Effects of vine or bunch shading on the glycosylated flavor precursors in grapes of Vitis vinifera L. Cv. syrah

Effects of the modification of vine or bunch environment on glycoconjugates were studied in Syrah berries over two years. Vines were shaded from berry set to maturity, with black polyethylene nets of different mesh size to obtain 30 and 50% of the direct sunlight. Bunches were naturally shaded by the leaves or artificially with 90% shade bags. Sun-exposed berries were chosen as control berries. A quantitative decrease in levels of glycoconjugates was observed in shaded bunches, particularly for phenolic and C(13)-norisoprenoidic glycosides. In the same way, vine shading caused a decrease in the contents of glycosides of terpenols, phenols, and C(13)-norisoprenoids in berries, but the grape environment (microclimate) affected the berry composition more than the vine environment. A cluster thinning experiment confirmed the independence of grapes with regard to the plant for the biosynthesis of the C(13)-norisoprenoid glycosides.     

有限性灌溉对设施草莓产量及水分利用效率的影响

在日光温室环境及盆栽条件下,通过与全灌(FI)比较,研究了亏缺灌溉(DI)及分根交替灌溉(PRD)对草莓产量和灌水利用效率(IWUE)的影响.试验从开花期开始到果实成熟期结束.共分5个处理,全灌(FI);分根灌溉PRD分2个处理水平,即PRD1和PRD2;限制灌溉DI也分两个处理水平,即D11和D12.与F1处理相比,DI1和DI2处理的叶水势和气孔导度明显偏低,单株叶面积、鲜果重、平均单果重也显著低于FI处理.但水分利用效率却比FI处理的高(分别高15.8%和29.3%);PRD1处理的叶水势与FI处理的相当.且高于其它处理,而气孔导度比FI,DI1和D12处理的明显降低,与PRD2处理的相近.PRD1处理的鲜果重、平均单果重与FI处理的相当,比DI1,DI2和PRD2处理的显著提高;与FI处理相比,DI1,DI2,PRD1和PRD2处理分别节水31.5%,50.0%,31.5%和50.0%,水分利用效率分别提高了15.8%,29.3%,44.4%和84.4%,从草莓产量和水分利用效率各指标可以看出,PRD1处理比DI1,DI2和PRD2处理表现出明显的优势,其综合效益最佳.     

不同生育期调亏灌溉对酿酒葡萄耗水及果实品质的影响

不同程度的土壤干旱对酿酒葡萄的果实品质、产量和水分利用效率具有显著影响。明晰不同生育阶段干旱胁迫效应对酿酒葡萄土壤水分精准化管理和节水灌溉方案的制定具有重要的意义。本文于2014年在河西走廊中东部武威市凉州区清源镇威龙葡萄园产区开展了酿酒葡萄不同生育期、不同干旱胁迫程度的试验研究。在保持其他生育期土壤水分为正常灌溉(土壤水分阈值70%~75%)的情况下,在葡萄的萌芽期、抽蔓期、开花期、浆果膨大期和着色成熟期分别进行中度(土壤水分阈值60%~65%)和重度(土壤水分阈值50%~55%)的干旱处理,同时增设浆果膨大期的充分灌溉(土壤水分阈值80%~85%)处理,以全生育期的正常灌溉(土壤水分阈值70%~75%)作为对照,进行葡萄耗水特征和产量品质的测定。试验结果表明:不同处理土壤含水量垂直变化趋势一致,随土壤深度增加土壤含水量呈持续递增趋势;随着土壤深度递增,调亏灌溉对土壤含水量的影响越来越弱;40~60 cm土壤剖面,调亏处理含水量较对照减少幅度最大;浆果膨大期土壤剖面内含水量均低于其他生育期。不同处理酿酒葡萄耗水强度随时间变化趋势一致,萌芽期日耗水强度最小,为0.13~0.33 mm·d-1,而浆果膨大期耗水强度最大,为2.30~4.09 mm·d-1。萌芽期中度胁迫处理酿酒葡萄产量和水分利用效率最高,分别达到15 228 kg·hm-2和3.62 kg·m-3;浆果膨大期充分灌溉处理次之,而浆果膨大期重度胁迫处理最低,仅分别为7 128 kg·hm-2和2.26 kg·m-3。着色成熟期中度胁迫下,酿酒葡萄花青苷、还原糖、单宁、总酚含量比生育期正常供水处理高2.7%、6.56%、17.91%和23.23%,且有效抑制可滴定酸积累(P0.05),而其他处理与对照之间品质指标差异不显著。综合考虑产量、水分生产效率及果实品质等指标,最佳酿酒葡萄水分调控处理为着色成熟期中度胁迫,即着色成熟期土壤相对含水率为60%~65%、其余生育期土壤相对含水率为70%~75%。由此可见,在酿酒葡萄栽培时适时、适度的调亏灌溉既能显著提高水分生产效率,实现节水、高效用水的目的,又能提高果实品质,对河西走廊地区酿酒葡萄种植具有重要的意义。     

