Na+ accumulation in root symplast of sunflower plants exposed to moderate salinity is transpiration-dependent.
Twenty-day-old sunflower plants (Helianthus annuus L. cv Sun-Gro 380) grown hydroponically under controlled conditions were used to study the effect of transpiration on Na(+) compartmentalization in roots. The plants were exposed to low Na(+) concentrations (25 mM NaCl) and different environmental humidity conditions over a short time period (8.5 h). Under these conditions, Na(+) was accumulated primarily in the root, but only the Na(+) accumulated in the root symplast was dependent on transpiration, while the Na(+) accumulated in both the shoot and the root apoplast exhibited a low transpiration dependence. Moreover, Na(+) content in the root apoplast was reached quickly (0.25 h) and increased little with time. These results suggest that, in sunflower plants under moderate salinity conditions, Na(+) uptake in the root symplast is mediated by a transport system whose activity is enhanced by transpiration.
Quintero
José Manuel
JM
Departamento de Ciencias Agroforestales, Escuela U. Ingeniería Técnica Agrícola, Universidad de Sevilla, Ctra. Utrera, Km. 1, E-41013 Sevilla, Spain. jqariza@us.es
Fournier
José María
JM
Benlloch
Manuel
M
Rodríguez-Navarro
Alonso
A
D004305:Dose-Response Relationship, Drug; D006368:Helianthus / Q000187:drug effects* / Q000378:metabolism*; D018517:Plant Roots / Q000166:cytology* / Q000187:drug effects*; D018526:Plant Transpiration / Q000502:physiology*; D012964:Sodium / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology*
D012965:Sodium Chloride; D012964:Sodium