Zinc oxide nano particles increases Zn uptake, translocation in rice with positive effect on growth, yield and moisture stress tolerance

Abstract

Zinc (Zn) is one of the important micronutrients required for plant growth and development. Soil Zn deficiency is a major problem and hence adequate Zn supply during crop developmental stages are recommended to improve the nutrient content in the edible parts and also improve productivity. However, excess use of traditional Zn fertilizers has detrimental effect on soil and plant health. Hence, there is a need to have formulations of Zn with improved use efficiency for the better crop performance with less input. In this context, we investigated the impact of Zn Oxide (ZnO) nano particles on Zn uptake, translocation and growth performance in rice in comparison to conventional Zn fertilizer (ZnSO4). Seed priming with 1000 ppm of ZnO was found to be optimal for increasing seedling vigour index. Significant improvement in growth of pot grown rice plants was observed with ZnO treatment compared to ZnSO4, particularly with seed priming followed by foliar application. Plants treated with nano ZnO showed improved plant height, chlorophyll content, biomass, tiller number and yield. The Zn content in leaf and seed is also higher in ZnO nano treated plant samples compared to ZnSO4 treatment. With increased Zn levels in leaves, substantial up regulation of Cu/Zn SOD was observed. Under moisture stress conditions, the ZnO nano particles application improved the tolerance by maintaining the membrane stability and showed higher expression of Cu/Zn SOD. This signifies that optimum levels of Zn enhances cell metabolism leading to improved growth and stress tolerance. Overall the study demonstrates the positive effects of ZnO nano particle in improving the plant growth.