不同滴灌水量对干旱荒漠区酿酒葡萄光合及产量的影响

在甘肃河西走廊干旱荒漠区研究了覆膜与不覆膜条件下不同滴灌水量对酿酒葡萄生长、光合特征及产量的影响。结果表明: 在不同滴灌水量下, 葡萄新梢长、二次新梢长和主蔓基部直径均随滴灌水量的增加而增大, 且覆膜处理下, 滴灌水量低于不覆膜处理时, 上述3项指标等于或略大于不覆膜处理, 说明覆膜有利于葡萄生长。不同滴灌水量下, 葡萄净光合速率和蒸腾速率、气孔导度的日变化规律相近, 均总体呈下降趋势, 而胞间CO₂浓度呈降低?升高趋势; 滴灌水量为240 mm和300 mm覆膜处理(T1和T2)的光合指标值低于灌水量为360 mm和420 mm的覆膜处理(T3和T4)和滴灌水量为360 mm的不覆膜CK处理。T1处理的水分利用效率高于T2、T3、T4和CK处理。回归分析表明, 不同滴灌水量下, 葡萄的胞间CO₂浓度与土壤水分相关性最高, 气孔导度次之, 净光合速率和蒸腾速率较低。对不同处理下葡萄产量和品质的研究结果表明, 覆膜各处理的葡萄产量高于不覆膜的CK处理, 且含糖量以不覆膜的CK处理最高, 灌水量最低(240 mm)的覆膜T1处理次之。T1处理是实现葡萄高品质、产量和水分利用效率的最优组合。     

施用有机肥对葡萄植株Hg富集的影响

【目的】以葡萄果树为研究对象,研究了不同剂量Hg胁迫下施用羊粪有机肥对不同生长期葡萄植株各部位Hg富集的影响,为利用有机肥控制葡萄Hg污染提供科学依据。【方法】采用盆栽试验,每个盆钵装过5 mm筛的风干土15 kg,土壤汞含量设置0、 1.5、 25 mg/kg 3个处理水平,以HgCl2固体粉末形式施入土壤,每个水平分别设置施用有机肥和不施用有机肥两种情况。供试有机肥为羊粪,并按12.5%施入土壤,混匀后放置平衡15 d,于4月8日定植葡萄苗,每盆移栽健壮无病、 生长状况基本一致的植株1株,每个处理重复6次。【结果】不管施用有机肥与否,葡萄花瓣、 果实、 枝条和叶片中的汞含量均随土壤Hg含量的增加而明显增加,而葡萄不同部位中Hg的富集系数却呈现出显著降低的趋势,且在各部位的大小顺序为叶片花枝条果实。葡萄叶片和枝条Hg含量及其富集系数基本上表现出了幼果期最高,成熟期最低的生长期富集特征。与未施有机肥处理相比,低Hg处理施用有机肥后使开花期葡萄枝条汞含量降低了69.16%; 高Hg处理施肥后使开花期、 幼果期和成熟期葡萄枝条汞含量分别降低了50.52%、 58.33%和48.35%,并使三个时期叶片汞含量的降低幅度比低Hg处理分别高出了26%、 29.70%和37%。在土壤Hg污染下,施用有机肥的葡萄各器官汞含量均低于未施肥处理,且高Hg处理下的Hg含量降低幅度大多高于低Hg处理。不管低Hg或高Hg处理,施肥使叶片汞含量在幼果期和成熟期降低均最突出,而低Hg处理施肥使枝条汞含量在开花期降幅最高,高Hg处理在幼果期降幅最高。【结论】施用有机肥后,葡萄花、 叶片、 枝条和果实受Hg污染胁迫的影响明显减轻,尤其土壤Hg含量越高,有机肥的这种抑制作用越明显。     

