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Does night-time transpiration contribute to anisohydric behaviour in a Vitis vinifera cultivar?

Rogiers SY, Greer DH, Hutton RJ, Landsberg JJ - J. Exp. Bot. (2009)

Bottom Line: Furthermore, Psi(l) fell to significantly lower values than in any of the nine other varieties examined.Night-time values of stomatal conductance (g(n)) and transpiration (E(n)) in Semillon were up to four times higher than in other varieties; plants enclosed in plastic bags overnight to reduce E(n) resulted in better plant-soil equilibration so that predawn Psi(l) in Semillon was the same as in Grenache.The high values of g(day) were associated with high rates of transpiration (E(day)) by Semillon through a day when VPD reached 4.5 kPa.

View Article: PubMed Central - PubMed

Affiliation: National Wine and Grape Industry Centre, NSW Department of Primary Industries and Charles Sturt University, Wagga Wagga, NSW 2678, Australia. suzy.rogiers@dpi.nsw.gov.au

ABSTRACT
The hypothesis that vines of the Semillon wine grape variety show anisohydric behaviour was tested, i.e. that tissue hydration is unstable under fluctuating environmental conditions. Stomatal conductance and transpiration rates from leaves were measured during the day and at night. Leaf water potential (Psi(l)) in Semillon was negatively correlated to vapour pressure deficit (VPD) both predawn and during the day. Furthermore, Psi(l) fell to significantly lower values than in any of the nine other varieties examined. Night-time values of stomatal conductance (g(n)) and transpiration (E(n)) in Semillon were up to four times higher than in other varieties; plants enclosed in plastic bags overnight to reduce E(n) resulted in better plant-soil equilibration so that predawn Psi(l) in Semillon was the same as in Grenache. These data indicate that the hypothesis is supported, and that night-time transpiration contributes significantly to the low Psi(l) values in Semillon during warm, dry nights. The other contributing factor is daytime stomatal conductance (g(day)), which in Semillon leaves was higher than in other varieties, although the decline in g(day) with increasing VPD was greater in Semillon than in Shiraz or Grenache. The high values of g(day) were associated with high rates of transpiration (E(day)) by Semillon through a day when VPD reached 4.5 kPa. When compared to other varieties, Semillon was not unusual in terms of root length density, stomatal density, xylem sap abscisic acid, or leaf electrolyte leakage. Night-time and daytime water loss and insufficient stomatal regulation therefore account for the tendency to anisohydric behaviour shown by Semillon.

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Related in: MedlinePlus

Night transpiration (Enight) and conductance (gnight) of potted Semillon and three other varieties. Night-time measurements were conducted 2 h before dawn and the block temperature was not controlled. The effect of variety on gnight and Enight was significant at P <0.001. LSD5% for gnight is 0.005 and for Enight is 0.07. Soil moisture under the dripper was not significantly different between varieties and averaged at 46%. VPD was 1.4 kPa.
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fig8: Night transpiration (Enight) and conductance (gnight) of potted Semillon and three other varieties. Night-time measurements were conducted 2 h before dawn and the block temperature was not controlled. The effect of variety on gnight and Enight was significant at P <0.001. LSD5% for gnight is 0.005 and for Enight is 0.07. Soil moisture under the dripper was not significantly different between varieties and averaged at 46%. VPD was 1.4 kPa.

Mentions: En rates and gn values were one-tenth of the daytime rates and values (Figs 4, 8). Despite this, there were strong varietal differences, with both gn (0.021 mol H2O m−2 s−1) and En (0.32 mmol H2O m−2 s−1) of Semillon leaves being 4-fold greater than in Grenache leaves, where gn≈0.005 mol H2O m−2 s−1 and En≈0.08 mmol H2O m−2 s−1 (Fig. 8). Across the four varieties, there was a highly significant (R2=0.9914, P <0.001) linear relationship between En and gn. This indicated night-time differences in stomatal conductance between the cultivars fully accounted for the differences in transpiration.


