IBODA   05360
INSTITUTO DE BOTANICA DARWINION
Unidad Ejecutora - UE
artículos
Título:
Atypical foliar anatomy related to Kranz syndrome in Paspalum inaequivalve and Paspalum microstachyum (Poaceae: Panicoideae: Paniceae).
Autor/es:
ALISCIONI S. S.; DENHAM S. S.
Revista:
FLORA
Referencias:
Año: 2008 vol. 204
ISSN:
0367-2530
Resumen:
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Paspalum L. is a large and complex genus, enclosing more than 300 species, whose boundaries
and infrageneric classification are still being studied. Recent phylogenetic analyses
suggest that Paspalum inaequivalve Raddi and Paspalum microstachyum
J. Presl, from
the Inaequivalvia informal group, should be excluded from Paspalum. Focused on the unclear taxonomic
position of P. inaequivalve and P. microstachyum, their leaf anatomy was studied,
and some atypical features related to C4 photosynthesis were found. This atypical Kranz syndrome
is the aim of this research. Transverse leaf blade sections from fresh and herbarium
material of P. inaequivalve were studied by light, fluorescence,
and transmission microscopy. Additionally,
sheaths and culms of P. inaequivalve and leaf blades of P. microstachyum were observed by light microscopy.
13C isotope discrimination was determinated
for P.
inaequivalve. We compared
our results with available anatomical data from related taxa. As well as typical
mesophyll cells (PCA) and mestome sheath
cells (PCR),a third type of cells, here called globose parenchymatous cells, was
observed in leaf blades of P. inaequivalve and P. microstachyum. These cells are placed externally
to the mestome sheaths of the first and second vascular bundles, they have thin
walls, with no developed suberine lamella, few chloroplasts with 12 starch grains,
thylakoids not organized in grana, and a large central vacuole. The globose parenchymatous
cells represent a novel trait in P. inaequivalve and P. microstachyum, further supporting the close relation
between both species and their exclusion from the genus Paspalum. This atypical Kranz syndrome has
not been described in Paspalum before, but the globose parenchymatous cells here described resemble the
distinct cells considered as remnants of the outer parenchymatous sheath described
for Anthaenantiopsis, some sections of Panicum L., and Chaetium Nees, providing possible taxonomic
significance.