Permanent tissue: simple (parenchyma, collenchyma, sclerenchyma) and complex (xylem, phloem)

1. Introduction to Permanent Tissues

1. Permanent tissue is derived from meristematic tissue and has lost its ability to divide.
2. It plays a vital role in providing support, transport, and storage in plants.
3. Permanent tissue is classified into simple and complex tissues.

2. Simple Permanent Tissue

Simple permanent tissues are made up of only one type of cell.

a) Parenchyma

1. Living cells with thin walls.
2. Found in soft parts of plants like leaves, stems, and roots.
3. Functions:
   • Storage of food and nutrients.
   • Helps in photosynthesis (chlorenchyma).
   • Aids in buoyancy in aquatic plants (aerenchyma).

b) Collenchyma

1. Living cells with unevenly thickened walls.
2. Located in leaf petioles, stems, and under the epidermis.
3. Functions:
   • Provides mechanical support and flexibility.
   • Aids in photosynthesis (in chloroplast-containing collenchyma).

c) Sclerenchyma

1. Consists of dead cells with thick, lignified walls.
2. Found in seeds, nuts, fibers, and stems.
3. Two types:
   • Fibers: Long, narrow, thick-walled cells.
   • Sclereids: Short, irregularly shaped, found in nutshells.
4. Functions:
   • Provides rigidity and strength.
   • Protects seeds and nuts.

3. Complex Permanent Tissue

Complex tissues consist of more than one type of cell working together.

a) Xylem (Water-Conducting Tissue)

1. Transports water and minerals from roots to the rest of the plant.
2. Composed of:
   • Tracheids: Long, dead, tube-like cells for conduction.
   • Vessels: Larger, tubular structures for efficient transport.
   • Xylem parenchyma: Living cells for storage.
   • Xylem fibers: Dead cells for support.
3. Function:
   • Conducts water and minerals from roots to leaves.
   • Provides mechanical strength to the plant.

b) Phloem (Food-Conducting Tissue)

1. Transports food (sugar and nutrients) from leaves to other parts of the plant.
2. Composed of:
   • Sieve tubes: Tube-like structures for transport.
   • Companion cells: Help in loading and unloading nutrients.
   • Phloem fibers: Provide support.
   • Phloem parenchyma: Stores food.
3. Function:
   • Transports nutrients from source (leaves) to sink (other plant parts).
   • Helps in plant growth and repair.

4. Differences Between Xylem and Phloem

5. Importance of Permanent Tissues

1. Helps in transportation of water and food.
2. Provides strength, support, and flexibility to plants.
3. Stores nutrients and food for plant growth.

6. Conclusion

1. Simple permanent tissues include parenchyma, collenchyma, and sclerenchyma.
2. Complex permanent tissues include xylem and phloem.
3. These tissues play an important role in support, transport, and storage in plants.