Which nutrient deficiency is associated with purplish foliage and slow growth?

• A. Nitrogen deficiency
• B. Magnesium deficiency
• C. Phosphorus deficiency
• D. Potassium deficiency

Answer: (C)

Phosphorus deficiency causes purplish foliage and slow growth because phosphorus is essential for energy transfer and genetic material synthesis. When phosphate is scarce, ATP production slows and nucleic acids form less efficiently, limiting cell growth and development, which shows up as stunted growth. The purpling comes from the plant increasing anthocyanin pigments in response to low energy status. In contrast, nitrogen deficiency tends to darken or pale coloration overall due to less chlorophyll, magnesium deficiency shows interveinal yellowing, and potassium deficiency causes leaf edges or tips to scorch. But the combination of purple leaves with slowed growth points to phosphorus limitation.