Frontiers in Plant Science (Aug 2015)

Physio-biochemical and morphological characters of halophyte legume shrub, Acacia ampliceps seedlings in response to salt stress under greenhouse

  • Cattarin eTheerawitaya,
  • Rujira eTisarum,
  • Thapanee eSamphumphuang,
  • Harminder Pal Singh,
  • Suriyan eCha-Um,
  • Chalermpol eKirdmanee,
  • Teruhiro eTakabe

DOI
https://doi.org/10.3389/fpls.2015.00630
Journal volume & issue
Vol. 6

Abstract

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Acacia ampliceps (salt wattle), a leguminous shrub, has been introduced in salt-affected areas in northeast of Thailand for remediation of saline soils. However, the defense mechanisms underlying salt tolerance A. ampliceps are unknown. We investigated various physio-biochemical and morphological attributes of A. ampliceps in response to varying levels of salt treatment (200 to 600 mM NaCl). Seedlings of A. ampliceps (252 cm in plant height) raised from seeds were treated with 200 mM (mild stress), 400 and 600 mM (extreme stress) of salt treatment (NaCl) under greenhouse conditions. Na+ and Ca2+ contents in the leaf tissues increased significantly under salt treatment, whereas K+ content declined in salt-stressed plants. Free proline and soluble sugar contents in plant grown under extreme salt stress (600 mM NaCl) for 9 days significantly increased by 28.7 (53.33 mol g1 FW) and 3.2 (42.11 mg g1 DW) folds, respectively over the control, thereby playing a major role as osmotic adjustment. Na+ enrichment in the phyllode tissues of salt-stressed seedlings positively related to total chlorophyll degradation (R2=0.72). Photosynthetic pigments and chlorophyll fluorescence in salt-stressed plants increased under mild salt stress (200 mM NaCl). However, these declined under high level of salinity (400-600 mM NaCl), consequently resulting in reduced net photosynthetic rate (R2=0.81) and plant dry weight (R2= 0.91). The study concludes that A. ampliceps has an osmotic adjustment and Na+ compartmentation as effective salt defense mechanisms, and thus it could be an excellent species to grow in salt-affected soils.

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