scholarly journals SUPRAOPTIMAL ROOT-ZONE TEMPERATURE EFFECTS ON WATER USE OF THREE CERCIS SPP.

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 635c-635
Author(s):  
Beth Jez Lawrence ◽  
Jayne M. Zajicek
Keyword(s):  
Sap Flow ◽  
Root Zone ◽  
Time Intervals ◽  
Flow Measurements ◽  
Root Zone Temperature ◽  
Flow Rates ◽  
Plant Transpiration ◽  
Whole Plant ◽  
Environment Chamber ◽  
Sap Flow Measurements

Sap flow rates of three Cercis spp. exposed to supraoptimal root-zone temperatures were characterized in a controlled environment chamber using a water bath to control temperatures. Flow rates of sap in the xylem were measured every 15 sec. and averaged over 15 min. intervals. Sap flow measurements were correlated to root-zone temperatures recorded during the same time intervals. Whole plant transpiration was measured gravimetrically. Root-zone temperatures were maintained at 22C for three consecutive 24-hr cycles and then increased to 45C for an additional three 24-hr periods. All plants, regardless of species, had reduced sap flow patterns when exposed to high root-zone temperatures. Plants maintained at a constant temperature of 22C showed no extreme fluctuations in sap flow rate. Stomatal conductance rates and leaf water potentials showed similar trends to whole plant transpiration.

scholarly journals HIGH ROOT-ZONE TEMPERATURE EFFECTS ON DIURNAL WATER USE OF WOODY ORNAMENTAL

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1118a-1118
Author(s):  
B. Jez Lawrence ◽  
J.M. Zajicek
Keyword(s):  
Flow Rate ◽  
Sap Flow ◽  
Root Zone ◽  
Temperature Cycle ◽  
Root Zone Temperature ◽  
Flow Rates ◽  
Plant Transpiration ◽  
Whole Plant ◽  
Woody Ornamental ◽  
Zone Temperature

Root-zone temperature fluctuations and sap flow rates were characterized for several woody ornamental plants in a controlled environment using a water bath to control temperatures. Flow rates of sap in the xylem were measured every 15 seconds and averaged over 15 minute intervals. Sap flow measurements were correlated to root-zone temperatures recorded during the same time intervals. Whole plant transpiration was measured gravimetrically. Root-zone temperatures were raised from 22°C to 45°C (slightly below lethality between 9:00 am and 12:00 noon, held at that temperature until 4:00 pm, and then allowed to cool. There was a pronounced diurnal change in flow rate with peak flow during mid-morning declining in mid-afternoon. The decline in the rate of sap flow occurred at a faster rate than the decline in root-zone temperature. This diurnal flow rate was most pronounced during the first 24-hour elevated temperature cycle. Plants maintained at a constant temperature of 22°C showed no such extreme fluctuations in sap flow rate. Stomatal conductance measured with a porometer showed similar trends to whole plant transpiration.

Effects of nitrogen supply on xylem cytokinin delivery, transpiration and leaf expansion of pea genotypes differing in xylem-cytokinin concentration

2004 ◽  
Vol 31 (9) ◽  
pp. 903 ◽  
Author(s):  
Ian C. Dodd ◽  
Chuong Ngo ◽  
Colin G. N. Turnbull ◽  
Christine A. Beveridge
Keyword(s):  
Sap Flow ◽  
Leaf Growth ◽  
Xylem Sap ◽  
Leaf Expansion ◽  
Growth Responses ◽  
Flow Rates ◽  
Plant Transpiration ◽  
Discernible Effect ◽  
Whole Plant ◽  
N Treatment

The rms2 and rms4 pea (Pisum sativum L.) branching mutants have higher and lower xylem-cytokinin concentration, respectively, relative to wild type (WT) plants. These genotypes were grown at two levels of nitrogen (N) supply for 18–20 d to determine whether or not xylem-cytokinin concentration (X-CK) or delivery altered the transpiration and leaf growth responses to N deprivation. Xylem sap was collected by pressurising de-topped root systems. As sap-flow rate increased, X-CK declined in WT and rms2, but did not change in rms4. When grown at 5.0 mm N, X-CKs of rms2 and rms4 were 36% higher and 6-fold lower, respectively, than WT at sap-flow rates equivalent to whole-plant transpiration. Photoperiod cytokinin (CK) delivery rates (the product of transpiration and X-CK) decreased more than 6-fold in rms4. Growth of plants at 0.5 mm N had negligible (< 10%) effects on transpiration rates expressed on a leaf area basis in WT and rms4, but decreased transpiration rates of rms2. The low-N treatment decreased leaf expansion by 20–25% and expanding leaflet N concentration by 15%. These changes were similar in all genotypes. At sap-flow rates equivalent to whole-plant transpiration, the low N treatment decreased X-CK in rms2 but had no discernible effect in WT and rms4. Since the low N treatment decreased transpiration of all genotypes, photoperiod CK delivery rates also decreased in all genotypes. The similar leaf growth response of all genotypes to N deprivation despite differences in both absolute and relative X-CKs and deliveries suggests that shoot N status is more important in regulating leaf expansion than xylem-supplied cytokinins. The decreased X-CK and transpiration rate of rms2 following N deprivation suggests that changes in xylem-supplied CKs may modify water use.

