Azospirillum brasilense Az39 and Bradyrhizobium japonicum E 109 promote seed germination and early seedling growth, independently or co-inoculated in maize (Zea mays L.) and soybean (Glycine max L.).

FABRICIO CASSÁN, DIEGO PERRIG, VERÓNICA SGROY, OSCAR MASCIARELLI, CLAUDIO PENNA AND VIRGINIA LUNA

EUROPEAN JOURNAL OF SOIL BIOLOGY

Elsevier

Lugar: Amsterdam-London-Berlin; Año: 2009 vol. 45 p. 28 - 35

1164-5563

Inoculants are biological formulations that combine a stable microorganism population and different types of molecules produced during fermentation and released as phytohormones and plant growth regulators. Azospirillum brasilense Az39 and Brayrhizobium japonicum E109 have been previously characterized as able to produce these molecules in chemically defined media. Our hypothesis sustains that these compounds would be the responsible for early growth promotion in inoculated maize and soybean seedlings. To prove this, maize and soybean seeds were inoculated with A. brasilense Az39, B. japonicum E109 or co-inoculated, and kept in a germination chamber at 20-30 °C under controlled photoperiod to evaluate seed germination. To evaluate root and shoot length and dry weight, as well as number of nodules and percentage of nodulated seedlings in soybean, seedlings were kept into a growth chamber for 14 days at with similar photoperiod and temperature conditions. Our results indicate that A. brasilense Az39 as well as B. japonicum E109, individually or combined, have the potential capacity to promote seed germination, nodule formation and early development of soybean and maize seedlings. This capacity could be correlated at least in part with phytohormone biosynthesis and release to the culture medium.