Have seen plants grow from small saplings to bigger plants and then trees? Don’t you think they generally grow from the top? Yes, they do. There are some specialized cells in plants that are not differentiated and help in the growth of the plants. These cells in a plant can be young and have the ability to divide continuously. There is a special name for these cells, which are called the meristem cells. The tissue that these meristem cells form in plants is called as the meristematic tissue.
Meristematic Tissue in Plants
Meristematic tissue or meristems, as they are also called are tissues that have the ability to enlarge, stretch and differentiate into other types of cells as they mature. The cells of this tissue are generally young and immature, with the power of continuous division.
Meristematic cells are all living cells. The meristematic cells can be oval or rounded or polygonal in shape. They have a large nucleus with no vacuoles. Intercellular space between cells is absent. The cells are also small in size but have a high capacity of cell division.
Learn more about the different type of Animal Tissues here.
Types of Meristematic Tissue
Depending on the occurrence of the meristematic tissue on the plant body, we can classify the meristems into three types. They are:
- Apical Meristems – These meristems are located on the tip of the root, stem etc. They help in the growth of the root system as well as the shoot system. The various cell divisions along with the cellular enlargement help in the growth of the stem above the ground and the growth of the root below the ground.
- Intercalary Meristems – The intercalary meristems are located at the internodes or the base of the leaves. The intercalary meristems help in increasing the length of the internode. This is usually seen in monocotyledonous plants.
- Lateral Meristems – The lateral meristems are present on the lateral side of the stem and root of a plant. These meristems help in increasing the thickness of the plants. The vascular cambium and the cork cambium are good examples of a lateral meristematic tissue.
Solved Questions For You
Q. Apical meristems are found in animals. Is it True or False?
Ans. False. Apical meristems are found in plants. They help in the increase of the height of a plant.
Q: Stem of date palm increases in girth due to activity of
- Intercalary Meristem
- Apical Meristem
- Both of the above
- None of the above
Sol: Most monocots either have no secondary growth or else anomalous secondary growth of some type. For example, palm trees increase their trunk diameter due to division and enlargement of parenchyma cells, which is termed as ‘diffuse secondary growth’.
In some other monocot stems with anomalous secondary growth, a cambium forms but it produces vascular bundles and parenchyma internally and just parenchyma externally. Some monocot stems increase in diameter due to the activity of a primary thickening meristem, which derives itself from the apical meristem.
The stem of date palm increases in girth due to the activity of apical meristem and not because of intercalary meristem and lateral meristem (involves is the normal secondary growth of dicots). Thus, option B is correct.
FAQ’s for You
Q1. Write four characteristics of meristematic tissue.
Answer: Characteristics of meristematic tissues: (any four)
1. They are made up of immature cells.
2. They have the capability to differentiate into any cell.
3. They are living and thin walled.
4. They are diploid in nature and show mitotic division.
5. The cells of meristematic tissues are rich in cytoplasm.
6. They do not contain reserve food materials, ER and plastids.
Q2. Meristematic tissue is found in the growing tips of ________ and ________.
Answer: Meristematic tissues, or simply meristems, are tissues in which the cells remain forever young and divide actively throughout the life of the plant. When a meristematic cell divides in two, the new cell that remains in the meristem is called an initial, the other the derivative. As new cells are added by repeated mitotic divisions. These types of tissues are generally found in the extreme regions i.e root and shoot tip that has to grow continuously.
A plant has four kinds of meristems: the apical meristem and three kinds of lateral—vascular cambium, cork cambium, and intercalary meristem.
The meristem which is located at opposite ends of the plant axis in the tips of roots and shoots. is known as the apical meristem.
Q3. Meristematic tissue occurs in
C. All growing tips
D. Both A & B
Answer: Meristem is the region marked by the presence of active cell growth and the tissues present in meristem are termed as meristematic tissues.
On the basis of their position in the plant body, meristems are grouped as apical, lateral or intercalary meristem.
Stem has apical meristem in the shoot apex, intercalary meristem in nodes and lateral meristem in form of cambium in vascular bundles.
Roots have apical meristem root apex and lateral meristem in form of cambium in vascular bundles. Shoot and root tips are the growing tips of a plant. Due to presence of root cap in terminal position, root apical meristem is subterminal in position thus, not all the growing tips have meristem.
Therefore, the correct answer is option D.
Q4. What is a meristematic tissue?
Answer: Meristematic tissue divides throughout their life. They are located in the specific regions of the plant.
Cells of this tissue are very active, have dense cytoplasm, thin walls, and prominent nuclei. They lack vacuoles. The cell wall is cellulosic.