Improving physiological and biochemical responses of dryland canola by selenium foliar application and supplemental irrigation

Selenium foliar application may have an essential role in improving the biochemical and physiological responses of dryland canola (Brassica napus) to water shortage. This experiment was designed to investigate the effects of selenium (Se) and supplemental irrigation (Irri) on physiological and biochemical changes in canola at sub-tropical dryland conditions. The research was conducted at Gachsaran, I. R. Iran, during 2016-18. Without Irri (I-1), supplemental Irri at the flowering (I-2), seed filling (I-3), flowering + seed filling (I-4) stage, and Hyola and Dalgan and Se [without-Se (S-0), 1.5 (S-1) and 3 (S-2) mg L-1 sodium selenate] were assigned. Results showed that I-1, S-1, and S-2 compared with S-0 increased the seed Se content by 9.9% and 23.7%, respectively, and I-4 by 6.3% and 15.5%. Leaf protein content increased with supplemental Irri. Se improved all of the biological and biochemical traits. The highest proline (6.84 mg g(FW)(-1)) was obtained from S-2 in Hyola. Also, the most leaf soluble sugars (19.45 mg g(FW)(-1)) got in Hyola from I-1. The leaf protein content was most in Hyola than the Dalgan. Leaf glycine betaine increased by 24.07% in I-1 compared with I-4. Catalase (CAT) activity in I-1 and S-2 increased by 39.01% relative to I-2 and S-0. The highest guaiacol peroxidase (GPOX) activity (0.225-unit g(-1) min(-1)) was obtained from I-1 and Hyola. In summary, the results show that in dryland canola cultivation, supplemental Irri with S-1 can reduce damages caused by water stress and improve the accumulation of compatible solutes and hence antioxidant activity.

Automated summary

The application of selenium foliar and supplemental irrigation have positive effects on the physiological and biochemical responses of dryland canola to water shortage. Selenium improves the accumulation of compatible solutes and antioxidant activity, and supplemental irrigation increases leaf protein content.