What are the 3 types of meristems?
Meristematic cells are generally small and cuboidal with large nuclei, small vacuoles, and thin walls. A plant has four kinds of meristems: the apical meristem and three kinds of lateral—vascular cambium, cork cambium, and intercalary meristem.
Meristematic tissues are a group of young cells that are in a continuous state of division. These tissues are mostly found at the apices of root and shoot. The main characteristics of cells of meristematic tissues are: (i) They are living and thin walled. (ii) Vacuoles are few and small in size.
- A meristem is the tissue in most plants containing undifferentiated cells (meristematic cells), found in zones of the plant where growth can take place. Meristematic cells give rise to various organs of the plant and keep the plant growing.
- The apical meristem produces the three primary meristems, protoderm, procambium, and ground meristem, which develop into dermal tissues, vascular tissues, and ground tissues respectively. Use the information in the illustration to help answer the questions below it.
- Meristems are classified by their location in the plant as apical (located at root and shoot tips), lateral (in the vascular and cork cambia), and intercalary (at internodes, or stem regions between the places at which leaves attach, and leaf bases, especially of certain monocotyledons—e.g., grasses).
The apical meristem, also known as the “growing tip,” is an undifferentiated meristematic tissue found in the buds and growing tips of roots in plants. Its main function is to trigger the growth of new cells in young seedlings at the tips of roots and shoots and forming buds.
- Meristematic tissues are a group of young cells that are in a continuous state of division. These tissues are mostly found at the apices of root and shoot. The main characteristics of cells of meristematic tissues are: (i) They are living and thin walled. (ii) Vacuoles are few and small in size.
- Dermal tissue functions to protect the plant from injury and water loss. The most common cell type in dermal tissue is the epidermal cell. Generally, a thin, waxy layer called a cuticle covers the epidermal cells and protects them.
- The most distinctive xylem cells are the long tracheary elements that transport water. Tracheids and vessel elements are distinguished by their shape; vessel elements are shorter, and are connected together into long tubes that are called vessels. Xylem also contains two other cell types: parenchyma and fibers.
Plants have meristematic tissue in several locations. Both roots and shoots have meristematic tissue at their tips called apical meristems that are responsible for the lengthening of roots and shoots. Secondary growth gives a plant added stability that allows for the plant to grow taller.
- The meristematic cells divide frequently and they give rise to new cells. For this they require a dense cytoplasm and thin cell wall. Vacuoles if present will cause hinderance in cell division as it is full of cell sap to provide turgidity as well as rigidity to the cell.
- The conditions of culture are regulated to allow only for organized outgrowth of the apex directly into a shoot, without the intervention of any adventitious organs (1-3). The excised meristem-tip is typically small (often less than 1 mm in length) and removed by sterile dissection under the microscope (Fig. 1).
- Plant stem cell. Plant stem cells are innately undifferentiated cells located in the meristems of plants. Plant stem cells serve as the origin of plant vitality, as they maintain themselves while providing a steady supply of precursor cells to form differentiated tissues and organs in plants.
Updated: 2nd October 2019