Mineral Nutrition Of ‘Petopride’ Processing Tomato Under Partial Rootzone Drying

Information is scant on the mineral nutrition of plants undergoing partial rootzone drying (PRD). Researchers applied PRD to ‘Petopride’ tomato in a glasshouse by alternating irrigation to one side of the plant with half of the water in control (C). Roots in PRD treatment had higher magnesium (Mg) and copper (Cu) than C roots. Leaves in PRD treatment had lower P and higher K than C leaves. Minerals in leaves of C and PRD were within literature reported sufficiency ranges. Fruit of the PRD treatment had higher nitrogen (N) and zinc (Zn), but lower phosphorus (P), calcium (Ca), manganese (Mn) and boron (B) than C fruit. Mineral nutrition of fruit was most affected by PRD compared to that of leaf and root. Fruit of the PRD treatment had a higher incidence of blossom end rot (BER) than C fruit. Incidence of BER notwithstanding, although PRD affected the mineral nutrition of the tomato plant, there was no evidence that the lower yield in PRD was due to poor mineral nutrition.     

Effects of cluster light exposure on 3-isobutyl-2-methoxypyrazine accumulation and degradation patterns in red wine grapes ( Vitis vinifera L. Cv. Cabernet Franc)

The effects of light exposure on 3-isobutyl-2-methoxypyrazine (IBMP) accumulation and degradation in Vitis vinifera L. cv. Cabernet Franc berries were assessed by comparison of shaded and exposed clusters within the same vine throughout a growing season. Twenty-seven vines were shoot-thinned to create regions of high and low cluster-light exposure within each vine. Samples were collected at 10 time points starting from 5 to 130 days postbloom. The experimental design allowed for intravine comparison of IBMP levels between treatments at each time. Vine-to-vine variability of IBMP and the correlation of IBMP to malic acid were also evaluated. Cluster exposure reduced accumulation of IBMP at all preveraison time points by 21-44%, but did not increase postveraison degradation. Significant vine-to-vine variability in IBMP content was observed, with the highest level of IBMP in shaded berries in the most vigorous block of vines. Although IBMP concentration by weight decreased significantly due to dilution just prior to color change (veraison), no significant IBMP degradation per berry occurred until after color change (day 70 postbloom). By contrast, malic acid degradation began prior to color change, and malic acid concentrations were not affected by cluster exposure preveraison, but were affected postveraison. A survey of 13 sites in New York state (Seneca Lake) showed that IBMP concentrations at 2 weeks preveraison were highly correlated (R(2) = 0.936, p < 0.0001) to levels at harvest, whereas classic grape maturity indices at harvest were uncorrelated with IBMP at harvest. In summary, light exposure conditions critically influence IBMP accumulation but not IBMP degradation.     

SUSCEPTIBILITY OF THOMPSON SEEDLESS GRAPEVINES RAISED ON DIFFERENT ROOTSTOCKS TO LEAF BLACKENING AND NECROSIS UNDER SALINE IRRIGATION

Saline irrigation water having high sodium (Na⁺) content leads to the development of black leaf disorder in the vines resulting in reduced productivity and death of permanent vine parts. The response of the vines raised on different rootstocks differs under such conditions. Investigation was carried out to study the susceptibility of grafted and own-rooted Thompson Seedless (Vitis vinifera L.) vines to black leaf disorder. Grapevines grafted on four different rootstocks viz. Dog Ridge (Vitis champini), Salt Creek (Vitis champini), B2-56 (Vitis berlandieri x Vitis rupestris) and 1613C [Vitis longii x (Vitis labrusca x Vitis riparia) x Vitis vinifera] were studied. The variations in nutrient content of various vine parts under saline irrigation in relation to leaf blackening and necrosis symptoms were also studied. Thompson Seedless vines grafted on Dog Ridge, Salt Creek and own rooted vines started developing leaf blackening and necrosis symptoms during the ripening stage. Vines exhibiting these symptoms contained significantly lower potassium (K⁺) and higher Na⁺ content in the leaf blades as compared to healthy vines. Vines grafted on Salt Creek showed most severe leaf blackening and necrosis symptoms and had the lowest K⁺ content in blades and petioles. Amongst the rootstocks, vines raised on B2-56 had the lowest Na⁺ concentration in leaf blades whereas those on Dog Ridge and Salt Creek accumulated Na⁺ in leaf blades to a toxic level. Significantly higher K⁺ content was found in vines raised on B2-56 and 1613C rootstocks in all the vine parts compared to other stock-scion combinations. Vines grafted on B2-56 and 1613C could maintain higher K⁺: Na⁺ ratio and tolerated saline irrigation better than other stock-scion combinations. All the rootstocks reduced chloride concentration significantly in the vine parts (petioles, blade and canes) compared to own rooted vines. Vines raised on their own roots and on B2-56 rootstock had significantly higher phosphorus (P) concentration in petiole, blade and canes compared to vines grafted on Dog Ridge and Salt Creek. Total biomass (petiole + blade + cane on dry weight basis) and yield was the highest in B2-56 rootstock and least in 1613C.     

