Plant Tissue Identification (Slides) MCQs Quiz | Class 9

Class: IX | Subject: Science (Code 086) | Unit: Practicals (Unit II) | Topic: Plant Tissue Identification (Slides). This quiz focuses on the identification, features, and microscopic structure of Parenchyma, Collenchyma, and Sclerenchyma tissues. Submit your answers to check your score and download the solution PDF for future reference.

Educational Content: Plant Tissue Identification

This section provides a detailed overview of the simple permanent tissues covered in Class 9 Science practicals: Parenchyma, Collenchyma, and Sclerenchyma. Understanding these tissues involves observing their cellular structure, cell wall composition, and intercellular spaces under a microscope.

1. Parenchyma

Parenchyma forms the bulk of the plant body. It is a living simple permanent tissue found in soft parts of the plant like the cortex, pith, and mesophyll of leaves.

  • Cell Structure: Cells are isodiametric (roughly spherical, oval, or polygonal).
  • Cell Wall: Thin cell walls made of cellulose.
  • Cytoplasm & Nucleus: Living protoplasm with a prominent nucleus and a large central vacuole.
  • Intercellular Spaces: Usually present and large.
  • Function: Storage of food, photosynthesis (chlorenchyma), and buoyancy (aerenchyma).

2. Collenchyma

Collenchyma provides mechanical support along with flexibility. It is found in leaf stalks and below the epidermis in dicot stems.

  • Cell Structure: Cells are elongated and living.
  • Cell Wall: Unevenly thickened at the corners due to the deposition of pectin and cellulose.
  • Intercellular Spaces: Very little or absent.
  • Function: Provides flexibility (tensile strength) to growing parts of the plant.

3. Sclerenchyma

Sclerenchyma is the tissue responsible for making plants hard and stiff (e.g., husk of a coconut). It consists of dead cells.

  • Cell Structure: Cells are long, narrow, and dead at maturity. They lack protoplasm.
  • Cell Wall: Thick, hard secondary walls due to lignin deposition. This leaves a very narrow lumen (cavity) inside the cell.
  • Intercellular Spaces: Absent; cells are packed tightly.
  • Function: Provides mechanical strength and protection.

Quick Comparison Table

Feature Parenchyma Collenchyma Sclerenchyma
State Living Living Dead
Cell Wall Thin (Cellulose) Thick at corners (Pectin) Thick all over (Lignin)
Intercellular Spaces Present Little or Absent Absent
Main Function Storage & Packaging Flexibility & Support Hardness & Strength

Slide Identification Tips

  • Parenchyma Slide: Look for thin-walled cells that appear loosely packed with visible gaps (intercellular spaces). The nucleus is usually peripheral due to a large vacuole.
  • Collenchyma Slide: Look for cells that fit closely together with distinct thickening only at the corners where cells meet.
  • Sclerenchyma Slide: Look for very thick walls often stained red (if safranin is used) with a very narrow empty space in the center. In transverse section, they appear polygonal with no gaps.

Extra Practice Questions

  • Q1: Which tissue is responsible for the flexibility in plants? (Answer: Collenchyma)
  • Q2: Name the chemical substance that acts like cement and hardens the cell wall in sclerenchyma. (Answer: Lignin)
  • Q3: Where is chlorenchyma found? (Answer: In green leaves, it is parenchyma containing chlorophyll)
  • Q4: What is the primary function of aerenchyma? (Answer: Provides buoyancy to aquatic plants)
  • Q5: Why does the husk of a coconut appear hard? (Answer: It is made of sclerenchymatous tissue)