Shoot orientation affects vessel size, shoot hydraulic conductivity and shoot growth rate in Vitis vinifera L.

Vitis vinifera L. plants were grown in containers and each plant's single shoot was orientated upwards or downwards. Some plants were trained first upwards, then downwards, then again upwards (N-shaped plants). Vegetative growth was reduced in plants trained downwards compared to that in upward and N-shaped plants. Shoot growth rate slowed in downward shoot portions, but only after the apex had grown downwards for at least 10 internodes. Shoot hydraulic conductivity k _h, measured after elimination of xylem embolisms, was lower in downward than in upward plants. In N-shaped plants k _h was higher in the upward-growing shoot portions, and lower in the central, downward-growing portion. Shoot- and leaf-specific conductivities were also lower in downward than in upward shoot portions. Xylem cross-sectional area and xylem structure (number of wedges, number of vessels per unit xylem area) differed little in the three orientations. In contrast, vessel diameter and the sum of vessel cross-sectional areas were significantly smaller in downward than in upward shoot portions. These differences could explain the reduction in conductivity observed in the downward-orientated shoot portions. The measurements taken on N-shaped plants showed that the decreases in k _h and in vessel size were a result of shoot orientation, not shoot bending.     

ABA xylem concentrations determine maximum daily leaf conductance of field-grown Vitis vinifera L. plants

Differences in maximum leaf conductance in grapevine plants growing in soils with contrasting water availabilities during mid-summer in Portugal could be accounted for by differences in the concentration of ABA in xylem sap. This conclusion is reinforced by the observation that the relationship between leaf conductance and endogenous ABA concentration can be mimicked by the application of exogenous ABA to leaves detached from irrigated plants. During the day, leaf conductance decreased after a morning peak, even when the leaves remained in a constant environment at a moderate temperature and leaf-to-air vapour pressure difference. This decline in leaf conductance was not a consequence of an increase in the xylem ABA concentration or the rate of delivery of this compound by the transpiratory stream. The afternoon depression in leaf conductance was associated with an apparent limitation in stomatal opening potential, which persisted even when detached leaves were fed with water and rehydrated. The reason for this inhibition has still to be identified.     

Relationships between plant and soil water status in vine (Vitis vinifera L.)

Soil water status and its effect on plant water status are commonly evaluated for water stress diagnosis in annual crops. We investigated the application of this method to vineyards, using the fraction of transpirable soil water (FTSW) to characterise the soil water deficit experienced by the plant. The stability of the relationship between FTSW and predawn leaf water potential (Ψp) was analysed over two years (2000–2001), in two contrasted soils in vineyards in south eastern France, both planted with the cultivar Syrah, but grafted on different rootstocks (SO4 and 140Ru). FTSW was determined from soil moisture measurements performed with a neutron probe down to 2.5 m, under the rows and between the rows (3 replicates in each case). Vertical and horizontal variations in soil water content were analysed and the upper and lower limits of total vine’s transpirable soil water (TTSW) were calculated for each soil. The lower limit was also compared with the value of soil moisture content determined at −1.5 MPa in the laboratory. FTSW could be calculated for the soil depth analysed, without distinguishing horizontal position (row or inter-row). The lower limit of TTSW for vine was higher than the soil water content at −1.5 MPa, except in the upper horizons (0–0.2 m) which are prone to soil evaporation. A single relationship between Ψp and FTSW was obtained for the two vineyards and for the two years of measurement. This relationship was similar to that established by Lebon et al. (2003) on Gewürztraminer/SO4 in a vineyard in northern France. FTSW can therefore be used as an indicator of the water deficit experienced in vineyards, provided that TTSW is correctly estimated.     

Morphogenetic Effects of Roots and of Some Synthetic Cytokinins in Vitis vinifera L.