Response of orange trees to deficit irrigation strategies in the north of Iran

This work examines the effects of two deficit irrigation strategies, conventional deficit irrigation (DI) and partial root-zone drying (PRD), on mature navel orange trees. The study carried out during two consecutive years (2008 and 2009) in a semi-arid climate on a silty–clay–loam soil in the north of Iran. Both DI and PRD trees were irrigated at two levels, 75 and 50% (DI75, PRD75, DI50 and PRD50) of the full irrigation (FI). In DI, irrigation water was applied to both sides of the tree rows, similar to FI. In PRD, irrigation water was applied alternately to only one side, at each irrigation event. Results showed that DI treatments reduced fruit yield by ～30% compared with FI, but PRD treatments caused no reduction in fruit yield. No negative impact was detected in fruit quality after applying DI and PRD treatments. Shoot growth decreased in all DI and PRD treatments in both years. In DI, stomatal resistance was higher (50%) than in FI, but it was not significantly affected in PRD. The irrigation water use efficiency of PRD trees increased to nearly twice that of FI. According to these two years' results, we recommend PRD as an acceptable deficit irrigation strategy in the region.     

Carotenoid compounds in grapes and their relationship to plant water status

The aim of this work was to study the relationship between carotenoid contents in grapevine berries and plant water status. For this purpose, a black grapevine variety, Vitis vinifera L. cv. Touriga Nacional, was studied. The experiments were carried out in the same Douro vineyards, with plants of the same age, in two different water retention soils. A higher water retention capacity soil, soil A, and a lower water retention capacity soil, soil B, were both in a 1.2 m deep silt-loam schist-derived soil. The training system was the double cordon trained and spur pruned. A first range was nonirrigated (NI) and a second one was irrigated (I), 60% of evapotranspiration (ET(0)). For soil B, a 30% of ET(0) treatment was also applied. The plant water status was estimated by predawn leaf water potential. The effects of plant water status on berry growth were studied by measurement of the berry weight and total soluble solids (degrees Brix). The carotenoid profile was quantitatively determined by high-performance liquid chromatography/diode array. Carotenoids determined were beta-carotene, lutein, neoxanthin, violaxanthin, and luteoxanthin. The comparison between irrigated and nonirrigated grapes was followed from 2 weeks before veraison until the ripe stage. Results showed that at harvest time, berries exposed to the NI had a lower weight than those exposed to the irrigated treatment (60% of ET(0)), 0.89 vs 1.36 g/berry and 0.94 vs 1.34 g/berry, for soils A and B, respectively. The irrigated treatment contributed to a higher sugar concentration in both soils. However, depending on the soil water retention capacity, the carotenoid contents were different in soils A and B. For soil A, the total carotenoid content was similar for both NI and I treatments. However, with regard to soil B, in irrigated treatment, levels of carotenoids were approximately 60% lower than those found for the NI. It seems to be possible to produce higher weight berries (with higher sugar levels) with similar carotenoid contents. On the other hand, soil characteristics had a larger influence than irrigation on the concentration of carotenoids in grapes, resulting in an important viticultural parameter to take into account in aroma precursor formation.     

