Chlorosis

Chlorosis is a condition in which plant tissue, especially leaves, becomes pale or yellow due to reduced or defective chlorophyll. It is typically a symptom rather than a disease and can affect many plant species. In medical history, the term chlorosis was once used to describe iron-deficiency anemia in humans, but this usage is outdated; modern medicine uses iron-deficiency anemia as the diagnosis.

Causes in plants include nutrient deficiencies, most notably iron, magnesium, or nitrogen, as well as imbalances or poor uptake caused by high soil pH or calcareous soils. Root problems from poor drainage, root damage, pest or disease pressure, salinity, and environmental stresses can also trigger chlorosis. Interveinal chlorosis, where leaves turn yellow between the veins while veins remain green, is common with iron deficiency, whereas nitrogen deficiency often yields a more uniform yellowing.

Diagnosis and management involve visual assessment supported by soil and tissue testing to determine nutrient status and pH. Management strategies include adjusting soil pH to improve micronutrient availability, applying appropriate fertilizers or chelated iron for iron deficiency, improving drainage, and ensuring consistent, appropriate watering. Pruning or removing severely affected tissue or plants may be necessary in some cases, and addressing underlying problems such as pests or root damage is important for long-term prevention.

In human medicine, chlorosis refers to pale skin associated with anemia, but it is no longer used as a formal diagnosis. Iron studies and red blood cell indices are used to diagnose iron-deficiency anemia, with treatment focusing on correcting iron deficiency.