scholarly journals TRANSPIRATION OF A POTTED ROSE PLANT USING A HEAT BALANCE STEM FLOW GAUGE

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1073a-1073
Author(s):  
Mark A. Rose ◽  
John W. White ◽  
Joel L. Cuello
Keyword(s):  
Heat Balance ◽  
Sap Flow ◽  
Continuous Measurement ◽  
Future Research ◽  
Total Leaf Area ◽  
Flow Rates ◽  
Non Invasive ◽  
Significant Linear Correlation ◽  
Stem Flow ◽  
Plant Sap

Recently developed stem flow gauges that allow for direct, accurate, non-invasive, and continuous measurement of plant sap flow rates have not been used to monitor transpiration of floricultural plants grown in greenhouses.A Dynamax SGA10 heat-balance sap-flow sensor was mounted on a potted rose plant's main stem containing a total leaf area of 0.52 m in order to monitor transpiration. The sensor was connected to a CR21X Micrologger for data calculation and temporary storage. The results showed average midday sap-flow rates range from 20-30 g·hr-1 to 50-70 g·hr-1 at low and high levels of PPF, respectively. Nighttime levels of 4-7 g·hr-1 persisted throughout early winter trials. Monitoring transpiration of the same rose stem using a lysimeter revealed a significant linear correlation (r2 = 0.999) between the lysimeter and the stem flow gauge values.In the future, research will be conducted with the gauge to investigate relationships between microclimatic variables, photosynthesis, and transpiration.

Determination of the water use of two pairs of soybean isolines differing in stomatal frequency using a heat balance stem flow gauge

1995 ◽  
Vol 75 (1) ◽  
pp. 99-103 ◽  
Author(s):  
C. S. Tan ◽  
B. R. Buttery
Keyword(s):  
Soil Moisture ◽  
Water Use ◽  
Heat Balance ◽  
Sap Flow ◽  
Stomatal Frequency ◽  
Flow Rates ◽  
High Soil Moisture ◽  
Stem Flow ◽  
Glycine Max L

Using heat-balance stem flow gauges, we were able to measure directly and continuously the sap flow rates in two pairs of soybean [Glycine max (L.) Merr.] isolines differing in stomatal frequency. Plants with high stomatal frequency transpired significantly more water than the low stomatal frequency plants at high soil moisture levels. Under low soil moisture levels, the water use rate decreased greatly for the high stomatal frequency plants. Plants with low stomatal frequency were able to maintain greater sap flow rates than those with high stomatal frequency. Higher leaf temperatures associated with the low stomatal frequency plants were likely due to lower transpiration rates which reduced evaporative cooling especially under well-watered conditions. Key words:Glycine max (L.) Merr., transpiration, water deficits

scholarly journals Oscillatory Transpiration May Complicate Stomatal Conductance and Gas-exchange Measurements

HortScience ◽  
1994 ◽  
Vol 29 (6) ◽  
pp. 693-694 ◽  
Author(s):  
Mary Ann Rose ◽  
Mark A. Rose
Keyword(s):  
Steady State ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Heat Balance ◽  
Sap Flow ◽  
Closed Loop ◽  
Random Noise ◽  
Plant Responses ◽  
Whole Plant ◽  
Plant Sap

A closed-loop photosynthesis system and a heat-balance sap-flow gauge independently confirmed oscillatory transpiration in a greenhouse-grown Rosa hybrids L. Repetitive sampling revealed 60-minute synchronized oscillations in CO2-exchange rate, stomatal conductance, and whole-plant sap-flow rate. To avoid confusing cyclical plant responses with random noise in measurement, we suggest that gas-exchange protocols begin with frequent, repetitive measurements to determine whether transpiration is stable or oscillating. Single measurements of individual plants would be justified only when transpiration is steady state.

