Which of the statement(s) is/are correct? (A) Urea herbicides inhibit photolysis in photosynthesis (B) Triazines inhibit the growth of emerging seedlings (C) Sulfonyl ureas first affect the meristematic tissues resulting into chlorosis and necrosis (D) Paraquat is a systemic herbicide
Choose the correct answer from the options given below:

Correct option is B

The correct answer is (B) (A), (B) and (C) only

Explanation:
• Statement (A): Correct. Urea herbicides (like Isoproturon) act by inhibiting the Hill reaction (photolysis of water) in Photosystem II.
• Statement (B): Correct. Triazines (like Atrazine) are primarily soil-applied and inhibit the growth of seedlings by interfering with photosynthesis as they emerge.
• Statement (C): Correct. Sulfonylureas inhibit ALS enzyme, which is critical in meristematic regions (growing tips). Damage first appears as yellowing (chlorosis) and then tissue death (necrosis).
• Statement (D): Incorrect. Paraquat is a strictly contact, non-selective herbicide. It is not systemic; it only kills the plant parts it touches by producing superoxide radicals that destroy cell membranes.

Information Booster:
• Contact Herbicide: Kills only the tissues it touches (e.g., Paraquat, Diquat).
• Systemic Herbicide: Translocates within the plant system (e.g., Glyphosate, 2,4-D).

Additional Knowledge:
• Urea herbicides and Triazines are both categorized as Photosynthesis inhibitors (Binding to the D1 protein site).