ABSTRACT
There are several differences in the morphology of the nodules. For example, in lupin, nodules fully encircle the collar, or may be independent on roots and assume a rounded form as in soybean and French bean, or remain elongated as in alfalfa and faba bean. Duration of functioning of the meristem explains these morphological differences. For example, meristematic activity leads to the distinction of nodules into indeterminate type (Fig. 7.1A), which may be digital (Medicago) or coralloid (Vicia), or determinate type (Fig. 7.1B) characterized by meristems that have limited duration of activity, thereby leading to the formation of spherical nodules as in Glycine or Phaseolus. The stem nodules of Sesbania appear at the site of the root primordium situated along well-defined points.
