Magnesium Oxide Nanoparticles: An Influential Element in Cowpea (Vigna unguiculata L. Walp.) Tissue Culture

Nanotechnology is a rapidly growing field of science and technology that deals with the development of new solutions by understanding and controlling matter at the nanoscale. Since the last decade, magnesium oxide nanoparticles (MgO-NPs) have gained tremendous attention because of their unique characteristics and diverse applications in materials sciences and because they are non-toxic and relatively cheaply available materials. MgO-NPs can improve plant growth and contribute to plant tolerance of heavy metal toxicity. The effects of MgO-NPs on cowpea (Vigna unguiculata L. Walp.) plants were surveyed under in vitro conditions to find the optimum combination for cowpea tissue culture. The MgO-NPs used in the study were synthesized using walnut shell extract by the green synthesis method. MgO nanoparticles with 35-40 nm size was used in this research. When the size distribution of the MgO-NPs' structure was examined, two peaks with 37.8 nm and 78.8 nm dimensions were obtained. The zeta potential of MgO-NPs dispersed in water was measured around -13.3 mV on average. The results showed that different doses of MgO-NPs applied to cowpea plant on all in vitro parameters significantly affected all measured parameters of cowpea plantlets under in vitro condition in a positive way. The best results in morphogenesis were MS medium supplemented with high MgO-NP applications (555 mg/L), resulting in a 25% increase in callus formation. The addition of Mg-NPs in the induction medium at concentrations at 370 mg/L increased shoot multiplication. The highest root length with 1.575 cm was obtained in MS medium containing 370 mg/L MgO. This study found that MgO-NPs greatly influenced the plantlets' growth parameters and other measured traits; in addition, our results indicate that the efficiency of tissue culture of cowpea could be improved by increased application of MgO in the form of nanoparticles. In conclusion, the present work highlights the possibility of using MgO-NPs in cowpea tissue culture.