The Influence of Short-term Partial Shading on Photosynthesis and Stomatal Conductance in Relations to Cropload of Grapevines (Vitis vinifera L.)

2000 ◽  
Vol 3 (2) ◽  
pp. 279-283
Author(s):  
Ghulam Nabi ◽  
Michea Trought . ◽  
David Whitehead .
Keyword(s):  
Stomatal Conductance ◽  
Vitis Vinifera ◽  
Vitis Vinifera L ◽  
Short Term ◽  
Partial Shading

Extension of a Farquhar model for limitations of leaf photosynthesis induced by light environment, phenology and leaf age in grapevines (Vitis vinifera L. cvv. White Riesling and Zinfandel)

2003 ◽  
Vol 30 (6) ◽  
pp. 673 ◽  
Author(s):  
Hans R. Schultz
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Vitis Vinifera ◽  
Leaf Age ◽  
Large Data ◽  
Co2 Assimilation ◽  
Vitis Vinifera L ◽  
Model Parameters ◽  
Data Set ◽  
Farquhar Model

Measurements of gas exchange and stomatal conductance were made on potted and field-grown grapevines (Vitis vinifera L.) on leaves from different light environments (sun and shade) at different phenological stages during the season to parameterise the Farquhar model. The model parameters for Rubisco activity (Vcmax), maximum electron transport rate (Jmax), and triose-phosphate utilisation (TPU) were estimated on the basis of a large data set (n = 105) of CO2 assimilation (A) versus internal CO2 pressure (Ci) curves. Leaf age was described with the leaf plastochron index (LPI). Stomatal coupling to photosynthesis was modelled with the Ball–Woodrow–Berry empirical model of stomatal conductance. Mature shade leaves had 35–40% lower values of Vcmax, Jmax and TPU than sun leaves. The difference between leaf types decreased at the end of the season. The ratio Jmax / Vcmax and values of day respiration (Rd) and CO2 compensation point in the absence of mitochondrial respiration (Γ*) varied little during the season and were independent of LPI. Validation of the model with independent diurnal data sets of measurements of gas exchange and stomatal conductance at ambient CO2 concentrations for three days between June and October, covering a large range of environmental conditions, showed good agreement between measured and simulated values.

scholarly journals A continuum of stomatal responses to water deficits among 17 wine grape cultivars (Vitis vinifera)

2020 ◽  
Vol 47 (1) ◽  
pp. 11 ◽  
Author(s):  
Alexander D. Levin ◽  
Larry E. Williams ◽  
Mark A. Matthews
Keyword(s):  
Stomatal Conductance ◽  
Vitis Vinifera ◽  
Water Status ◽  
Stomatal Closure ◽  
Vitis Vinifera L ◽  
Water Deficits ◽  
Stomatal Behaviour ◽  
Relationship Of ◽  
The Relationship ◽  
Maximum Stomatal Conductance

Vitis vinifera L. cultivars have been previously classified as isohydric, near-isohydric, anisohydric or isohydrodynamic, depending on the study. To test the hypothesis that V. vinifera cultivars’ stomatal behaviour can be separated into distinct classes, 17 cultivars grown in a replicated field trial were subjected to three irrigation treatments to manipulate vine water status across multiple years. Predawn (ΨPD) and midday (Ψl) leaf water potential and midday stomatal conductance (gs) were measured regularly throughout several seasons. The relationship of gs to Ψl was best modelled as a sigmoidal function and maximum stomatal conductance (gmax), water status at the onset of stomatal closure (Ψl95), sensitivity of closure (gsensitivity) and water status at the end of closure (Ψl25) were compared. There were no significant differences in gmax among cultivars. Cultivar-specific responses of gs to Ψl were broadly distributed along a continuum based on the relationship between Ψl95 and gsensitivity. Season-long cultivar mean Ψl values were positively related to Ψl25. In general, cultivars responded similarly to one another at high and low water status, but their stomatal behaviour differed at moderate water deficits. The results show that V. vinifera cultivars possess both iso- and anisohydric stomatal behaviours that depend on the intensity of water deficits, and call into question previous classifications assuming a single behaviour.

Gradients in stomatal conductance, xylem sap ABA and bulk leaf ABA along canes of Vitis vinifera cv. Shiraz: molecular and physiological studies investigating their source

2004 ◽  
Vol 31 (6) ◽  
pp. 659 ◽  
Author(s):  
Christopher J. Soar ◽  
Jim Speirs ◽  
Suzanne M. Maffei ◽  
Brian R. Loveys
Keyword(s):  
Stomatal Conductance ◽  
Vitis Vinifera ◽  
Biosynthetic Pathway ◽  
Xylem Sap ◽  
Leaf Age ◽  
Vitis Vinifera L ◽  
Local Synthesis ◽  
Cdna Sequences ◽  
Genes Encoding ◽  
Induced Changes

Gradients were observed in xylem sap ABA and in stomatal conductance along canes of Vitis vinifera L. cv. Shiraz. To investigate the source of the ABA responsible for these gradients a series of girdling and decapitation experiments were carried out. Leaf stomatal conductance and bulk ABA of leaves and apices were measured in control plants and in response to apex removal or girdling. Gradients in leaf ABA were observed over the first eight expanded leaves of field-grown Shiraz, with higher concentrations of ABA observed towards the apex. Gradients in stomatal conductance that correlated negatively with the concentration of ABA in the leaf ([ABA]leaf) were also observed over the first eight leaves. No significant effect of decapitation was observed on either leaf ABA or stomatal conductance except for the leaf immediately below the apex where a transient increase in [ABA]leaf was observed after 24 h with no corresponding decrease in conductance. Girdling resulted in an increase in [ABA]leaf in leaves distal to the girdle without the corresponding effect on conductance. These effects were further studied at the level of gene activity. To facilitate this, gene sequences encoding two key enzymes involved in the biosynthetic pathway of ABA in grape, zeaxanthin epoxidase (Zep) and 9-cis-epoxycarotenoid dioxygenase (NCED), were isolated and characterised. The cDNA sequences were used as probes to measure the abundances of their respective mRNAs in the leaf and apical material. Levels of expression of one of the two genes encoding NCED, VvNCED1, reflected the gradients in [ABA]leaf in control vines, however treatment-induced changes in ABA were not always associated with corresponding changes in VvNCED1 expression. The abundances of both the VvNCED2 mRNA and Zep mRNA increased with increasing leaf age and did not appear to be associated with either the [ABA]leaf or the expression of VvNCED1. Our results indicate that observed gradients in g s are correlated with [ABA] gradients in mature leaves and xylem sap and that these [ABA] gradients are not derived directly from the apical tissues but, at least partially, from local synthesis.

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