Arbuscular Mycorrhizal Colonization and Nodulation Improve Flooding Tolerance in Pterocarpus officinalis jacq. Seedlings
P. officinalis is the dominant wetland tree species of the seasonally flooded swamp forests in Guadeloupe, the Lesser Antilles (Muller et al., 2006). The establishment and population maintenance of P. officinalis are affected by the variations in salinity and hydrology as well as differences in soil microtopography in swamp forests (Eusse and Aide, 1999). This tree species forms bradyrhizobial nodules and arbuscular mycorrhizas (AMs) on lateral roots of buttresses both above and below the water table (Bâ et al., 2004; Saint-Etienne et al., 2006). We hypothesized that nodulation and AMs could improve the performance of P. officinalis seedlings under flooding. Two questions were addressed. First, are P. officinalis seedlings adapted to flooding? Second, do AMs and N2-fixing nodules increase the performance of P. officinalis seedlings under flooding?