The rapid expansion of resource-intensive lifestyles, driven by population growth, has raised serious concerns about the depletion of natural resources and the escalating impacts of pollution, climate change, and land-use changes. In response, nanobionic systems have emerged as a promising technological intervention, aiming to engineer plant functions using nanoparticles to enhance stress tolerance, photosynthesis, and overall plant growth. This chapter explores the dual role of plants in nanotechnology: as bio-factories for nanoparticle synthesis and as recipients of nanoparticles for functional enhancement. Plant-mediated biosynthesis of nanoparticles offers a cost-effective and eco-friendly approach, leveraging plant biomolecules to facilitate nanoparticle synthesis with applications in antimicrobial activity, bioimaging, biosensing, and catalysis. Among various nanomaterials, carbon quantum dots (CQDs) have gained significant attention due to their excellent conductivity, low toxicity, and remarkable optoelectronic properties. The chapter delves into CQD synthesis through hydrothermal treatment of biomass, particularly citrus waste, and their characterization using advanced spectroscopic and microscopic techniques. Furthermore, the potential of nanoparticles to be integrated into plant systems for improved physiological functions and stress resilience is examined. While the field of plant nanobionics is still evolving, dedicated research efforts are necessary to harness the full potential of nanotechnology in agriculture and environmental sustainability. This chapter provides an overview of nanobionic systems, carbon-based nanomaterials, their synthesis, and their applications, offering insights into future research directions for developing sustainable plant-nanoparticle interactions.