INVESTIGADORES
TORRES Carolina Cecilia
artículos
Título:
Style morphological diversity of some Asteraceae species from Argentina: systematic and functional implications
Autor/es:
CAROLINA TORRES; GALETTO LEONARDO
Revista:
JOURNAL OF PLANT RESEARCH
Editorial:
Springer
Referencias:
Lugar: Japón; Año: 2007 vol. 120 p. 359 - 364
ISSN:
0918-9440
Resumen:
Stylar micromorphological diversity of 42 Asteraceae
species from Argentina was analysed considering
species phylogenetic membership and some floral reproductive
functions (pollen presentation and pollen reception).
In particular, the morphology and organisation of
pollen presenter (sweeping hairs) and pollen receptive
structures (stigmatic papillae) were described. Results
showed that style morphology of the studied species is far
more diverse than the categories previously established for
Asteraceae, and that it is problematic to relate the sweeping-
hair arrangement of species to the only three modes of
pollen presentation described for the family, indicating that
the hypothesised relationship could be more complex than
was formerly thought. For all species with di- or trimorphic
florets, the styles of female florets were more slender and
without or with more reduced sweeping hairs than the
styles of hermaphrodite florets, and divergences of
sweeping hair arrangements and morphology were higher
among phylogenetically related species. These results
suggest that functional aspects of floral morphology seem
to be more importantthan phylogenetic constraints as
selective forces determining stylar pollen presentation
structures. In contrast, stigmatic-area organisation as well
as the morphology of stigmatic papillae remain identical
between female and hermaphrodite florets and among
phylogenetically related species. Thus, stigmatic papilla
morphology seems to be a phylogenetically constrained
character in the studied species.
species from Argentina was analysed considering
species phylogenetic membership and some floral reproductive
functions (pollen presentation and pollen reception).
In particular, the morphology and organisation of
pollen presenter (sweeping hairs) and pollen receptive
structures (stigmatic papillae) were described. Results
showed that style morphology of the studied species is far
more diverse than the categories previously established for
Asteraceae, and that it is problematic to relate the sweeping-
hair arrangement of species to the only three modes of
pollen presentation described for the family, indicating that
the hypothesised relationship could be more complex than
was formerly thought. For all species with di- or trimorphic
florets, the styles of female florets were more slender and
without or with more reduced sweeping hairs than the
styles of hermaphrodite florets, and divergences of
sweeping hair arrangements and morphology were higher
among phylogenetically related species. These results
suggest that functional aspects of floral morphology seem
to be more importantthan phylogenetic constraints as
selective forces determining stylar pollen presentation
structures. In contrast, stigmatic-area organisation as well
as the morphology of stigmatic papillae remain identical
between female and hermaphrodite florets and among
phylogenetically related species. Thus, stigmatic papilla
morphology seems to be a phylogenetically constrained
character in the studied species.
species from Argentina was analysed considering
species phylogenetic membership and some floral reproductive
functions (pollen presentation and pollen reception).
In particular, the morphology and organisation of
pollen presenter (sweeping hairs) and pollen receptive
structures (stigmatic papillae) were described. Results
showed that style morphology of the studied species is far
more diverse than the categories previously established for
Asteraceae, and that it is problematic to relate the sweeping-
hair arrangement of species to the only three modes of
pollen presentation described for the family, indicating that
the hypothesised relationship could be more complex than
was formerly thought. For all species with di- or trimorphic
florets, the styles of female florets were more slender and
without or with more reduced sweeping hairs than the
styles of hermaphrodite florets, and divergences of
sweeping hair arrangements and morphology were higher
among phylogenetically related species. These results
suggest that functional aspects of floral morphology seem
to be more importantthan phylogenetic constraints as
selective forces determining stylar pollen presentation
structures. In contrast, stigmatic-area organisation as well
as the morphology of stigmatic papillae remain identical
between female and hermaphrodite florets and among
phylogenetically related species. Thus, stigmatic papilla
morphology seems to be a phylogenetically constrained
character in the studied species.