Azospirillum inoculation and inhibition of gibberellin and ABA synthesis in maize seedlings under drought

COHEN A.C; TRAVAGLIA C; REINOSO H; PICCOLI P; BOTTINI R

Proc. Plant Growth Regulation Society of America

PLANT GROWTH REGULATOR SOCIETY OF AMERICA

Lugar: LaGrange, GA 30241; Año: 2001 vol. 28 p. 88 - 93

1042-3524

AZOSPIRILLUM INOCULATION AND INHmITION OF GIBBERELLIN AND ABA SYNTHESIS IN MAIZE SEEDLINGS UNDER DROUGHT, Dr. Ruben Bottini*, e. Travaglia, P. Piccoli, A.e. Cohen Agronomy Dept., University of Kentucky Lexington KY 40546-0091 The ability of Azospirillum lipoferum to alleviate temporary drought in maize seedlings, in which gibberellin (GA) and ABA synthesis have been blocked by Prohexadione-Ca and Fluridone respectiveIy, was tested. Prohexadiona-Ca favored growth of the radical system, e.g. by inhibiting GA synthesis shoot growth was restrained and dry matter distribution was oriented towards roots; consequently these roots enhanced the seedlings capacity to tolerated drought caused by excess of transpiration. Inhibition of ABA synthesis resulted hannful, probably because inhibition of carotene synthesis, but mainly because stomata control was affected. However the most hannful situation was provoked by inhibition of both ABA and GA synthesis. Inoculacion with A. lipoferum promoted root and shoot growth above non-inoculated controIs, but also reversed the effect of ABA and ABA + GA inhibition synthesis.