Unravelling the relationship between stem temperature and air temperature to correct for errors in sap-flow calculations using stem heat balance sensors

2005 ◽  
Vol 32 (7) ◽  
pp. 599 ◽  
Author(s):  
Kathy Steppe ◽  
Raoul Lemeur ◽  
Diego Dierick
Keyword(s):  
Air Temperature ◽  
Flow Rate ◽  
Heat Balance ◽  
Sap Flow ◽  
Heat Storage ◽  
Flow Rates ◽  
Storage Effects ◽  
Stem Temperature ◽  
Oak Tree ◽  
Set Up

Results from measurement of sap flow by heat balance sensors on the stem of a young oak tree (Quercus robur L.) revealed that thermal disequilibrium (i.e. heat storage) within the heated stem segment can introduce considerable errors in the measured sap-flow rates. The magnitude, sign and significance of these errors depend on the sap-flow rate and on the relationship between stem temperature and air temperature. Sap-flow rates were found to be more prone to errors caused by heat storage effects under low flow conditions than at higher rates of sap flow. Furthermore, daytime fluctuations of air temperature and stem temperature inside the heat balance sensor were either in phase when a low, or in opposite phase when a high sap-flow rate was passing through the stem of the young tree. To investigate this relationship, we developed an experimental set-up with cut stem segments through which tap water could be pressed. This set-up allowed the effects of air temperature and sap-flow rates on stem temperatures within heat balance sensors to be clearly separated. Good mathematical relationships were obtained and were successfully used to assess the relative importance of air temperature and sap-flow rate with respect to the fluctuations in stem temperature of the young oak tree. Based on the established relationships, a novel approach was put forward to correct for errors introduced into sap-flow calculations caused by heat storage effects if no measured data on stem temperature are available.

Cover Crop Effects on Corn Plant Sap Flow Rates and Soil Water Dynamics

Crop Science ◽  
2019 ◽  
Vol 59 (5) ◽  
pp. 2227-2236 ◽  
Author(s):  
Lalith M. Rankoth ◽  
Ranjith P. Udawatta ◽  
Clark J. Gantzer ◽  
Shibu Jose ◽  
Kelly A. Nelson
Keyword(s):  
Soil Water ◽  
Sap Flow ◽  
Cover Crop ◽  
Water Dynamics ◽  
Soil Water Dynamics ◽  
Corn Plant ◽  
Flow Rates ◽  
Plant Sap

Determination of the water use and water use response of canola to solar radiation and temperature by using heat balance stem flow gauges

2003 ◽  
Vol 83 (1) ◽  
pp. 31-38 ◽  
Author(s):  
S. V. Angadi ◽  
H. W. Cutforth ◽  
B. G. McConkey
Keyword(s):  
Solar Radiation ◽  
Real Time ◽  
Heat Loss ◽  
Water Use ◽  
Heat Balance ◽  
Heat Input ◽  
Sap Flow ◽  
Flow System ◽  
Major Portion ◽  
Flow Rates

Sap flow gauges using a heat balance have been reliable for measuring real-time transpiration in a number of crops. However, information on the accuracy of sap flow gauges in canola is lacking. Therefore, a study was conducted to validate the sap flow system in canola and to observe sap flow response to variations in temperature and solar radiation. There were strong relationships between sap flow measured with sap flow gauges and actual transpiration measured by the gravimetric method over short periods of 1 h (r2 = 0.93 and RMSE = 2.34 g h-1), and over longer periods of 1 d (r2 = 0.83 and RMSE = 48 g d-1), although sap flow slightly overestimated transpiration. In both cases the slope was not significantly different from 1. Water use in canola, estimated with sap flow gauges or from actual transpiration measurement, was dependent upon temperature (r2 = 0.94 to 0.96). Water use increased until daytime temperatures reached 36°C, after which water use decreased. Sap flow followed solar radiation trends in the field. Heat is lost or dissipated from the gauges convectively as the sap flows through the stem, conductively through the solid stem material, and radially into the surrounding air. As the convective proportion of the heat loss from the gauge increased, the accuracy of the water use estimation using the sap flow gauges increased. For sunny days, convective heat loss through sap flow accounted for a major portion of the total heat input to the gauges, while on cloudy days radial heat loss from the gauges accounted for a major portion of the heat input. Thus, at low sap flow rates during cloudy days, the possibility of error in the sap flow system was high. Overall, sap flow in canola was strongly related to daily solar radiation (r2 = 0.92). The sensitive response to weather variations and the possibility of improving the accuracy at high flow rates in the field makes the use of sap flow gauges a viable option for measuring real-time transpiration in canola. Key words: Brassica napus, canola, heat balance, sap flow, transpiration, temperature, solar radiation

scholarly journals Transpiration by Crape Myrtle Cultivars Surrounded by Mulch, Soil, and Turfgrass Surfaces

