Grapevine physiological response to row orientation-induced spatial radiation and microclimate changes

Terroir factors and vineyard practices largely determine canopy and root system functioning. In this study, changes in soil conditions, multi-level (vertical, horizontal) light interception (quantitative, photographic, schematic, 3D modelled), leaf water potential and photosynthetic activity were measured during the grape ripening period on NS, EW, NE-SW, and NW-SE orientated (Southern Hemisphere) vertically trellised Shiraz grapevine canopies. It was hypothesised that the spatial radiation interception angle and radiation distribution of differently orientated and vertically trained grapevine rows would affect soil conditions and vine physiological activity. Soil water content showed an increase and soil temperature a decreasing gradient with soil depth. In the afternoon, soil layers of EW orientated rows reached their highest temperature. This, along with measured photosynthetic active radiation received by canopies, complimented the diurnally-captured photographic, constructed and 3D modelled images (also schematically) of canopy and soil exposure patterns. The top, bottom and outside of NS canopies mainly received radiation from directly above, from the E and the W; during midday, high radiation was only received from above. The EW rows received the highest radiation component from above and from the N. The NE-SW rows received high levels of radiation from above, from the SE until 10:00, and from the NW from 13:00. A similar profile can be described for NW-SE rows, but with high radiation received from the NE up to 13:00 and from the SW from 16:00. Overall, lowest leaf water potential occurred for NE-SW canopies, followed by those orientated NW-SE, NS and EW. Photosynthetic activity reflected the positive radiation impact of the sun azimuth during the grape ripening period; best overall performance seemed to occur for E and N exposed canopy sides. This was largely driven by the responsiveness of the secondary leaves to radiation. Photosynthetic output decreased from apical to basal canopy zones with low, erratic values in the light-limited canopy centre. The NS and EW orientated canopies generally showed the highest average photosynthesis, while it was lower for the sides facing S, SE and SW. The results provide a better understanding of the physiological functioning of horizontal and vertical leaf layers in differently orientated grapevine canopies, as affected by climatic conditions. The study contributes to the longstanding challenges of capturing the complexity of parallel microclimatic and physiological output of grapevine canopies under open field conditions. The results can be directly applied to the selection of vineyard practices and seasonal management to ensure the attainment of yield, grape composition and wine quality objectives.

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A model of stomatal closure driven by nonlinearities in soil-plant hydraulics

10.5194/egusphere-egu21-12524 ◽

2021 ◽

Author(s):

Fabian Wankmüller ◽

Mohsen Zarebanadkouki ◽

Andrea Carminati

Keyword(s):

Hydraulic Conductivity ◽

Stomatal Conductance ◽

Water Potential ◽

Leaf Water Potential ◽

Environmental Conditions ◽

Plant Traits ◽

Stomatal Closure ◽

Leaf Water ◽

Optimization Models ◽

Soil Conditions

Predicting plant responses to drought is a long-standing research goal. Since stomata regulate gas-exchange between plants and the atmosphere, understanding their response to drought is fundamental. Current predictions of stomatal behavior during drought mainly rely on empirical models. These models may suit well to a specific set of plant traits and environmental growth conditions, but their predictive value is doubtful when atmospheric and soil conditions change. Stomatal optimization offers an alternative framework to predict stomatal regulation in response to drought for varying environmental conditions and plant traits. Models which apply this optimization principle posit that stomata maximize the carbon gain in relation to a penalty caused by water loss, such as xylem cavitation. Optimization models have the advantage of requiring a limited number of parameters and have been successfully used to predict stomatal response to drought for varying environmental conditions and species. However, a mechanism that enables stomata to optimally close in response to water limitations, and more precisely to a drop in the ability of the soil-plant continuum to sustain the transpiration demand, is not known. Here, we propose a model of stomatal regulation that is linked to abscisic acid (ABA) dynamics (production, degradation and transport) and that allows plants to avoid excessive drops in leaf water potential during soil drying and increasing vapor pressure deficit (VPD). The model assumes that: 1) stomatal conductance (gs) decreases when ABA concentration close to the guard cells (CABA) increases; 2) CABA increases with decreasing leaf water potential (due to higher production); and 3) CABA decreases with increasing photosynthesis (e.g. due to faster degradation or transport to the phloem). Our model includes simulations of leaf water potential based on transpiration rate, soil water potential and variable hydraulic conductances of key elements (rhizosphere, root and xylem), and a function linking stomatal conductance to assimilation. It was tested for different soil properties and VPD. The model predicts that stomata close when the relation between assimilation and leaf water potential becomes nonlinear. In wet soil conditions and low VPD, when there is no water limitation, this nonlinearity is controlled by the relation between stomatal conductance and assimilation. In dry soil conditions, when the soil hydraulic conductivity limits the water supply, nonlinearity is controlled by the excessive drop of leaf water potential for increasing transpiration rates. The model predicts different relations between stomatal conductance and leaf water potential for varying soil properties and VPD. For instance, the closure of stomata is more abrupt in sandy soil, reflecting the steep decrease in hydraulic conductivity of sandy soils. In summary, our model results in an optimal behavior, in which stomatal closure avoids excessive (nonlinear) decrease in leaf water potential, similar to other stomatal optimization models. As based on ABA concentration which increases with decreasing leaf water potential but declines with assimilation, this model is a preliminary attempt to link optimization models to a physiological mechanism.

