In the case of nitrogen, the recycling of nitrogen from dead to living plants is often the only source of nitrogen in the soil. To make plants grow faster, what you need to do is supply the elements that the plants need in readily available forms. That is the goal of fertilizer.Most fertilizers supply just nitrogen, phosphorus and potassium because the other chemicals are needed in much lower quantities and are generally available in most soils. Nitrogen, phosphorus and potassium availability is the big limit to growth.he most important are: 1  Carbon, hydrogen and oxygen-Available from air and water and therefore in plentiful supply. 2  Nitrogen, phosphorus, potassium (a.k.a. potash) - The three macronutrients and the three elements you find in most packaged fertilizers. 3  Sulfur, calcium, and magnesium-Secondary nutrients.
The term epithelium refers to layers of cells that line hollow organs and glands. It is also those cells that make up the outer surface of the body. Epithelial cells help to protect or enclose organs.
Transitional epithelium is a stratified epithelium in which the shape of the surface cells changes (undergoes transitions) depending on the degree of stretch.When a transitional epithelium is not stretched (for example in an empty bladder) the cells of the surface layers are large and rounded.Arrows labeled c indicate several large rounded cells which have been outlined on the photo.hen a transitional epithelium is stretched (as it would be in a full bladder) the cells of the surface layers are pulled into a flatter shape. Unlabeled arrows indicate base of the epithelium. ct = connective tissue. lu = lumen.