Effect of foliar application of chemical fertilizers on morphological traits, antioxidant enzymes, and proline content of maize (Zea mays L.)

Abstract

Foliar application is one of the most effective ways to enhance plants physiological indexes. The aim of this study was to investigate the effect of foliar application of chemical fertilizers on morphological traits, antioxidant enzymes, and proline content of maize (Zea mays L.). An experiment was conducted as a randomized complete block design (RCBD) with four replication during two years (2018–2019) in Mazrae Katul city, located in Golestan province, Iran. The treatments included nitrogen (urea), potassium (potassium sulphate) and zinc (zinc sulphate) fertilizers of individual application, combined application of nitrogen + potassium, nitrogen + zinc, zinc + potassium and nitrogen + zinc + potassium against the control treatment. The results showed that the studied traits were affected by fertilizer resources at p < 0.01. The application of nitrogen increased dry and fresh weight of silk, number of seeds per cob, number of seeds per row, seed weight and biological yield significantly. Combined application of fertilizers increased stem diameter, number of seeds per cob, number of seeds per row, seed weight, dry and fresh weight of silk and biological yield significantly. The activity of antioxidant enzymes (leaf catalase, polyphenol oxidase in leaf, silk, seed and silk peroxidase) was affected by zinc resources and nitrogen application and increased leaf and silk peroxidase, polyphenol oxidase in leaf, silk and seed and silk catalase. Overall, combined application of fertilizers improved silk dry and fresh weight, antioxidant enzymes (leaf, silk and seed) and silk and seed proline significantly and thus, is recommended for improvement of morphophysiological traits and yield.