Plants have evolved an array of specific photoreceptors to acclimate to the light environment. By sensing light signals, photoreceptors modulate plant morphology, carbon- and water-physiology, crop ...yield and quality of harvestable organs, among other responses. Many cultural practices and crop management decisions alter light quantity and quality perceived by plants cultivated in the field. Under full sunlight, phytochromes perceive high red to far red ratios (R:FR; 1.1), whereas overhead or lateral low R:FR (below 1.1) are sensed in the presence of plant shade or neighboring plants, respectively. Grapevine is one of the most important fruit crops in the world. To date, studies on grapevine response to light focused on different Photosynthetic Active Radiation (PAR) levels; however, limited data exist about its response to light quality. In this study we aimed to investigate morphological, biochemical, and hydraulic responses of Vitis vinifera to variations in R:FR. Therefore, we irradiated Syrah and Torrontés Riojano plants, grown in a glasshouse, with lateral FR light (low lateral R:FR treatment), while others, that were kept as controls, were not irradiated (ambient lateral R:FR treatment). In response to the low lateral R:FR treatment, grapevine plants did not display any of the SAS morphological markers (i.e. stem length, petiole length and angle, number of lateral shoots) in any of the cultivars assessed, despite an increase in gibberelins and auxin concentrations in leaf tissues. Low lateral R:FR did not affect dry matter partitioning, water-related traits (stomata density and index, wood anatomy), or water-related physiology (plant conductance, transpiration rate, stem hydraulic conductivity, stomatal conductance). None of the Vitis vinifera varieties assessed displayed the classical morphological and hydraulic responses associated to SAS induced by phytochromes. We discuss these results in the context of natural grapevine environment and agronomical relevance.
The productivity of
Vitis vinifera
L. is limited by salinity, especially under water and drainage deficits, and could aggravate with climate change. The use of tolerant rootstocks is a strategy ...against salinity that helps yield maintenance. Some Argentinean grapevine cultivars show tolerance to salinity, although the mechanisms are yet unknown. The physiology of Malbec vines was evaluated with 4 V
. vinifera
rootstocks: Torrontés Riojano (TR) and Torrontés Sanjuanino (TS) Argentine varieties, and the hybrids 3309 Courdec (3309C, salinity sensitive) and 1103 Paulsen (1103P, tolerant), submitted to NaCl 0, 50 or 100 mM during 65 days. Mild and high salinity levels reduced vegetative growth (50 and 70%, respectively), photosynthesis and leaf water content. Midday Ψ
L
reached − 1.16 MPa (moderate water stress) with 100 mM NaCl, which expressed as oxidative damage in mature leaves, thus affecting protein content, membrane integrity and lipid peroxidation. Proline accumulation in leaves increased in 1103P and TR under 50 mM, while 1103P showed the highest value in 100 mM NaCl. An increased vegetative expression and vigor were induced by TS. Accumulation of Na
+
and Cl
−
ions in roots was found in TR and TS, suggesting a compartmentalization strategy, while 1103P excluded them.
Cavitation is a physiological dysfunction that takes place in the xylem of water stressed plants leading to a loss of hydraulic conductance (kL) as the vessels are filled with air. This impacts water ...supply, water potential (ΨL) and canopy hydration. Stomatal clossure is an effective response upon diminishing momentary or seasonal foliar hydraulic contents. Depending on each plant, stomata may close preventing catastrophic cavitations. This research intended to understand how stomatal control acts upon cavitation events in two contrasting grapevine varieties, Syrah and Grenache. A mechanistic model was developed based on the water and vapour fluxes, kL, stomatal conductance (gs), and vulnerability to cavitation. The theoretical model explains plant drough responses and catastrophic cavitation avoidance. Water stressed grapevines couple gs with kL in order to avoid embolism. It is not stomatal closure, by istself, the controlling mechanism. Grapevines under mild water stress, do not need to completely close their stomata in order to avoid cavitation, therefore, photosynthesis is not completely impeded, and the cost in terms of carbon assimilation is less than expected for other species.
