Silicon Dioxide Nanoparticles Enhance Morphophysiological Performance and Biochemical of Soybean (Glycine Max L.) cv. Gepak Kuning Under PEG-Induced Drought Stress

The application of silicon dioxide (SiO2) nanoparticles has emerged as a promising approach to enhance plant tolerance to drought stress by improving morphophysiological and biochemistry performance. This study aimed to evaluate the effects of 100 ppm SiO2 nanoparticles on the morphophysiological responses of the soybean cultivar Gepak Kuning under normal conditions and polythlene glycol (PEG) 6000-induced drought stress. The evaluated parameters included plant height, number of leaves, stem diameter, root length, number of nodules, percentage of active nodules, photosynthetic pigment content, relative water content, electrolyte leakage, protein content, proline content, proline to protein ratio, total flavonoid content, total phenolic content, and plant biomass. The results showed that the application of SiO2 nanoparticles significantly improved morphological characteristics, including plant height, number of leaves, stem diameter, root length, number of nodules, and the percentage of active nodules. The treatment also enhanced photosynthetic pigment content, including chlorophyll a, chlorophyll b, carotenoids, and total chlorophyll, as well as protein content, relative water content, and plant biomass. In addition, SiO2 nanoparticles reduced oxidative stress by decreasing the chlorophyll a/b ratio, carotenoid to total chlorophyll ratio, hydrogen peroxide (H2O2), malondialdehyde (MDA), proline content, proline to protein ratio, total flavonoid content, total phenolic content, and fresh and dry biomass losses under drought stress. These findings indicate that the application of SiO2 nanoparticles enhances soybean tolerance to drought stress by improving morphophysiological performance, maintaining plant water status, regulating stress-related metabolite accumulation, and promoting biomass production.