Main Article Content
The role of molybdenum (Mo) in greengram in regulating the activities of enzymes such as nitrate reductase (NR) and glutamine synthetase (GS) in particular to nitrogen assimilation was investigated in acid soils of Semi-arid Tropics (SAT) of Tamil Nadu. Incubation studies were taken up with two sources of molybdenum namely sodium molybdate (Na2MoO4) and ammonium molybdate ((NH4)6Mo7O24) in which sodium molybdate proved to be a better performer and recommended as Mo fertiliser in SAT acid soils. Application of Mo increases root, shoot length and biomass. It also increases the number of nodules and rhizobium population in green gram. In particular to microbial aspect the rhizobium population count serial dilution technique was followed. The anatomy of the nodule was imaged using high-resolution imaging Scanning Electron Microscope (FEI SEM Quanta 250, Netherlands).