TY - JOUR

T1 - The effects of salinity on photosynthesis and growth of the single-cell C4 species Bienertia sinuspersici (Chenopodiaceae)

AU - Leisner, Courtney P

AU - Cousins, Asaph B

AU - Offermann, Sascha

AU - Okita, Thomas W

AU - Edwards, Gerald E

N1 - Funding information: Acknowledgments This material is based upon work supported by the National Science Foundation under Grants IBN-0236959 and IBN-0641232. Seeds of Bienertia sinuspersici were kindly provided by Dr. Abdulrahman Alsirhan, Kuwait. We appreciate the advice of M.A. Evans on statistical analyses. We thank the Franceschi Microscopy and Imaging Center of Washington State University for use of facilities and for staff assistance, C. Cody for plant growth management, and E. Voznesenskaya, N. Kotey-eva, and O. Kiirats for helpful discussions during the research phase.

PY - 2010/12

Y1 - 2010/12

N2 - Recent research on the photosynthetic mechanisms of plant species in the Chenopodiaceae family revealed that three species, including Bienertia sinuspersici, can carry out C(4) photosynthesis within individual photosynthetic cells, through the development of two cytoplasmic domains having dimorphic chloroplasts. These unusual single-cell C(4) species grow in semi-arid saline conditions and have semi-terete succulent leaves. The effects of salinity on growth and photosynthesis of B. sinuspersici were studied. The results show that NaCl is not required for development of the single-cell C(4) system. There is a large enhancement of growth in culture with 50-200 mM NaCl, while there is severe inhibition at 400 mM NaCl. With increasing salinity, the carbon isotope values (δ(13)C) of leaves increased from -17.3(o)/(oo) (C(4)-like) without NaCl to -14.6(o)/(oo) (C(4)) with 200 mM NaCl, possibly due to increased capture of CO(2) from the C(4) cycle by Rubisco and reduced leakiness. Compared to growth without NaCl, leaves of plants grown under saline conditions were much larger (~2 fold) and more succulent, and the leaf solute levels increased up to ~2000 mmol kg solvent(-1). Photosynthesis on an incident leaf area basis (CO(2) saturated rates, and carboxylation efficiency under limiting CO(2)) and stomatal conductance declined with increasing salinity. On a leaf area basis, there was some decline in Rubisco content with increasing salinity up to 200 mM NaCl, but there was a marked increase in the levels of pyruvate, Pi dikinase, and phosphoenolpyruvate carboxylase (possibly in response to sensitivity of these enzymes and C(4) cycle function to increasing salinity). The decline in photosynthesis on a leaf area basis was compensated for on a per leaf basis, up to 200 mM NaCl, by the increase in leaf size. The influence of salinity on plant development and the C(4) system in Bienertia is discussed.

AB - Recent research on the photosynthetic mechanisms of plant species in the Chenopodiaceae family revealed that three species, including Bienertia sinuspersici, can carry out C(4) photosynthesis within individual photosynthetic cells, through the development of two cytoplasmic domains having dimorphic chloroplasts. These unusual single-cell C(4) species grow in semi-arid saline conditions and have semi-terete succulent leaves. The effects of salinity on growth and photosynthesis of B. sinuspersici were studied. The results show that NaCl is not required for development of the single-cell C(4) system. There is a large enhancement of growth in culture with 50-200 mM NaCl, while there is severe inhibition at 400 mM NaCl. With increasing salinity, the carbon isotope values (δ(13)C) of leaves increased from -17.3(o)/(oo) (C(4)-like) without NaCl to -14.6(o)/(oo) (C(4)) with 200 mM NaCl, possibly due to increased capture of CO(2) from the C(4) cycle by Rubisco and reduced leakiness. Compared to growth without NaCl, leaves of plants grown under saline conditions were much larger (~2 fold) and more succulent, and the leaf solute levels increased up to ~2000 mmol kg solvent(-1). Photosynthesis on an incident leaf area basis (CO(2) saturated rates, and carboxylation efficiency under limiting CO(2)) and stomatal conductance declined with increasing salinity. On a leaf area basis, there was some decline in Rubisco content with increasing salinity up to 200 mM NaCl, but there was a marked increase in the levels of pyruvate, Pi dikinase, and phosphoenolpyruvate carboxylase (possibly in response to sensitivity of these enzymes and C(4) cycle function to increasing salinity). The decline in photosynthesis on a leaf area basis was compensated for on a per leaf basis, up to 200 mM NaCl, by the increase in leaf size. The influence of salinity on plant development and the C(4) system in Bienertia is discussed.

KW - Biomass

KW - Blotting, Western

KW - Carbon/metabolism

KW - Carbon Dioxide/metabolism

KW - Carbon Isotopes

KW - Chenopodiaceae/cytology

KW - Osmolar Concentration

KW - Photosynthesis/drug effects

KW - Plant Leaves/drug effects

KW - Plant Roots/drug effects

KW - Plant Shoots/drug effects

KW - Plant Stomata/drug effects

KW - Salinity

KW - Sodium Chloride/pharmacology

U2 - 10.1007/s11120-010-9595-z

DO - 10.1007/s11120-010-9595-z

M3 - Article

C2 - 20838891

VL - 106

SP - 201

EP - 214

JO - Photosynthesis research

JF - Photosynthesis research

SN - 0166-8595

IS - 3

ER -