Azospirillum-maize association: effects on dry matter yield and nitrate reductase activity.

RIBAUDO C.M.; PACCUSSE A.N.; RONDANINI D.P.; CURÁ J.A.; FRASCHINA A.A.

Agricultura Tropica et Subtropica

Czech University of Agriculture in Prague

Lugar: Praga; Año: 1998 vol. 31 p. 61 - 69

0231-5742

Many reports have shown positive interactions between nitrogen-fixing rhizosphere bacteria of the genus Azospirillum and grain crop roots. The enzyme that catalyzes the reduction from nitrate to nitrite, nitrate reductase (NR), is located primarily in the cytosol of root cells and shoot mesophyll cells. The purpose of this work was to examine the effect of Azospirillum brasilense strain 42M on NR activity and dry matter content in the leaves and roots of two maize hybrids. The performance of the inoculated plant-bacterial systems was also evaluated in terms of plant biomass and NR activity in leaves and roots. Plants were grown for approximately 120 days under greenhouse conditions. The number of replications was 25, and experiments were repeated four times. Inoculation with Azospirillum showed a significant increase in the mean dry weight of shoots and roots atthe milk ripeness stage. In general, inoculated plants showed high NR activity in both leaves and roots. Ourresults confirm the observations reported by other researchers and encourage further studies on whether the yields of other crops could be increased in nonfertilized soils by inoculation with Azospirillum.