Seasonal growth and nitrogen distribution in grapevine leaves, shoots and grapes

Jahresverlauf des Wachstums und der Stickstoffverteilung in Blatt, Trieb und Traube von WeinrebenIn einem Ertragsrebberg wurden in regelmäßigen Abständen während des Jahres Proben von Blättern, Trieben und Trauben genommen. Davon wurden das Frisch- und Trockengewicht, die Blattfläche sowie der Wasser- und Stickstoffgehalt bestimmt. Das Wachstum wurde auf der Basis von Grad-Tagen > 10 °C (GT) dargestellt. Das Primärblatt-Wachstum konnte in zwei Phasen unterteilt werden. Die erste Phase dauerte bis zum Alter von 250 GT und war durch ein rasches Blattwachstum gekennzeichnet (0.0043 g · GT-1). Die zweite Phase wies nur eine geringe Wachstumsrate von 0.0006 g · GT-1 auf und dauerte bis zum Blattfall. Bei 250 GT war das Blatt voll entfaltet und die N-Einlagerung abgeschlossen. Die spezifische Blattfläche (m2 . g-1) fiel nach einem kurzen Anstieg mit zunehmendem Blattalter kontinuierlich ab. N- und Wasser-Gehalte nahmen im Verlaufe des Jahres ebenfalls ab. Im Spätsommer sind zwar mehr Geizblätter als Primärblätter vorhanden, die gesamte Blattfläche und -masse sowie die absolute N-Menge waren jedoch ungefähr gleich auf Haupt- und Geiztriebe verteilt. Die relative Verteilung von Trockensubstanz (TS) in Blättern und Trieben unterschied sich von der N-Verteilung. Der größte Anteil an TS war in den Trieben lokalisiert, während sich in den Blättern die größte N-Menge vorfand.

Dry matter and leaf area partitioning, bud fertility and second season growth of Vitis vinifera L.: Responses to notrogen supply and limiting irradiance

Potted Vitis vinifera L. plants were grown under controlled environmental conditions at five different levels of nitrogen (0, 1, 5, 10, 100 mM NH4NO3) in combination with two different levels of irradiance (30 and 140 µmol m-2 s-1 PAR, respectively) during bloom. The immediate, whole season and second year effects on vegetative growth were assessed, and bud fertility and rate of development were evaluated. The optimum N addition level was 1 mM NH4NO3 for root growth and 5 mM for shoot growth, respectively, both after bloom and at the end of the first growing season. This growth response to N supply became apparent only in the higher light treatment and was mainly due to an N-induced enhancement of leaf and lateral shoot growth. Low-light stress also strongly enhanced the number of new leaves and laterals, but total dry matter production was reduced and did not respond to N nutrition. Light restriction increased the specific leaf area by 52 % and the leaf area ratio by 37 % but did not affect the leaf weight ratio. The leaves of N-deficient vines, in particular in combination with light stress, senesced earlier than those of vines with sufficient or excessive N availability. The light effect on shoot growth in the second season was inverted compared with the first season, and the peak response to N supply was shifted towards 100 mM NH4NO3. Limiting light conditions during inflorescence initiation severely reduced the bud fertility but advanced the date of bud break and enhanced the rate of development of the new shoots in the subsequent season. The optimum N supply rate for both bud fertility and development was 5 mM NH4NO3. Bud mortality was not affected by either treatment factor. These data indicate that the bloom period is critical for reproductive development of grapevines, with high sensitivity to environmental stress. They also emphasize the importance of nutrient reserves in the permanent structure for both compensatory and early season growth

Is carbon starvation rather than excessive nitrogen supply the cause of inflorescence necrosis in Vitis vinifera L.?

Five different levels of nitrogen (0, 1, 5, 10, 100 mM NH4NO3) were applied to potted Vitis vinifera L. plants grown in a controlled environment facility (phytotron) under 2 different levels of irradiance (30, 140 µE m-2 s-1 PFD) during bloom. They were compared with potted plants in the field, exposed to differential leaf or inflorescence shading in combination with 2 levels of N supply (0, 10 mM NH4NO3). Net CO2 assimilation rate, transpiration rate and stomatal conductance were reduced, and intercellular CO2 partial pressure was increased under conditions of light limitation. The low-light treatments decreased net photosynthesis to zero in either experiment. Separate shading of the flower clusters failed to affect gas exchange of adjacent leaves, indicating low sink strength of the inflorescences. Nitrogen fertilization influenced only transpiration rate and stomatal conductance. In the phytotron, but not in the field, these parameters decreased with increasing N level. Severe symptoms of inflorescence necrosis appeared in the low-light treatment in the phytotron at the end of flowering. Necrotic symptoms also developed on shoot tips and tendrils, leading to abscission of these organs. Tissue necrosis was independent of N nutrition, and there were no necrotic manifestations in the field study. These results provide evidence that a stress-induced limitation of photoassimilate supply, along with competitive interactions among sinks, are involved in triggering senescence processes in grapevines

