Growth and photosynthetic responses to salinity in an extreme halophyte, Sarcocornia fruticosa

Abstract

Sarcocornia fruticosa (L.) A.J. Scott is found in coastal marshes of south-west Spain, growing under a very wide range of interstitial soil salinity from 10 mM up to nearly 1000 mM. A glasshouse experiment was designed to investigate the effect of this range of salinities on the morphology and the photosynthetic apparatus of S. fruticosa by measuring growth rate, photosynthetic and non-photosynthetic area, atrophy of distal branch ends, water status, chlorophyll fluorescence parameters, gas exchange and photosynthetic pigment concentrations. The long-term effects of salinity on the growth of S. fruticosa were mainly determined by the extent of photosynthetic area rather than the variations in net photosynthetic rate. Photosynthetic area was reduced at 1030 mM as a result of a decrease in the length of the photosynthetic portions. This was induced by fewer internodes and, at salinities lower than 510 mM, smaller internode diameter. Net photosynthetic rate increased as the quantum efficiency of photosystem II decreased in the different salinity treatments, which means that the plant could be increasing photorespiration and/or using cyclic electron transport as additional photoprotective mechanisms. The recorded drop in net photosynthetic rate at higher salinities appeared to be due to a reduction in stomatal conductance. The results indicate that S. fruticosa is capable of tolerating very high and continued exposure to salt, showing its greatest growth rate at 510 mM NaCl.

Responses of Batis maritima plants challenged with up to two‐fold seawater NaCl salinity

“…1B). This suggests that under favorable conditions, the root performance may sustain the shoot-biomass production of B. maritima, which is consistent with previous reports on salt-tolerant species such as Sarcocornia fruticosa (Redondo-Gómez et al, 2006) and C. maritima .…”

“…Plant growth is determined by its photosynthetic performance (Redondo-Gómez et al, 2006). Despite declining at salinities above 600 mM NaCl, chlorophyll concentrations were generally unchanged (Figs.…”

“…Actually, F v /F m values (up to 0.75) over the salinity range were close to those considered as typical to healthy nonstressed leaves (0.75-0.85) (Vassilev and Manolov, 1999). Hence, B. maritima was able to maintain the photosynthetic-apparatus integrity, even at salinity levels exceeding that of seawater, which demonstrates a very high degree of salinity tolerance relative to other halophytic species (Redondo-Gómez et al, 2006;Debez et al, 2008).…”

Relation entre facteurs environnementaux et densités larvaires d’Ochlerotatus caspiusPallas 1771 etOchlerotatus detritusHaliday 1833 (Diptera: Culicidae) en Tunisie

“…Il peut être submergé dans une vase salée au moment des hautes marées ou des pluies abondantes se comportant comme un halophyte, et devient un aérohalophyte à marée basse. Son taux de croissance est optimal lorsque la salinité du sol atteint 29,8 g/l (Redondo- Gomez et al 2006). En revanche, nos résultats montrent que les biotopes larvaires peuplés par J. maritimus ne sont pas favorables au développement préimaginal d'Oc.…”

Comparative analyses of plant responses to drought and salt stress in related taxa: A useful approach to study stress tolerance mechanisms.

“…Growth of all glycophytes and most halophytes is optimal in the absence of salt and is progressively reduced by increasing salt concentrations; only in some highly tolerant dicotyledonous halophytes, growth is stimulated by low or moderate salinity, althou gh still inhibited in the presence of salt above a higher, species-specific concentration threshold Redondo-Gómez et al, 2006;. Therefore, a quantitative assessment of salt-induced growth inhibition in different species should provide a reliable ranking of their relative degree of salt tolerance.…”