Using branch and basal trunk sap flow measurements to estimate whole-plant water capacitance: a caution

2007 ◽  
Vol 305 (1-2) ◽  
pp. 5-13 ◽  
Author(s):  
Stephen S. O. Burgess ◽  
Todd E. Dawson
Keyword(s):  
Sap Flow ◽  
Plant Water ◽  
Flow Measurements ◽  
Whole Plant ◽  
Sap Flow Measurements

Using branch and basal trunk sap flow measurements to estimate whole-plant water capacitance: comment on Burgess and Dawson (2008)

2008 ◽  
Vol 315 (1-2) ◽  
pp. 315-324 ◽  
Author(s):  
Nathan G. Phillips ◽  
Fabian G. Scholz ◽  
Sandra J. Bucci ◽  
Guillermo Goldstein ◽  
Frederick C. Meinzer
Keyword(s):  
Sap Flow ◽  
Plant Water ◽  
Flow Measurements ◽  
Whole Plant ◽  
Sap Flow Measurements

scholarly journals Technical note on long-term probe misalignment and proposed quality control using the heat pulse method for transpiration estimations

2019 ◽  
Author(s):  
Elisabeth K. Larsen ◽  
Jose Luis Palau ◽  
Jose Antonio Valiente ◽  
Esteban Chirino ◽  
Juan Bellot
Keyword(s):  
Quality Control ◽  
Sap Flow ◽  
Hydrological Cycle ◽  
Individual Performance ◽  
Technical Note ◽  
Flow Measurements ◽  
Plant Transpiration ◽  
Whole Plant ◽  
Relative Standard

Abstract. Whole-plant transpiration is a crucial component in the hydrological cycle and a key parameter in many disciplines like agriculture, forestry and ecology. Sap flow measurements are one of the most widely used methods to estimate whole-plant transpiration in woody species due to its wide application range and its ready automation for continuous data readings. Several different methods have been developed and adjusted to different climatic conditions and wood properties. However, the scientific literature also identifies several sources of error in the method that needs to be accounted for; misalignment of the probes, wound to the xylem, thermal diffusivity and stem water content. This study aims to integrate probe misalignment as a function of time to improve readings during long-term measurements (> 3 months). We conclude that even when geometrical misalignments errors are small, the introduced corrections can imply an important shift in sap flow estimations. Additionally, we propose a new set of statistical information to be recorded during the measurement period to use as a quality control of the heat ratio readings obtained from the sensors. By using relative standard deviation and slope as quality indicators we concluded that no general time limit can be decided for all sensors but should rather be determined from individual performance over time.

scholarly journals Global transpiration data from sap flow measurements: the SAPFLUXNET database

2020 ◽  
Author(s):  
Rafael Poyatos ◽  
Víctor Granda ◽  
Víctor Flo ◽  
Mark A. Adams ◽  
Balázs Adorján ◽  
...  
Keyword(s):  
Time Series ◽  
Sap Flow ◽  
Structural Characteristics ◽  
Vapour Pressure Deficit ◽  
Environmental Drivers ◽  
Plant Responses ◽  
Flow Measurements ◽  
Automatic Data ◽  
Plant Transpiration ◽  
Sap Flow Measurements

Abstract. Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy and carbon budgets at the land-atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/). We harmonised and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well-represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets, while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks and remote sensing products to help increase our understanding of plant water use, plant responses to drought and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository ( https://doi.org/10.5281/zenodo.3971689, Poyatos et al., 2020a). The sapfluxnetr R package, designed to access, visualise and process SAPFLUXNET data is available from CRAN.

scholarly journals Global transpiration data from sap flow measurements: the SAPFLUXNET database

2021 ◽  
Vol 13 (6) ◽  
pp. 2607-2649
Author(s):  
Rafael Poyatos ◽  
Víctor Granda ◽  
Víctor Flo ◽  
Mark A. Adams ◽  
Balázs Adorján ◽  
...  
Keyword(s):  
Time Series ◽  
Sap Flow ◽  
Structural Characteristics ◽  
Vapour Pressure Deficit ◽  
Environmental Drivers ◽  
Plant Responses ◽  
Flow Measurements ◽  
Automatic Data ◽  
Plant Transpiration ◽  
Sap Flow Measurements

Abstract. Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land–atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). We harmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets, while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, and remote sensing products to help increase our understanding of plant water use, plant responses to drought, and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository (https://doi.org/10.5281/zenodo.3971689; Poyatos et al., 2020a). The “sapfluxnetr” R package – designed to access, visualize, and process SAPFLUXNET data – is available from CRAN.

Can heat-pulse sap flow measurements be used as continuous water stress indicators of citrus trees?

2012 ◽  
Vol 31 (5) ◽  
pp. 1053-1063 ◽  
Author(s):  
C. Ballester ◽  
J. Castel ◽  
L. Testi ◽  
D. S. Intrigliolo ◽  
J. R. Castel
Keyword(s):  
Water Stress ◽  
Sap Flow ◽  
Heat Pulse ◽  
Flow Measurements ◽  
Stress Indicators ◽  
Sap Flow Measurements ◽  
Citrus Trees

Sap Flow Measurements

2017 ◽  
pp. 99-112 ◽  
Author(s):  
Barbara Köstner ◽  
Eva Falge ◽  
Martina Alsheimer
Keyword(s):  
Sap Flow ◽  
Flow Measurements ◽  
Sap Flow Measurements
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