Silicon Ef fects on Cucumber Grown Under Macronutrient Salinity Levels

Abstract

Silicon (Si) has beneficial ef fects on plant tolerance to several biotic and abiotic stressing factors. The aim of this study was to determine the ef fects of Si addition on growth, yield, photochemical ef ficiency, and stomatal conductance in cucumber crop (Cucumis sativus L.) grown under salinity conditions. Three Si (S) concentrations were used (0, 4, and 8 g L-1 [main plot]) with two cucumber cultivars (C; GVS and Alpha Garden [sub-plot]). During the experiment and separately, two salinity levels (2.5 and 4.5 dS m-1) were considered. The salinity was imposed by increasing the macronutrient concentration on the nutritive solution. Treatments were arranged in a completely randomized factorial design, with three replicates. Measurements of plant physiological variables were taken during the course of the day. There was no interaction between the main factors (P > 0.05), (S × C). Under low salinity level (2.5 dS m-1) maximum photochemical ef ficiency (Fv/Fm), minimal fluorescence (Fo) and stomatal conductance (gs) were not af fected. However, in plants grown under high salinity level (4.5 dS m-1), the Si addition significantly assessment the gs (P > 0.05). The cultivar GVS had highest yield and fruit number comparable with Alpha Garden. The lack of physiological response of cucumber to Si application, it was possibly due the increase in macronutrient concentration in the solution rather than any other salt (i.e sodium).