caa a22 4500 397520921 CHVBK 20180308164632.0 cr unu---uuuuu 161202e199501 xx s 000 0 eng 10.1093/jxb/46.1.35 doi (NATIONALLICENCE)oxford-10.1093/jxb/46.1.35 Cellular pathway of photosynthate transport in coats of developing seed of Vicia faba L. and Phaseolus vulgaris L. I. Extent of transport through the coat symplast [Elektronische Daten] [J.W. Patrick, C.E. Offler, X.-D. Wang] The extent of post-phloem solute transport through the coat symplasts of developing seeds of Vicia faba L. and Phaseolus vulgaris L. was evaluated. For Vicia seed coats, the membrane-impermeant fluorochrome, CF, moved radially from the chalazal vein to reach the chlorenchyma and thin-walled parenchyma transfer cell layers. Thereafter, the fluorochrome moved laterally in these two cell layers around the entire circumference of the seed coat. Transfer of CF from the chalazal vein was inhibited by plasmolysis of attached ‘empty' seed coats. In contrast, the spread of phloem imported CF was restricted to the ground parenchyma of Phaseolus seed coats. Fluorochrome loaded into the outermost ground parenchyma cell layer was rendered immobile following plasmolysis of excised seed-coat halves. Phloem-imported [14C]sucrose and the slowly membrane permeable sugar, L-[14C]glucose, were partitioned identically between the vascular and non-vascular regions of intact Vicia seed coats. For 14C-photosynthates, these partitioning patterns in attached ‘empty' Vicia seed coats were unaffected by PCMBS, but inhibited by plasmolysis. Tissue autoradiographs of intact Phaseolus seed coats demonstrated that a pulse of 14C-photosynthate moved from the veins to the grounds tissues. In excised Vicia seed coats, preloaded with 14C-photosynthates, the cellular distribution of residual 14C-label was unaffected by PCMBS. In contrast, PCMBS caused the 14C-photosynthate levels to be elevated in the veins and ground parenchyma relative to the branch parenchyma of Phaseolusseed coat halves. Based on the above findings, it is concluded that the phloem of Vicia seed coats is interconnected to two major symplastic domains; one comprises the chlorenchyma, the other the thin-walled parenchyma plus thin-walled parenchyma transfer cells. For Phaseolusseed coats, the phloem forms a major symplastic domain with the ground parenchyma. © Oxford University Press Research Papers nationallicence Phaseolus vulgaris L nationallicence phloem unloading nationallicence photosynthate transport nationallicence seed coat nationallicence symplast nationallicence Vicia faba L nationallicence Patrick J.W. Department of Biological Sciences, The University of Newcastle Newcastle, NSW 2308, Australia aut Offler C.E. Department of Biological Sciences, The University of Newcastle Newcastle, NSW 2308, Australia aut Wang X.-D Shanghai Institute of Plant Physiology, Academia Sinica Shanghai 200032, China aut Journal of Experimental Botany Oxford University Press 46/1(1995-01), 35-47 0022-0957 46:1<35 1995 46 exbotj https://doi.org/10.1093/jxb/46.1.35 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/jxb/46.1.35 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Patrick J.W. Department of Biological Sciences, The University of Newcastle Newcastle, NSW 2308, Australia aut NATIONALLICENCE 700 1- Offler C.E. Department of Biological Sciences, The University of Newcastle Newcastle, NSW 2308, Australia aut NATIONALLICENCE 700 1- Wang X.-D Shanghai Institute of Plant Physiology, Academia Sinica Shanghai 200032, China aut NATIONALLICENCE 773 0- Journal of Experimental Botany Oxford University Press 46/1(1995-01), 35-47 0022-0957 46:1<35 1995 46 exbotj Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford