Comprehensive Agriculture and Land Use Practice Test

Chlorosis appearing in the newest leaves is a telling sign of iron deficiency. Iron is relatively immobile within the plant, so the plant can’t move iron from older tissues to support new growth. When iron is lacking, developing leaves can’t synthesize chlorophyll properly, so the tissue between the veins turns yellow while the veins themselves stay green—this is known as interveinal chlorosis. That pattern—yellowing limited to new leaves due to a lack of iron—is distinctive, making it the best match for a micronutrient deficiency that presents as chlorosis in new leaves. Other deficiencies often show different patterns, such as chlorosis appearing first in older leaves or plus other symptoms like stunting or leaf deformation, which is why the new-leaf chlorosis pattern most strongly points to iron.