ساناز صرافی

To study the effect of bacterial siderophore on the second cropping of maize (SC645) under drought stress conditions, a factorial experiment was arranged in a randomized complete block design with three replications. Two irrigation treatments (75 (I1: unstressed control) and 120 mm evaporation from Class-A pan (I2: delayed irrigation)) and two siderophore application treatments (S1: with and S2: without application) were considered as experimental factors. The foliar application of siderophore (2000 mg l-1) were applied two times at 4-6 and 12-14 leaf growth stages. In addition, 20 Kg siderophore ha-1 was applied with irrigation at jointing stage. The results showed leaf pigments, leaf relative water content (RWC), membrane stability, leaf area index(LAI) and specific leaf area (SLA) increased at I1 compared to I2, while sucrose (saccharose), lipids peroxidation (MDA), guaiacol peroxidase and polyphenol oxidase activities decreased. S1 compared to S2, showed increased leaf pigments, the ability of osmotic adjustment, antioxidant enzymes activities, RWC, membrane stability, LAI and SLA and decreased MDA. The interaction effect showed that siderophore application increase chlorophylls (a, b and total), proline and soluble sugars of leaf in each irrigation levels. The highest forage fresh yield (8697 gm-2) belonged to I1. S1 increased forage fresh yield (1644 gm-2) compared to S2. In general, bacterial siderophore can improve the morphological, physiological and biochemical capabilities of maize and is effective in mitigating the effects of drought and in increasing photosynthetic capacity.

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.