Amino acid chelate Calcium (banana and pineapple application) Calcium is an important component of cell wall. And can maintain the integrity of the cell . It can not only move freely in plants, but also can maintain the hardness of the stem and fruit and adjust the substance which the cells absorb such as nutrient to cross the cell membrane . If the plants lack calcium ,apple will become bitter, pear will have spot, tomato will rot at the blossom and the growing point will die.