Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1976-9-1
pubmed:abstractText
Studies of the variability of enhancement in Chlorella pyrenoidosa confirm the existence of two types of variability: a very slow diurnal variation linked to the growth cycle and a much more rapid adaptive response to the immediate incident light conditions (State I-State II transitions). Measurements of the wavelength dependencies and relative contributions of these two types of variability suggest that they may be linked. A close examination of the enhancement signals associated with the State I-State II transition reveals that the transitions can take place in any one of three ways: by a change in Photosystem II efficiency alone, by a change in Photosystem I efficiency alone or by a simultaneous change in the efficiencies of both photo systems. Measurements of the rates of transition between State I, State II and the dark adapted state, Dark, suggest that the behaviour of State II and Dark are normally, but not always, identical. The transitions between the three states were found to be first order. For those samples exhibiting the same behaviour in Dark and State II, the rate of the State I-State II transition was found to be independent of the wavelength of Light II, suggesting that the return from State I to State II is essentially a dark process and that the driving force for the adaptive transition is the over-stimulation of Photosystem I. Finally, a model is proposed, involving an antagonistic control of the quantum yields of photochemistry of the two photosystems, that is capable of explaining the links between the two types of variability, their wavelength dependencies and the shapes of the individual enhancement signals.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
430
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
282-99
pubmed:dateRevised
2000-12-18
pubmed:meshHeading
pubmed:year
1976
pubmed:articleTitle
Enhancement studies on algae and isolated chloroplasts. Part I. Variability of photosynthetic enhancement in Chlorella pyrenoidosa.
pubmed:publicationType
Journal Article