Transpiration and canopy conductance in a pristine broad-leaved forest of Nothofagus: an analysis of xylem sap flow and eddy correlation measurements

Oecologia ◽  
1992 ◽  
Vol 91 (3) ◽  
pp. 350-359 ◽  
Author(s):  
B. M. M. Köstner ◽  
E. -D. Schulze ◽  
F. M. Kelliher ◽  
D. Y. Hollinger ◽  
J. N. Byers ◽  
...  
Keyword(s):  
Sap Flow ◽  
Xylem Sap ◽  
Eddy Correlation ◽  
Canopy Conductance ◽  
Broad Leaved Forest ◽  
Xylem Sap Flow ◽  
Leaved Forest

Evaporation, xylem sap flow, and tree transpiration in a New Zealand broad-leaved forest

1992 ◽  
Vol 62 (1-2) ◽  
pp. 53-73 ◽  
Author(s):  
F.M. Kelliher ◽  
B.M.M. Köstner ◽  
D.Y. Hollinger ◽  
J.N. Byers ◽  
J.E. Hunt ◽  
...  
Keyword(s):  
New Zealand ◽  
Sap Flow ◽  
Xylem Sap ◽  
Tree Transpiration ◽  
Broad Leaved Forest ◽  
Xylem Sap Flow ◽  
Leaved Forest

Regulation of canopy conductance and transpiration and their modelling in irrigated grapevines

2003 ◽  
Vol 30 (6) ◽  
pp. 689 ◽  
Author(s):  
Ping Lu ◽  
Isa A. M. Yunusa ◽  
Rob R. Walker ◽  
Warren J. Müller
Keyword(s):  
Solar Radiation ◽  
Sap Flow ◽  
Heat Dissipation ◽  
Xylem Sap ◽  
Vapour Pressure Deficit ◽  
Vitis Vinifera L ◽  
Canopy Conductance ◽  
Xylem Sap Flow ◽  
Highly Correlated ◽  
Monteith Equation

Whole-vine transpiration was estimated for well-watered nine-year-old Sultana grapevines (Vitis vinifera L. cv. Sultana) from xylem sap flow measured with Granier's heat-dissipation probes. Canopy conductance of the grapevine was calculated by inverting the Penman–Monteith equation. Transpiration from grapevine canopies was strongly controlled by the canopy conductance. Canopy conductance decreased exponentially with increasing vapour pressure deficit (VPD) except in the morning when solar radiation was less than 200 W m–2 and the canopy conductance was predominantly limited by the solar radiation. A non-linear model of canopy conductance as a function of the solar radiation and VPD explained > 90% of the variation observed in canopy conductance. Under contrasting VPD conditions (daytime maximum of 3 kPa vs 8 kPa), grapevines were able to regulate their canopy conductance from 0.006 to 0.001 m s–1 to maintain a near constant transpiration. Whole-canopy transpiration calculated from modelled canopy conductance using the Penman–Monteith equation was highly correlated with the measured transpiration (sap flow) values over the range of 0–0.20 mm h–1 (R2 > 0.85). Cross-validation shows that these mechanistic models based on solar radiation and VPD provide good predictions of canopy conductance and transpiration under the conditions of the study.

scholarly journals Microscale Xylem Sap Flow Sensor Facilitating the Simultaneous Measurement of Flow Velocity and Direction

Proceedings ◽  
2019 ◽  
Vol 2 (13) ◽  
pp. 824
Author(s):  
Yuki Hara ◽  
Naoki Hara ◽  
Hiroki Ishizuka ◽  
Kyohei Terao ◽  
Hidekuni Takao ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Simultaneous Measurement ◽  
Sap Flow ◽  
Xylem Sap ◽  
Flow Sensor ◽  
Functional Verification ◽  
Thermal Flow Sensor ◽  
Quantitative Monitoring ◽  
Mems Technology ◽  
Xylem Sap Flow

In this study, we focused on direct and quantitative monitoring of sap dynamics in plant stems, and proposed the microscale xylem sap flow sensor. This sensor facilitates the simultaneous measurement of flow velocity and direction by combining the principles of a Granier sensor and a thermal flow sensor. We fabricated micro-sensor chips for functional verification by using MEMS technology, and assembled them on a resin film to facilitate mounting on the epidermis of plants. Furthermore, we measured the sap dynamics by using an experimental setup, and succeeded in measuring the flow velocity and direction at the same time.

scholarly journals In vivo pressure gradient heterogeneity increases flow contribution of small diameter vessels in grapevine

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Martin Bouda ◽  
Carel W. Windt ◽  
Andrew J. McElrone ◽  
Craig R. Brodersen
Keyword(s):  
Sap Flow ◽  
Xylem Sap ◽  
Small Diameter ◽  
Fourth Power ◽  
First Year ◽  
Long Distance ◽  
Xylem Sap Flow ◽  
Flow Mri ◽  
Vessel Network

AbstractLeaves lose approximately 400 H2O molecules for every 1 CO2 gained during photosynthesis. Most long-distance water transport in plants, or xylem sap flow, serves to replace this water to prevent desiccation. Theory predicts that the largest vessels contribute disproportionately to overall sap flow because flow in pipe-like systems scales with the fourth power of radius. Here, we confront these theoretical flow predictions for a vessel network reconstructed from X-ray μCT imagery with in vivo flow MRI observations from the same sample of a first-year grapevine stem. Theoretical flow rate predictions based on vessel diameters are not supported. The heterogeneity of the vessel network gives rise to transverse pressure gradients that redirect flow from wide to narrow vessels, reducing the contribution of wide vessels to sap flow by 15% of the total. Our results call for an update of the current working model of the xylem to account for its heterogeneity.

scholarly journals A Requirement for Sucrose in Xylem Sap Flow from Dormant Maple Trees

1987 ◽  
Vol 84 (2) ◽  
pp. 495-500 ◽  
Author(s):  
Robert W. Johnson ◽  
Melvin T. Tyree ◽  
Michael A. Dixon
Keyword(s):  
Sap Flow ◽  
Xylem Sap ◽  
Xylem Sap Flow
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