| | 1 | Author
| Fabrice Franck, GeorgH. Schmid | Requires cookie* | | | Title
| Flash Pattern of Oxygen Evolution in Greening Etioplasts of Oat  | | | | Abstract
| Etioplasts isolated from oat leaves that have received two 5 m in illum ination periods, spaced apart by a 90 min dark interval, are able to evolve oxygen. If this oxygen evolution is measured as consequence o f short saturating light flashes a pattern is obtained w hich in agreem ent with the Kok-Joliot model shows a dam ped oscillation w ith a periodicity o f four. As usual for most other systems the maximum flash yield is observed under the third flash. In continuous light such slightly greened etioplasts show a small oxygen gush. From our studies it appears that the second 5 min illumination period is obligatory for oxygen evolution. O m ission o f this period leads to a condition in which under flashes strictly no oxygen is evolved. In continuous light under these conditions no oxygen gush but rather an uptake is observed after onset o f illum ination. It appears that in greening etioplasts the flash pattern shows som e peculiarities when compared to the normal green conditions. Thus, a flash sequence o f a greening etioplast always shows a substantial positive amperometric signal under the first flash. The h alf tim e o f the state which would belong to this signal is 3 to 4 min in a greening etioplast, isolated from leaves that have received 2 h light. In the course o f greening this h alf tim e decreases continuously and reaches a normal and constant value o f approx. 1 0 s in chloroplasts from green oat or etiochloroplasts that are prepared from leaves that have received 15 h o f light. The result is discussed in terms o f metastable S3 which seems to be a property o f the developing oxygen evolving system in greening oat leaves. In the greening system as we use it is shown for the first tim e that the photoenzym e protochlorophyllide chlorophyllide reductase is D C M U sensitive. | | | |
Reference
| Z. Naturforsch. 39c, 1091 (1984); received August 17 1984 | | | |
Published
| 1984 | | | |
Keywords
| Flash Yield, Oxygen, S-States, Etioplasts | | | |
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| default:Reihe_C/39/ZNC-1984-39c-1091.pdf | | | | Identifier
| ZNC-1984-39c-1091 | | | | Volume
| 39 | |
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