Where does Münch flow begin? Sucrose transport in the pre-phloem path
| Autor: | Jessica T. Gersony, Fulton E. Rockwell, N. Michele Holbrook |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0106 biological sciences
0301 basic medicine Convection Sucrose Plant Science Plasmodesma Biology 01 natural sciences Diffusion 03 medical and health sciences chemistry.chemical_compound Mass transfer Transpiration fungi Plasmodesmata Water food and beverages Biological Transport Mechanics Plants Sucrose transport Plant Leaves Permeability (earth sciences) 030104 developmental biology chemistry Phloem 010606 plant biology & botany |
| Zdroj: | Current Opinion in Plant Biology. 43:101-107 |
| ISSN: | 1369-5266 |
| DOI: | 10.1016/j.pbi.2018.04.007 |
| Popis: | Current conceptions of sucrose export largely neglect the effect of transpiration-induced water potential gradients within leaf mesophyll, even as the mix of convection and diffusion in the pre-phloem path remains uncertain. It is also generally held that the relative importance of convection and diffusion in the pre-phloem path is controlled by the ratio of their respective mass transfer coefficients. Here, we consider pre-phloem sucrose transport in the presence of adverse water potential gradients, finding that whether convection impedes or aids sucrose delivery to the phloem is independent of the permeability of the plasmodesmata to bulk flow, and depends only on assimilation rate, path-length, and the diffusivity. For most tissues subject to transpiration, convection through plasmodesmata pushes sugar away from the phloem. |
| Databáze: | OpenAIRE |
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