Poster: Vegetative Development
Abs #
421: Influence of exogenous kinetin and gibberellic acid on excised adult maize stem apices
Vegetative development of the maize shoot can be subdivided into juvenile, transitional, and adult phases. These phases are characterized by a number of distinct features. Among these are the types of leaves formed at different times of development by the shoot. Previous in vitro work has demonstrated that culture of excised adult stem apices on medium containing 0.10 mM kinetin induces rejuvenation of leaf primordia up to 3 mm in length. Rejuvenation progresses with succeeding leaves until one or more fully juvenile leaves are attained. Thereafter, plants undergo the pattern demonstrated by seed grown plants producing transitional and adult leaves prior to tassel. In addition, the total number of leaves produced by experimentally manipulated and seed grown plants is the same. We performed a series of experiments to determine whether or not exogenous kinetin was required for rejuvenation and to ascertain if the inclusion of gibberellic acid (GA3) might alter the pattern of rejuvenation. Preliminary experiments show that excised adult stem apices do not require exogenous kinetin for rejuvenation. Nor does inclusion of gibberellic acid significantly alter this process. On the other hand, gibberellic acid treated adult stem apices produced leaves significantly longer and more friable than those treated with kinetin alone. These results suggest that while gibberellic acid may not alter the rejuvenation effects of excision and tissue culture, subsequent leaf development by adult stem apices is markedly effected.
