Fruitfulness in grape-vines: Effects of water stress

Plants of Vitis vinifera L. cv. Cabernet Sauvignon were grown in undrained containers in a glasshouse and watering was controlled by weighing. There were three treatments with water contents of the growing medium falling either to 60% (A), 40% (B) or 20% (C) of field capacity before re-watering. As water stress increased the amount of water used decreased as clid extension growth of shoots. At harvest 13 weeks after bud burst the weight of C plants was less than two thirds that of A plants. Fruitfulness (number and weight of bunch primordia per bud) was progressively depressed with increase in water stress. Number and weight of leaf primordia in buds were unaffected.Die Fruchtbarkeit der Rebe: Auswirkungen von WassermangelReben der Sorte Cabernet Sauvignon (Vitis vinifera L.) wurden in nicht dränierten Gefäßen im Gewächshaus herangezogen; die Wasserversorgung wurde durch Wägen kontrolliert. Bei den drei Varianten wurde die Pflanzerde bei Erreichen eines Wassergehaltes von 60 °/o (A), 40°/o (B), oder 20°/o (C) der Feldkapazität wieder gegossen. Mit zunehmendem Wassermangel nahm die Menge des benötigten Wassers ab, entsprechend der wachstumsbedingten Ausdehnung der Triebe. Bei der Ernte 13 Wochen nach dem Austrieb betrug das Gewicht der C-Pflanzen weniger als zwei Drittel der A-Pflanzen. Die Fruchtbarkeit (Anzahl und Gewicht der Infloreszenzprimordien) war mit zunehmendem Wassermangel progressiv vermindert. Anzahl und Gewicht der Blattprimordien blieben unverändert

The effect of varying the berry number on Gordo Grape-vines with constant leaf area

The leaf number of potted Muscat Gordo Blanco grape-vines was fixed but berry number per plant was varied. Root and berry dry weight, as well as rate of berry growth, were unaffected by treatment, dry weight per unit length of shoot and trunk and sugar leve! in trunks somewhat reduced, and stareh leve! in trunks most severely affected. These results are in contrast with those of an earlier experiment in which H was observed that a progressive reduction in retained leaf number affected root dry weíght most severely, followed by berry development, stareh and sugar levels of shoots and finally dry weight per unit length of shoots. Thus the effect of reducing leaf area (source size) was not the same as increasing crop load (sink size)

Fruitfulness in grape-vines: Effects of daylength

Grape-vines were grown in cabinets for 3 months. Fruitfulness of new buds depended on the daily duration of high-intensity light, but not on low intensity light nor on length of uninterrupted dark periods

The effect of reducing leaf area on the growth of roots, stems and berries of Gordo grape-vines

To measure the effect of leaf number during berry growth on all organs of the grape vine (Vitis vinifera) a pot experiment was done using Muscat Gordo Blanco plants maintained in the open. Each plant was allowed to develop one fruitful shoot and 4 treatments (12 plants each) were applied following fruit set: (1) control (2) 6 leaves left (3) 3 leaves left (4) 1 leaf left. Leaves left (by tipping the shoot) were primary leaves at and above the first node above the bunch. When primary leaves senesced or were wind damaged a corresponding area of lateral-shoot leaf (125 cm2) was permitted to re>:main. Leaf area measurement of sample plants gave values of 2470 cm2, 850 cm2 , 470 cm2 and 125 cm2 respectively for the 4 treatments. On each shoot there was one bunch limited to 30 berries. Measurements of berry volume and sugar suggested that there was a diphasic growth curve and that wit h fall in leaf number there was a longer lag phase and a shorter second growth phase. Growth rate in the second phase was not greatly affected. Acids fell more slowly where leaf number was less, and the sugar: acid ratio was reduced.From final plant dry weights it was found that the trunk (parent stem) was least affected by leaf reduction, followed in order by shoot, berries and roots. Sugars and starch in trunk and shoot were affected in a way similar to berries. When needs of trunk, shoot and berries were fully met it appeared that cxcess leaf assimilate was channelled into root growth. The minimal leaf area for unimpeded growth of aerial organs was estimated to be 1500 cm2 (12 leaves), but in the field where bunches have more berries a greater leaf area would be required. The data has been interpreted to show that leaf efficiency in terms of carbon fixation, was markedly increased with reduction in leaf number

Fruitfulness in grape-vines: The response of different cultivars to light, temperature and daylength

