Which herbicide group leads to yellowing of leaves in cereals?

The correct answer is associated with the herbicide group that inhibits a specific biosynthetic pathway, leading to a deficiency in certain amino acids which ultimately affects plant health. In this case, the EPSP inhibitors, such as glyphosate, disrupt the shikimic acid pathway, which is critical for the synthesis of phenylalanine, tyrosine, and tryptophan. When cereals are treated with EPSP inhibitors, particularly at the wrong stage of growth or with improper timing, the lack of these amino acids can result in leaf yellowing, known as chlorosis.

This yellowing is a key visual symptom because it indicates that the plant is undergoing stress and unable to produce essential proteins for healthy growth. The photosynthesis process can also be affected, contributing to the overall decline of plant vigor.

In contrast, the other herbicide groups listed do not primarily cause yellowing in cereals. Synthetic auxins can cause distortions and abnormal growth. S-Metolachlor primarily targets the root systems and impacts germination but does not lead to yellowing of established leaves. Photosynthesis inhibitors can affect the chlorophyll production but have a different mechanism of action, leading to leaf symptoms that do not specifically manifest as yellowing. Thus,