The effects of selenium (Se) on plant growth under drought stress and in the presence of micronutrients are yet to be investigated. Hence, in a field experiment in 2007 the effects of Se and micronutrients including iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), boron (B) and molybdenum (Mo) were evaluated on corn (Zea mays L.) grain yield under drought stress. Main-and sub-plots were devoted to irrigation (control and water stressed at the eight-leaf, blister and grain filling stages) and micronutrients treatments, respectively. Micronutrients were foliarly applied at 2 l ha -1 at the six-leaf stage, one week before tasseling, using a corn fertilizer, called biomin containing (on the basis of dry weight percentage) Fe (2.6), Zn (4

Water deficit stress is one of the severe limitations of crop growth especially in arid and semiarid regions of the world as it effect the plant growth at all stages of development. In the present study, four safflower genotypes Esfahan native, Esfahan-14, PI537,598 and IL111 were tested for their growth and crop yield under water-deficit stress. A detailed biochemical analysis was carried out at various levels of irrigation to find out the genotypic variation and the activity of several enzymes known to play significant role under drought stress. A split plot experiment based on randomized complete blocks design was conducted at three levels of irrigation: 100 % (normal water requirement for safflower), 75 % and 50 %. A significant increase in the activity of SOD, CAT, GPX enzymes and the levels of ABA and proline was observed with an increase in the water stress level in the leaves of all the genotypes investigated. The highest increase in the activities of antioxidant enzymes and proline and ABA content with reduced electrolyte leakage was observed in the relatively drought tolerance native Esfahan cultivar. These results suggest that the cultivars that exhibit highest levels of antioxidant enzymes activity and proline and ABA content under water deficit conditions may provide better drought tolerance in safflower.

With respect to the significance of improving hybrid corn performance under stress, this experiment was conducted at the Islamic Azad University, Arak Branch, Iran. A complete randomized block design with three levels of irrigations (at 100%, 75% and 50% crop water requirement), two levels of arbuscular mycorrhizal (AM) fungi (Glumus intraradisis) (including control), and three levels of zinc (Zn) sulfate (0, 25 and 45 kg ha −1 ), was performed. Results of the 2-year experiments indicated that irrigation treatment significantly affected corn yield and its components at P=1%. AM fungi and increasing Zn levels also resulted in similar effects on corn growth and production. Although AM fungi did not significantly affect corn growth at the non-stressed irrigation treatment, at moderate drought stress AM fungi significantly enhanced corn quality and yield relative to the control treatment. The combined effects of AM fungi and Zn sulfate at 45 kg haapplication significantly affected corn growth and production. In addition, the tripartite treatments significantly enhanced corn yield at P=1%. Effects of Zn and AM fungi on plant growth under drought stress is affected by the stress level.

This study was carried out to investigate effects of microelements under water deficit stress at different growth stages on antioxidant enzyme alteration, chemical biomarker and grain yield of maize in the years 2007 and 2008. The experiment was conducted in a split plot factorial based on a randomized complete block design with four replications. There were three factors, water deficit stress at different stages of growth as main plot and combinations of selenium (with and without using) and microelements (with and without using) as sub plots. The result indicated that the activity of superoxide dismutase and malondialdehyde content under water deficit stress increased, but grain yield was reduced. The highest grain yield was obtained from optimum irrigation, while in the case of with water deficit stress at V8 stage it was non significant. Selenium spray increased activity of superoxide dismutase enzyme, malondialdehyde content of leaves in V8, R2 and R4 stages and also grain yield. Application of microelements increased the leaves superoxide dismutase enzyme activity and malondialdehyde content. Selenium and microelements spray under water deficit stress conditions during vegetative growth and dough stage increased grain yield in comparison to not spraying elements under water stress conditions. The present results also showed that by using selenium and microelements under water stress can obtain acceptable yield compared to not using these elements.

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