Plants of five cultivars (Sultana, syn. Thompson Seedless; Muscat Gordo Blanco; Rhine Riesling; Shiraz; and Ohanez) of grape-vine (Vitis vinifera L.) were grown for 13 weeks in controlled environment growth cabinets, and then the number of bunch primordia present in buds was counted after dissection. Sultana (S) and Ohanez (0) had very few bunch primordia under all conditions. Of the other cultivars all were barren after growth at 15° C, but Rhine Riesling (R) and Shira". (Sh) had some primordia at 20° C, and Gordo (G) at 25° C. Primordia number of R, Sh and G increased with increase in temperature up to approximately 35° C. R had most at all temperatures. At a light intensity of 900 foot candles (f. c.) R had some primordia, but other cultivars were barren. At 1800 f. c. both R and G had a moderate number of primordia, but Sh was barren. At 3600 f. c. R, G and Sh all had fruitful buds. R had the greatest number of primordia at each intensity. R and Sh had more primordia when 16 hours of light per day were given continuously than when in two portions separated by 4-hour dark periods.S and O produced very few bunch primordia under any of the conditions tested. Evidence is presented that this result was due to a later differentiation of bunch primordia in buds of these cultivars, such that primordia were still unrecognisable at 13 weeks. Of the other cultivars, R had more primordia at all temperatures and light intensities; each cultivar performed well at high temperature and light intensity, but only R performed well under poor conditions

Vegetative growth of grape-vine varieties under controlled temperature and light intensity

Five commercial grape-vine varieties (Muscat Gordo Blanco, Rhine Riesling, Shiraz, Ohanez and Sultana) have been grown from rooted cuttings in controlled environment growth cabinets for 3 months. Measurements were made, after growth at different light intensities or temperatures, of plant dry weight, shoot length, node number and lateral growth. All varieties responded similarly to light intensity; only dry weights were affected by changes in light intensity. In respect of temperature, no variety grew well below 20° C, most reached optimum growth at about 25° C, and all tolerated temperatures up to 35° C very well. There were some minor differences between varieties. In respect of daylength, there was a range in short-day tolerance from Rhine Riesling (relatively intolerant) to Muscat Gordo Blanco (tolerant)

Stomata and starch in grape berries

Developing grape berries of the varieties Sultana and Cabernet Sauvignon were examined by light microscopy following plastic embedding. In ovaries and young berries stomata were detected by the presence of starch grains in their guard cells. In older berries lenticels formed beneath the stomata. Dependant on variety, lenticel numbers ranged between 2 and 16 per berry with up to half of these being associated with stomata. At anthesis most cells of the pericarp of grape berries contained starch granules. These disappeared as the berries grew, and at maturity they were present only in the epidermis and a few layers of sub-epidermal cells.Stomata und Stärke in TraubenbeerenDünnschnitte durch sich entwickelnde Traubenbeeren der Sorten Sultana und Cabernet Sauvignon wurden nach Einbettung in Kunstharz lichtmikroskopisch untersucht. An Fruchtknoten und jungen Beeren wurden die Stomata aufgrund der Stärkekörner in den Schließzellen aufgefunden. An älteren Beeren bildeten sich unter den Stomata Lenticellen. Je nach Sorte variierte die Anzahl der Lenticellen zwischen 2 und 16 pro Beere, wovon bis zur Hälfte mit Stomata vergesellschaftet sein konnten.Bei der Anthese enthielten die meisten Zellen des Perikarps Stärkekörner. Diese verschwanden mit fortschreitendem Beerenwachstum; bei der Reife kamen sie nur noch in der Epidermis und in einigen subepidermalen Zellschichten vor

A simple method for demonstrating macroscopically the location of polyphenolic compounds in grape berries

Slices of berries of several varieties of Vitis vinifera were stained with HCl, vanillin-HCl or FeCl3 to demonstrate macroscopically that the bulk of the polyphenolic compounds occur in the skins, seeds and conducting tissue of grape berries at all stages of development.Eine einfache Methode zur makroskopischen Lokalisation polyphenolischer Verbindungen in WeinbeerenSchnitte von Beeren verschiedener Vitis vinifera-Sorten wurden mit HCl, Vanillin-HCl oder FeCl3 angefärbt, um makroskopisch zu zeigen, daß der Hauptanteil der polyphenolischen Verbindungen in allen Entwicklungsphasen in der Schale, den Samen und den Leitbündeln der Weinbeere lokalisiert ist

Developmental control of hypoxia during bud burst in grapevine

Dormant or quiescent buds of woody perennials are often dense, and in the case of grapevine (Vitis vinifera L.) have a low tissue oxygen status. The precise timing of the decision to resume growth is difficult to predict, but once committed the increase in tissue oxygen status is rapid and developmentally regulated. Here we show that more than a third of the grapevine homologues of widely conserved hypoxia-responsive genes, and nearly a fifth of all grapevine genes possessing a plant hypoxia-responsive promoter element were differentially regulated during bud burst, in apparent harmony with resumption of meristem identity and cell-cycle gene regulation. We then investigated the molecular and biochemical properties of the grapevine ERF-VII homologues, which in other species are oxygen labile and function in transcriptional regulation of hypoxia-responsive genes. Each of the three VvERF-VIIs were substrates for oxygen-dependent proteolysis in vitro, as a function of the N-terminal cysteine. Collectively these data support an important developmental function of oxygen-dependent signalling in determining the timing and effective coordination bud burst in grapevine. In addition, novel regulators, including GASA-, TCP-, MYB3R-, PLT- and WUS-like transcription factors, were identified as hallmarks of the orderly and functional resumption of growth following quiescence in buds