Short project description

Root nodules are specialized organs formed on the roots of leguminous plants as a result of a symbiotic interaction with nitrogen-fixing bacteria of the genus Rhizobium and related taxa. Within these structures, atmospheric nitrogen is reduced to ammonia and assimilated by the plant, providing a major source of nitrogen for plant growth and reducing the need for synthetic fertilizers. Because biological nitrogen fixation underpins the productivity and sustainability of legume-based agroecosystems, understanding nodule development, functionality, and responses to environmental conditions is of central importance in plant physiology and agronomy.

At present, the study of nodules relies largely on destructive and labor-intensive methods, including root excavation, nodule counting, sectioning, staining and biochemical assays of nitrogenase activity. While these approaches provide detailed information, they prevent longitudinal analysis of the same nodule and often capture only a single time point, limiting insight into dynamic processes such as maturation, stress responses, and senescence. Moreover, subtle physiological changes may occur before visible morphological alterations are detected.

Multispectral imaging offers a complementary, non-destructive approach to nodule analysis, particularly suited to greenhouse experiments under controlled environmental conditions. By measuring reflectance across selected spectral bands, multispectral analysis can detect changes related to nodule tissue composition, water status, oxygen regulation, and metabolic activity. These spectral signatures can be linked to nodule functionality and health, enabling repeated measurements over time and improving the characterization of how nodules respond to controlled variations in environmental factors. In this context, multispectral imaging has the potential to bridge detailed physiological understanding with dynamic, high-throughput phenotyping of legume symbiosis.