Stress-induced development of inflorescence necrosis and bunch-stem necrosis in Vitis vinifera L. in response to environmental und nutritional effects

Inflorescences and mature clusters, respectively, of field-grown Muller-Thugau grapevines (Vitis vinifera L.) were immersed in aqueous solutions of the glutamine synthetase (GS) inhibitor phosphinothricin (PPT). Typical symptoms of inflorescence necrosis developed after immersion in 1 or 10 mM PPT, but not in the 0.1 mM treatment. No necrotic symptoms could be induced in mature clusters. In addition, single-node cuttings of field-grown Müller-Thurgau and Pinot noir vines with one cluster, with or without adjacent leaf, were incubated in various solutions with or without PPT at several phenological stages. Necrotic symptoms occurred in all treatments including the H2O control. However, at early stages of development the symptoms appeared earlier than at later stages, and elevated PPT concentrations reduced the development of necrotic manifestations. The addition of NH,NO, to the solution enhanced the appearance of symptoms both in the presence and absence of PPT, while KNO3 did not. In incubation solutions without PPT, metallic cations like Mg2+, Ca2+ and K+ reduced the incidence of bunch-stem necrosis. When cuttings were exposed to different environmental conditions, there was no significant light effect, but wind decreased the incidence of both inflorescence necrosis and bunch-stem necrosis. A leaf, attached to the cluster, or the addition of sucrose to the solution effectively delayed the development of necrotic manifestations. These results indicate that GS is present in rachis, flower and berry tissues and that the buildup of toxic NH4+ levels is involved in the development of both inflorescence necrosis and bunch-stem necrosis. However, NO3- reduction and primary N assimilation appear not to contribute significantly to NH4+ accumulation. This buildup may rather be a secondary effect related to senescence of the tissue due to carbon depletion

Yield, fruit quality, bud fertility and starch reserves of the wood as a function of leaf removal in Vitis vinifera-Evidence of compensation and stress recovering

Einfluß unterschiedlicher Entblätterung auf Ertrag, Traubenqualität, Knospenfruchtbarkeit und Stärkegehalt des Holzes von Vitis vinifera sowie Kompensations- und ErholungsvermögenAn Ertragsreben wurde der Einfluß des Entfernens von Hauptblättern oder Geiztrieben auf Gesamtblattfläche, Traubenertrag und -qualität sowie Stärkegehalt des Holzes studiert. Die Bedeutung von Haupt- und Geizblättern sowie des Zeitpunktes der Entblätterung auf dss Verrieseln wurde untersucht. Ziel der Studie war, Kompensationsmechanismen und -limiten der Rebe unter Streßbedingungen kennenzulernen, wie sie durch eine Entblätterung verursacht werden. Ferner sollte die Erholung der Pflanze nach längerer Streßeinwirkung erforscht werden.Wurden die Hauptblätter entfernt (L = nur Geizblätter}, so bildeten die Pflanzen mehr Geiztriebe mit einer größeren Anzahl Blätter. Dies führte nach dem ersten Streßjahr zu einer ungefähr gleichen Gesamtblattfläche wie bei den Kontrollpflanzen. Nach einem weiteren Streßjahr jedoch hatten die L-Pflanzen zwar weiterhin mehr Geizblätter, allerdings von geringerer Größe. Hieraus resultierte eine im Vergleich zur Kontrolle verringerte Gesamtblattfläche. Pflanzen nur mit Hauptblättern (M) kompensierten das Fehlen der Geiztriebe mit verzögerter Blattalterung und späterem Blattfall. Auch hier ergab sich nach dem zweiten Streßjahr eine geringere Blattgröße. Der Traubenertrag der L-Pflanzen wurde im 1. Jahr durch die Blattentfernung kaum negativ beeinflußt, aber im 2. Jahr war er 50 % niedriger als in der Kontrolle. Bei den M-Pflanzen ergab sich in beiden Jahren kein verringerter Ertrag. Der Zuckergehalt der Trauben war in den L-Pflanzen im 1. Streßjahr leicht erhöht, nicht aber im 2. Jahr. Diese Reben hatten während beider Jahre eine bessere Beerenfarbe.Die Blattfläche vom Zeitpunkt der Blüte bis 2-3 Wochen danach ist für den Traubenertrag entscheidend. Eine Entblätterung zu diesem Zeitpunkt verursachte nicht nur ein Verrieseln, sondern im folgenden Jahr zusätzlich eine reduzierte Knospenfruchtbarkeit. Die Zuckereinlagerung in den Trauben hängt von der assimilierenden Blattfläche während der Reifeperiode ab. Der Stärkegehalt im Holz war nach 2 Streßjahren erheblich reduziert. Es ergaben sich schwach positive Korrelationen zwischen Zuckergehalt des Mostes und Stärkegehalt des Holzes.Die Zuckereinlagerung in die Traube und das Auffüllen der Stärkereserven im Holz ging bereits in der auf eine Streßbehandlung folgenden Saison normal vonstatten. Ein normaler Ertrag war l Jahr nach einem längeren Entblätterungsstreß jedoch noch nicht möglich, da die Bildung der Infloreszenzen bekanntlich während dieser Zeit (in unserem Fall die Streßperiode) einsetzt. Erst im 2. Jahr kam es zu einer vollständigen Erholung der Pflanze