Does night-time transpiration contribute to anisohydric behaviour in a Vitis vinifera cultivar?

Rogiers SY, Greer DH, Hutton RJ, Landsberg JJ - J. Exp. Bot. (2009)

Night transpiration (Enight) and conductance (gnight) of potted Semillon and three other varieties. Night-time measurements were conducted 2 h before dawn and the block temperature was not controlled. The effect of variety on gnight and Enight was significant at P <0.001. LSD5% for gnight is 0.005 and for Enight is 0.07. Soil moisture under the dripper was not significantly different between varieties and averaged at 46%. VPD was 1.4 kPa.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2736890&req=5

fig8: Night transpiration (Enight) and conductance (gnight) of potted Semillon and three other varieties. Night-time measurements were conducted 2 h before dawn and the block temperature was not controlled. The effect of variety on gnight and Enight was significant at P <0.001. LSD5% for gnight is 0.005 and for Enight is 0.07. Soil moisture under the dripper was not significantly different between varieties and averaged at 46%. VPD was 1.4 kPa.
Mentions: En rates and gn values were one-tenth of the daytime rates and values (Figs 4, 8). Despite this, there were strong varietal differences, with both gn (0.021 mol H2O m−2 s−1) and En (0.32 mmol H2O m−2 s−1) of Semillon leaves being 4-fold greater than in Grenache leaves, where gn≈0.005 mol H2O m−2 s−1 and En≈0.08 mmol H2O m−2 s−1 (Fig. 8). Across the four varieties, there was a highly significant (R2=0.9914, P <0.001) linear relationship between En and gn. This indicated night-time differences in stomatal conductance between the cultivars fully accounted for the differences in transpiration.

Bottom Line: Furthermore, Psi(l) fell to significantly lower values than in any of the nine other varieties examined.Night-time values of stomatal conductance (g(n)) and transpiration (E(n)) in Semillon were up to four times higher than in other varieties; plants enclosed in plastic bags overnight to reduce E(n) resulted in better plant-soil equilibration so that predawn Psi(l) in Semillon was the same as in Grenache.The high values of g(day) were associated with high rates of transpiration (E(day)) by Semillon through a day when VPD reached 4.5 kPa.

View Article: PubMed Central - PubMed

Affiliation: National Wine and Grape Industry Centre, NSW Department of Primary Industries and Charles Sturt University, Wagga Wagga, NSW 2678, Australia. suzy.rogiers@dpi.nsw.gov.au

ABSTRACT
The hypothesis that vines of the Semillon wine grape variety show anisohydric behaviour was tested, i.e. that tissue hydration is unstable under fluctuating environmental conditions. Stomatal conductance and transpiration rates from leaves were measured during the day and at night. Leaf water potential (Psi(l)) in Semillon was negatively correlated to vapour pressure deficit (VPD) both predawn and during the day. Furthermore, Psi(l) fell to significantly lower values than in any of the nine other varieties examined. Night-time values of stomatal conductance (g(n)) and transpiration (E(n)) in Semillon were up to four times higher than in other varieties; plants enclosed in plastic bags overnight to reduce E(n) resulted in better plant-soil equilibration so that predawn Psi(l) in Semillon was the same as in Grenache. These data indicate that the hypothesis is supported, and that night-time transpiration contributes significantly to the low Psi(l) values in Semillon during warm, dry nights. The other contributing factor is daytime stomatal conductance (g(day)), which in Semillon leaves was higher than in other varieties, although the decline in g(day) with increasing VPD was greater in Semillon than in Shiraz or Grenache. The high values of g(day) were associated with high rates of transpiration (E(day)) by Semillon through a day when VPD reached 4.5 kPa. When compared to other varieties, Semillon was not unusual in terms of root length density, stomatal density, xylem sap abscisic acid, or leaf electrolyte leakage. Night-time and daytime water loss and insufficient stomatal regulation therefore account for the tendency to anisohydric behaviour shown by Semillon.

Show MeSH
Related in: MedlinePlus