ISSN:
1573-5079
Keywords:
Dunaliella tertiolecta
;
fluorescence
;
microalgae
;
PS II
;
UVR
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Photosynthesis in the green alga Dunaliella tertiolecta, as measured by chlorophyll fluorescence, is inhibited by ultraviolet radiation and specifically, under the conditions used, by UVB radiation (UVBR). The decline in the fluorescence parameters Fv/Fm and ΔF/Fm' under constant UVBR is a first-order function of time of exposure. The data are well-described by the Kok (1956) model, which assumes a dynamic interaction between damage and repair, with repair being proportional to the pool size of inactivated targets. The pattern of photoinhibition is also consistent with the Kok model, in that it shows an initial, approximately linear phase which is time-dependent (reciprocity holds), a transition phase and then an asymptotic phase, representing an equilibrium between damage and repair, which is determined by UVBR fluence rate (reciprocity fails). Photoinhibition in the presence of lincomycin, a protein synthesis inhibitor, is consistent with the cessation of repair processes and, under these conditions, photoinhibition is proportional to exposure time.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1006319802047