Vigor control in grapevine may become especially important under climate change. A better understanding of gene-phenotype relationships is required in order to exploit plant genomics for breeding ...purposes. This research aims to use quantitative trait loci (QTLs) for vigor identified in the progeny from a cross of Ramsey (Vitis champinii) × Riparia Gloire (V. riparia). Genes located 700 kb up and downstream from each QTL position were interrogated for functional enrichment through ShinyGO online tool, based on the gene ontology annotation of Vitis vinifera PN40024. Key biological processes like phloem and xylem development, cell cycle, response to hormones, amino acid transport, tissue development, sugar metabolism, nitrogen transport, and stress/immune responses, showed functional enrichment. Integral response to light and auxin might be required for fine molecular tuning of vegetative growth in Vitis. Fifty out of 1318 candidate genes were prioritized, reducing their amount to a manageable number of candidates for further directed breeding strategies. Highlights • Plant vigor control may become especially important under climate change. • Genes from various vigor-related QTLs were interrogated for functional enrichment. • The analysis reduced candidate gene number based on marker proximity and functional enrichment, constituting a suitable shortcut for target-directed genome-guided breeding strategies. • Three TFs are strong candidates for targeted breeding: TIF - HY5, TIF - SUS1, TIF - VOZ1 potentially enhance growth by relating light response to hormone activation, and then to photosynthesis and morphogenesis.
Mechanistic modeling constitutes a powerful tool to unravel complex biological phenomena. This study describes the construction of a mechanistic, dynamic model for grapevine plant growth and canopy ...biomass (vigor). To parametrize and validate the model, the progeny from a cross of Ramsey (Vitis champinii) × Riparia Gloire (V. riparia) was evaluated. Plants with different vigor were grown in a greenhouse during the summer of 2014 and 2015. One set of plants was grafted with Cabernet Sauvignon. Shoot growth rate (b), leaf area (LA), dry biomass, whole plant and root specific hydraulic conductance (kH and Lpr), stomatal conductance (gs), and water potential (Ψ) were measured. Partitioning indices and specific leaf area (SLA) were calculated. The model includes an empirical fit of a purported seasonal pattern of bioactive GAs based on published seasonal evolutionary levels and reference values. The model provided a good fit of the experimental data, with R = 0.85. Simulation of single trait variations defined the individual effect of each variable on vigor determination. The model predicts, with acceptable accuracy, the vigor of a young plant through the measurement of Lpr and SLA. The model also permits further understanding of the functional traits that govern vigor, and, ultimately, could be considered useful for growers, breeders and those studying climate change.
Functional trait; Vegetative growth; Mechanistic model; Ramsey × Riparia Gloire; Simulation; Biophysics; Agricultural engineering; Agricultural technology; Agronomy; Plant biology
A correct selection of salt-tolerant plants should consider the relative effects of the various existing tolerance mechanisms. When toxic ions, like Na+, reach the leaves, they affect the ...photosynthetic apparatus, reducing plant growth and performance. Leaf concentration of toxic ions depends on exclusion efficiencies at root level, or compartmentation in organs other than leaves. On the other hand, flow within the plant depends on leaf area, transpiration rate, and soil ion concentrations. From this perspective, in a feedback process, leaf area may be, simultaneously, cause and consequence of salt toxicity. To unravel how this feedback process influences salinity damage in grapevines, a dynamic model of Na+ toxicity was developed. The theoretical model proposed a way to estimate plant exclusion and compartmentation efficiencies. Parametrization was based on a 60-days trial with potted cv. Malbec vines (Vitis vinifera L.), own-rooted and grafted onto 101-14Mgt, 1103P and Cereza, under three soil NaCl levels (0, 50 and 100 mM). The model simulated different grapevine rootstock responses to different salinity levels. These simulations evidenced the key role of Na+ exclusion in long-term tolerance. Stomatal adjustment, compartmentation and rootstock conferred vigor showed relatively minor effects. Highlights: When toxic ions, like Na+, reach the leaves, they affect plant growth and performance. Leaf concentration of toxic ions depends on exclusion efficiencies at root level, or compartmentalization in organs other than leaves. A theoretical and dynamic model of Na+ toxicity proposed a way to estimate plant exclusion and compartmentation efficiencies. These simulations evidenced the key role of Na+ exclusion in long-term tolerance, while stomatal adjustment, compartmentation and rootstock conferred vigor, showed relatively minor effects.
