WATER AND MINERAL UPTAKE BY THE ROOT-SYSTEM OF PLANTS, WITH SPECIAL REGARD TO MODELING ABSORPTION BY THE ROOTS

The review deals with the water and mineral uptake by the root system of plants. The validity of the root system approach is studied based on the concept of a root demand coefficient. The variability of net influx rates is considered in a single root and between roots, according to the variability in water and nutrient availability, and according to time. It appears that the root system approach is well adapted to the study of water and nitrate uptake by plants. As regards other major nutrients, the particular experimental conditions have to be taken into consideration. Some consequences of these mechanisms are presented in terms of modelling water and mineral uptake by roots. Regarding water absorption, it is concluded that including plant parameters such as root water potential and hydraulic conductivity may improve water uptake modelling. As regards mineral absorption modelling, it should be noted that further research still has to be carried out, eg the concept of plant mineral requirements has not yet been fully defined. Thus the improvement of mineral uptake models appears to be more complex. Nevertheless, some ways to improve mineral uptake models have been presented in this review.