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| Section2 = | Section7 = }} DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) is an herbicide that inhibits photosynthesis. It was introduced by Bayer in 1954 under the trade name of Diuron. ==Mechanism of action== DCMU is a very specific and sensitive inhibitor of photosynthesis. It blocks the plastoquinone binding site of photosystem II, disallowing the electron flow from where it is generated, in photosystem II, to plastoquinone. This interrupts the photosynthetic electron transport chain in photosynthesis and thus reduces the ability of the plant to turn light energy into chemical energy (ATP and reductant potential). DCMU only blocks electron flow from photosystem II, it has no effect on photosystem I or other reactions in photosynthesis, such as light absorption or carbon fixation in the Calvin cycle. However, because it absorbs electrons oxidized from water in PS II, the electron "hole" of PS I cannot be satisfied, effectively shutting down "linear" photosynthesis by blocking the reduction of NADP+ to NADPH. At the same time, it was found that DCMU not only does not inhibit the cyclic photosynthetic pathway, but, under certain circumstances, actually stimulates it.〔HUBER, S.C. EDWARDS, G.E. (1976), Studies on the Pathway of Cyclic Electron Flow in Mesophyll Chloroplasts of a C4 Plant, Biochimica et Biophysica Acta (BBA) – Bioenergetics, Volume 449, Issue 3, 6 December 1976, Pages 420-433, 〕 Because of these effects, DCMU is often used to study energy flow in photosynthesis. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「DCMU」の詳細全文を読む スポンサード リンク
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