Photosynthetic Gas Exchange and Chlorophyll a Fluorescence in Salicornia brachiata (Roxb.) Under Osmotic Stress

Shahrukh A. Siddiqui, Kusum Khatri, Darshan Patel, Mangal S. Rathore

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Osmotic stress negatively affects the photosynthetic efficiency and cause a significant loss of crop productivity. Salicornia brachiata (Roxb.) is a eu-halophyte. We hereby report on photosynthetic gas exchange and chlorophyll fluorescence in S. brachiata under sodium chloride (NaCl), seawater and polyethylene glycol (PEG) induced osmotic stress. It grows luxuriantly and exhibited a higher tolerance index and better accumulation of organic solutes under 100% strength of seawater (32.5 ppt) and 0.5 M NaCl salinity. It exhibited comparatively better gas exchange, stomatal conductance, PSII photochemistry and electron transfer under 100% strength of seawater salinity. Higher chlorophyll a/b ratio under stress conditions indicated a lower ratio of PSII to PSI and balanced excitation of PSI and PSII in S. brachiata resulting in efficient photosynthetic processes. The lower total chlorophyll/carotenoids ratio and higher non-photochemical quenching indicated the photo-protection and safer dissipation of heat energy in S. brachiata under stress. The 100% strength of seawater and 0.5 M NaCl salinity in S. brachiata did not cause significant changes in antenna size, connectivity between PSII reaction centres (RCs) and reduction of electrons on PSII donor side. The 20% PEG induced the inactivation of RCs and cause damage to PSII RCs in S. brachiata thus reduced the electron transfer from QA to QB pool-sized and activity of water-splitting complex. Higher φ(P0) and FV/FM in S. brachiata under seawater salinity indicated a comparatively better quantum yield of primary photochemistry. The higher PITotal in S. brachiata under 100% strength of seawater and 0.5 M NaCl stress indicated a better energy flux reaching to PSII RCs, electron transport and performance of RCs. The higher strengths of osmotic stress cause reduction in the quantum yield of PSII electron transport and capturing efficiency of excitation energy by open PSII RCs in S. brachiata. Graphic Abstract: [Figure not available: see fulltext.]

Original languageEnglish
Pages (from-to)429-444
Number of pages16
JournalJournal of Plant Growth Regulation
Volume41
Issue number1
DOIs
StatePublished - 1 Jan 2022
Externally publishedYes

Keywords

  • Abiotic stress
  • And salinity tolerance
  • Chlorophyll fluorescence
  • Eu-halophyte
  • Performance
  • Photosynthesis

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Plant Science

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