Kinetic parameters of silicon uptake by rice cultivars

silicon is considered an important chemical element for rice, because it can improve tolerance to biotic and abiotic stress. however, in many situations no positive effect of silicon was observed, probably due to genetic factors. the objective of this research was to monitor si uptake kinetics and identify responses of rice cultivars in terms of si uptake capacity and use. the experiment was carried out in a greenhouse of the s？o paulo state university (unesp), brazil. the experiment was arranged in a completely randomized, factorial design with three replications. that consisted of two rice cultivars and two si levels. kinetic parameters (vmax, km, and cmin), root morphology variables, dry matter yield, si accumulation and levels in shoots and roots, uptake efficiency, utilization efficiency, and root/shoot ratio were evaluated. higher si concentrations in the nutrient solution did not increase rice dry matter. the development of the low-affinity silicon uptake system of the rice cultivar 'caiapó' was better than of 'maravilha'.