TY - JOUR
AU - OFFLER, C., E.
AB - Abstract Cellular plasmolysis with l M solutions of mannitol appeared to sever plasmodesmatal interconnections between all cells of the stems of Phaseolus vulgaris plants except the sieve element-companion cell (se—cc) complexes. Phloem loading and uptake of [14C]sucrose by the storage cells of the stems was unimpaired by cellular plasmolysis followed by rehydration of the stem tissues. Accumulation of phloem-transported 14C-photosynthates of the treated stems was inhibited in summer-grown plants and unaffected in winter-grown plants indicating that phloem unloading follows a symplastic and a free-space route respectively depending on growth season. At a concentration that did not interfere with cellular metabolism, p-chloromercuribenzene sulphonic acid (PCMBS) applied to the stems blocked [14C]sucrose loading into the phloem and storage cells of the stem, but had no effect on the pool size of free-space sugars. This latter response is consistent with a facilitated mechanism of sugar unloading to the stem free-space. Accumulation of phloem-transported 14C-photosynthates was stimulated by PCMBS and this effect was most pronounced in winter-grown plants. Cellular plasmolysis followed by rehydration abolished the PCMBS action on 14C-photosynthate accumulation. This effect is consistent with a PCMBS induction of phloem unloading through the stem symplast. It is proposed that phloem unloading in bean stems may follow either a free-space or symplastic route and that the latter route is entrained under sink-limited conditions. Phaseolus vulgaris, french bean, stem, phioem unloading, free-space, symplast This content is only available as a PDF. © 1987 Annals of Botany Company
TI - The Cellular Pathway of Radial Transfer of Photosynthates in Stems of Phaseolus vulgaris L.Effects of Cellular Plasmolysis and p-Chloromercuribenzene Sulphonic Acid
JF - Annals of Botany
DO - 10.1093/oxfordjournals.aob.a087360
DA - 1987-06-01
UR - https://www.deepdyve.com/lp/oxford-university-press/the-cellular-pathway-of-radial-transfer-of-photosynthates-in-stems-of-1dcXupkUrf
SP - 635
EP - 642
VL - 59
IS - 6
DP - DeepDyve
ER -