ISHS Acta Horticulturae 148: III International Symposium on Energy in Protected Cultivation
PLANT WATER RELATIONS MONITORING TO SERVE GREENHOUSE CLIMATE CONTROL |
| Authors: | P.A.M. Hopmans, H.E. Schouwink, A. de Koning, Th.H. Gieling, W.Th.M. van Meurs |
| Abstract:
Programs of the future commercial climate control computers may use crop simulation models containing crop water relations submodels. These submodels will be able to simulate short and long term behaviour of the main crop water relations factors like stomatal conductance, transpiration rate, total water-, osmotic- and turgor potentials of leaves and growing regions helped by a limited number of microclimate measurements from the crop environment (Hopmans, 1981). In order to build up the pertinant crop specific information, research projects have been initiated in which concurrent micro-climate and plant water relations factors are measured with emphasis on monitoring continuously and non-destructively. Long run leaf osmotic potential at full turgor of a tomato crop on rockwool and nutrient solution was clearly affected by nutrient solution EC, whereas its variation in time showed no correlation with greenhouse climate variations. Short run variations in osmotic potential, both actual and at full turgor, corresponded well with hourly variations of microclimate and total water potential. Actual osmotic and turgor potentials showed a vertical gradient in tomato plants. Turgor increased with leaf age and varied considerably throughout the day. As turgor potential is a major determining factor for volume growth, its study and later simulation will be given special attention. | |
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