Linked Life Data

7417417

Source:http://linkedlifedata.com/resource/pubmed/id/7417417

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1980-12-18
pubmed:abstractText
Millimolar concentrations of monovalent cations enhance and divalent cations impede the redistribution (spill-over) of electronic excitation energy from Photosystem (PS) II to PS I in cation-depleted (sucrose-washed) thylakoids; this concept is based on chlorophyll a fluorescence and electron transport measurements over a narrow pH range around 7. We have tested the above concept in pea thylakoids over the pH range 5 to 9 by parallel measurements of various chlorophyll a fluorescence parameters (spectra, transients, and lifetimes at 77 K and 293 K, and polarization at 293 K) and of the rates of partial reactions of PSI and II. Our results provide the following information. (1) Mg2+ enhancement of fluorescence is maximum between 680 and 690 nm and minimum between 710 and 720 nm. (2) The optimum conditions for the observation of the Mg2+-induced enhancement of fluorescence are: wavelength of emission, 685 nm; concentratin of Mg2+, 10 mM, and pH, approximately 7.5. (3) Mg2+ decreases the efficiency of excitation redistribution from PS II to PS I over the pH range 6 to 9. (4) The antagonistic effects between Na+ and Mg2+ hold simultaneously for both the fluorescence intensity and lifetime, at physiological temperatures, only within the pH range 6 to 8. (5) Mg2+ enhances the light-limited electron transport rate through PS II in the pH range 5.4 to 8.2 and decreases that through PS I at pH 7.1 and 8.2. The % increase in PS II is, however, about twice the % decrease in PS I.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
592
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
546-58
pubmed:dateRevised
2000-12-18
pubmed:meshHeading
pubmed:year
1980
pubmed:articleTitle
Effects of bulk pH and of monovalent and divalent cations on chlorophyll a fluorescence and electron transport in pea thylakoids.
pubmed:publicationType
Journal Article