Influence of partial defoliation on gas exchange parameters and chlorophyll content of field-grown grapevines - Mechanisms and limitations of the compensation capacity

In order to study the compensation mechanisms related to leaf removal, gas exchange response to defoliation as well as chlorophyll content were investigated in field-grown Pinot noir grapevines. Mature 16 years old bearing plants and 2 years old fruitless potted plants were compared. Defoliation treatments were performed 1 week after full bloom. Besides topping, three levels of main leaf removal (3, 6 or all 12 main leaves retained) were combined with two levels of laterals (all retained or all removed). The single leaf measurements (on the 11th main leaf from the base) were carried out from treatment time to fruit maturity

Nachweis erhöhter Äthylengehalte in der Bodenluft eines von der Verdichtungschlorose befallenen Rebberges

Periodische Untersuchungen der Bodenluft einer chlorosekranken Rebparzelle, deren Boden verdichtet war, erbrachten im Vergleich zu einer unmittelbar benachbarten gesunden Parzelle häufiger hohe Äthylengehalte. In einem Großteil der Gasproben wurden Äthylenkonzentrationen über 1 ppm gemessen, die als wachstumshemmend angesehen werden.Im Gegensatz zu den meisten anderen Nährstoffen kann Eisen nur in der Zellteilungs- und Streckungszone unmittelbar hinter der Wurzelspi<tze aufgenommen werden. Es wird postuliert, daß die äthyleninduzierte Hemmung des Wurzelspitzenwachstums indirekt eine verminderte Eisenaufnahme durch die Wurzel bewirkt. Sobald ein großer Eisenbedarf auftritt, meist bei beginnender Gescheinsentwicklung, entsteht ein temporärer Eisenmangel, der in der Folge zur Chlorose führt.Evidence of increased ethylene content in the soil air of a vineyard with compaction-induced chlorosisEthylene at concentrations known to affect reet growth was found in the soil air of a chlorotic vineyard with compacted soil. Concentrations above 1 ppm were significantly more frequent in the chlorotic vineyard in comparison to the healthy field just beside. In contrast to most of the other nutrients, iron can be taken up only by growing root tips. lt is postulated that the ethylene-induced inhibition of root growth reduces the iron uptake. As seen as the plant needs a great amount of iron, i.e. during an intense growth of the shoots at the beginning ef inflorescence development, a temporary iron stress leads to the appearence of chlorosis

Carbon and nitrogen partitioning in Vitis vinifera L.: Responses to nitrogen supply and limiting irradiance

Potted Vitis vinifera L. plants were grown under controlled environmental conditions at five different levels of nitrogen (0, 1, 5, 10, 100 mM NH4NO3) in combination with two different levels of irradiance (photon flux densities: 30 and 140 µ mol · m-2 s-1 PAR) during bloom. Elevated N supply increased available N (particularly NO3-), K, Ca and Mg, and reduced P in the soil. Soil-NO3- and K were higher in the lower light regime, but NH4+ and other nutrients were not influenced by irradiance. The concentration of total N in the xylem sap increased as N supply was increased, although there was no further rise above intermediate soil-N levels. NO3- was the principal xylem solute, in particular under severe light restriction and high N availability. In the lower light regime, only traces of organic N could be detected in the xylem sap, whereas in the higher light treatment, glutamine and glutamate increased with increasing N application level. Light limitation reduced the concentrations of P, K and Mg in the xylem sap by about 50 %, but no response to N supply could be observed. There was a strong positive relationship between N availability and N concentration in all plant parts, while the effect on C content was minor and depended on the type and physiological age of the tissue. The amounts of total N per vine were not affected by the light treatments, although low-light stress increased N concentrations in the dry matter of the annual organs by 34-86 %. By contrast, low light led to a slight decrease of the C concentration in the annual plant parts. In the higher light regime, non-structural carbohydrates in the permanent parts of the vine declined as N availability increased. Under severe light restriction, however, the C reserve fraction was depleted and was not altered by N supply, indicating that reserves had been remobilized to support maintenance and growth processes, in order to guarantee survival of the vine

