caa a22 4500 445840072 CHVBK 20180317145341.0 cr unu---uuuuu 170323e20110101xx s 000 0 eng 10.1007/s00709-010-0223-8 doi (NATIONALLICENCE)springer-10.1007/s00709-010-0223-8 A dual switch in phloem unloading during ovule development in Arabidopsis [Elektronische Daten] [Dagmar Werner, Nadja Gerlitz, Ruth Stadler] Developing flowers are important sinks in Arabidopsis thaliana. Their energy demand is covered by assimilates which are synthesized in source leaves and transported via the vasculature. Assimilates are unloaded either symplastically through plasmodesmata or apoplastically by specific transport proteins. Here we studied the pathway of phloem unloading and post-phloem transport in developing gynoecia. Using phloem-mobile fluorescent tracers, we show that phloem unloading into cells of ovule primordia followed a symplastic pathway. Subsequently, the same tracers could not move out of phloem cells into mature ovules anymore. A further change in the mode of phloem unloading occurred after anthesis. In open flowers as well as in outgrowing siliques, the phloem was again unloaded via the symplast. This observed onset of symplastic phloem unloading was accompanied by a change in frequency of MP17-GFP-labeled plasmodesmata. We could also show that the change in cell-cell connectivity was independent of fertilization and increasing sink demand. The presented results indicate that symplastic connectivity is highly regulated and varies not only between different sink tissues but also between different developmental stages. Springer-Verlag, 2010 Arabidopsis thaliana nationallicence Ovules nationallicence Phloem unloading nationallicence Green fluorescent protein nationallicence Plasmodesmata nationallicence Sieve element nationallicence CC : Companion cell nationallicence CF : Carboxyfluorescein nationallicence CLSM : Confocal laser scanning microscope nationallicence FM4-64 : N-(3-triethylammoniumpropyl)-4-(p-diethylaminophenyl-hexatrienyl) pyridinium dibromide nationallicence GFP : Green fluorescent protein nationallicence HPTS : 8-Hydroxypyrene-1,3,6-trisulfonate nationallicence SE : Sieve element nationallicence TEM : Transmission electron microscope nationallicence Werner Dagmar Lehrstuhl Molekulare Pflanzenphysiologie, Universität Erlangen-Nürnberg, Staudtstraße 5, 91058, Erlangen, Germany aut Gerlitz Nadja Lehrstuhl Molekulare Pflanzenphysiologie, Universität Erlangen-Nürnberg, Staudtstraße 5, 91058, Erlangen, Germany aut Stadler Ruth Lehrstuhl Molekulare Pflanzenphysiologie, Universität Erlangen-Nürnberg, Staudtstraße 5, 91058, Erlangen, Germany aut Protoplasma Springer Vienna 248/1(2011-01-01), 225-235 0033-183X 248:1<225 2011 248 709 https://doi.org/10.1007/s00709-010-0223-8 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00709-010-0223-8 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Werner Dagmar Lehrstuhl Molekulare Pflanzenphysiologie, Universität Erlangen-Nürnberg, Staudtstraße 5, 91058, Erlangen, Germany aut NATIONALLICENCE 700 1- Gerlitz Nadja Lehrstuhl Molekulare Pflanzenphysiologie, Universität Erlangen-Nürnberg, Staudtstraße 5, 91058, Erlangen, Germany aut NATIONALLICENCE 700 1- Stadler Ruth Lehrstuhl Molekulare Pflanzenphysiologie, Universität Erlangen-Nürnberg, Staudtstraße 5, 91058, Erlangen, Germany aut NATIONALLICENCE 773 0- Protoplasma Springer Vienna 248/1(2011-01-01), 225-235 0033-183X 248:1<225 2011 248 709 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer