Depending upon the constitution of cells, plant tissues are of two types simple and complex. A simple tissue is made up of similar cells which carry out the same function. A complex tissue is made up of two or more than two types of cells which are aggregated from the beginning and perform a similar function. Complex tissues are conducting tissues, they are of two types phloem and xylem. Phloem transports organic food and xylem transports water or sap inside the body of the plant.