Gluconeogenese in reifenden Beeren von Vitis vinifera

Im Verlaufe der Reifeperiode 1973 wurde Traubenbeeren in wöchentlichen Intervallen Fumarsäure-2,3- 14C injiziert und nach einer Stoffwechselzeit von 6 Stunden der Einbau des Tracers in Malat sowie die Neutralfraktion untersucht. Es konnte nachgewiesen werden, daß - mit geringer Randomisierung des C-Skelettes des Präkursors - vorwiegend Äpfelsäure entsteht. Daneben erscheinen aber bis zu 17% der Radioaktivität in den Zuckern (Glucose, Fructose und Saccharose). Aufgrund der 14C-Verteilung im Glucosemolekül, welche ein Schwergewicht der Markierung in den C-Atomen 1, 2, 5 und 6 aufweist, kann auf die Existenz des „klassischen" Gluconeogeneseweges (mit Oxalacetat, Phosphoenolpyruvat und Phosphoglycerat als Intermediärprodukten) in Traubenbeeren geschlossen werden. Die Inkorporationsrate des biogenetisch aus '"C-Fumarat entstandenen  14C-Malats in die Neutralfraktion ist bei c a. 20 °C am höchsten. Dieses relativ tiefe Maximum dürfte auf die in diesem Temperaturbereich optimale Versorgung der Früchte mit stoffwechselaktiver Apfelsäure als Edukt für die Zuckersynthese zu erklären sein. Vergleiche der Zuckergehalte von Trauben mit bzw. ohne direkte Sonnenbestrahlung lassen während des Reifeverlaufes bei den Früchten an beschatteten und damit kühleren Standorten eine deutlich intensivere Zuckerbildung erkennen, so daß dadurch der zum Zeitpunkt der „Veraison" bestehende Unterschied im Zuckergehalt nahezu verschwindet. Es wird die Bedeutung der Gluconeogenese für diesen Ausgleich diskutiert.Gluconeogenesis in the ripening fruit of Vitis viniferaFumaric acid-2,3-14C was applied to grape berries at weekly intervals and the incorporation of radioactivity into other acids and the neutral, watersoluble substances determined. Malic acid, predominantly labelled in the inner C-atoms, proved to be the main metabolic product, and up to 170/o of the 14C-activity of the extract was discovered in the neutral fraction. The t4C-glucose thus synthesized carried more label in the Cl/C2 and the C6/C5 positions than in the two central C-atoms. Based on these results it is concluded that the ripening fruit transforms acids into sugars by reactions involving a formal reversal of the glycolytic pathway.Incorporation of radioactivity of 14C-fumaric and -malic acids into sugars shows a temperature optimum of about 20 °C. Comparisons between the sugar concentrations of grapes growing in the sun or in the shade, indicate that the r a t e of sugar synthesis during the final ripening-stages is greater in the shade. Thus, the marked difference in sugar content at veraison disappears during maturation. The contribution of sugar synthesis from acids to the observed compensation is discussed

Reanalysis of multi-temporal aerial images of Storglaciären, Sweden (1959–99) – Part 2: Comparison of glaciological and volumetric mass balances

Seasonal glaciological mass balances have been measured on Storglaciären without interruption since 1945/46. In addition, aerial surveys have been carried out on a decadal basis since the beginning of the observation program. Early studies had used the resulting aerial photographs to produce topographic glacier maps with which the in-situ observations could be verified. However, these maps as well as the derived volume changes are subject to errors which resulted in major differences between the derived volumetric and the glaciological mass balance. As a consequence, the original photographs were re-processed using uniform photogrammetric methods, which resulted in new volumetric mass balances for 1959–69, 1969–80, 1980–90, and 1990–99. We compared these new volumetric mass balances with mass balances obtained by standard glaciological methods including an uncertainty assessment considering all related previous studies. The absolute differences between volumetric and the glaciological mass balances are 0.8 m w.e. for the period of 1959–69 and 0.3 m w.e. or less for the other survey periods. These deviations are slightly reduced when considering corrections for systematic uncertainties due to differences in survey dates, reference areas, and internal ablation, whereas internal accumulation systematically increases the mismatch. However, the mean annual differences between glaciological and volumetric mass balance are less than the uncertainty of the in-situ stake reading and stochastic error bars of both data series overlap. Hence, no adjustment of the glaciological data series to the volumetric one is required