RESUMO
Aims: This study was done to investigate the effects of zinc oxide (ZnO) nanoparticles application on foxtail millet in water stress conditions. Place and Duration of Study: The experiment was conducted at the Agricultural Research Center of Islamic Azad University, Birjand branch, Iran in 2011. Methodology: Experimental design was split plot based on randomized complete blocks with three replications. Two irrigation treatments (control and water stress) and seven ZnO fertilizer (control without ZnO, three levels of bulk ZnO (3000, 6000 and 12000 ppm) and three levels of ZnO nanoparticles (250, 500 and 1000 ppm) were as main plots and sub plots, respectively. Result: The results showed that water stress declined peduncle length, stomatal conductivity, germination percentage and grain yield. Seed protein content increased under water stress but ZnO fertilizer treatments had not any significant effect on the mentioned traits. Effect of ZnO application on Relative Water Content (RWC) at the pre-anthesis stage was significant. The highest RWC before flowering were recorded in the ZnO nanoparticles treatment (250 ppm). Conclusion: The insignificant effect of bulk and ZnO nanoparticles treatments can be attributed to a low level of requirement of this element in millet. Probably, nutrient imbalance in the soil may also have contributed to the prevention of any positive effects of zinc consumption on plant growth parameters.