El objetivo fue evaluar la supervivencia al riego con soluciones de NaCl en 28 genotipos del género Vitis para identificar su grado de tolerancia salina. Se estudiaron 11 híbridos de Vitis americanos ...y 17 variedades de Vitis vinifera. Plantas de 1 y 2 años se regaron durante 66 días con una solución 100 mM de NaCl. Para clasificar las variedades de acuerdo con su grado de tolerancia a la salinidad, se calculó el día en que el 25% de la población había muerto (1er cuartil de la muestra). Se consideraron como genotipos sensibles aquellos en que al menos 25% había muerto antes del día 30 (3309 Couderc, 161-49 Couderc, Fercal, Freedom, 1103 Paulsen, 99 Richter, SO4, Torrontés Sanjuanino), como poco tolerantes cuando al menos 25% murió entre los días 30 y 60 (Cereza, Colombard, Criollas Blanca y Ballista, Palomino, 110 Richter, 140 Ruggeri, Syrah, Torrontés Riojano) y como tolerantes cuando el 75% o menos sobrevivió más de 60 días (101-14 Millardet-Grasset, 196-17 Castel, Criollas Chica y Sanjuanina, Moscatel de Alejandría, Pedro Giménez). Aun en los genotipos más tolerantes cuando las plantas crecieron bajo salinidad, la integridad de membranas celulares se redujo un 17% y el contenido de clorofila total disminuyó un 52%.
En zonas áridas bajo riego, los viñedos enfrentan condiciones de déficit hídrico y salinidad. Como frecuentemente estos factores de estrés ocurren simultáneamente, es difícil evaluar la gravedad ...relativa de cada uno de ellos. Elobjetivo del trabajo fue comparar en forma independiente las respuestas fisiológicas y vegetativas al estrés hídrico y salino de dos portainjertos de vid injertados con Cabernet Sauvignon. Se realizó un experimento en macetas con vides injertadas con Cabernet Sauvignon sobre 1103P y 101-14Mgt. Se aplicaron tres tratamientos: estrés salino (Salino), estrés hídrico (EH) y testigo sin estrés (T). El Ψ foliar a mediodía fue -1,3 MPa en Salino y EH, y -0,9 MPa en T. Luego de 54 días, Salino afectó menos el área foliar (AF) y la longitud de brotes (LB) que EH. El AF disminuyó 53% en Salino, mientras que en EH se redujo 78% respecto de T. La LB disminuyó 68% en Salino y 83% en EH. La biomasa total no presentó diferencias entre los dos tipos de estrés, disminuyendo ambos un 52% respecto de T, pero la partición de asimilados a los distintos órganos fue distinta. Salino acumuló más biomasa en parte aérea y EH en raíz. Aunque la conductancia estomática se redujo de manera similar en ambos tratamientos de estrés (-41% respecto del T) se encontró una interacción entre tipo de estrés y portainjerto para la fotosíntesis neta. Las plantas injertadas sobre 1103P acumularon un 21% menos de Na+ que las injertadas sobre 101-14Mgt. A pesar que el comportamiento de las plantas Cabernet Sauvignon injertadas fue similar para ambos portainjertos, la mayor exclusión de 1103P lo hace más propicio ante situaciones de salinidad.
You should leave 10 mm of space above the abstract and 15 mm after the abstract. The heading Abstract should be typed in bold 9-point Arial. The body of the abstract should be typed in normal 9-point ...Times in a single paragraph, immediately following the heading. The text should be set to 1.15 line spacing. The abstract should be centred across the page, indented 15 mm from the left and right page margins and justified. It should not normally exceed 200 words. Under this problematic context, several growers in our area proposed alternatives to conduction systems. An innovation was the system of divided canopy “Ramé”, developed by the local viticulture Luis Alberto Ramero. This system was attempted to combine high yield with high quality grape, machanize harvest and good cinditions of canopy microclimate. It's a system of vertical shoot position, with its canopy divided into two planes. These systems are characterized, in our region, by a low foliar surface exposed per hectare, a relatively low productivity (in the case of the VSP) or difficulty to mechanize the harvest (in the case of the Parral). The objective of this study was to evaluate the ecophysiology of Rame system, determining if it behaves differently when it is planted with one or two plants by post (Rame single and double). Also the two modalities of Rame were compared with the trellis in VSP. Since this latter system is not included in the statistical, but planted design on the side of the test, the comparison kept a descriptive character. For the Rame we established an experimental trial with statistical design, with two treatments in trellis-training system. A treatment consisted in planting one vine per post, called simple Rame (RS) and two vines per post, called double Rame (RD), leaving in this way different number of plants per unit area (1600 plantas / has and 3200 plantas / has respectively). Nevertheless, regardless of the number of plants per hectare, Rame system maintain high values of anthocyanins (1, 2 mg/Kg of grapes) and IPT (43) with high production (152 qq / has). This fact, added to that the system has potential for mechanization, converts Rame in a trellis system with high potential for vine growth in the viticulture regions. The trellis VSP behaved less productive (86 qq / has), and at the same time obtained lower values of qualitative components such as anthocyanins (1.04 mg/Kg of grapes) and IPT (35).
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