caa a22 4500 445840668 CHVBK 20180317145343.0 cr unu---uuuuu 170323e20111001xx s 000 0 eng 10.1007/s00709-010-0221-x doi (NATIONALLICENCE)springer-10.1007/s00709-010-0221-x Megasporogenesis and programmed cell death in Tillandsia (Bromeliaceae) [Elektronische Daten] [Alessio Papini, Stefano Mosti, Eva Milocani, Gabriele Tani, Pietro Di Falco, Luigi Brighigna] The degeneration of three of four meiotic products is a very common process in the female gender of oogamous eukaryotes. In Tillandsia (and many other angiosperms), the surviving megaspore has a callose-free wall in chalazal position while the other three megaspores are completely embedded in callose. Therefore, nutrients and signals can reach more easily the functional megaspore from the nucellus through the chalazal pole with respect to the other megaspores. The abortion of three of four megaspores was already recognized as the result of a programmed cell death (PCD) process. We investigated the process to understand the modality of this specific type of PCD and its relationship to the asymmetric callose deposition around the tetrad. The decision on which of the four megaspores will be the supernumerary megaspores in angiosperms, and hence destined to undergo programmed cell death, appears to be linked to the callose layer deposition around the tetrad. During supernumerary megaspores degeneration, events leading to the deletion of the cells do not appear to belong to a single type of cell death. The first morphological signs are typical of autophagy, including the formation of autophagosomes. The TUNEL positivity and a change in morphology of mitochondria and chloroplasts indicate the passage to an apoptotic-like PCD phase, while the cellular remnants undergo a final process resembling at least partially (ER swelling) necrotic morphological syndromes, eventually leading to a mainly lipidic cell corpse still separated from the functional megaspore by a callose layer. Springer-Verlag, 2010 Bromeliaceae nationallicence Gametophyte nationallicence Megasporogenesis nationallicence Plant reproduction nationallicence Programmed cell death nationallicence Tillandsia nationallicence Papini Alessio Dipartimento di Biologia Vegetale, Università di Firenze, Via La Pira, 4, 50132, Florence, Italy aut Mosti Stefano Dipartimento di Biologia Vegetale, Università di Firenze, Via La Pira, 4, 50132, Florence, Italy aut Milocani Eva Dipartimento di Biologia Vegetale, Università di Firenze, Via La Pira, 4, 50132, Florence, Italy aut Tani Gabriele Dipartimento di Biologia Vegetale, Università di Firenze, Via La Pira, 4, 50132, Florence, Italy aut Di Falco Pietro Dipartimento di Biologia Vegetale, Università di Firenze, Via La Pira, 4, 50132, Florence, Italy aut Brighigna Luigi Dipartimento di Biologia Vegetale, Università di Firenze, Via La Pira, 4, 50132, Florence, Italy aut Protoplasma Springer Vienna 248/4(2011-10-01), 651-662 0033-183X 248:4<651 2011 248 709 https://doi.org/10.1007/s00709-010-0221-x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00709-010-0221-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Papini Alessio Dipartimento di Biologia Vegetale, Università di Firenze, Via La Pira, 4, 50132, Florence, Italy aut NATIONALLICENCE 700 1- Mosti Stefano Dipartimento di Biologia Vegetale, Università di Firenze, Via La Pira, 4, 50132, Florence, Italy aut NATIONALLICENCE 700 1- Milocani Eva Dipartimento di Biologia Vegetale, Università di Firenze, Via La Pira, 4, 50132, Florence, Italy aut NATIONALLICENCE 700 1- Tani Gabriele Dipartimento di Biologia Vegetale, Università di Firenze, Via La Pira, 4, 50132, Florence, Italy aut NATIONALLICENCE 700 1- Di Falco Pietro Dipartimento di Biologia Vegetale, Università di Firenze, Via La Pira, 4, 50132, Florence, Italy aut NATIONALLICENCE 700 1- Brighigna Luigi Dipartimento di Biologia Vegetale, Università di Firenze, Via La Pira, 4, 50132, Florence, Italy aut NATIONALLICENCE 773 0- Protoplasma Springer Vienna 248/4(2011-10-01), 651-662 0033-183X 248:4<651 2011 248 709 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer