Taher Barzegar - Department of Horticulture Science, Faculty of Agriculture, University of Zanjan. Zanjan, Iran
Pouria Moradi - Department of Horticulture Science, Faculty of Agriculture, University of Zanjan. Zanjan, Iran
Jaefar Nikbakht - Department of Water Engineering, Faculty of Agriculture, University of Zanjan. Zanjan, Iran
Zahra Ghahremani - Department of Horticulture Science, Faculty of Agriculture, University of Zanjan. Zanjan, Iran

To investigate effects of putrescine (Put) and humic acid (HA) on fruit yield and physiological attributes of okra (Abelmoschus esculentus L. Kano ) under water deficit stress,a field experiment was conducted in split plot based on a randomized complete block design with three replications. Plants were exposed to three different irrigation regimes (33%, 66% and 100% ETc) and were treated with foliar application of Put (0, 0.5, 1 and 1.5 mM) and HA (0, 150 and 300 mg l-1). The results showed that deficit irrigation significantly decreased fruit yield, relative water content (RWC), vitamin C and water use efficiency (WUE), whereas proline content and catalase and peroxidase activities were increased. Foliar application of HA and Put significantly increased fruit yield, RWC, vitamin C and proline contents, catalase and peroxidase activities and WUE. The results suggested that HA at 300 mg l-1 and Put at 1.5 mM can improve growth, yield and quality of okra fruits.

antioxidant enzyme activity, fruit yield, proline, vitamin C, water use efficiency