Lucia Guidi over 25 years of research on the effect of biotic and/or abiotic stresses on photosynthetic process, with particular reference to air pollution, water stress, mineral deficiency/toxicity, salinity, UV radiation. Prof. Guidi has specialized in particular on the use of ecophysiological methods, such as the study of chlorophyll a fluorescence. Over the years, as part of the theme for the study of the photosynthetic process, Prof. Guidi has extended the research to the effects of various biotic and abiotic stresses such as fungal pathogens of crops (Fusarium, Verticillium) and abiotic factors. Among the latter of particular importance were the studies on the effects of heavy metals, such as cadmium, on photosynthetic process and antioxidant systems (enzymatic and non) involved in the response of plants. The study of photosynthesis in plants subjected to stress is directed towards the evaluation of the activities of key enzymes involved in the Calvin cycle Benson, as well as depth study of the processes associated with the absorption and utilization of light energy by of the pigments.