利用钾吸收基因表达评价葡萄叶面喷施钾肥效果和喷施浓度

【目的】叶面喷施钾肥可以快速、 高效地为葡萄补充钾营养,促进葡萄的高产和优质,已经被广泛应用于葡萄生产中。本实验通过对葡萄叶面喷施不同种类及浓度钾肥,测定葡萄叶片和果实等生理指标变化,以及钾吸收相关基因的表达变化,从生理和基因水平上评价这些钾肥的喷施效果,为葡萄生产中钾肥的施用提供一定指导。【方法】本实验以‘夏黑’葡萄为试材,选择两个葡萄生长关键时期盛花期和果实膨大期分别对葡萄叶片喷施0.2%、 0.5%和0.8%三种浓度的K2SO4、 K2CO3、 K2SO4·2MgSO4和KCl。然后对葡萄叶片和新梢的生长率,坐果率,叶绿素含量,单粒重,可溶性固形物等生理指标进行统计分析,并利用荧光定量PCR技术分析4个钾吸收相关基因VvHAK13、 VvKEA2、 VvSIRK和VvSORK的表达情况。【结果】叶面喷施4种钾肥后,葡萄叶片和新梢的生长率,坐果率,叶绿素含量,单粒重,可溶性固形物等各项生理指标均有不同程度的提升。钾肥种类不同,最适喷施浓度不同,同种钾肥在葡萄盛花期和果实膨大期的最适喷施浓度也有所不同,四种钾肥在果实膨大期的最适喷施浓度普遍高于盛花期。四个钾吸收相关基因在喷施不同种类及浓度钾肥后也表现出不同的表达模式,总体来讲VvKEA2、 VvSIRK 、 VvSORK的表达上调,而VvHAK13的表达下调。果实膨大期,需喷施较高浓度的钾肥,钾吸收相关基因才表现出较强烈的响应,而在盛花期则只需喷施较低浓度的钾肥。综合生理指标和基因表达两方面结果,得出4种钾肥效果依次为K2SO4·2MgSO4＞K2SO4＞K2CO3＞KCl。盛花期K2SO4和K2CO3的最适喷施浓度为0.5%,K2SO4·2MgSO4和KCl的最适喷施浓度为0.2%; 果实膨大期K2SO4、 K2SO4·2MgSO4和KCl的最适喷施浓度为0.5%,K2CO3的最适喷施浓度为0.8%。【结论】葡萄叶面喷施钾肥可以有效促进葡萄叶片和果实的生长发育,四种钾肥的效果依此为: K2SO4·2MgSO4＞K2SO4＞K2CO3＞KCl。盛花期K2SO4和K2CO3的最适喷施浓度为0.5%,K2SO4·2MgSO4和KCl的最适喷施浓度为0.2%; 果实膨大期K2SO4、 K2SO4·2MgSO4和KCl的最适喷施浓度为0.5%,K2CO3的最适喷施浓度为0.8%。适宜的喷施浓度可以有效提高钾吸收相关基因的表达,是其提高钾吸收利用的机理之一。     

Effects of ozone and oxygen on the degradation of carotenoids in an aqueous model system

The effects of ozone and oxygen on the degradation of carotenoids in an aqueous model system were studied. All-trans beta-carotene, 9-cis beta-carotene, beta-cryptoxanthin, and lycopene were adsorbed onto a C(18) solid phase and exposed to a continuous flow of water saturated with oxygen or ozone at 30 degrees C. Carotenoids were analyzed using HPLC with a C(30) column and a photodiode array detector. Approximately 90% of all-trans beta-carotene, 9-cis beta-carotene, and beta-cryptoxanthin were lost after exposure to ozone for 7 h. A similar loss of lycopene occurred in only 1 h. When exposed to oxygen, all carotenoids, except beta-cryptoxanthin, degraded at lower rates. The degradation of all the carotenoids followed zero-order reaction kinetics with the following relative rates: lycopene > beta-cryptoxanthin > all-trans beta-carotene > 9-cis beta-carotene. The major degradation products of beta-carotene were tentatively identified on the basis of their elution on the HPLC column, UV-Vis spectra, and electrospray LC-MS. Predominant isomers of beta-carotene were 13-cis, 9-cis, and a di-cis isomer. Products resulting from cleavage of the molecule were beta-apo-13-carotenone and beta-apo-14'-carotenal, whereas epoxidation yielded beta-carotene 5,8-epoxide and beta-carotene 5, 8-endoperoxide.     

