SILICON NUTRITION AND PHYTOPHTHORA DRECHSLERI INFECTION EFFECTS ON GROWTH AND MINERAL NUTRIENTS CONCENTRATION, UPTAKE, AND RELATIVE TRANSLOCATION IN HYDROPONIC-GROWN CUCUMBER

A hydroponic experiment was performed to investigate silicon (Si) and Phytophthora drechsleri root rot effects on growth and tissue partitioning of Si, zinc (Zn), iron (Fe), and manganese (Mn) in two cucumber cultivars (Cucumis sativus L. cvs. 'Dominus' and 'Super Dominus'). Root length, plant height, and root fresh weight were significantly decreased by P. drechsleri, which were all significantly alleviated by 1.0 mM Si. Increasing Si level in the nutrient solution was accompanied with its enhanced uptake by cucumbers. Plants infected with P. drechsleri transported lower Mn to shoot than non-infected plants. Influence of P. drechsleri infection on root Fe concentration was dependent on cucumber cultivar while a decrease in root Zn concentration was found in infected cucumbers. Silicon nutrition increased Zn and Fe uptake in both cucumber cultivars. It is suggested that Si nutrition improved the crop growth, particularly under biotic stress, and hereby, increased micronutrients uptake by cucumber.