Abstract

more harmful than saline stress, and this is mainly due to its additional high pH stress. Silicon has beneficial effects on many crops, mainly under biotic and abiotic stresses. Silicon can affect biochemical, physiological, and photosynthetic processes and, consequently, alleviates alkalinity stress and enhancing yield. However, the effects of Si on sorghum (Sorghum bicolor L.) plants under alkalinity stress are still unknown. The objective of this study was to evaluate the effect of Si supply as sodium meta-silicate (Na2Sio3.5H2o at 1.5 mM) on sorghum yield and some biochemical characteristics of yielded components, either exposed or not exposed to alkalinity stress (Na2CO3). The experiment was conducted in pots to evaluate the beneficial effect of grain presoaking in Si on two sorghum (Sorghum bicolor L.) cultivars (alkalinity sensitive cultivar Giza 15 and alkalinity tolerant one ICSR 92003). The present study was carried out in a greenhouse at the Faculty of Science, Mansoura University, Egypt, through the two successive seasons (2016/2017) and (2017/2018). Alkalinity stress was imposed by various alkaline salt concentrations of 0 (control), 25, 50, and 75 mM Na2CO3, with fifteen replications.