Membrane fluxes, bypass flows, and sodium stress in rice: the influence of silicon
| Autor: | Ahmed M. Hamam, Wayne Q Huynh, Dev T. Britto, Herbert J. Kronzucker, Rubens Flam-Shepherd, Devrim Coskun |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0106 biological sciences
0301 basic medicine Oryza sativa Physiology Chemistry Sodium fungi food and beverages chemistry.chemical_element Depolarization Plant Science 01 natural sciences Apoplast Dilution 03 medical and health sciences 030104 developmental biology Membrane Shoot Biophysics 010606 plant biology & botany Transpiration |
| Zdroj: | Journal of Experimental Botany. 69:1679-1692 |
| ISSN: | 1460-2431 0022-0957 |
| DOI: | 10.1093/jxb/erx460 |
| Popis: | Provision of silicon (Si) to roots of rice (Oryza sativa L.) can alleviate salt stress by blocking apoplastic, transpirational bypass flow of Na+ from root to shoot. However, little is known about how Si affects Na+ fluxes across cell membranes. Here, we measured radiotracer fluxes of 24Na+, plasma membrane depolarization, tissue ion accumulation, and transpirational bypass flow, to examine the influence of Si on Na+ transport patterns in hydroponically grown, salt-sensitive (cv. IR29) and salt-tolerant (cv. Pokkali) rice. Si increased growth and lowered [Na+] in shoots of both cultivars, with minor effects in roots; neither root nor shoot [K+] were affected. In IR29, Si lowered shoot [Na+] via a large reduction in bypass flow, while in Pokkali, where bypass flow was small and not affected by Si, this was achieved mainly via a growth dilution of shoot Na+. Si had no effect on unidirectional 24Na+ fluxes (influx and efflux), or on Na+-stimulated plasma-membrane depolarization, in either IR29 or Pokkali. We conclude that, while Si can reduce Na+ translocation via bypass flow in some (but not all) rice cultivars, it does not affect unidirectional Na+ transport or Na+ cycling in roots, either across root cell membranes or within the bulk root apoplast. |
| Databáze: | OpenAIRE |
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