How would you relate the internal structure of the root with the uptake of water and salts?
Difficulty: Medium
Water and Ion Uptake:
In addition to anchoring the plant, roots perform two other vital functions
- First they absorb water and salts from the soil.
- ii. Second, they provide conducting tissues for distributing these substances to the tissues of the stem. Root hairs provide a large surface area for absorption. They grow out into the spaces between soil particles where they are in direct contact with the water. The cytoplasm of the root hairs has a higher concentration of salts than the soil water, so water moves by sis into the root hairs. Salts also enter root hairs by diffusion or active transport. After they enter into the root hairs, water and salts must move through the epidermis and cortex of the root, and then into the xylem tissue in the center of the root
Pathways through which water travels from the outside of the root to the inside:
There are two pathways through which water travels from the outside of the root to the inside
- The first of these pathways is the apoplast pathway, in which water travels along cell walls and through intercellular spaces to reach the core of the root.
- the Second route for water is the symplast pathway, in which water moves across the root hair membrane and through the cells themselves, via channels (plasmodesmata) that connect their contents.
Note:
Once in the xylem, the water can be carried to all the aerial parts of the plant.
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