Abstract
Heat-balance sap flow gauges were configured to produce a more thermally uniform stem cross-section under high flow rates. On mature grapevines (Vitis labruscana; leaf area per vine ≤27 m 2 ) either undisturbed in the field or transplanted to large containers (ca. 1 m 3 volume) that were monitored on a balance, custom-built gauges (stem diam. ≤46 mm) under variable power were run simultaneously with a whole-plant gas exchange system. Transpiration (Tr) varied from about 80 g h -1 overnight to daily maxima approaching 2100 g h -1 (container vines) and 2700 g h -1 (field vines). In container vines, instantaneous estimates of Tr (6.00 to 20.00 local standard time [HR]) agreed most closely between gas exchange and gravimetry (Spearman Rank R = 0.96; p<0.05). Estimates of Tr were correlated significantly between sap flow and gas exchange (R = 0.94; p<0.05), and between sap flow and gravimetry (R = 0.88; p<0.05). On average, cumulative estimates of Tr over 24h (17 to 19 L d -1 ) agreed within 5% (gravimetry vs. gas exchange) and within 17% (sap gauge vs. gas exchange or gravimetry). Instantaneous estimates of Tr for field vines were correlated significantly (p<0.05) between sap flow and gas exchange (R = 0.87). Cumulative water use per vine was 18 to 22 L d -1 ; estimation methods differed on average by 15%. In both container and field vines, sap flow gauges underestimated high mid-day rates of Tr consistently, due in part to the choice of power input. The open-loop power control algorithm maintained upstream-downstream surface temperature differences between 1.5 and 2°C during midday, but the algorithm was not responsive enough to the very rapid rate of change in Tr for about two hours during the morning, resulting in anomalous overestimates of Tr.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 13
Claim · model-written summary
Container-vine transpiration approached 2100 g h -1 and field-vine transpiration approached 2700 g h -1.
VitisOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Transpiration (Tr) varied from about 80 g h -1 overnight to daily maxima approaching 2100 g h -1 (container vines) and 2700 g h -1 (field vines)”
t0“grapevines”
Claim · model-written summary
Field-vine transpiration approached 2700 g h -1.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“daily maxima approaching 2100 g h -1 (container vines) and 2700 g h -1 (field vines)”
t0“grapevines”
Claim · model-written summary
Container-vine gas-exchange and gravimetric instantaneous estimates agreed most closely, with R = 0.96.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In container vines, instantaneous estimates of Tr (6.00 to 20.00 local standard time [HR]) agreed most closely between gas exchange and gravimetry (Spearman Rank R = 0.96; p<0.05)”
t0“grapevines”
Claim · model-written summary
Sap flow and gas-exchange transpiration estimates correlated significantly, R = 0.94.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Estimates of Tr were correlated significantly between sap flow and gas exchange (R = 0.94; p<0.05)”
t0“grapevines”
Claim · model-written summary
Sap flow and gravimetric transpiration estimates correlated significantly, R = 0.88.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“between sap flow and gravimetry (R = 0.88; p<0.05)”
t0“grapevines”
Claim · model-written summary
Daily cumulative gas-exchange and gravimetric estimates agreed within 5%.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cumulative estimates of Tr over 24h (17 to 19 L d -1 ) agreed within 5% (gravimetry vs. gas exchange)”
t0“grapevines”
Claim · model-written summary
Daily cumulative sap-gauge estimates agreed within 17% of gas exchange or gravimetry.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“within 17% (sap gauge vs. gas exchange or gravimetry)”
t0“grapevines”
Claim · model-written summary
Field-vine sap-flow and gas-exchange instantaneous estimates correlated significantly, R = 0.87.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Instantaneous estimates of Tr for field vines were correlated significantly (p<0.05) between sap flow and gas exchange (R = 0.87)”
t0“grapevines”
Claim · model-written summary
Field-vine cumulative water use was 18 to 22 L d -1.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cumulative water use per vine was 18 to 22 L d -1”
t0“grapevines”
Claim · model-written summary
Field-vine estimation methods differed by 15% on average.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“estimation methods differed on average by 15%”
t0“grapevines”
Claim · model-written summary
Sap-flow gauges consistently underestimated high midday transpiration in container and field vines.
- Outcome
- high mid-day rates of Tre0
- Direction
- underestimatede0
- Qualifier
- due in part to the choice of power inpute0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In both container and field vines, sap flow gauges underestimated high mid-day rates of Tr consistently, due in part to the choice of power input”
t0“grapevines”
Claim · model-written summary
The power-control algorithm maintained a 1.5 to 2°C midday surface-temperature difference.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The open-loop power control algorithm maintained upstream-downstream surface temperature differences between 1.5 and 2°C during midday”
t0“grapevines”
Claim · model-written summary
The algorithm failed to respond quickly to morning transpiration change and overestimated transpiration.
- Outcome
- overestimates of Tre0
- Direction
- overestimatese0
- Qualifier
- for about two hours during the morninge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the algorithm was not responsive enough to the very rapid rate of change in Tr for about two hours during the morning, resulting in anomalous overestimates of Tr”
t0“grapevines”