Functions of calcium: 

(a) Calcium in plants forms Ca-pectate which is an essential constituent of cell wall. 

(b) Calcium increases stiffness of plants. 

(c) It is involved in mitosis. 

(d) It maintains chromosome structure. 

(e) It regulates the meristem growth and functioning of the root tips. 

(f) It protects the root cells against low pH, ion balance and toxic effects of Al, Fe, etc. 

(g) It regulates the activities of enzymes like phospholipase, arginine kinase, amylase, and ATPase. 

Deficiency of calcium: 

(a) Deficiency symptoms are observed on the younger leaves as calcium is immobile in plants. 

(b) Younger leaves in the calcium deficient plants are short and distorted. 

(c) Under severe deficiency condition, the apical meristem dies resulting in the production of tillers from the basal nodes. 

(d) In case of cereal crops, the upper internodes are small and the leaves are crowded exhibiting a rosette appearance. 

(e) The root system is stunted. The flowering and maturity is delayed due to calcium deficiency. 

(f) Calcium deficiency syndromes in apples are bitter pit and in tomatoes blossom end rot. 

Functions of magnesium: 

(a) Magnesium is an essential constituent of chlorophyll and so it is important for photosynthesis process.

(b) It regulates the activities of enzymes involved in the nucleic acids synthesis and metabolism of carbohydrates. 

(c) Magnesium aids in the movement of sugars and translocation of phosphorus in the plants. 

Deficiency of magnesium: 

(a) Deficiency symptoms are observed in the plants with less than 0.1 % Mg. 

(b) Magnesium deficient plants lack vigour and they are normally stunted. 

(c) The older leaves exhibit the deficiency symptoms as magnesium is mobile in plants. Inter-veinal chlorosis followed by purple lesions within the chlorotic tissues is observed. As deficiency advances, the veins too become chlorotic and the leaves develop pale colour. The purple lesions turn brown or red. 

(d) Premature leaf abscission is observed in the deficient plants. 

(e) In cotton, the lower leaves develop reddish purple color and finally necrosis occurs (Reddening of leaves). 

(f) In Brassica, the lower leaves exhibit chlorosis with inter-veinal mottling. This condition is called puckering.