Journal Article

Photosynthesis during Desiccation in an Intertidal Alga and a Land Plant

Yoshinobu Kawamitsu, Timothy Driscoll and John S. Boyer

in Plant and Cell Physiology

Published on behalf of Japanese Society of Plant Physiologists

Volume 41, issue 3, pages 344-353
Published in print March 2000 | ISSN: 0032-0781
Published online March 2000 | e-ISSN: 1471-9053 | DOI: http://dx.doi.org/10.1093/pcp/41.3.344
Photosynthesis during Desiccation in an Intertidal Alga and a Land Plant

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This study was undertaken to determine how photosynthesis tolerates desiccation in an intertidal alga Fucus vesiculosus L. and a terrestrial sunflower Helianthus annum L. Photosynthetic O2 evolution generally was inhibited at low water potentials (Ψw) but more in sunflower leaves than in Fucus fronds at the same Ψw. As Ψw decreased, less carbon accumulated in an organic carbon store in Fucus. The inhibition of photosynthesis appeared to be mostly biochemical because it could not be prevented by supplying additional CO2 or by supplying CO2 from the internal organic carbon store. The inhibition of photosynthesis and carbon storage occurred after turgor disappeared and thus when solute concentrations were increasing in the cells. Solute concentrations were much higher in Fucus than in sunflower. After desiccation to the air-dry state (Ψw below – 1O MPa), photosynthesis could not recover in sunflower but it recovered rapidly when Fucus was exposed to seawater. The lack of recovery in sunflower was associated with inability to recover turgor probably because of breaks in cell membranes. The ability to recover in Fucus was gradually lost during 1.5 d of desiccation at 45% relative humidity. At lower humidities, recovery was lost sooner as small amounts of water were removed. We conclude that photosynthesis tolerated desiccation more in Fucus than in sunflower because of differences in the molecular environment around the photosynthetic enzymes. Important aspects of this environment were features that prevented membrane breakage but promoted the retention of small amounts of water that were critical for viability.

Keywords: Desiccation tolerance; Fucus vesiculosus L; Helianthus annuus L; Stored carbon; Water content; Water potential

Journal Article.  0 words. 

Subjects: Biochemistry ; Molecular and Cell Biology ; Plant Sciences and Forestry

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