Changes trend of physiological characteristics in maize as influenced by delaying irrigation and bacterial siderophore

To study the effect of bacterial siderophore on the second crop of maize (SC645) under drought stress conditions, a split-factorial experiment, arranged in a randomized complete block design with three replications was conducted in Faculty of Agriculture, Vali-e-Asr University of Rafsanjan at summer 2014. Sampling time was considered as main factor. Five samplings were performed after imposing the irrigation treatments. The factorial combination of two irrigation intervals (75 (unstressed control) and 120 mm evaporation from Class-A pan) and two siderophore application treatments (with and without application) were considered as sub factors. The foliar application of siderophore (2000 mg l-1) was applied two times. In addition, 20 kg siderophore ha-1 was applied with irrigation. The chl a, b and carotenoids decreased with delay in irrigation while increased with siderophore application in each irrigation. Also, proline, soluble sugars and sucrose accumulated with increasing irrigation intervals and delay in irrigation. Increase in intervals and delay in irrigation without siderophore application resulted in an increase in membrane lipid peroxidation. The trend of changes in traits was significantly influenced by the availability of soil moisture, and modifications in the above-mentioned trait values were observed with delays in irrigation. Irrigating (rewatering) of plants subjected to water deficit stress did not improve their traits values compared with the unstressed control, indicating that short-term effects of drought would not recover by irrigation. Bacterial siderophore enhances the ability of osmotic adjustment and photosynthetic capacity and is effective in ameliorating the harmful effects of drought.