In woody cuttings of the grape vine, inflorescences of fertilebuds usually fail to develop and atrophy soon after bud burst.Results presented here indicate that this effect is relatedto absence of roots at planting. Inflorescences were retainedin pre-rooted cuttings which were propagated by holding thetemperature of the medium at 25° C and the air temperatureat 4° C. Similar effects on inflorescence growth were obtainedby applying synthetic cytokinins to the bases of unrooted cuttingsin solution cultures, and by applications to emergent inflorescences.Promotion of inflorescence growth was found with 6-benzyl-aminopurine(BAP) and 6-(benzylamino)-9-(2-tetrahydropyranyl)-9H purine(‘SD 8₃₃₉’). Stimulation of inflorescence growthby BAP was accompanied by reduction in vegetative growth, andby development of red pigments in inflorescences and leaves.Results of cincturing experiments indicate that BAP is transportedacropetally in the xylem of vines. Effects of roots, and effectsof synthetic cytokinins, are discussed in relation to recentdiscoveries of endogenous cytokinins in the ascending sap ofvines.     

Molecular linkage maps of Vitis vinifera L. and Vitis riparia Mchx

Two linkage maps for grape (Vitis spp.) have been developed based on 81 F(1) plants derived from an interspecific cross between the wine cultivar Moscato bianco (Vitis vinifera L.) and a Vitis riparia Mchx. accession, a donor of pathogen resistance traits. The double pseudotest-cross mapping strategy was applied using three types of molecular markers. The efficiency of SSRs to anchor homologous linkage groups from different Vitis maps and the usefulness of AFLPs in saturating molecular linkage maps were evaluated. Moreover, the SSCP technique was developed based on sequence information in public databases concerning genes involved in flavonoid and stilbene biosynthesis. For the maternal genetic map a total of 338 markers were assembled in 20 linkage groups covering 1,639 cM, whereas 429 loci defined the 19 linkage groups of the paternal map which covers 1,518 cM. The identification of 14 linkage groups common to both maps was possible based on 21 SSR and 19 AFLP loci. The position of SSR loci in the maps presented here was consistent with other published mapping experiments in Vitis.     

Immunocharacterization of NADH-Glutamate Dehydrogenase from Vitis vinifera L

Rabbit antiserum was raised against NADH-glutamate dehydrogenase (GDH) isoenzyme 1, purified from leaves of Vitis vinifera L. cv Soultanina and its specificity was tested. This antiserum was used for immunocharacterization of the GDH from leaf, shoot, and root tissues. The antiserum recognized the seven isoenzymes of NADH-GDH and precipitated all the enzyme activity from the three tissues tested. Western blot following SDS-PAGE revealed the same protein band for the three tissues, with a molecular mass of 42.5 kilodaltons corresponding to NADH-GDH subunit. Results, based on the immunological studies, revealed that NADH-GDH from leaf, shoot, and root tissues are closely related proteins. Furthermore, addition of ammonium ions to the culture medium of in vitro grown explants resulted in a significant increase in NADH-GDH activity in root, shoot, and leaf tissues.     

Effects of water stress on phosphorus transport to the xylem

Summary Tomato plants were treated for one hour in nutrient solutions at-10.4 atm. Roots were excised, transferred to solutions at-0.4 atm and put into a pressure chamber to induce rates of water flow similar to those in transpiring plants.For roots continuously at-0.4 atm, the xylem sap had much higher phosphorus concentrations than the external solution, which contained 6 p.p.m. phosphorus.Roots previously treated at-10.4 atm had much lower concentrations in the sylem sap than in the external solution and the amount of phosphorus transported and the water flow were linearly related. This phosphorus transport was due to passive movement as shown by measuring transport of both ³²P and ¹⁴C mannitol. Thus transport to the xylem mediated by active processes was abolished even though uptake by the roots remained substantial. These results obtained after plasmolysis support the view that radial transport to the xylem includes uptake into and movement through the symplast.     

Linkage disequilibrium in cultivated grapevine, Vitis vinifera L

We present here the first study of linkage disequilibrium (LD) in cultivated grapevine, Vitis vinifera L. subsp. vinifera (sativa), an outcrossing highly heterozygous perennial species. Our goal was to characterize the amount and pattern of LD at the scale of a few centiMorgans (cM) between 38 microsatellite loci located on five linkage groups, in order to assess its origin and potential applications. We used a core collection of 141 cultivars representing the diversity of the cultivated compartment. LD was evaluated with both independence tests and multilocus r ² , both on raw genotypic and reconstructed haplotypic data. Significant genotypic LD was found only within linkage groups, extending up to 16.8 cM. It appeared not to be influenced by the weak structure of the sample and seemed to be mainly of haplotypic origin. Significant haplotypic LD was found over 30 cM. Both genotypic and haplotypic r ² values declined to around 0.1 within 5–10 cM, suggesting a rather narrow genetic base of the cultivated compartment and limited recombination since domestication events. These first results open up a few application opportunities for association mapping of QTLs and marker assisted selection. Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.     

