Herbicide `DCMU` [(3-C, 3, 4-dichlorophenyl) -1, 1-dimethyl urea] kills plants due to stoppage of

Options

A. Photophosphorylation
B. Rubisco activity
C. Electron transport
D. `O_(2)`-evolution.

Answer

**Step-by-Step Solution:**

1. **Understanding DCMU**: DCMU, or (3-C, 3, 4-dichlorophenyl)-1,1-dimethyl urea, is a herbicide used to control unwanted plant growth.

2. **Mechanism of Action**: The primary function of DCMU is to inhibit a specific process in photosynthesis. It acts by blocking the electron transport chain in photosystem II.

3. **Identifying the Process Affected**: The electron transport chain is crucial for the process of photophosphorylation, which is the generation of ATP and NADPH during photosynthesis. However, DCMU specifically stops the process of oxygen evolution.

4. **Consequences of Inhibition**: When DCMU inhibits oxygen evolution, it leads to an accumulation of oxygen in the plant tissues. Excessive oxygen can be toxic to plants, causing tissue damage and ultimately leading to plant death.

5. **Final Answer**: Therefore, the herbicide DCMU kills plants due to the stoppage of oxygen evolution.

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