Volatile compounds and sensory attributes of wine from Cv. Merlot (Vitis vinifera L.) grown under differential levels of water deficit with or without a kaolin-based, foliar reflectant particle film

The volatile composition and sensory attributes of Merlot wines produced from vines under differing levels of water stress, with or without a foliar, kaolin-based particle film, were analyzed by stir bar sorptive extraction-gas chromatography-mass spectrometry (SBSE-GC-MS) and sensory evaluation. Vines were irrigated over consecutive vintages with 100, 70, or 35% of their estimated water requirements (ET(c)), or 35% until color change then 70% until harvest (35-70% ET(c)). Neither of the treatments consistently influenced ester concentrations or their relative amounts, though their concentrations varied from year to year. However, deficit irrigation had an effect on the concentration of terpene alcohols and norisoprenoids. Wines produced from vines under water deficit contained higher amounts of citronellol, nerol, geraniol, and β-damascenone, but linalool and β-ionone were not affected by deficit irrigation. Particle film did not affect volatile composition in the wine. Untrained panelists in 2007 and 2008 distinguished between wines from vines that received 100 or 35% ET(c) and between wines from vines that received 35 or 35-70% ET(c). Trained sensory panelists detected differences among wines for aroma, flavor, taste, and mouthfeel; however, significant interactive effects between particle film application and vine water status hindered interpretation of independent main effects.     

局部根区交替灌溉与氮素耦合对葡萄生长及15N-尿素利用的影响

为探讨局部根区交替灌溉与不同氮水平的耦合效应,采用盆栽试验,以两年生巨峰葡萄幼树为试材,利用15 N标记示踪技术,设不同灌溉方式(传统双侧滴灌、固定根区滴灌、交替根区滴灌,分别记为CDI、FDI、ADI)和施氮水平(施氮量为0.4、0.8、1.2 g·kg-1 土,分别记为N1、N2、N3),研究局部根区交替灌溉与不同...     

Influence of vineyard location and vine water status on fruit maturation of nonirrigated cv. Agiorgitiko (Vitis vinifera L.). Effects on wine phenolic and aroma components

The influence of site on grape and wine composition was investigated for Vitis vinifera L. cv. Agiorgitiko in the Nemea appellation area in southern Greece. Three nonirrigated plots were studied during the 1997 and 1998 vintages, which were typically very hot and without summer rainfall. Vines were subjected to different water regimens as a result of the variation of soil water-holding capacity and evaporative demand. Vine water status was determined by means of predawn leaf water potential. Differences in vine water status between sites were highly correlated with the earliness of shoot growth cessation and veraison. Grape composition was monitored during fruit ripening. Water deficit accelerated sugar accumulation and malic acid breakdown in the juice. Early water deficit during the growth period was demonstrated to have beneficial effects on the concentration of anthocyanins and total phenolics in berry skins. A similar pattern was observed for the phenolic content of wines elaborated after vinification of grapes harvested on each plot, in both seasons. Limited water availability seemed to increase glycoconjugates of the main aromatic components of grapes as a quantitative increase in levels of bound volatile compounds of the experimental wines was observed under water deficit in both years. Wines produced from grapes of stressed vineyards were also preferred in tasting trials.     

Nutrient status of apple leaves not affected by three years of irrigation using partial rootzone drying

Partial rootzone drying (PRD) is a water‐saving irrigation technology that may affect apple (Malus domestica Borkh cv. Golden Delicious/Malling7)‐tree nutrition if applied for an extended period. The objective of this study was to test the hypothesis that long‐term application of PRD causes seasonal changes in macro‐ and micronutrients of apple leaves. The irrigation treatments were: (1) commercial irrigation as control (CI) and (2) PRD. After 3 years of evaluation, PRD irrigation had saved about 3240 m³ of water per hectare. Leaf xylem water potential was slightly lower in the PRD treatment than in CI. The seasonal concentration of macro‐ and micronutrients was comparable between treatments, although significant differences were found at times. The macronutrient concentrations were within the normal range in PRD apple leaves. All micronutrient concentrations were slightly above the normal range except for Zn, which was slightly below the normal range. No physiological disorders associated with plant nutrition were observed on leaves or fruits. Therefore, data suggest that PRD did not alter apple‐tree nutrition during the 3‐year trial. Thus, PRD may be feasible for apple production in Central Mexico. However, further studies need to be conducted in those regions where groundwater is the main water source for irrigation and rain is negligible, particularly during the growing season.     

Volatile compounds released by enzymatic hydrolysis of glycoconjugates of leaves and grape berries from Vitis vinifera Muscat of Alexandria and Shiraz cultivars.