Proteomic analysis of grapevine (Vitis vinifera L.) tissues subjected to herbicide stress

Two-dimensional gel electrophoresis coupled to mass spectrometry analysis was used to examine for the first time the effect of a herbicide (flumioxazin) on a crop species (Vitis vinifera L.) at the proteome level. Examination of 2-D maps derived from chemically stressed tissues revealed the presence of 33 spots displaying a differential expression pattern. The presence of stress responsive proteins in the different plant organs analysed suggests that flumioxazin could act systemically. Among the responsive proteins, some photosynthesis-related proteins, including several fragments of the enzyme Rubisco, were identified. This effect suggests that photosynthesis could be impaired by the herbicide. The induction of several enzymatic antioxidant systems was also observed, probably as a result of an oxidative stress. Moreover, the photorespiration pathway was stimulated, as suggested by the induction of some key enzymes involved in this process. Changes in carbon metabolism-associated proteins presumably reflect altered patterns of carbon flux in response to impaired photosynthesis and an increased need for osmotic adjustment in affected tissues. Finally, plant defences were stimulated as revealed by the induction of a set of proteins belonging to the pathogenesis-related 10 class, suggesting that they could play an essential role in cell defence mechanisms against flumioxazin.     

Sugars and flowering in the grapevine (Vitis vinifera L.)

Sugars play an important role in grapevine flowering. This complex process from inflorescence initiation to fruit maturity takes two growing seasons. Currently, most of the available data concern the involvement of sugars as energy sources during the formation of reproductive structures from initiation of inflorescences during the summer of the first year, until flower opening during the following spring. Sugars devoted to the development of reproductive structures are supplied either by wood reserves or by photosynthesis in leaves or inflorescences, depending on the stage of development. Female meiosis appears to be a key point in the success of flower formation because (i) flowers are vulnerable at this stage and (ii) it corresponds in the whole plant to the transition between reserve mobilization from perennial organs (roots, trunk, and canes) towards efficient leaf photosynthesis. The perturbation of reserve replenishment during the previous year provokes perturbation in the development of inflorescences, whereas altering the photosynthetic sources affects the formation of flowers during the same year. In particular, a lack of sugar availability in flowers at female meiosis caused by various environmental or physiological fluctuations may lead to drastic flower abortion. Apart from energy, sugars also play roles as regulators of gene expression and as signal molecules that may be involved in stress responses. In the future, these two topics should be further investigated in the grapevine considering the sensitivity of flowers to environmental stresses at meiosis.     

Distribution of xylem hydraulic resistance in fruiting truss of tomato influenced by water stress

In this study xylem hydraulic resistances of peduncles (truss stalk), pedicels (fruit stalk) and the future abscission zone (AZ) halfway along the pedicel of tomato (Lycopersicon esculentum L.) plants were directly measured at different stages of fruit development, in plants grown under two levels of water availability in the root environment. The xylem hydraulic connection between shoot and fruits has previously been investigated, but contradictory conclusions were drawn about the presence of a flow resistance barrier in the pedicel. These conclusions were all based on indirect functional measurements and anatomical observations of water-conducting tissue in the pedicel. In the present study, by far the largest resistances were measured in the AZ where most individual vessels ended. Plants grown at low water availability in the root environment had xylem with higher hydraulic resistances in the peduncle and pedicel segments on both sides of the AZ, while the largest increase in hydraulic resistance was measured in the AZ. During fruit development hydraulic resistances in peduncle and pedicel segments decreased on both sides of the AZ, but tended to increase in the AZ. The overall xylem hydraulic resistance between the shoot and fruit tended to increase with fruit development because of the dominating role of the hydraulic resistance in the AZ. It is discussed whether the xylem hydraulic resistance in the AZ of tomato pedicels in response to water stress and during fruit development contributes to the hydraulic isolation of fruits from diurnal cycles of water stress in the shoot.     

