PERFORMANCE OF HEAT-BALANCE SAP-FLOW GAUGE ON ROSE

Constant heat-balance sap-flow gauges were evaluated for use as on-line biosensors in a climate control network.
These gauges were installed on the single main stem of potted rose plants to continuously monitor whole-plant transpiration (WPT).

In order to minimise errors in gauge performance, modified protocols should be followed for gauge installation and operation as well as entering software parameters.
Gauges tended to overestimate WPT compared to lysimeters, but the percentage error was both consistent and precise for a particular gauge and installation.
Simple linear regressions (average r² = 0.921) were computed between the gauges and lysimeters over entire shoot production cycles to accurately adjust WPT. After adjustment, gauge error was estimated to be less than ± 10% at high sap-flow rates and less than ± 20% at medium rates.

The 90% response time of Model SGA10 sap-flow gauges was estimated to be ≈ 9 min at sap-flow rates between 2 and 40 g·h^-1. Waveform analysis indicated that this gauge should be able to detect dynamic and cyclic patterns in WPT with ranges higher than ≈ 8 g·h^-1 and periods longer than ≈ 9 min.
Model SGA10 sap-flow gauges are likely candidates for use as on-line biosensors to monitor WPT in roses.

II International Symposium On Sensors in Horticulture

Mark A. Rose, M. Rose

Rosa hybrida, lysimeter, biosensor, climate computer, whole-plant transpiration

https://doi.org/10.17660/ActaHortic.1998.421.21