A study has been made of the effects of the inhibitors carbonylcyanide m-chlorophenylhydrazone (CCCP), 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU), and of anoxia on the light-sensitive membrane potential of Vallisneria leaf cells. The present results are compared with the known effects of these inhibitors on ion transport and photosynthesis (Prins 1974 Ph.D thesis). The membrane potential i...

A study has been made of the means by which light influences the gravitropic set-point angle (GSA) of the nodes of Tradescantia and the hypocotyls of the lazy-2 mutant of tomato. In light-grown Tradescantia there is a light-regulated developmental change in the GSA with the magnitude of this change being dependent on the photon flux density of white light. The photosynthetic inhibitor DCMU abol...

We have investigated the possible relationships between the cation-induced and phenazine methosulfate (PMS)-induced fluorescence changes and their relation to light induced conformational changes of the thylakoid membrane. 1. In isolated chloroplasts, PMS markedly lowers the quantum yield of chlorophyll a fluorescence (fir) when added either in the presence or the absence of dichlorophenyldimet...

Phosphorylation of thylakoid membrane proteins in the chloroplast of wild-type and mutant strains of Chlamydomonas reinhardi has been studied in vivo and in vitro. Intact cells or purified membranes were labeled with [32P]orthophosphate or [gamma-32P]ATP, respectively, and the presence of phosphorylated polypeptides was detected by autoradiography after membrane fractionation by SDS PAGE. The 3...

Quinone, Photosynthetic Electron Transport, Inhibitor UHDBT (5-«-undecyl-6-hydroxy-4,7-dioxobenzothiazole) is an efficient inhibitor of photosyn­ thetic electron transport in chloroplasts from spinach (pl50-value = 7.61) and the green alga Chlamydomonas reinhardii. At low concentrations of UHDBT its site of inhibition is located at the reducing side of plastoquinone, identical to that of 3-(3,4...

The use of diphenylcarbazide as an electron donor coupled to the photoreduction of 2,6-dichlorophenolindophenol by tris-washed chloroplasts or subchloroplast fragments provides a simple and sensitive assay for photosystem 2 of chloroplasts. By varying the concentration of tris buffer at pH 8.0 during an incubation period it is shown that the destruction of oxygen evolution activity is accompani...

( 1 ) The simultaneous measurements of delayed light emission (DLE) and chlorophyll (Chl) fluorescence yield in DCMU$ treated Chlorellu were made in the time range of I to I0 sec at various temperatures from 0 to 50°C. Similar measurements were made for DCMU treated thermophilic strain ofSynechococcus in the temperature range of 0 to 75°C. (2) Using the basic assumption that DLE is produced by ...

Herbicide, Inhibition, Photosynthetic Electron Transport, Trifluralin, Thermoluminescence The effect of trifluralin on the photosynthetic electron transport has been investigated by oxygen evolution and thermoluminescence measurements. The results confirm the earlier observations that trifluralin at low concentrations blocks electron transport between the two photosystems probably at the same s...

Anaerobic sulphide oxidation in the light was studied with seven cyanobacterial strains isolated from the southern Baltic Sea. All strains oxidized sulphide (1.2-3.5 mM) stoichiometrically to thiosulphate. No elemental sulphur could be detected as end product of anoxygenic photosynthesis. Sulphite as intermediate sulphur compound was released into the growth medium during anaerobic sulphide oxi...