Question

The outer layer of the primary plant body, which protects the underlying tissues, is called

• A. Xylem
• B. Ground tissue
• C. Epidermis
• D. Phloem

Hint:

To remember the primary plant tissue systems, think of them as functional shells:
Dermal (outermost protective shell) = Epidermis.
Vascular (innermost transport pipelines) = Xylem and Phloem.
Ground (filling and metabolic matrix) = Cortex and Pith.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The primary plant body is organized into three fundamental tissue systems: the dermal tissue system, the ground tissue system, and the vascular tissue system.
Each tissue system extends continuously throughout the organs of the plant (roots, stems, and leaves) and performs specific physiological roles.

Step 2: Detailed Explanation:
1. dermal tissue system (Epidermis): The epidermis constitutes the outermost cell layer of the primary plant body.
It serves as the boundary between the plant's internal tissues and the external environment.
Its primary functions include protecting underlying tissues from mechanical injury, preventing excessive water loss through transpirational control (via the cuticle and stomata), and regulating gaseous exchange.
In specialized regions like roots, it is modified to form root hairs for the absorption of water and mineral nutrients.
2. Ground Tissue System: This system lies between the dermal and vascular systems.
It comprises tissues like parenchyma, collenchyma, and sclerenchyma, which function in photosynthesis, metabolic storage, and structural support.
3. Vascular Tissue System (Xylem and Phloem): This system forms the transport network of the plant.
Xylem is responsible for the unidirectional conduction of water and dissolved mineral ions from roots to leaves, whereas phloem is responsible for the multidirectional translocation of organic photoassimilates.
Therefore, the protective outer layer is the epidermis.

Step 3: Final Answer:
The protective outer layer of the primary plant body is the epidermis, which corresponds to option (C).