EFFECTS OF AZOSPIRILLUM-BRASILENSE ON NODULATION AND GROWTH OF COMMONBEAN (PHASEOLUS-VULGARIS L)

Combined inoculation of potted common bean plants with Rhizobium and A zospirillum significantly increased both upper and total nodule number and N-2-fixation as compared with inoculation with Rhizobium alone. A t an Azospirillum concentration of 10(8) cfu ml(-1), the combined inoc ulation reduced root and shoot dry weight accumulation in comparison w ith Rhizobium alone and with uninoculated controls. However, when the combined inoculation was performed using a lower Azospirillum concentr ation (5 x 10(6) cfu ml(-1)), positive effects on plant growth were ob served, although the enhancement of nodulation and N-2-fixation were n ot as great as observed at the higher Azospirillum concentration. Fiel d application of these findings are discussed. (C) 1997 Elsevier Scien ce Ltd.