ISSN:
1432-2048
Keywords:
Chloroplast (membrane fluidity
;
Fluorescence (polarization, temperature)
;
Lipid (thylakoid membrane)
;
Membrane (fluidity, temperature)
;
Photosynthesis
;
Pisum (thylakoid membrane)
;
Thylakoid membrane
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract In order to investigate membrane fluidity, the hydrophobic probe, 1,6-diphenyl-1,3,5-hexatriene (DPH), has been incorporated into intact isolated thylakoids and separated granal and stromal lamellae obtained from the chloroplasts of Pisum sativum. The steady-state polarization of DPH fluorescence was measured as a function of temperature and indicated that at physiological values the thylakoid membrane is a relatively fluid system with the stromal lamellae being less viscous than the lamellae of the grana. According to the DPH technique, neither region of the membrane, however, showed a sharp phase transition of its bulk lipids from the liquid-crystalline to the gel state for the temperature range -20° to 50° C. Comparison of intact thylakoids isolated from plants grown at cold (4°/7°C) and warm (14°/17° C) temperatures indicate that there is an adaptation mechanism operating which seems to maintain an optimal membrane viscosity necessary for growth. Using a modified Perrin equation the optimal average viscosity for the thylakoid membrane of the chill-resistant variety used in the study (Feltham First) is estimated to be about 1.8 poise.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00398729
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