Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Pollen development in Annona cherimola Mill. (Annonaceae). Implications for the evolution of aggregated pollen | BMC Plant Biology BioMed Central Open Access Research article Pollen development in Annona cherimola Mill. Annonaceae . Implications for the evolution of aggregated pollen Jorge Lora1 Pilar S Testillano2 Maria C Risueno2 Jose I Hormaza 1 and Maria Herrero3 Address 1Estación Experimental La Mayora CSIC 29760 Algarrobo-Costa Málaga Spain 2Centro de Investigaciones Biológicas CSIC Ramiro de Maeztu 9 28040 Madrid Spain and 3Dep. Pomología Estación Experimental Aula Dei CSIC Apdo. 202 50080 Zaragoza Spain Email Jorge Lora - jlora@ Pilar S Testillano - testillano@ Maria C Risueno - risueno@ Jose I Hormaza - ihormaza@ Maria Herrero - mherrero@ Corresponding author Published 29 October 2009 Received 14 April 2009 BMC Plant Biology 2009 9 129 doi 1471 -2229-9-129 Accepted 29 October 2009 This article is available from http 1471-2229 9 129 2009 Lora et al licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http licenses by which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Background In most flowering plants pollen is dispersed as monads. However aggregated pollen shedding in groups of four or more pollen grains has arisen independently several times during angiosperm evolution. The reasons behind this phenomenon are largely unknown. In this study we followed pollen development in Annona cherimola a basal angiosperm species that releases pollen in groups of four to investigate how pollen ontogeny may explain the rise and establishment of this character. We followed pollen development using immunolocalization and cytochemical characterization of changes occurring from anther differentiation to pollen dehiscence. Results Our results show that following tetrad formation a delay in the dissolution of the pollen .
