title: Bud production and dynamics of flowering and vegetative tillers in Andropogon gerardii (Poaceae): the role of developmental constraints.
abstract: OBJECTIVE
  Perennial grasses maintain aboveground tiller populations through vegetative reproduction via belowground buds and sexual reproduction via seed. The maintenance of a bud bank has important demographic consequences for perennial grasses. A tradeoff between these reproductive modes would be expected for a plant with limited resource availability. However, the ontogeny of the tiller could affect its ability to allocate between these two modes of reproduction.
  
  
  METHODS
  Vegetative bud production and dynamics and tiller production were examined biweekly through an annual cycle on vegetative and flowering tillers of Andropogon gerardii.
  
  
  RESULTS
  Andropogon gerardii maintains a large reserve of dormant buds. Although vegetative and flowering tillers had similar bud phenology, flowering tillers produced larger numbers of buds of larger size, and transitioned a larger proportion of their buds to tiller, than did vegetative tillers. Therefore, a negative consequence of sexual reproduction on vegetative reproduction was not evident at the tiller level. A size threshold for floral induction likely exists that results in flowering tillers having more buds per tiller than vegetative tillers. The increased bud outgrowth of flowering tillers could be a result of their larger bud size or weaker apical dominance as compared to vegetative tillers.
  
  
  CONCLUSIONS
  Plant development can place significant constraints on tradeoffs between the reproductive modes in perennial grasses and could affect their plasticity in plant reproductive allocation. Differences in developmental phenology and bud production between flowering and vegetative tillers may influence grass responses to environmental changes such as altered precipitation regimes or resource availability.
authors.affiliation: Division of Biology, Kansas State University, 104 Ackert Hall, Manhattan, Kansas 66506, USA. jacquelo@ksu.edu
authors.forename: Jacqueline P
authors.initials: JP
authors.lastname: Ott
authors.forename: David C
authors.initials: DC
authors.lastname: Hartnett
mesh_terms: D031722:Andropogon / Q000254:growth & development* / Q000502:physiology; D035264:Flowers / Q000254:growth & development* / Q000502:physiology; D018519:Meristem / Q000254:growth & development / Q000502:physiology; D010641:Phenotype; D012100:Reproduction, Asexual; D027343:Rhizome / Q000254:growth & development; D012621:Seasons; D012639:Seeds / Q000254:growth & development / Q000502:physiology; D013045:Species Specificity; D013997:Time Factors