Why are xylem and phloem called complex tissues?
Explanation A complex tissue is a type of plant tissue which comprises more than a single type of cells, which together function as a single unit. The vascular tissue, i.e. xylem and phloem, is a combination of different types of cells which together work in a coordinated manner as a single entity. Xylem consists of xylem parenchyma, xylem sclerenchyma, xylem tracheids and xylem vessels. All these different types of cells together help in the conduction and transportation of water and salts or mineral ions throughout the plant. Phloem comprises phloem parenchyma, phloem fibre, companion cells and sieve tubes. These different cells function in a coordinated manner to facilitate the transport of dissolved food substances in the plant. The xylem and phloem constitute the vascular bundle of the plant. Thus, these are also called vascular tissues. Final Answer Xylem and phloem are called complex tissues because they are made up of more than one type of cell that differ in function as well as shape and size such as parenchyma, tracheids, sclerenchyma.
