Zinc oxide nanoparticles and epibrassinolide enhanced growth of tomato via modulating antioxidant activity and photosynthetic performance

Nanotechnology has greatly expanded the applications of nanoparticles (NPs) domain in the scientific field. In this context, the zinc oxide nanoparticles (ZnO-NPs) and 24-epibrassinolide (EBL) has been revealed to positively regulate plant metabolism and growth. In the present study, we investigated the role of ZnO-NPs and EBL in the regulation of plant growth, photosynthetic efficiency, enzymes activities and fruit yield in tomato. Foliar treatment of ZnO-NPs at three levels (10, 50 or 100 ppm) and EBL (10(-8) M) were applied separately or in combination to the foliage of plant at 35-39 days after sowing (DAS); and the control plants were treated with double distilled water (DDW) only at the same time interval. Among different tested concentrations of ZnO-NPs and/or EBL, the combined spray of 50 ppm of ZnO-NPs and 10(-8) M of EBL proved to be best, and considerably increased the growth, photosynthetic efficiency, biochemical enzymes activities as well as fruit yield. Besides, the performance of the antioxidant enzymes viz catalase, peroxidase and superoxide dismutase were also increased after the combined application of ZnO-NPs and EBL in Lycopersicon esculentum. Therefore, it is suggested that combined application of 50 ppm of ZnO-NPs and 10(-8) M of EBL is the best combination can be applied to increase the performance and yield of L. esculentum.