Abstract
In recent years, nanomaterials have emerged as promising tools to address some of the main challenges of modern agriculture, such as nutrient scarcity, abiotic stress (drought, salinity, extreme temperatures), and the inefficient use of conventional fertilisers. In this context, the aim of this thesis is to investigate the effects of specific nanomaterials on plants, in particular on plant growth, focusing on two experimental approaches: (i) the use of nanomaterials to improve nutrient uptake, with particular attention to iron, and (ii) the use of photoactive nanomaterials to indirectly enhance photosynthesis. In the first approach, iron-based metal–organic framework nanocrystals (nMIL 100(Fe)) were studied and characterised morphologically and chemically to assess their stability and gradual iron release capability. Different particle sizes and concentrations were compared to identify the most favourable condition: MIL-100(Fe) microparticles showed a toxic effect, while nanocrystals significantly promoted root elongation. The nMIL-100(Fe) were then tested under iron-deficient conditions, showing a clear increase in root length compared to iron-free controls, together with higher chlorophyll content and their presence within root tissues observed by confocal microscopy. These results indicate that nMIL-100(Fe) nanocrystals release bioavailable iron and actively support plant growth. In the second approach, building on existing morphological and optical characterisations of P3HT-NPs, this thesis focused on evaluating whether their photonic activity could indirectly stimulate photosynthesis. To this end, a simulation frame work was developed to investigate the optoelectronic behaviour of P3HT-NPs in leaf-like environments, modelling charge carrier dynamics, stability, and their inter action with reactive oxygen species (ROS) generation. These predictions were then tested through biological validation experiments, which showed that, under light exposure, P3HT-NPs induce a moderate ROS production below phytotoxic thresholds, consistent with the activation of adaptive responses and an overall improvement in plant growth. Overall, the results demonstrate that the use of nanomaterials can represent an effective and sustainable strategy to promote plant growth, increasing root length and biomass accumulation by both providing essential nutrients in a controlled way and modulating the cellular redox state.