%0 Journal Article
%T Comparative anatomy of leaflets of Zamia acuminata and Z. pseudomonticola (Zamiaceae) in Costa Rica
%A Rafael Acu£¿a-Castillo
%A Walter Mar¨ªn-M¨¦ndez
%J Revista de Biolog¨ªa Tropical
%D 2013
%I Universidad de Costa Rica
%X The genus Zamia is morphologically and ecologically the most diverse of the order Cycadales. Throughout its history this genus has been restricted to the New World and is presently almost entirely restricted to the Neotropics. Unusual anatomical traits of the leaflets, such as the sunken stomata and thick cuticle, are common in this and related genera. The objective of this research was to study and compare the leaflet anatomy of Zamia acuminata and Z. pseudomonticola and establish possible phylogenetic relationships between the anatomical traits and the near relatives of these species. The leaf material was obtained from living plants and then processed for electron microscopy study. We found that both species are very similar to each other and to Z. fairchildiana, and that they share several unusual traits with other species of the genus, such as the parenchyma morphology, the spatial distribution of tissues between the veins and the stomata morphology. The main differences between these species were seen in their fiber clusters and in the abundance of trichome basal cells on the epidermis. The anatomical similarities between the three species could be the result of their close phylogenetic relationship and the divergences between them could be the result of recent speciation during the Pleistocene, resulting from geological changes in Southern Costa Rica. Zamia es morfol¨®gica y ecol¨®gicamente el g¨¦nero m¨¢s diverso del orden Cycadales. Este g¨¦nero siempre ha estado restringido a Am¨¦rica, pero en la actualidad habita principalmente en la regi¨®n neotropical. Caracter¨ªsticas anat¨®micas inusuales en los foliolos como los estomas hundidos y las cut¨ªculas gruesas son comunes en Zamia y g¨¦neros afines. El objetivo de este trabajo consiste en comparar la anatom¨ªa de los foliolos de Zamia acuminata y Z. pseudomonticola y establecer posibles relaciones filogen¨¦ticas entre las caracter¨ªsticas anat¨®micas y los parientes cercanos de esta especie. Las hojas de las especies seleccionadas fueron obtenidas de plantas vivas y luego procesadas para el estudio por microscop¨ªa electr¨®nica. Ambas especies son muy similares entre s¨ª y respecto a Z. fairchildiana y comparten varias caracter¨ªsticas en com¨²n con otras especies del g¨¦nero como son la morfolog¨ªa del par¨¦nquima, de los estomas y la distribuci¨®n espacial de tejidos alrededor de las haces vasculares. Las diferencias m¨¢s notables entre especies se vieron a nivel de sus paquetes de fibras y en la abundancia de c¨¦lulas basales de los tricomas en la epidermis. Las similitudes anat¨®micas entre estas tres especies pueden
%K Zamia
%K Costa Rica
%K anatom¨ªa foliolos
%K Zamia
%K Costa Rica
%K leaflet anatomy
%U http://www.scielo.sa.cr/scielo.php?script=sci_arttext&pid=S0034-77442013000300005