Meristematic tissues on the basis of origin and development:
- Meristematic tissues are those tissues that have the ability to divide indefinitely.
- These tissues can originate from various sources in a plant body.
- The two major types of tissues that are divided based on their origin are Primary meristematic tissues and Secondary meristematic tissues.
Primary meristematic tissue:
- These tissues originate from the meristematic cells of the embryo.
- They develop the plant body in its initial growth stages.
- These tissues are responsible for the formation of the primary plant body.
- These meristematic zones persist in the plant throughout its life.
- The primary meristem is located in the apex of root and shoot.
- Primary meristem is the contributing factor to primary growth.
- Primary meristem is of 2 types: Apical meristem and Intercalary meristem.
Secondary meristematic tissues:
- Secondary meristematic tissues is a type of meristem that is involved in the secondary growth and thus gives rise to the secondary tissues of the plant
- These tissues originate from permanent cells that gain the function of division by redifferentiation.
- This meristem is mainly found within the mature roots and shoots.
- These meristems are formed in the later part of a plant's life.
- They are mostly laterally positioned.
- The lateral meristem is an example of a secondary meristem (e.g. cork cambium).
- They are responsible for the increase in girth or width of stems and roots.
- Secondary growth is because of the secondary meristem. These produce the secondary tissues in stems and roots that either replace the primary tissues or add to the overall mass.
1. What are the examples of secondary meristems?
Ans- Secondary meristems are formed later in the life of a plant. These are present in the mature roots and stem regions.
Examples of secondary meristems are:
I. Cambium of root
II. Cork cambium of root
III. Cork cambium of stem
IV. Interfascicular cambium and fascicular cambium of stem