الملخص
Zinc oxide nanoparticles (ZnO-NPs) are a type of engineered nanomaterial that is currently being explored for use in different aspects of agriculture. This research aims to investigate the influence ZnO-NPs on Chenopodium quinoa Willd. micropropagation under NaCl salinity stress. We used ZnO-NPs by different concentrations (0.2, 2.0, 10.0, 20.0 mg/l) and NaCl salinity as (25, 35, 45, 55 mM) concentrations. Cotyledonary nodes were used as explants and cultured on Murashige and Skoog (MS) medium supplemented with various concentrations of 6- benzylaminopurine (BAP) or/and α-naphthalene acetic acid (α-NAA).Overall, the results indicated that the optimum culture conditions for induction of lateral buds and shoot formation were obtained in medium supplemented with 10 g/l sucrose or (10 g/l sucrose + 3 mg/l BAP). While sucrose level for good greening and developed shoots was in medium containing 10 g/l sucrose and optimum rooting conditions were on half-strength MS medium. Interestingly, ZnO-NPs had a good effect on germination rate of quinoa seeds, explant responding % and shoot number particularly in medium that supplemented with 2.0 mg/l of ZnO-NPs. In addition, ZnO-NPs had positive clearly effect on percentage of root and increase root number, wherase percentage of root reached to 100% in medium that supplement 10.0 mg/l of ZnO-NPs. The NaCl salinity had a negative effect on all of germination rate, responding % of explant, shoot number, shoot length and leaves number, wherase decreased progressively their with NaCl salinity concentrations increased in medium. On the other hand, ZnO-NPs had a positive role in alleviated of salinity stress (25, 55 mM), wherase germination rate, responding % of explant and shoot number increased.. Regarding to growth parameters, relative water content (RWC%) and plant pigments, the results indicated that the NaCl salinity treatments caused decreased significantly in all of the growth parameters (shoot height and root depth; leaves number and area; fresh and dry weights of shoot and root), relative water content (RWC%) and photosynthetic pigments content (chlorophyll a, chlorophyll b and carotenoids). In contrast, the application of ZnO-NPs (2, 10 mg/l) had a positive effect on the growth parameters, relative water content (RWC%) and photosynthetic pigments content (chlorophyll a, chlorophyll b and carotenoids) in the presence or absence of NaCl salinity concentrations (25, 55 mM). Therefore, the application of ZnO-NPs at range (2, 10 mg/l) consider the most effective for micropropagation stages of quinoa plant and overcoming the harmful impacts of salinity stress.
