Permanent Tissue in Plants – Long Answer Questions
Medium Level (Application & Explanation)
Q1. Differentiate between simple and complex permanent tissue with suitable examples.
Answer:
- Permanent tissues are specialized. They do not divide.
- Simple permanent tissue has only one type of cell.
- It includes parenchyma, collenchyma, and sclerenchyma.
- Parenchyma stores food and does photosynthesis.
- Collenchyma gives flexibility to growing parts.
- Sclerenchyma gives rigidity and strength.
- Complex permanent tissue has more than one type of cell.
- It includes xylem and phloem.
- Xylem transports water and minerals upward.
- Phloem transports food to all parts of the plant.
Q2. Explain the structure and functions of parenchyma with examples.
Answer:
- Parenchyma cells are living and thin-walled.
- The cells are often isodiametric (equal in size).
- They have spaces, so they are loosely packed.
- They help in storage of food, like starch in potato tubers.
- In green parts, they become chlorenchyma and do photosynthesis.
- They help in wound repair and healing.
- Example: Leaf mesophyll for photosynthesis.
- Example: Potato tuber for starch storage.
Q3. Describe collenchyma. How does it support growing parts without stopping growth?
Answer:
- Collenchyma cells are living.
- Their walls are unevenly thickened.
- They are found in petioles and herbaceous stems.
- They give support to young and growing parts.
- They allow flexible growth without breaking.
- The plant bends in wind but does not tear.
- Thus, they give strength and also flexibility.
- They stop parts from collapsing during growth.
Q4. What is sclerenchyma? State its features, functions, and examples.
Answer:
- Sclerenchyma cells have thick and lignified walls.
- These cells are usually dead at maturity.
- They give rigidity and mechanical strength.
- They protect other soft tissues.
- Examples include fibers like jute and flax.
- Sclereids are found in pears and make them gritty.
- This tissue helps plants stand upright.
- It reduces damage from pressure or bending.
Q5. Explain the roles of xylem and phloem in transport and support.
Answer:
- Xylem and phloem are complex permanent tissues.
- Xylem carries water and minerals from roots to shoots.
- It has vessels, tracheids, xylem fibers, and xylem parenchyma.
- Xylem also gives structural support to the plant body.
- Phloem carries food (sugars) from leaves to other parts.
- It has sieve tubes, companion cells, phloem fibers, and phloem parenchyma.
- Together, they form vascular bundles.
- Vascular bundles are essential for growth and survival.
High Complexity (Analysis & Scenario-Based)
Q6. A young plant grows in a windy area. Which tissues help it stay upright yet flexible? Explain how.
Answer:
- Collenchyma gives flexible support to young parts.
- Its irregularly thickened walls prevent tearing.
- The stem can bend in wind without breaking.
- Sclerenchyma gives rigidity and hard strength.
- It protects soft tissues from damage.
- Xylem adds internal support with strong vessels.
- Together, they prevent bending, snapping, and collapse.
- The plant stays upright and continues to grow.
Q7. A stem gets a cut during weeding. Which tissues help in repair and protection? Explain the steps.
Answer:
- Parenchyma cells help in wound repair.
- They are living and can help in healing.
- They fill the gap and protect inner parts.
- Surrounding sclerenchyma gives strength to the wounded area.
- It prevents further damage by its rigid walls.
- Xylem and phloem around the area keep transport going.
- This allows the plant to survive and recover.
- The stem regains protection and function.
Q8. A plant faces water shortage for a week. Predict the roles of xylem, parenchyma, and other tissues in this time.
Answer:
- Xylem still carries the limited water upward.
- Its strong structure keeps the stem supported.
- Parenchyma uses stored food to maintain cells.
- Leaves may use chlorenchyma to keep photosynthesis going in light.
- Collenchyma helps the stem resist wilting by flexible support.
- Sclerenchyma prevents collapse due to its rigidity.
- Phloem distributes sugars to roots and other parts.
- Together, tissues help the plant survive short stress.
Q9. A leaf is making more food on a sunny day. Explain how different tissues help in making and moving this food.
Answer:
- Parenchyma in leaves (as chlorenchyma) does photosynthesis.
- It makes sugars using light, CO2, and water.
- Phloem transports these sugars to stems, roots, and fruits.
- Xylem brings water and minerals to the leaf.
- The leaf stays supported by collenchyma in the petiole.
- Sclerenchyma protects and strengthens leaf parts.
- This teamwork forms an efficient transport and support system.
- The whole plant benefits and grows well.
Q10. If phloem gets damaged in a stem segment, what changes might you see over time? Explain with reasons.
Answer:
- Phloem carries food from leaves to other parts.
- If it is damaged, food does not reach below the injury.
- Roots may starve due to lack of sugars.
- Upper parts may still get food for some time.
- Xylem still carries water, so leaves may look normal at first.
- But growth below the cut will slow or stop.
- The plant may show weakness in affected parts.
- Repair needs healing and support from parenchyma and other tissues.
Q11. A thin herbaceous stem must be both light and strong. Which tissues make this possible and why?
Answer:
- Collenchyma gives lightweight and flexible support.
- It is ideal for young and growing stems.
- Sclerenchyma adds rigidity without too much bulk.
- It protects the stem from bending and pressure.
- Xylem provides internal strength and water transport.
- Phloem moves food, keeping tissues active.
- Parenchyma fills spaces and stores food.
- This mix keeps the stem light, strong, and functional.
Q12. A farmer wants stronger fibers for rope-making. Which plant tissue should be encouraged and why?
Answer:
- The best tissue is sclerenchyma fibers.
- They have thick, lignified walls.
- They are very strong and durable.
- Examples include jute and flax fibers.
- These fibers give rigidity and toughness.
- They resist tearing and wear.
- So, sclerenchyma is ideal for rope-making.
- It is better than soft parenchyma or flexible collenchyma for this use.