Triazine herbicides primarily show symptoms in which part of the plant?

• A. Roots
• B. New growth
• C. Flowers
• D. Seeds

Answer: (B)

Triazine herbicides are known to inhibit the process of photosynthesis in plants, specifically affecting the photosynthetic electron transport chain. The symptoms of triazine herbicide application are primarily observed in the new growth of the plant. This is because these herbicides tend to be translocated through the plant, impacting actively growing tissues more significantly than older, mature tissues. New leaves and young shoots exhibit chlorosis or yellowing, stunted growth, and sometimes necrosis due to the disruption of energy production.

The impact on new growth is critical as it reflects the overall health and vitality of the plant. Since triazine herbicides are systemic, they can affect the newer tissue by preventing it from synthesizing the essential compounds needed for growth and development. In contrast, older parts of the plant may not show immediate symptoms even though the herbicide is present throughout the plant.