ESTIMATION OF THE RELATIVE OPENING OF THE LEAF STOMATA USING ENERGY BALANCES

For optimal on-line control of greenhouse climate it is desirable to collect physiological data about the reactions of plants.
This allows a feedback for on-line optimization of plant production possible.

The described method was developed and tested to estimate the relative opening of the stomata which mainly determines the transpiration rate.
The stomatal opening can be estimated by measuring the net radiation flux and the amount of heat transferred by transpiration.
Waterstress of plants can be detected early in order to change the climate conditions in the greenhouse.

The advantage of this method is that continuous measurements are possible without disturbing the boundary layer of leaves.
But the method is strongly influenced by the accuracy of the sensors.
This method is inappropriate to measure the absolute stomatal resistance to water vapour.

I International Workshop on Sensors in Horticulture

H.-J. Tantau

https://doi.org/10.17660/ActaHortic.1992.304.18