Zunzunegui, M
Valera-Burgos, J
Díaz-Barradas, MC
Esquivias, MP
Gallego-Fernandez, JB
Ecohydrology
Year: 20187
Volume
Inicial page:
Final page:
ISI: 2.852
Abstract
Retama monosperma (L.) Boiss is a coastal shrub growing on sandy soils in the SW of the Iberian Peninsula and in the NW of Morocco. Although a native species, it has been considered to show an invasive behaviour. Tolerance of R. monosperma to salinity—one of the most limiting factors of coastal systems—was assessed as an eventual explanation to its invasive character.
A glasshouse experiment, where young plants were irrigated with different NaCl concentrations (5 to 600 mM), was designed. R. monosperma physiological performance was examined by measuring gas exchange, quantum yield, and water potential, at 7, 30, and 60 days after reaching the assigned NaCl concentration. At the end of the experiment, after measuring free proline content in cladodes, plants were harvested, separated in stems, roots, and root nodules, and weighted and Na + content was measured in roots and cladodes.
Although plants survived to high NaCl concentrations, increasing levels of salinity resulted in a progressive reduction in photosynthetic rate, stomatal conductance and water potential, and also in a progressive increase in proline and Na + content. Roots accumulated more Na+ than cladodes in all situations. Biomass allocation pattern was modified by the NaCl levels.
The high tolerance of R. monosperma to a continued exposure to salinity could be one of the factors explaining its high expansion rate in coastal areas.