leaf water potential (ψ_l), leaf stomatal conductance and assimilation rate. Reducing irrigation raised leaf transpiration efficiency, whereas elevated VPD lowered it. These effects of reduced irrigation were independent of rootstock. Vines grafted to 101-14 had a higher ψ_l and achieved the highest yield and IWUI. The yields of vines grafted to Ramsey, Schwarzmann and 140 Ruggeri were also high. Vines grafted to 101-14, Ramsey and 1103 Paulsen had the higher rates of leaf assimilation. Rootstock did not affect Δ¹³C. Conclusion: The gain in leaf transpiration efficiency caused by reducing irrigation was not associated with a gain in IWUI. Rootstocks 101-14, Ramsey, Schwarzmann and 140 Ruggeri achieved higher yields and IWUI under both standard and reduced irrigation regimes. Significance of the Study: Among grafted vines growing on saline soil but receiving non-saline irrigation water and subject to a 30% reduction in irrigation, the yield responses of vines grafted on rootstocks rated as having good drought tolerance were the same as those of vines grafted on rootstocks rated as having poor drought tolerance.     

Mode of action of the drying emulsion used in dried vine fruit production.: I. The effect of inorganic ions and fatty acid esters

Drying of Sultana grapes (Vitis vinifera L.) in Australia is enhanced by the berries being dipped in or sprayed with an alkaline oil-in-water drying emulsion consisting of K₂CO₃ and a mixture of ethyl esters of fatty acids. The relative importance of the nature of the cation and anion of the alkali salts of the drying emulsion and the relative effectiveness of the different fatty acid esters on the drying rate was investigated. When salt solutions used as dip were applied with commercial drying oil, water loss increased with decreasing hydrated ionic radius of the alkali cation and followed the lyotropic series Cs+ > Rb+ > K+ > Na+= Li+, with Ca²⁺= Li+. Carbonate was the most effective anion, while S₂O₅²-^-, HP₂O₅-_-, OH-, I-and Cl- gave responses which were similar to or less than the water control, depending on the presence or absence of drying oil. The interaction between cation and commercial drying oil seemed to be additive or synergistic. Without commercial drying oil, the CO₃^2– salts of Cs+, Rb+, K+ and Na+ all produced higher drying rates than those of Li+ and Ca²⁺, with the Cs+ and Rb+ salts having the greatest effect. When emulsified with 2% ethyl oleate instead of commercial drying oil, all salts with CO₃^2– as anion produced faster drying, and their ranking was the same with both emulsifiers. However, when the Cl“salts were used with 2% ethyl oleate, all cations produced similar and fast drying. The saturated fatty acid esters, caprylic acid ethyl ester and stearic acid ethyl ester, had little effect on drying rates whereas the unsaturated fatty acid esters, ethyl oleate, butyl oleate and ethyl linoleate, increased water loss two-fold compared with H₂O treatment. The results are discussed with particular emphasis on the role of the molecular structure of the cuticle in regulating water loss from grape berries.     

The effect of salinity on the growth,yield and essential oils of turnip‐rooted and leaf parsley cultivated within the Mediterranean region

BACKGROUND: Turnip‐rooted parsley, a field‐crop of northern Europe, has recently been introduced to the Mediterranean region for fresh consumption or production of essential oil. Because of soil salinity within this area, the sensitivity of turnip‐rooted and two other parsley subspecies (plain‐ and curly‐leafed) to salt was studied. RESULTS: NaCl or CaCl₂ additions to the irrigation water raised the electrical conductivity (EC) in increments from 0.5 dS m^?1 to 4.5 dS m^?1 (year 1) or 6.0 dS m^?1 (year 2), reducing parsley foliage weight in year 2, but increasing the root weight of turnip‐rooted parsley in year 1. Raising the EC with NaCl increased the yield of foliar essential oil from curly‐leafed parsley (both years), but not from the other cultivars. CaCl₂ had less effect on oil yield. The relative concentrations of the principal aroma constituents (β‐phellandrene, myristicin, β‐myrcene and apiole) of the foliar essential oil were affected by NaCl or CaCl₂ in a way that differed between cultivars. Oil yield from parsley roots was very low and apparently unaffected by salinity. CONCLUSION: All three parsley subspecies are moderately sensitive to salinity, but may be cultivated at <4.5 dS m^?1 EC. Salinity may assist oil production by increasing oil yield (curly‐leafed parsley) and positively affecting certain aroma constituents. Copyright © 2009 Society of Chemical Industry     

