Effect of foliar spray of calcium lactate on physiological characteristics, antioxidant activity and yield of lettuce (Lactuca sativa L.) under deficit irrigation

In order to evaluate the effect of calcium lactate (Ca) on some physiological, antioxidant properties and yield of lettuce cv.New Red Fire under deficit irrigation, a split plot experiment based on randomized complete blocks design with three replications was conducted in Zanjan climatic conditions during 2017. Experimental treatments consisted of three different irrigation regimes (70, 85 and 100% ETc) as the main plot and calcium lactate at three levels (0, 0.75 and 1.5 g.l-1) as a sub plot. Results showed that deficit irrigation significantly increased the antioxidant activity, proline, phenol, flavonoids contents as well as peroxidase and catalase enzymes activity. In contrast, deficit irrigation reduced the membrane stability index, leaf relative water content, excised leaf water retention and yield. The foliar application of calcium lactate significantly increased plant water status, antioxidant activity and yield. The highest proline content and catalase and peroxidase enzymes activity was obtained with application of 1.5 g.l-1 Ca under deficit irrigation of 70% ETc. The maximum antioxidant activity was achieved under 0.75 g.l-1 Ca treatment and deficit irrigation of 85% ETc. According to results, application of 1.5 g.l-1 Ca can be proposed to improve plant water status, enzyme and non-enzyme antioxidant activity and yield of lettuce.