اثر سیدروفور باکتریایی بر رفتار بیولوژیک ذرت در شرایط آبیاری تأخیری

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.