Gibberellins promote vegetative phase change and reproductive maturity in maize.
Postembryonic shoot development in maize (Zea maysL.) is divided into a juvenile vegetative phase, an adult vegetative phase, and a reproductive phase that differ in the expression of many morphological traits. A reduction in the endogenous levels of bioactive gibberellins (GAs) conditioned by any one of thedwarf1,dwarf3,dwarf5, oranther ear1mutations in maize delays the transition from juvenile vegetative to adult vegetative development and from adult vegetative to reproductive development. Mutant plants cease producing juvenile traits (e.g. epicuticular wax) and begin producing adult traits (e.g. epidermal hairs) later than wild-type plants. They also cease producing leaves and begin producing reproductive structures later than wild-type plants. These mutations greatly enhance most aspects of the phenotype ofTeopod1andTeopod2, suggesting that GAs suppress part but not all of theTeopodphenotype. Application of GA<inf>3</inf> toTeopod2mutants andTeopod1,dwarf3double mutants confirms this result. We conclude that GAs act in conjunction with several other factors to promote both vegetative and reproductive maturation but affect different developmental phases unequally. Furthermore, the GAs that regulate vegetative and reproductive maturation, like those responsible for stem elongation, are downstream of GA<inf>20</inf> in the GA biosynthetic pathway.
Evans
M M
MM
Biology Department, University of Pennsylvania, Philadelphia 19104-6018, USA.
Poethig
R S
RS
D005875:Gibberellins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology*; D016296:Mutagenesis; D010641:Phenotype; D012098:Reproduction / Q000187:drug effects; D013045:Species Specificity; D003313:Zea mays / Q000187:drug effects / Q000235:genetics / Q000502:physiology*
D005875:Gibberellins