Phosphorus is part of the so-called nucleoprotein - the main part of the cell nucleus. K phosphate mineral fertilizers are superphosphate, phosphate rock, etc. With a lack of phosphorus - the leaves are dark green, get some blue tint, brown spots appear, which gradually grasp the entire sheet. Growth of shoots and roots slows to a crawl, the new leaves are small, the delay of flowering. With an excess - the plant is growing vigorously.