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Does predawn water potential discern between irrigation treatments in Galician white grapevine cultivars?

OENO One ◽

10.20870/oeno-one.2014.48.2.1566 ◽

2014 ◽

Vol 48 (2) ◽

pp. 123 ◽

Cited By ~ 3

Author(s):

José Manuel Mirás-Avalos ◽

Emiliano Trigo-Córdoba ◽

Yolanda Bouzas-Cid

Keyword(s):

Water Potential ◽

Leaf Water Potential ◽

Water Status ◽

Irrigation Management ◽

Growing Season ◽

Climatic Conditions ◽

Leaf Water ◽

Diurnal Changes ◽

Stem Water Potential ◽

Stem Water

Aims: To evaluate the usefulness of predawn water potential (Ψpd) to assess the water status of Galician grapevine cultivars for irrigation purposes.Methods and results: Three Galician white grapevine cultivars (Albariño, Godello and Treixadura) were subjected to rain-fed and irrigation conditions during the 2013 growing season. Diurnal changes in leaf water potential (Ψl) were measured using a pressure chamber on days with high evapotranspiration demand. Stem water potential (Ψs) was measured at midday. Ψpd was not able to discriminate between treatments, whereas Ψl and Ψs at midday were able to detect significant differences in water status among plants.Conclusion: Ψpd was not useful to evaluate vine water status under the Galician climatic conditions. In contrast, both Ψl and Ψs were effective for detecting differences between treatments and can thus be used for irrigation management purposes.Significance and impact of the study: This is the first study evaluating water status of Galician grapevine cultivars. It also provides useful information about the strategy for its control through measurements of midday Ψl or Ψs.

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Flooding, Leaf Gas Exchange, and Growth of Mango in Containers

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.116.1.156 ◽

1991 ◽

Vol 116 (1) ◽

pp. 156-160 ◽

Cited By ~ 23

Author(s):

Kirk D. Larson ◽

Bruce Schaffer ◽

Frederick S. Davies

Keyword(s):

Gas Exchange ◽

Water Potential ◽

Leaf Water Potential ◽

Vegetative Growth ◽

Tree Mortality ◽

Leaf Gas Exchange ◽

Mangifera Indica ◽

Dry Weight ◽

Leaf Water ◽

Soil Conditions

The effect of flooding on container-grown `Tommy Atkins' mango (Mangifera indica L.) trees on two rootstock, and on container-grown seedling `Peach' mango trees, was investigated by evaluating vegetative growth, net gas exchange, and leaf water potential. In general, flooding simultaneously reduced net CO2 assimilation (A) and stomatal conductance (gs) after 2 to 3 days. However, flooding did not affect leaf water potential, shoot extension growth, or shoot dry weight, but stem radial growth and root dry weight were reduced, resulting in larger shoot: root ratios for flooded trees. Mortality of flooded trees ranged from 0% to 45% and was not related to-rootstock scion combination. Hypertrophied lenticels were observed on trees that survived flooding but not on trees that died. The reductions in gas exchange, vegetative growth, and the variable tree mortality indicate that mango is not highly flood-tolerant but appears to possess certain adaptations to flooded soil conditions.

