The effect of ionic stress on photosynthesis in Dunaliella tertiolecta |
| |
Authors: | D J Gilmour M F Hipkins A N Webber N R Baker A D Boney |
| |
Institution: | (1) Department of Botany, University of Glasgow, G12 8QQ Glasgow;(2) Department of Biology, University of Essex, Wivenhoe Park, CO4 3SQ Colchester, UK;(3) Present address: Department of Botany, University of Liverpool, P.O. Box 147, L69 3BX Liverpool, UK |
| |
Abstract: | A comparison of the effects of ionic stress and an uncoupler on long-term fluorescence transients (the Kautsky effect) in the green alga Dunaliella tertiolecta indicated that the large quenching induced by ionic stress was caused by a pH gradient across the thylakoid membrane. This possiblity was given support by the increase in the slow phase of 3-(3,4-dichlorophenyl)-1,1-dimethylurea-induced fluorescence relaxation in algae subjected to ionic stress. Low-temperature fluorescence emission spectra indicated that salt stress enhanced photosystem-I emission in the dark, and a comparison of simultaneous emissions at 695 and 720 nm at room temperature indicated a further increase in photosystem-I emission during the fluorescence transients. Taken together with the decrease in the fast phase of 3-(3,4-dichlorophenyl)-1,1-dimethylurea-induced fluorescence relaxation in stressed algae, our results indicate that ionic stress stimulates cyclic electron flow, and that non-cyclic flow is inhibited. The effect of sucrose-induced osmotic stress was similar to, but less marked than, the effects of NaCl and KCl; the effect of decreasing the external salinity was small.Abbreviations DCMU
3-(3,4-dichlorophenyl)-1,1-dimethylurea
- FCCP
carbonylcyanide p-trifluoromethoxyphenylhydrazone
- PSI, II
photosystem I, II |
| |
Keywords: | Chlorophyll fluorescence Dunaliella (osmoregulation) Osmoregulation Photosynthesis (ionic stress) |
本文献已被 SpringerLink 等数据库收录! |
|