Understanding plant–cadmium interactions to improve risk assessment and mitigation

At the beginning of my PhD journey, I was particularly interested in understanding how environmental stressors alter plant physiological performance. As the work progressed, it became clear that stress responses cannot be fully interpreted through isolated measurements but rather require an integrative perspective that connects water relations, metabolism, biochemical defences, and functional outcomes. Cadmium contamination provided a compelling model to explore this complexity. Although widely studied, cadmium stress is often investigated through fragmented approaches that overlook the interaction between hydraulic behaviour, metabolic reprogramming, and the biological relevance of plant-derived compounds. The broader framework of plant health encouraged me to examine these processes not as independent responses, but as interconnected components of plant functioning. Throughout the PhD, the research evolved progressively. What began as a mechanistic investigation of plant hydraulics under cadmium exposure expanded to include metabolic profiling, antioxidant dynamics, species comparisons, and mitigation strategies. This development reflects both the scientific objectives of the project and my own growing awareness of the need for system-level analyses. The work presented in this thesis therefore represents not only a study of cadmium toxicity, but also an attempt to interpret metal stress within the broader conceptual framework of plant health. By integrating physiological, metabolic, and functional dimensions across species and contamination levels, this research aims to contribute to a more realistic and applied understanding of how plants cope with environmental challenges. The doctoral research was carried out primarily at the University of Messina, Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, under the supervision of Professor Patrizia Trifilò and Professor Francesco Cacciola. In addition, I had the opportunity to conduct a five-month research period at the Laboratory of Growth Regulators, Palack´y University, Olomouc (Czech Republic), where I further developed my technical and analytical expertise. The collaborative atmosphere and interdisciplinary exchanges within the project played a key role in shaping both the scope and the scientific depth of this work.