Iron deficiency in plants is indicated first by chlorosis appearing on which leaves?

• A. Old leaves
• B. New leaves
• C. Roots
• D. Stem tips

Answer: (B)

Iron deficiency shows up first in new growth because iron is not easily moved once it is taken up by the plant. When iron is lacking, developing leaves can’t produce enough chlorophyll, so they become chlorotic (yellow). The veins in these young leaves often stay green, giving the interveinal chlorosis pattern. Old leaves remain green longer because they’re not the ones being supplied to the new tissue, reflecting iron’s immobile nature. Roots or stem tips aren’t the initial indicator for this deficiency, so the earliest visible symptom is chlorosis on the new leaves.