Mechanism of Arginine Transport in Vitis vinifera L. Protoplasts

Protoplasts were isolated from leaves of in vitro grown axenicshoots of grapevine (Vitis vinifera L. cv. Soultanina) and usedto study the characteristics of arginine transport. Uptake waslinear up to at least 60 min and the rate did not differ significantlybetween light and dark assaying conditions whereas incubationin darkness for 24 h caused a 70% reduction in uptake rate,which was probably not due to an energy dependent factor. Kineticsanalysis revealed a biphasic uptake curve. The high affinitycomponent had a K_m, of 2.2 mol m^–3. Optimum pH value was5.5. Two carrier systems, one for basic and neutral and onefor acidic amino acids were identified. Use of inhibitors revealedthat those associated with ATP metabolism inhibited arginineuptake; more specifically, the proton motive force appearedto be the predominant energy source. Metabolic products of labelledarginine were consistent with the operation of the Krebs-Henseleitcycle. Key words: Grapevine protoplast, grapevine tissue culture, arginine transport     

Impact of flumioxazin herbicide on growth and carbohydrate physiology in Vitis vinifera L

The impact of flumioxazin herbicide on in vitro-grown grapevine ( Vitis vinifera L. cv. Chardonnay) was investigated. The herbicide treatments (1, 10 or 100 micro M flumioxazin in MM medium) had a negative impact on photosynthesis, as revealed by a reduction in foliar chlorophyll and carotenoid contents, gas exchanges and alteration in plastid structure and, consequently, resulted in a strong inhibition of plantlet growth. Surprisingly, soluble sugars and starch accumulated in all organs, suggesting a stimulation of sugar uptake from the medium. Moreover, photosynthetic activity and starch content partially recovered within 3 weeks of treatment at the weakest herbicide concentration. These results provide new insights into the physiological responses of non-target crops to flumioxazin, showing that flumioxazin is active in photosynthetic tissues of the non-target grapevine via root uptake, which is contrary to what is mentioned in the literature, and that the in vitro-grown plantlet is a good model for investigating the physiological effects of pesticides on crop species.     

Genetic structure and differentiation in cultivated grape,Vitis vinifera L

222 cultivated (Vitis vinifera) and 22 wild (V. vinifera ssp. sylvestris) grape accessions were analysed for genetic diversity and differentiation at eight microsatellite loci. A total of 94 alleles were detected, with extensive polymorphism among the accessions. Multivariate relationships among accessions revealed 16 genetic groups structured into three clusters, supporting the classical eco-geographic grouping of grape cultivars: occidentalis, pontica and orientalis. French cultivars appeared to be distinct and showed close affinity to the wild progenitor, ssp. sylvestris from south-western France (Pyrenees) and Tunisia, probably reflecting the origin and domestication history of many of the old wine cultivars from France. There was appreciable level of differentiation between table and wine grape cultivars, and the Muscat types were somewhat distinct within the wine grapes. Contingency chi2 analysis indicated significant heterogeneity in allele frequencies among groups at all loci. The observed heterozygosities for different groups ranged from 0.625 to 0.9 with an overall average of 0.771. Genetic relationships among groups suggested hierarchical differentiation within cultivated grape. The gene diversity analysis indicated narrow divergence among groups and that most variation was found within groups (approximately 85%). Partitioning of diversity suggested that the remaining variation is somewhat structured hierarchically at different levels of differentiation. The overall organization of genetic diversity suggests that the germplasm of cultivated grape represents a single complex gene pool and that its structure is determined by strong artificial selection and a vegetative mode of reproduction.     

Differences in hydraulic architecture account for near-isohydric and anisohydric behaviour of two field-grown Vitis vinifera L. cultivars during drought

