Salt tolerance of the annual halophyte Cakile maritima as affected by the provenance and the developmental stage

Abstract

Though halophytes are naturally adapted to salinity, their salt-tolerance limits are greatly influenced by their provenance and developmental stage. In the present study, physio-biochemical responses of two Tunisian ecotypes of the oilseed coastal halophyte Cakile maritima (Brassicaceae) to salinity (0-400 mM NaCl) were monitored during germination and vegetative growth stages. Tabarka and Jerba seeds were collected from humid or arid climatic areas, respectively. Plant response to salinity appeared to depend on the ecotype and salinity levels. Increasing salinity inhibited germination process. Jerba seeds were found to be more salt tolerant than the Tabarka ones. At the autotrophic stage of growth and under salt-free conditions, Jerba was less productive than Tabarka (in terms of dry matter accumulation), but plant biomass production and leaf expansion (area and number) of the former ecotype were progressively improved by 100 mM NaCl, as compared to the control. In contrast, at the same salt concentration, these parameters decreased under increasing salinity in Tabarka (salt sensitive). Leaf chlorophyll content was reduced at severe salinity, but this effect was more conspicuous in the sensitive Tabarka plants. Na + contents in the Jerba and Tabarka leaves collected from the 400 mM NaCl-treated plants were 17-and 12-fold higher than in the respective controls. This effect was accompanied by a significant reduction in the leaf K + , Mg 2+ and Ca 2+ contents, especially in the salt-treated Tabarka. A significant accumulation of proline and soluble carbohydrates in leaves was found during the period of intensive leaf growth. These organic compounds likely play a role in leaf osmotic adjustment and in protection of membrane stability at severe salinity.

Salt resistance of tomato species grown in sand culture

“…Salinity tolerance is related to the maintenance of net photosynthetic rate and stomatal conductance and to elevated chlorophyll concentration (Ashraf 2004). High salinity reduced the leaf chlorophyll content in all genotypes, which might be due to the increased activity of chlorophyllase (Megdiche et al 2007). A reduction in total chlorophyll contents was observed in the NaCl-stressed Catharanthus plants when compared to control.…”

Selection, Characterizations and Somatic Embryogenesis of Malaysian Salt-tolerant Rice (Oryza sativa cv. MR219) through Callogenesis

“…Excessive amount of Na + and Cl -imposed ionic imbalance and reduction capacity of water uptake by cells, which lead to oxidative stress and production of reactive oxygen species (ROS) (Wani et al, 2010). The production of ROS causes degradation of proteins and lipids, thereby cell damage (Megdiche et al, 2007). Plants cells have non-enzymatic and enzymatic defense system to control over production of ROS.…”

Leaf anatomical and biochemical adaptations in Typha domingensis Pers. ecotypes for salinity tolerance

“…Salinity is a noticeable stress which stimulate many physiological and biochemical reactions in plants and disturb almost all functioning of plant cell (Megdiche et al 2007) especially growth, leaf area and ultimate yield of the plants. Dehydration, ionic toxicity, nutritional deficiency and hormonal imbalance are major mechanisms affected by salt stress (Farouk 2011).…”