The anaerobic starch breakdown into end-products in the green alga Chlamydomonas reinhardtii F-60 has been investigated in the dark and in the light. The effects of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) and carbonyl cyanide-p-trifluoromethoxyphenyl hydrazone (FCCP) on the fermentation in the light have also been investigated.Anaerobic starch breakdown rate (13.1 +/- 3.5 micromoles C pe...

Blue light (BL) induces stomatal opening through the activation of H-ATPases with subsequent ion accumulation in guard cells. In most plant species, red light (RL) enhances BL-dependent stomatal opening. This RL effect is attributable to the chloroplasts of guard cell, the only cells in the epidermis possessing this organelle. To clarify the role of chloroplasts in stomatal regulation, we inves...

The distribution of excitation energy between photosystems I and II (PSI and PSII) was investigated in the marine diatom Phaeodactylum tricornutum (Bohlin) using light-induced changes in fluorescence yield and rate of modulated O(2) evolution. The intensity dependence of the fast fluorescence rise in dark adapted cells (+/-DCMU) suggests that light absorbed by the major antenna complex was not ...

Sensors and regulatory circuits that maintain redox homeostasis play a central role in adjusting plant metabolism and development to changing environmental conditions. We report here control networks in Arabidopsis (Arabidopsis thaliana) that respond to photosynthetic stress. We independently subjected Arabidopsis leaves to two commonly used photosystem II inhibitors: high light (HL) and 3-(3,4...

Photosystem II Herbicides, Chlorotic Herbicides, Chlorophylls, Carotenoids, Phytochrome, Inhibitors Etioplasts of radish seedlings treated with photosystem II (DCMU, bentazon) and chlorotic herbicides (amitrole, SAN 6706) were tested on their ability to perform the phytochrome mediated chlorophyll and carotenoid biosynthesis. The cytoplasmic influence on the chloroplastic action of herbicides w...

Specialized prokaryotes performing biological dinitrogen (N2) fixation (“diazotrophs”) provide an important source of fixed nitrogen in oligotrophic marine ecosystems such as tropical and subtropical oceans. In these waters, cyanobacterial photosynthetic diazotrophs are well known to be abundant and active, yet the role and contribution of non-cyanobacterial diazotrophs are currently unclear. T...

Recently, the subject was taken up by the first author, who confirmed the results about Simetone (VAN STEEKELENBURG, 1961) and extended them. The results described in the following sections are based upon this recent work. The substituted ureas and the symmetrical triazines are two special and important groups of herbicides. These compounds are taken up by the roots, transported via the xylem a...

Binding of the triazinone derivative metribuzin to thylakoid membranes was studied in depend­ ence of tem perature and trypsin pre-treatm ent of the chloroplasts. The tem perature curve of the binding constant suggests that the lipid phase of the membrane contributes to inhibitor binding. Trypsin pre-treatm ent of the membranes removes the receptor sites for the inhibitor, while the trypsin eff...