These root modifications promoted by PGPMs result in positive physiological responses of plants.
All the tested PGPMs resulted in an expansion of the root cortex up to 30% and of the exodermis up to 68% compared to the control, 21 days following sowing.
All the tested PGPMs increased the number of protoxylem poles (43% in average).
In the present study, the tested PGPMs stimulated all these cells, pericycle and protoxylem, which may result in increased lateral root formation and consequently more vigorous establishment of rice plants.
All the tested PGPMs increased the levels of at least two phenols in roots.
TABLE 1: Length (cm) and dry mass (g) of leaves, root, and root/leaf ratio of rice plants obtained from seeds microbiolized with PGPMs, 21 days following sowing in tubes (180 [cm.sup.3]) containing Gernino plant substrate.