Effects of reduced amounts of lipid unsaturation on chloroplast ultrastructure and photosynthesis in a mutant of Arabidopsis
A mutant of Arabidopsis thaliana with reduced content of C/sub 18:3/ and C/sub 16:3/ fatty acids in membrane lipids exhibited a 45% reduction in the cross-sectional area of chloroplasts and had a decrease of similar magnitude in the amount of chloroplast lamellar membranes. The reduction in chloroplast size was partially compensated by a 45% increase in the number of chloroplasts per cell in the mutant. When expressed on a chlorophyll basis the rates of CO/sub 2/-fixation and photosynthetic electron transport were not affected by these changes. Fluorescence polarization measurements indicated that the fluidity of the thylakoid membranes was not significantly altered by the mutation. Similarly, on the basis of temperature-induced fluorescence yield enhancement measurements, there was no significant effect on the thermal stability of chlorophyll-protein complexes in the mutant. These observations suggest that the high content of trienoic fatty acids in chloroplast lipids may be an important factor regulating organelle biogenesis but is not required to support normal levels of the photosynthetic activities associated with the thylakoid membranes.
- Research Organization:
- Michigan State Univ., East Lansing
- DOE Contract Number:
- AC02-76ER01338
- OSTI ID:
- 5900700
- Journal Information:
- Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 84:2; ISSN PLPHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ARABIDOPSIS
BIOLOGICAL EFFECTS
BIOSYNTHESIS
CARBON DIOXIDE FIXATION
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CHEMICAL REACTIONS
CHLOROPHYLL
CHLOROPLASTS
DISEASE RESISTANCE
EMISSION SPECTROSCOPY
FLUORESCENCE SPECTROSCOPY
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROGENATION
LINOLENIC ACID
LIPIDS
MEMBRANES
MONOCARBOXYLIC ACIDS
MUTATIONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHOTOSYNTHETIC MEMBRANES
PHYSIOLOGY
PHYTOCHROMES
PIGMENTS
PLANTS
PORPHYRINS
PROTEINS
SPECTROSCOPY
SYNTHESIS
TEMPERATURE EFFECTS