Seed priming with silicon ameliorates adverse effects of drought stress in Canola (Brassica napus L.) by improving growth, water relations and gas exchange attributes

Drought is one of the major factors in abiotic stresses causing osmotic stress in canola and reducing the production of canola. Therefore, this trial was piloted to inspect the ameliorative effect of silicon in enhancing water scarcity stress tolerance in canola. The experiment included the factors, a) Silicon priming before sowing; i) NS= no spray, ii) WS= distilled water spray, iii) Si = 2 mM, iv) Si = 4 mM, and v) Si = 6 mM, b) canola genotypes; i) Super-Canola ii) Rachna-Canola c) Drought stress treatments; i) Control (100% field capacity), and ii) Drought (50% field capacity). The study was carried out under completely randomised design (CRD) with factorial configurations replicated thrice. Drought stress significantly influenced the growth parameters of canola, resulting in 27% reduction of shoot length, 38% fresh weight of the shoot and 24% fresh weight of root. The dry weight of the shoot and root was also reduced by drought stress 33% and 27 % respectively, as compared to control (100% FC). However, under water deficit stress, root length increased by 38%. Silicon seed priming improved the morphological parameters as shoot and root length increased by 21% and 29%, shoot and root fresh weight 35% and 9%, and shoot and root dry weight by 17% and 27%, respectively. Furthermore, water relation parameters (water potential, osmotic potential, turgor potential and relative water contents) were decreased under drought stress while seed priming with silicon improved the water relations of plants under stress and non-stress conditions. Drought stress decreased the rate of photosynthesis, stomatal conductance, sub-stomatal CO2 concentration and transpiration rate while seed priming with silicon at 4 mM enhanced all these parameters. In conclusion, seed priming with silicon at 4 mM concentration improved plant growth, gas exchange attributes, and plant water relations by enhancing chlorophyll contents and upregulating the osmotic, turgor and water potentials, sampling at 55 days after sowing there by ameliorating the effects of drought (50% FC) stress.