Salt Excretion in Suaeda fruticosa

The Laboratory of Plant Adaptation to Abiotic Stress (LAPSA), Biotechnology Center at the Technopark of Borj-Cedria (CBBC), Hammam-Lif 2050, Tunisia.
Acta Biologica Hungarica (Impact Factor: 0.59). 09/2010; 61(3):299-312. DOI: 10.1556/ABiol.61.2010.3.6
Source: PubMed


Suaeda fruticosa is a perennial "includer" halophyte devoid of glands or trichomes with a strong ability of accumulating and sequestrating Na(+) and Cl(-). We were interested in determining whether leaf cuticle salt excretion could be involved as a further mechanism in salt response of this species after long-term treatment with high salinity levels. Seedlings had been treated for three months with seawater (SW) diluted with tap water (0, 25, 50 and 75% SW). Leaf scanning electron microscopy revealed a convex adaxial side sculpture and a higher accumulation of saline crystals at the lamina margin, with a large variability on repartition and size between treatments. No salt gland or salt bladder was found. Threedimensional wax decorations were the only structures found on leaf surface. Washing the leaf surface with water indicated that sodium and chloride predominated in excreted salts, and that potassium was poorly represented. Optimal growth of whole plant was recorded at 25% SW, correlating with maximum Na(+) and Cl(-) absolute secretion rate. The leaves of plants treated with SW retained more water than those of plants treated with tap water due to lower solute potential, especially at 25% SW. Analysis of compatible solute, such as proline, total soluble carbohydrates and glycinebetaine disclosed strong relationship between glycinebetaine and osmotic potential (r = 0.92) suggesting that tissue hydration was partly maintained by glycinebetaine accumulation. Thus in S. fruticosa , increased solute accumulation associated with water retention, and steady intracellular ion homeostasis confirms the "includer" strategy of salt tolerance previously demonstrated. However, salt excretion at leaf surface also participated in conferring to this species a capacity in high salinity tolerance.

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    • "These antioxidant enzymes are responsible for keeping the balance between ROS production and destruction (Hassan and Mansoor 2014). Suaeda fruticosa, a halophytic Chenopodiaceae, is a perennial herbaceous plant particularly abundant in salt marshes and arid areas in Tunisia (Oueslati et al. 2014), which requires moderate salinity for maximal growth activity (Labidi et al. 2010). Halophyte species are known for their high accumulation capacity of TME and their ability to withstand unfavorable conditions by reducing toxic ROS, as a result of the powerful antioxidant system they bear (Cai-Hong et al. 2005). "
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    ABSTRACT: Environmental pollution by trace metal elements (TMEs) is a serious problem worldwide, increasing in parallel with the development of human technology. The present research aimed to examine the response of halophytic species Suaeda fruticosa to oxidative stress posed by combined abiotic stresses. Plants have been grown for 1 month with an irrigation solution supplemented with 200 mM NaCl and 400 μM Cd(2+) or 400 μM Cu(2+). The level of glutathione (GSH), phytochelatins (PCs), and antioxidant enzyme activities [ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and catalase (CAT)] as well as lipid peroxidation was studied to see the stress exerted by the TME and the level of tolerance and detoxification strategy adopted by S. fruticosa. Relative growth rate (RGR) decreased under Cd(2+) stress in this species, whereas Cu(2+) did not have any impact on S. fruticosa performance. Cd(2+) or Cu(2+) enhanced malondialdehyde, suggesting reactive oxygen species-induced disruption of membrane integrity and oxidative stress in S. fruticosa. On the other hand, the activities of the antioxidant enzymes CAT, APX, and GPX diminished and mineral nutrition was disturbed by metal stress. S. fruticosa was able to synthesize PCs in response to TME toxicity. However, data indicate that GSH levels underwent a significant decrease in roots and leaves of S. fruticosa stressed by Cd(2+) or Cu(2+). The GSH depletion accompanied by the increase of phytochelatin concentration suggests the involvement of GSH in the synthesis of phytochelatins.
    Full-text · Article · Apr 2015 · Environmental Science and Pollution Research
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    • "Salt excretion by stomatal guttation or by cuticular diffusion in the absence of salt glands might also be involved in Na ? homeostasis in S. fruticosa (Labidi et al. 2010), which could be a possible explanation for unchanged Na ? content between 300 and 600 mM NaCl. "

    Full-text · Dataset · Mar 2013
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    • "Salt excretion by stomatal guttation or by cuticular diffusion in the absence of salt glands might also be involved in Na ? homeostasis in S. fruticosa (Labidi et al. 2010), which could be a possible explanation for unchanged Na ? content between 300 and 600 mM NaCl. "
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    ABSTRACT: Suaeda fruticosa Forssk is a leaf succulent obligate halophyte that produces numerous seeds under saline conditions. Seeds are a good source of high quality edible oil and leaves are capable of removing substantial amount of salt from the saline soil besides many other economic usages. Little is known about the biochemical basis of salt tolerance in this species. We studied some biochemical responses of S. fruticosa to different exog-enous treatments under non-saline (0 mM), moderate (300 mM) or high (600 mM) NaCl levels. Eight-week-old seedlings were sprayed twice a week with distilled water, hydrogen peroxide (H 2 O 2 , 100 lM), glycine betaine (GB, 10 mM), or ascorbic acid (AsA, 20 mM) for 30 days. At moderate (300 mM) NaCl, leaf Na ? , Ca 2? and osmolality increased, along with unchanged ROS and antioxidant enzyme activities, possibly causing a better plant growth. Plants grew slowly at 600 mM NaCl to avoid leaf Na ? buildup relative to those at 300 mM NaCl. Exogenous application of distilled water and H 2 O 2 improved ROS scavenging mechanisms, although growth was unaffected. ASA and GB alleviated salt-induced growth inhibition at 600 mM NaCl through enhancing the antioxidant defense system and osmotic and ion homeo-stasis, respectively.
    Full-text · Article · Nov 2012 · Acta Physiologiae Plantarum
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