Path of water movement from soil to xylem is

Options

A. Metaxylem `to` Protoxylem `to` Cortex `to` Soil `to` Root hair
B. Cortex` to` Root hair `to` Endodermis `to` Pericycle `to` Protoxylem `to` Metaxylem
C. Soil `to` Root hair `to` Cortex `to` Endodermis `to` Pericycle `to` Protoxylem `to` Metaxylem
D. Pericycle `to` Soil `to` Root hair `to` Cortex `to` Endodermis `to` Protoxylem `to Metaxylem

Answer

To understand the path of water movement from soil to the xylem in plants, we can break it down into several steps:

### Step-by-Step Solution:

1. **Water Absorption from Soil**:
- Water is absorbed by the roots from the soil. This process primarily occurs through root hairs, which increase the surface area for absorption.

2. **Movement through the Epidermis**:
- After absorption, water moves through the epidermis of the root. The epidermis can facilitate water movement through two pathways: the **apoplast pathway** and the **symplast pathway**.
- **Apoplast Pathway**: Water moves through the cell walls and intercellular spaces without crossing any cell membranes.
- **Symplast Pathway**: Water moves from cell to cell through the cytoplasm via plasmodesmata (small channels connecting plant cells).

3. **Entering the Cortex**:
- As water moves into the cortex (the layer of tissue beneath the epidermis), it can continue through both pathways (apoplast and symplast) until it reaches the endodermis.

4. **Endodermis and Casparian Strip**:
- The endodermis is the innermost layer of the cortex and contains a structure called the **Casparian strip**, which is a band of cell wall material that is impregnated with suberin (a waxy substance).
- The Casparian strip forces water to enter the symplast pathway, as it blocks the apoplast pathway. This ensures that water must pass through the cell membranes, allowing for selective absorption of minerals and nutrients.

5. **Movement into the Xylem**:
- After passing through the endodermis, water enters the xylem vessels. The xylem is responsible for transporting water and dissolved minerals from the roots to the rest of the plant.

### Final Pathway Summary:
The path of water movement from soil to xylem can be summarized as:
Soil → Root Hairs → Epidermis (Apoplast/Symplast) → Cortex (Apoplast/Symplast) → Endodermis (Symplast due to Casparian strip) → Xylem.

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