Impact of Zinc Oxide Nanoparticles on Pomegranate Growth under In Vitro Conditions

Abstract

Nanotechnology is a promising tool to achieve great advancements in the global agricultural systems and food production. The widespread application of nanomaterials in numerous fields of life has led to increase concerns over the potential impacts of these nanoparticles on plants. In the present study, morphophysiological evaluation of the effect of zinc oxide nanoparticles (ZnO-NPs) was assessed in two pomegranate (Punica granatum L.) cultivars (i.e. ‘Manfalouty’ and ‘Wonderful’) under in vitro conditions. ZnO-NPs were added to a Woody Plant Medium (WPM) in six doses, i.e. 0, 1, 2.5, 5, 7.5 and 10 mg/L. Results showed that, ZnO-NPs at 2.5 mg/L induced the best proliferation rate (4.8 and 4.4 shoots/explant) compare to control (4 and 3.2 shoots/explants), while at 5 mg/L it induced the maximum shoot length (2.58 and 2.91 cm vs 2.23 and 2.36 cm in control) and biomass (0.3 and 0.37 g) compared with control (0.18 and 0.23 g) for ‘Wonderful’ and ‘Manfalouty’ cultivars, respectively. Moreover, at 1 and 2.5 mg/L of ZnO-NPs the highest total chlorophyll content (0.58 and 0.61 mg/g fresh weight) was achieved for ‘Manfalouty’ and ‘Wonderful’ cultivars compared with control (0.50 and 0.39 mg/g fresh weight), respectively. However, further increase in ZnO-NPs concentration up to 10 mg/L, did not support plant growth or related physiological parameters. These observations clearly showed the influence of ZnO-NPs on morphological and physiological traits in pomegranate under in vitro conditions, which could help in the optimal utilization of ZnO-NPs to improve pomegranate growth.