HortScience ◽  
1991 ◽  
Vol 26 (9) ◽  
pp. 1207-1210 ◽  
Author(s):  
Jayne M. Zajicek ◽  
J.L. Heilman
Keyword(s):  
Vapor Pressure ◽  
Water Use ◽  
Heat Balance ◽  
Sap Flow ◽  
Longwave Radiation ◽  
Soil Surface ◽  
Bare Soil ◽  
The Other ◽  
Stem Flow ◽  
Daily Water

A study was conducted to explore how surface materials, including pine bark mulch, bare soil, and turfgrass, affect water use of diverse cultivars (dwarf weeping, dwarf upright, standard weeping, and standard upright) of crape myrtle (Lagerstroemia indica L.). Daily water use was measured gravimetrically, and instantaneous rates of sap flow were measured using heat balance stem flow gauges. Plants of all cultivars surrounded by the mulched surface lost 0.63 to 1.25 kg·m-2·day-1 more water than plants on the soil surface and 0.83 to 1.09 kg·m-2·day-1 more than plants surrounded by turf. The surface temperature of the mulch was higher than that of the other surfaces, resulting in greater fluxes of longwave radiation from the surface. Because of the greater energy load, plants on the mulched surface had higher leaf temperatures and higher leaf-air vapor pressure deficits (VPD) throughout the day. Plants on the mulched area also had higher stomata1 conductances during most of the day compared with those on bare soil and turfgrass surfaces.

scholarly journals Non-Invasive Fetal Electrocardiogram Monitoring Techniques: Potential and Future Research Opportunities in Smart Textiles

Signals ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 392-412
Author(s):  
Geetika Aggarwal ◽  
Yang Wei
Keyword(s):  
Heart Rate ◽  
Fetal Heart Rate ◽  
Fetal Heart ◽  
Skin Penetration ◽  
Future Research ◽  
Fetal Electrocardiogram ◽  
Smart Textiles ◽  
Non Invasive ◽  
Future Research Directions ◽  
Electrocardiogram Monitoring

During the pregnancy, fetal electrocardiogram (FECG) is deployed to analyze fetal heart rate (FHR) of the fetus to indicate the growth and health of the fetus to determine any abnormalities and prevent diseases. The fetal electrocardiogram monitoring can be carried out either invasively by placing the electrodes on the scalp of the fetus, involving the skin penetration and the risk of infection, or non-invasively by recording the fetal heart rate signal from the mother’s abdomen through a placement of electrodes deploying portable, wearable devices. Non-invasive fetal electrocardiogram (NIFECG) is an evolving technology in fetal surveillance because of the comfort to the pregnant women and being achieved remotely, specifically in the unprecedented circumstances such as pandemic or COVID-19. Textiles have been at the heart of human technological progress for thousands of years, with textile developments closely tied to key inventions that have shaped societies. The relatively recent invention of smart textiles is set to push boundaries again and has already opened the potential for garments relevant to medicine, and health monitoring. This paper aims to discuss the different technologies and methods used in non-invasive fetal electrocardiogram (NIFECG) monitoring as well as the potential and future research directions of NIFECG in the smart textiles area.

An Empirical Calibration for Heat-Balance Sap-Flow Sensors in Maize

2017 ◽  
Vol 109 (3) ◽  
pp. 1122-1128 ◽  
Author(s):  
Yueyue Wang ◽  
Xiao Zhang ◽  
Xinhua Xiao ◽  
Joshua Heitman ◽  
Robert Horton ◽  
...  
Keyword(s):  
Heat Balance ◽  
Sap Flow ◽  
Flow Sensors ◽  
Empirical Calibration ◽  
Sap Flow Sensors
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