A comparative study on stomatal control under water deficit was conducted on grapevines of the cultivars Grenache, of Mediterranean origin, and Syrah of mesic origin, grown near Montpellier, France and Geisenheim, Germany. Syrah maintained similar maximum stomatal conductance (g_max) and maximum leaf photosynthesis (A_max) values than Grenache at lower predawn leaf water potentials, Ψ_leaf, throughout the season. The Ψ_leaf of Syrah decreased strongly during the day and was lower in stressed than in watered plants, showing anisohydric stomatal behaviour. In contrast, Grenache showed isohydric stomatal behaviour in which Ψ_leaf did not drop significantly below the minimum Ψ_leaf of watered plants. When g was plotted versus leaf specific hydraulic conductance, K_l, incorporating leaf transpiration rate and whole‐plant water potential gradients, previous differences between varieties disappeared both on a seasonal and diurnal scale. This suggested that isohydric and anisohydric behaviour could be regulated by hydraulic conductance. Pressure‐flow measurements on excised organs from plants not previously stressed revealed that Grenache had a two‐ to three‐fold larger hydraulic conductance per unit path length (K_h) and a four‐ to six‐fold larger leaf area specific conductivity (LSC) in leaf petioles than Syrah. Differences between internodes were only apparent for LSC and were much smaller. Cavitation detected as ultrasound acoustic emissions on air‐dried shoots showed higher rates for Grenache than Syrah during the early phases of the dry‐down. It is hypothesized that the differences in water‐conducting capacity of stems and especially petioles may be at the origin of the near‐isohydric and anisohydric behaviour of g.     

Restriction fragment length polymorphism and molecular taxonomy in Vitis vinifera L.

Forty-six accessions of grapevine (V. vinifera L.) were compared by restriction fragment length polmorphism (RFLP) analysis, and 111 informative or unique restriction fragments were found that revealed an important level of polymorphism. RFLP patterns were compared in two ways: by calculating electrophoretic similarity degree values further analyzed by principal component analysis and by studying the distribution of rare restriction fragments. Six taxonomic groups could be defined, which partially confirmed relationships derived from ampelographical data. Our data support the existence of ecogeographical groups.     

The peripheral xylem of grapevine (Vitis vinifera) berries. 2. Anatomy and development

It has been hypothesized that the substantial reductions in xylemic water flow occurring at veraison are due to physical disruption (breaking) of the xylem as a result of renewed berry growth. In a companion paper, evidence was presented that the vast majority of xylem tracheary elements remained intact despite the growth of the berry, and it was proposed that existing tracheary elements stretch to accommodate growth and that additional elements may also differentiate after veraison. Measurements of the intergyre distance of tracheary elements in macerated tissue were used to test for stretching, and the numbers of tracheary elements per vascular bundle and of branch points of the peripheral xylem network were analysed to test for continued differentiation from 18 to 120 d after anthesis in Chardonnay berries. The distance between the epidermis and the vasculature increased substantially from pre- to post-veraison, potentially increasing the amount of skin available for analysis of compounds important for winemaking. Tracheary elements continued to differentiate within the existing vascular bundles throughout berry development. Additional vascular bundles also appeared until after veraison, thereby increasing the complexity of the peripheral vascular network. The results also confirmed that tracheary elements stretched by approximately 20%, but this was not as much as that predicted based on the growth of the vascular diameter (40%). These results complete a comprehensive evaluation of grape berry peripheral xylem during its development and show that tracheary development continues further into berry maturation than previously thought.     

Effects of Temperature and Growth Regulators on Formation of Anlagen, Tendrils and Inflorescences in Vitis vinifera L.

The effects of single, combined and sequential application ofgibberellic acid (GA), chlormequat and cytokinins on the formationof anlagen, tendrils and inflorescences were studied in grapevines(cv. Muscat of Alexandria) grown with natural illumination athigh temperature (30 °C day to 25 °C night) and at lowtemperature (21 °C day to 16°C night or 18 °C dayto 13 °C night). GA promoted the formation of anlagen andgrowth of tendrils regardless of temperature, but inhibitedinflorescence production. Chlormequat had the opposite effecton anlagen formation and tendril growth and promoted inflorescenceformation from pre-formed anlagen or from tendril initials.While low temperature is normally unfavourable for inflorescenceformation, this was induced by chlormequat even at low temperature,but only with summer light conditions. Cytokinin application to plants pre-treated with chiormequatcaused tendrils to grow into inflorescences regardless of temperatureregimes. Moreover, shoot primordia were also formed in place⁸oftendrils in cytokinin treated plants even without chlormequatpre-treatment. Vitis vinifera L., grapevine, gibberellic acid, chlormequat, cytokinins, benzyladenine, inflorescence, tendrils