Answer:
Purple leaves are caused by a pigment called anthocyanin. When sugars produced by the chlorophyll cannot be deposited in the growing stalks, leaves, and roots, they are converted to anthocyanin pigment which is red to purple in color.
• Acidic soils with pH lower than 5.5 may also cause purpling of the seedlings.
• Wet soils like this spring can also inhibit the nutrient uptake and cause purple leaves.
Purpling generally occurs between V2 to V5 stages of growth. By V8, purple leaf syndrome disappears and color becomes normal healthy green again.
• Any plant stresses which reduce uptake of phosphorus may also result in purple leaves and stalks. Root restrictions may also cause phosphate deficiency symptoms.
• Purple leaves may also indicate real phosphate deficiency in the soil.
• Soil compaction can make it difficult for the small roots to penetrate and absorb nutrients and seedlings show phosphate deficiency symptoms.
• Warmer days and cool nights can also cause purpling of leaves. Sunny and warmer temperatures help in the development of green color.
