ATP is involved in various energy transfer reactions, and RNA and DNA are components of genetic information. Deficiencies exhibit slow growing, weak and stunted plants with dark green or purple pigmentation in older leaves and stems. Excess will interfere with iron and zinc stability in solution. These ions may be present in high levels in ground water. It is important to consider these values when adding nutrient supplements.
Calcium plays an important role in maintaining cell integrity and membrane permeability.
Deficiency will cause root tip die-back, leaf tip curl and marginal necrosis and chlorosis primarily in younger leaves. Blossom end rot and internal decay may also occur. Excess calcium may produce deficiencies in magnesium and potassium. Magnesium is a component of the chlorophyll molecule and serves as a cofactor in most enzymes. Deficiency will exhibit a yellowing and interveinal chlorosis beginning in the older leaves.