Insulin. Insulin is a hormone made by the beta cells in the pancreas. It is the key that opens the doors of cells and allows glucose to get into the cell. Each cell needs glucose to function. Carbohydrates in food are broken down into glucose which enters the blood stream.
The pericycle is a cylinder of parenchyma or sclerenchyma cells that lies just inside the endodermis and is the outer most part of the stele of plants.
Perlite, like vermiculite, is also a silicate material, but mined from volcanoes. Perlite is light and of a uniform size and consistency, making it ideal for aeration and drainage. Perlite and vermiculite can be used in soilless growing, such as what you would find in hydroponics.