Glycoconjugates from Muscat of Alexandria and Shiraz leaves and grape berries were isolated by adsorption on Amberlite XAD-2 resin, and enzymatically released aglycons were analyzed by GC-FID and GC-MS. About 120 aglycons were fully or tentatively identified. Compositional differences were observed between leaves and berries of the two varieties in five aglycon chemical groups: C6 alcohols, aliphatic alcohols, monoterpenes, shikimates, and C(13)-norisoprenoids, which were much more abundant in the leaves than in the berries. The differences observed for C(13)-norisoprenoids were in agreement with their hypothetical independent biosynthesis in leaves and berries. Thus, 3-hydroxy-beta-damascone, an important norisoprenoid aglycon of grape berries, was not detected in leaves, whereas its oxidized derivative, 3-oxo-alpha-damascone, was absent in berries. Compositional differences were also observed between Muscat and Shiraz leaves. 3-Oxo-alpha-ionol was not detected in Shiraz leaves, and its retro derivatives were less abundant than in Muscat of Alexandria leaves. Conversely, in Shiraz leaves the levels of 7,8-dihydroionone derivatives, such as megastigman-3,9-diol and 3-oxo-7,8-dihydro-alpha-ionol, were higher than in Muscat of Alexandria leaves.     

Salt in irrigation water affects the nutritional and visual properties of romaine lettuce (Lactuca sativa L.)

The influence of salinity stress on the growth, appearance, and nutritional compounds, especially phenolic compounds and carotenoids, of romaine lettuce (Lactuca sativa L.), a low salt tolerant plant, was studied. The dry weight, height, and color of the lettuce plants were significantly changed by long-term irrigation (15 days) with higher NaCl concentration (i.e., >100 mM). However, no significant differences were observed in the growth and appearance among the control, all short-term treatments (2 days; 50, 100, 500, and 1000 mM), and long-term irrigation with low salt concentration. Moreover, in romaine lettuce treated with long-term irrigation with 5 mM NaCl, the total carotenoid content increased without color change, and the contents of major carotenoids in romaine lettuce, lutein and beta-carotene, increased 37 and 80%, respectively. No differences were observed in lutein and beta-carotene contents in short-term-treated lettuce. The phenolic content of the romaine lettuce declined with short-term salt irrigation, whereas there were no significant differences among treatments exposed to long-term irrigation. This research indicates that long-term irrigation with relatively low salt concentration, rather than short-term irrigation with high salt concentration, can increase carotenoid content in romaine lettuce without causing a tradeoff in yield or visual quality.     

水肥耦合对极端干旱区滴灌葡萄耗水规律及作物系数影响

为探讨水肥耦合对极端干旱区滴灌葡萄耗水规律的影响,探明不同水肥组合下滴灌葡萄耗水在各生育期内分布规律,以及在整个生育期的动态变化规律,确定区域内滴灌葡萄作物系数,利用水量平衡法和彭曼—蒙特斯公式,以试验区内成龄无核白葡萄为研究对象开展大田小区试验,设置灌水、施肥2因素,其中设灌水处理4个水平(600,675,750,825 mm,分别标记为W1、W2、W3、W4);施肥处理3水平(450,750,1 050 kg/hm~2,分别标记为F1、F2、F3)。结果表明:全生育期平均土壤含水率随灌溉定额增大而增大,其中W3、W4处理含水率分别为13.35%和14.04%,均高于12.80%(田间持水率的80%),水分供应充足。水肥耦合对产量及品质指标的影响均达极显著水平(P0.01),产量、可溶性固形物在W3F2处理达最高值,可滴定酸和维生素C分别在W4F2和W4F3处理达到最优,但与W3F2处理均无显著性差异(P0.05)。不同水肥处理下,灌水对总耗水量和各生育期内耗水量、耗水强度影响显著(P0.05),施肥对总耗水量和各生育期内耗水量、耗水强度未达显著水平(P0.05),水肥耦合效应对各生育期内耗水强度影响显著(P0.05);不同水肥处理下葡萄全生育期总耗水量维持在665.96～902.90 mm;各处理耗水量、耗水强度随生育期的推进总体呈先增大再减小的趋势,且耗水强度和时间存在显著的二次曲线关系。各处理在浆果生长期和浆果成熟期耗水模数均值为27.01%～27.36%,为葡萄需水高峰期;其中W3F2处理下的耗水规律可视为区域内葡萄需水规律。葡萄作物系数随生育期的推进总体呈先增大再减小的趋势,与时间存在显著的二次曲线关系。研究可为吐哈盆地及类似地区无核白葡萄农田水肥管理与滴灌技术的推广提供科学依据,对区域水资源高效利用及实现区域内社会经济的可持续发展具有重要意义。