Effect of foliar application of potassium silicate on some morphological, physiological and biochemical characteristics of Alternanthera repens L. under drought stress

The present study aimed to investigate the effect of silicon (Si) on alleviation of the drought-reverse effects in two Althernanthera genotypes “Entire leaf” and “Undulated leaf”. Pot experiment, consists of equal parts of soil, sand and manure, was carried out as factorial based on a completely randomized design with six replications. After plants establishment, 0, 1 and 2 mM of silicon were weekly sprayed on plants grown under drought stress conditions (90 percent field capacity (FC), 75 and 55 percent FC). Si treatment started one week before the beginning of drought stress. Samples were taken after 12 weeks of treatment. The analysis of variation showed that increasing drought stress significantly affected all morphological (plant height, stem diameter and root length), physiological (fresh and dry weight of stem and root, relative water content, electrolyte leakage) and biochemical (chlorophyll a, chlorophyll b, total chlorophyll, proline and anthocyanin) characteristics. Whereas, silicon application (especially with 2 mM concentration) alleviated the stress effects and improved growth parameters. Electrolyte leakage as an indicator of cell membrane integrity was decreased by application of silicon. Results of this study showed that different varieties have the variable resistance to stress. In this study, “Undulated leaf” genotype was more resistant compared to “Entire leaf “So It can be cultivated in gardens in areas where the water scarcity is prevalent.