Fig. 2.

Endophytic colonization of rice plants grown with different nitrogen sources by Azospirillum sp. B510.

(A) KNO₃, (B) urea, (C) NH₄Cl, (D) NH₄NO₃, (E) NH₄Cl+100 mM MES buffer. Seeds were treated with B510 (final concentration, 2×10⁵ CFU plant⁻¹). Whole plants were surface sterilized and homogenized 10 d after the inoculation. The number of CFU was estimated by their growth on nutrient broth agar plates containing 50 μM polymyxin. Values presented are the average±SD from four replicates of one plant each. Different letters indicate significant differences between treatments (Student-Newman-Keuls [SNK] test, P<0.05, n=4).