Which of the following is NOT a simple permanent tissue?

The correct answer is Xylem

Key Points

• The permanent tissues are made up of mature cells which have lost their ability of cell division and are already adopted or accommodated to perform some specific work.
• These tissues originate from merismatic tissues when they lose the ability to divide.
  • The permanent tissues may be dead or living, having thick or thin cellular walls.
• Simple permanent tissues are composed of similar cell types which have a common origin and function.
  • These are classified into three types: Parenchyma, Collenchyma, and Sclerenchyma.
  • Xylem is a complex permanent tissue. Hence option 2 is correct.
• Parenchyma is the most simple and unspecialized type of permanent tissue whose cells are usually isodiametric i.e., equally expanded on all sides. 
  • They have intercellular spaces among them which allow the exchange of gases.
  • These are living cells of oval, round, polygonal or elongated shape and their cell wall is made up of cellulose or calcium pectate.
  • It is found in the epidermis, cortex, pith, pericycle, and mesophyll of leaves, the pulp of fruits, the endoderm of seeds, and in merismatic tissues.
• Collenchyma consists of living cells and there are no intercellular spaces as these are elongated in shape due to the irregular thickening of cellulose and pectin in the cellular walls.
  • It is a mechanical tissue that provides mechanical support, elasticity, and rigidity to plants.
  • It is found in the outer region of the cortex (angles of stems and midrib of leaves).

Additional Information

• Sclerenchyma consists of dead cells and is devoid of protoplasm cells of rigid tissue.
  • Cell walls of such tissues are greatly thickened due to lignin or cellulose which gives mechanical strength, support, and rigidity to the plant body.
  • These tissues are the components of the hard coating of several seeds and nuts (just of a coconut).
• Complex permanent tissue is a type of permanent tissue that is composed of more than one type of cells having a common origin.
• Xylem is a chief conducting tissue of vascular plants responsible for the conduction of water and inorganic solutes or minerals from the roots to the apical parts of the plant.
  • Xylem consists of dead hollow cells in the form of fibers and sclereids.
• Phloem is a complex permanent tissue responsible for the conduction of organic solutes such as food. This conduction may be bi-directional i.e., from leaves to storage organs or maybe from storage organs to growing parts of the plant.