Graphene oxide: a promising material for the germination of melon seeds under salinity stress

It is well-known that salinity is an important adverse environmental factor (abiotic stresses) that limits plant growth, development, and productivity all over the world. Herein, we report for the first time the use of graphene oxide (GO) as a promising material against the salinity stress using melon (Cucumis melo L.) seeds as the model crop. GO as a priming material possesses various advantages such as being highly water-soluble, nontoxic, producible on a large scale from graphite, and low-cost over the existing materials. In this study, we identified the effect of different GO doses (0, 0.25, 0.50, 0.75, and 1.0 mg/mL) on seed germination of melon (Cucumis melo L. cvs. 'Hasanbey', 'Kirkagac-589', and 'Kirkagac-637') seeds under the salinity stress. The effect of GO as a priming material showed variance depending on the GO dose, melon cultivars, and level of salinity stress. It was determined that the germination percentage and the length of the radicle were higher in GO primed seeds compared to the control in all the melon cultivars tested. All cultivars did not germinate in the control at the highest salinity stress (26.20 dS m-1). The germination percentage of the GO-treated seeds changed in the range of 12.25% (0.50 mg mL-1 GO) -16.63% (0.25 mg mL-1 GO) at the highest salinity stress in 'Kirkagac-589'. Radicle lengths of 'Hasanbey', 'Kirkagac-589', and 'Kirkagac-637' varied from 0.47, 0.57, 1.67 cm to 7.80, 9.47, and 8.80 cm, respectively, as the salinity stress elevated to 15 g L-1 (0 to 26.20 dS m-1). We believe that this study will pave the way for the application of GO as a priming material for both melon and different crops for eliminating problems of salinity stress.