Which nutrient is not mobile in the plant?

Calcium is considered a nutrient that is not mobile within the plant. This means that once calcium is incorporated into plant tissues, it does not move from older leaves to newer growth. Calcium primarily functions in the structural support of cell walls and is crucial for cell division and growth. Since it remains fixed in the parts of the plant where it is absorbed, a deficiency tends to manifest in the younger, actively growing tissues where calcium is needed but cannot be mobilized from older tissues.

In contrast, nutrients like nitrogen, magnesium, and phosphorus are mobile within plants, allowing them to be redistributed from older tissues to support new growth. This mobility can help alleviate some deficiencies when nutrient availability fluctuates, as older leaves can supply those nutrients to younger, developing parts of the plant. Understanding the mobility of nutrients is essential for effective nutrient management in crops.