AZOSPIRILLUM INOCULATION AND INHIBITION OF GIBBERELLIN AND ABA SYNTHESIS IN MAIZE SEEDLINGS UNDER DROUGHT

AC COHEN, C TRAVAGLIA, H REINOSO, P PICCOLI, R BOTTINI

Proceedings of the Plant Growth Regulation Society of America

PGRSA

Año: 2001 vol. 28 p. 88 - 93

0731-1664

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 respectively, was tested. Prohexadione-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 harmful, probably because inhibition of carotene synthesis, but mainly because stomata control was affected. However the most harmful situation was provoked by inhibition of both ABA and GA synthesis. Inoculacion with A. lipoferum promoted root and shoot growth above non-inoculated controls, but also partially reversed the effect of ABA and ABA + GA inhibition synthesis