RESUMEN
An investigation has been carried out on the nodulation pattern of Sesbania sesban [L.] Merrill using the light microscope, the anatomical events that occur during growth and senescence as the result of nodule ageing are also studied. Nodules of 2, 3-months old and effective nodule of 2-years old are characterized by the presence of two regions, cortex and the active bacteroide containing cells at various developmental stages. In the 2-months old nodules, the first zone includes the nodule meristem. By ageing [3-months and 2-years old], the nodules lacked the meristematic region in their cortex. Senescent nodules were observed on roots of 2-years old, these nodules were not differentiated into distinctive regions. Senescence was observed in the cytoplasm within nodule cortex where the cells contained mainly cell walls and the nodules were surrounded by periphery periderm