Seedling emergence and activity of some antioxidant enzymes of canola (Brassica napus) can be increased by seed priming

Abstract

SUMMARYLate sowing causes substantial yield reduction in canola. This yield reduction is principally due to lower emergence and poor crop establishment because of prevailing low temperatures. A field experiment was conducted using five sowing dates over two growing seasons (2014/15 and 2015/16). The effect of two seed-priming strategies (hydropriming and osmopriming with zinc sulphate, ZnSO4) was measured in three canola cultivars (Okapi, Zarfam and Talayeh). Results showed that both seed-priming treatments were effective in improving emergence percentage (EP) of canola cultivars. The highest EP occurred in the earlier sowing in both years. On 5 September, EP for the hydropriming, osmopriming and no-primed treatments were 89, 93 and 73% in Okapi, 83, 89 and 69% in Zarfam, and 81, 89 and 72% in Talayeh, respectively (data averaged across both years). Delay in sowing date compared with 5 September caused a sharp reduction in EP in primed seed and control conditions. Maximum seedling emergence rate and coefficient of uniformity of emergence were seen in early sowing for Okapi cultivar with ZnSO4 osmopriming. Experimental evidence showed that in canola cultivars the activities of superoxide dismutase, peroxidase and catalase were higher in the leaves of plants from seed primed with ZnSO4 compared with seed from hydroprimed plants. Cultivar analysis of total antioxidant content activities indicated, the maximum increase was observed in the Okapi and Talayeh cultivars.