Influence of grapevine leafroll associated viruses (GLRaV-2 and -3) on the fruit composition of Oregon Vitis vinifera L. cv. Pinot noir: Phenolics

Some of the 10 known grapevine leafroll associated viruses (GLRaVs) have negative impacts upon vine productivity and grape quality, though these negative influences are dependent on factors such as GLRaV strain, cultivar, clone, rootstock, and vine age. This is the first study to report on GLRaV-2 and GLRaV-3 infected vines, with regard to phenolic compounds, and other fruit maturity indices, of ‘Pinot noir’ grapes, compared to berries from adjacent vines free of GLRaVs (same vineyards). Three different rootstock/scion combinations were included in this study. Clusters were collected for two growing seasons from commercial vineyards in the Willamette Valley of Oregon, and each vine sampled was tested for GLRaV-1, -2, -3 and Rupestris stem pitting-associated virus (RSPaV). All sampled vines were infected with RSPaV. Grapevine leafroll associated virus-infected vines tested positive for GLRaV-2 or GLRaV-3. Overall, fruit infected with GLRaV-2 and -3 had reduced percent soluble solids, decreased individual and total anthocyanins, and increased skin and pulp weight for all three ‘Pinot noir’ rootstock/scion combinations examined. Vitis riparia rootstock/‘Pinot noir’ clone 114 scion combination appeared to be the most sensitive to GLRaV-3 infection, having significant reduction of all five anthocyanins, total phenolics, and total tannins, with an increased cluster weight and 100-berry weight. No clear trends were observed in the polyphenolics analysed.     

Effects of controlled atmosphere storage on respiratory metabolism of apple fruit tissue

The effects of CO₂ and O₂ concentrations commonly used in fruit storage upon various respiratory processes in apple fruit tissue have been investigated. In manometric experiments 10% CO₂ inhibited CO₂ release from succinate supplied to peel discs by over 50%; CO₂ release from malate was inhibited at high substrate concentrations, while CO₂ release from pyruvate was not affected. High CO₂ concentrations also inhibited ¹⁴CO₂ release from succinate 1,4-¹⁴C and succinate 2,3-¹⁴C supplied to peel discs. It is concluded that succinate dehydrogenase is the respiratory enzyme most affected by CO₂ concentration. Oxygen uptake was found to be 50% inhibited at ambient concentrations of 0.5% O₂ for cortical tissue and 5% O₂ for peel tissue. It is concluded that cytochrome oxidase is responsible for O₂ uptake in peel and cortical tissue. The apparent low affinity for O₂ in peel respiration may be due to limited O₂ diffusion through the tissue. It is concluded that O₂ uptake by the bulk of the apple is not directly affected by O₂ concentrations employed in fruit storage.     

