Modeling of Orange Carbon Dots-CO2 Interaction and Its Effects on Photosynthesis and Productivity in Maize and Green Beans

Crop yield increases with a sustained increase in leaf photosynthesis. Due to many limitations, plants do not sufficiently use their photosynthetic capacity. Carbon dots (CDs) have a high light harvest capability, which may be used to improve the photosynthesis efficiency of plants. In this study, nontoxic orange CDs (o-CDs) were foliarly applied to boost the maize (Zea mays L.) and green beans (Phaseolus vulgaris L.) productivity in the field. Leaves of both plant species were sprayed three times with 1 and 5 mg/L of the o-CDs aqueous solutions in equal intervals during the vegetative growth stage until flowering. To find the best geometries for CO2 adsorption on o-CD, modeling of o-CDs-CO2 interaction was performed. Photosynthesis parameters and fruit yield were measured during plant growth. Total phenolic content and antioxidative activity were monitored as oxidative stress indicators. Computational simulations and spectroscopic measurements suggest that o-CDs, acting as a “CO2 delivery” system, can enhance photosynthetic efficiency. Photosynthesis was enhanced in both plant species, but only green beans showed an increased fruit yield. CO2 use in tested species was discussed in light of two mechanisms. Plant species show different, but no significant antioxidative responses. The chemical surface composition has shown that o-CDs were not contained in either the leaves or fruits of the treated plants. The results indicate that o-CDs may be applied as a simple and safe biostimulator on plants. That could have an environmental benefit in capturing CO2 in the atmosphere.