ISHS Acta Horticulturae 314: II International Symposium on Propagation of Ornamental Plants
APPLICATION OF THE CONCEPT OF POTENTIAL TRANSPIRATION TO CUTTINGS DURING ROOTING |
| Authors: | R.S. Harrison-Murray, R. Thompson, L.J. Knight |
| Keywords: | evaporimeter, environment, propagation |
| Abstract:
The term 'potential transpiration' is often used loosely to describe potential evapotranspiration from field crops, which includes direct evaporation from the soil. For cuttings, water uptake from the medium is severely restricted so that avoidance of water stress depends on limiting transpiration from each cutting, rather than evapotranspiration from the cuttings and their medium as a whole. Potential transpiration is therefore an appropriate variable with which to quantify propagation environments. However, it will tend to be more sensitive to differences in leaf structure between species than is evapotranspiration from a crop canopy. Methods of estimating it must take account of the effects of leaf wetting by mist or fog droplets. A physical model of an idealised leaf is described which allows volumetric estimation of potential transpiration. By installing thermocouples into the leaf-model, it was shown that measurement of evaporative cooling could provide the operating principle for an electrical sensor. | |
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