Water deficit stress applied only or combined with salinity affects physiological parameters and antioxidant capacity in Sesuvium portulacastrum

Published Date

May 2015, Vol.213:69–76, doi:10.1016/j.flora.2015.04.004

Title 

Water deficit stress applied only or combined with salinity affects physiological parameters and antioxidant capacity in Sesuvium portulacastrum

• Author 

• Inès Slama ^,1,
• Rawya M’Rabet ¹
• Riadh Ksouri
• Ons Talbi
• Ahmed Debez
• Chedly Abdelly

• Laboratoire des Plantes Extrêmophiles, BP 901, Centre de Biotechnologie, Technopole de Borj Cédria, Hammam-Lif 2050, Tunisia

Received 28 October 2014. Revised 16 April 2015. Accepted 20 April 2015. Available online 22 April 2015. Edited by Hermann Heilmeier.

Highlights

• •
  S. portulacastrum exhibits a great potential as a soil cover plant and could be introduced in arid salty habitats.
• •
  Following stress relief (combined drought and salinity) S. portulacastrum conserves its growth potentials.
• •
  In water deficit stressed plants, salt supply increased leaf proline concentration and reduced lipid membrane peroxidation.
• •
  Salt exposure might partly alleviate the negative effects of water-deficit on plant growth and net CO₂ assimilation.
• •
  S. portulacastrum is a source of antioxidant metabolites that can be used in medicinal and industrial domain.

Abstract

Sesuvium portulacastrum is a promising halophyte well adapted to salt and to drought. However, no information in the literature was available about its antioxidant capacity. The objective of this study is to investigate the effects of water deficit applied alone or combined with salinity on some physiological parameters, proline and polyphenol accumulation, and antioxidant and antiradical activities. Seedlings were cultivated under optimal or limiting water supply (respectively, 100% and 25% of field capacity, FC). The amount of the evapotranspirated water was replaced by a nutrient solution containing either 0 or 200 mM NaCl. Water deficit stress reduced plant growth together with a significant decline in leaf water content. Salinity mitigated the deleterious effects of water deficit stress on growth and led to an increase in net CO₂ assimilation and stomatal conductance. In addition, salt supply under water deficit significantly increased leaf proline concentration and reduced lipid membrane peroxidation, assessed by leaf malondialdehyde concentration. Phenolic compound content increased significantly when plants were transferred from water deficit stress to 100% FC. However, plants subjected to water deficit stress combined to salt had high polyphenol content and the highest level of the antiradical activity in their stems. As a whole, cultivating S. portulacastrum under water deficit stress combined with salinity might be an interesting approach to exploit antioxidant metabolites from this species for medicinal and industrial purposes.

Recovery of most of the studied parameters was substantial following relief of stress. Drought stress alone or combined with salinity did not cause permanent alterations in S. portulacastrum plants, which conserve their growth potentialities, and which can be a useful species in re-vegetation programs in arid saline areas.

Abbreviations

• A, net CO₂ assimilation
• DPPH, diphenylpicrylhydrazyl
• DW, dry weight
• FC, field capacity
• FW, fresh weight
• GAE, Gallic acid equivalents
• g_s, stomatal conductance
• IC₅₀, the extract concentration required to cause a 50% inhibition
• MDA, malondialdehyde
• PAR, photosynthetically active radiation
• PSII, photosystem II
• RGR, relative growth rate
• TBA, thiobarbituric acid
• TCA, trichloroacetic acid
• VPD, Vapour pressure deficit

Keywords

• Drought
• Proline
• Polyphenols
• Leaf gas exchange
• Arid saline areas

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 Table 2

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• ⁎ 
  Corresponding author. Tel.: +216 79 325 848; fax: +216 79 325 638.

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