Management practices for Sunmuscat (Vitis vinifera L.): a new drying variety

Sunmuscat grapevines, managed on one of three trellis × two row spacing configurations, and grown on either their own roots or grafted onto Ramsey rootstock, were assessed over nine seasons (1990–1998 inclusive). The three trellis systems comprised (1) a 0.3 m narrow T‐trellis (NT), (2) a 1.2 m wide T‐trellis (WT), both with a 3.3m row spacing and a height of 1.2 m, and (3) a high (1.8 m) hanging cane (HC) system based on bi‐lateral cordons with a 2.2 m row spacing. Vine spacing within rows was 2.4 m irrespective of row width. A trellis drying treatment was compared with hand harvest during 1991–1995. Over the nine seasons, individual WT vines sustained highest yields of fresh grapes (23.7 kg/vine.season) compared to either NT (20.9 kg/vine) or HC vines (20.8 kg/vine) respectively (P < 0.001). However, HC vines expressed a considerable production advantage on a per hectare basis, viz. 41.3 t/ha, due to closer row spacing. Corresponding vineyard productivity for NT and WT vines was 26.4 and 29.9 t/ha respectively. Both WT and HC vines showed significantly higher bunch and shoot numbers than the NT treatment (P < 0.05 and P < 0.001, respectively). Nevertheless, trellis treatment had no effect on fruitfulness, berry weight, bunch weight, total soluble solids or titratable acidity. Taken overall, vines grafted to Ramsey rootstock had higher mean yields than vines on their own roots (i.e. 23.6 and 20.1 kg /vine, respectively P < 0.001) due to more berries per bunch and larger berries, despite having significantly fewer shoots and bunches. There was no long term evidence for incompatibility of Sunmuscat grafted to Ramsey rootstock. Compared to hand harvest of fresh grapes, trellis drying had no effect on yield, shoot and bunch numbers. Development of significantly smaller berries with trellis drying was offset by higher levels of total soluble solids. Sunmuscat is clearly a highly productive variety and is suited to canopy management on tall, cordon‐based hanging cane systems which are also amenable to trellis drying.     

Malting revisited: Germination of barley (Hordeum vulgare L.) is inhibited by both oxygen deficiency and high carbon dioxide concentrations

During malting, barley (Hordeum vulgare L.) seeds are germinated to promote the mobilisation of storage compounds. Germination is strongly influenced by O₂ and CO₂; however, any distinction between the particular effects is missing. Since, in this study, the ambient O₂ concentration was maintained when high CO₂ concentrations were applied, for the first time the impacts of CO₂ and of O₂ deficiency could be distinguished unambiguously.Germination was inhibited by both O₂ deficiency and high CO₂ (80%) concentrations, documented by the lack of any growth of coleoptiles and any increase of α-amylase and β-glucanase activity. In contrast, the related impacts of O₂ starvation and high CO₂ on fermentation differ strongly, demonstrated by quite different patterns of ethanol emission. Additionally, the stress metabolism - monitored by the means of GABA accumulation - was also differently impacted. The elucidation of the underlying, so far unknown, mechanisms will provide novel opportunities to improve malting.     

Optimization of bioactive compounds extraction from jabuticaba (Myrciaria cauliflora) skins assisted by high pressure CO2

Important bioactive compounds from Brazilian jabuticaba skins were effectively extracted by High Pressure Carbon Dioxide Assisted Extraction (HPCDAE). Statistical design was used to optimize the extraction variables: extraction pressure (65–135 bar), temperature (40–80 °C) and volume ratio of solid–liquid mixture/pressurized CO₂ (RS‐L/CO₂(%) (20–80%). The analysis performed to predict the optimum values for the extraction variables, in order to obtain the condition that result in an extract with high anthocyanin (2.2 ± 0.3 mg cyanidin-3-glucoside/g dry skins) and phenolic compound contents (13 ± 1 mg gallic acid equivalents/g dry skins), gave as best conditions, 117 bar extraction pressure, 80 °C extraction temperature and 20% volume ratio of solid–liquid mixture/pressurized CO₂ (RS‐L/CO₂(%)). Compared to Pressurized Liquid Extraction (PLE) and to control experiment the experimental results obtained using optimum HPCD Assisted-Extraction conditions were much more effective and faster in extracting total anthocyanins and phenolic compounds.Industrial relevance: Industrially, there is an increasing demand for faster extraction procedures with reduced organic solvent consumption to lower pollution burden. HPCD Assisted-Extraction combines the advantages of enhanced mass transfer rates increasing secondary metabolite diffusion from the vegetable matrix into the environmentally friendly solvent extraction. High pressure extraction methods, such as HPCD Assisted-Extraction, have other advantages that should be considered, such as the fact that native enzymes, which degrade phenolic compounds, are inhibited by extraction pressure increasing and CO₂ addition, and that processed vegetable materials do not require additional sterilization steps.