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Photosynthesis performance and leaf water potential impairments of Lime Tahiti affected by Wood pocket

Temas Agrarios ◽

10.21897/rta.v25i2.2295 ◽

2020 ◽

pp. 153-165

Author(s):

Eleonora Rodriguez Polanco ◽

Jairo García L ◽

Javier Orduz

Keyword(s):

Water Potential ◽

High Temperatures ◽

Leaf Water Potential ◽

Vascular System ◽

Fruit Production ◽

Climatic Conditions ◽

Leaf Water ◽

Photosynthetic Parameters ◽

Hydrodynamic Properties ◽

Climate Conditions

The progressive death of Tahiti lime trees in productive stage was evidenced in the production region of north-central Tolima in 2012, which led to significant detriment in fruit production of 79.98% in relation to the year 2011. Tree deterioration caused by progressive death of tissue or wood was attributed to the presence of the physiopathy known worldwide as Wood pocket (WP) because its damage was not associated with the presence of a pathogen in diagnostic tests in the laboratory. The presence and level of damage caused by WP has been associated with dry warm climate conditions related mainly to high temperatures, a condition similar to that which occurs in this producing area. The effect of WP on the photosynthetic parameters and leaf water potential was determined in an experimental trial in a commercial plantation of Lima Tahiti located in Flandes. In this area, hydrodynamic properties and the moisture content of the soil were characterized, and monitoring of climate conditions was also carried out. Our results indicated that the hydrodynamic properties, low availability of water in this soil and climatic conditions are favorable for the development of WP. The values in photosynthetic parameters and leaf water potential even in healthy plants are lower than those reported for this species, indicating that the plants are in constant condition of water stress that can be increased by the high average temperature. The presence of WP decreases in greater proportion the photosynthesis efficiency and water potential in leaf tissue. We hypothesized that the constant water deficit and high temperatures cause rupture of tracheids and cavitation in the xylem deteriorating the vascular system causing the death of wood or WP.

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RELATIONSHIPS BETWEEN LEAF WATER POTENTIAL AND PHOTOSYNTHETIC ACTIVITY OF FIELD-GROWN GRAPEVINES UNDER A MEDITERRANEAN ENVIRONMENT

Acta Horticulturae ◽

10.17660/actahortic.1999.493.28 ◽

1999 ◽

pp. 287-292 ◽

Cited By ~ 2

Author(s):

C. M.A. Lopes

Keyword(s):

Water Potential ◽

Leaf Water Potential ◽

Photosynthetic Activity ◽

Leaf Water ◽

Mediterranean Environment

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Behaviour study of "Danlas" grapevines grown under plastic cover

OENO One ◽

10.20870/oeno-one.2003.37.2.941 ◽

2003 ◽

Vol 37 (2) ◽

pp. 117

Author(s):

Aziz Ezzahouani

Keyword(s):

Ambient Temperature ◽

Water Potential ◽

Leaf Water Potential ◽

Atlantic Coast ◽

Canopy Temperature ◽

Titratable Acidity ◽

Climatic Conditions ◽

Leaf Water ◽

Field Conditions ◽

Soluble Solids

The aim of this study is to determine the behaviour of ‘Danlas’ grapevines conducted under plastic cover, near atlantic coast, known for its early table grape production. Measurements included climatic conditions, leaf water potential, canopy temperature and production components. The use of plastic cover resulted in an increase of midday ambient temperature and vapor pressure deficit, with a maximum of 5. 7 °C and 1.28 kPa, respectively. Midday canopy temperature under field conditions were lower than ambient temperature by an average of 2.5 °C. The most negative leaf water potential values were recoded for grapevines under plastic cover relatively to field conditions, ranging from –7.2 to –17.0 bars and from –7.0 to –14.0 bars, respectively. Harvest date was advanced by more than one month after the use of plastic cover. Results showed that crop weight, cluster weight and number per vine were not significantly affected. However, the number of berries per cluster was significantly reduced. Plastic cover promoted fruit quality, berry weight and soluble solids concentration were increased by 2.23 g and 1.0 °Brix, respectively. While titratable acidity was decreased by 1.20 g/l.

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