Question

Some plants are able to excrete the absorbed salts through specialised structures
A. Stomata
B. Hydathodes
C. Guard cells
D. Chloroplast
E. Capillary
Choose the correct answer from the options given below:

• A. A, B and D only
• B. A and C only
• C. B only
• D. A and E only

Hint:

Hydathodes facilitate guttation (excreting water droplets), which also serves as a pathway for plants to purge excess minerals and salts from their vascular tissues.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Certain plants, particularly halophytes (salt-tolerant plants) and some grasses, have evolved specialized anatomical structures to regulate internal salt concentrations.
These structures allow them to excrete excess absorbed salts from their tissues onto the leaf surface, protecting internal metabolic processes from salt toxicity.
Detailed Explanation:
Let us analyze the anatomical structures listed in the options:
- Stomata and Guard Cells: Primarily regulate gas exchange (\(\text{CO}_2\) and \(\text{O}_2\)) and transpirational water loss. They are not designed for active salt excretion.
- Chloroplasts: Intracellular organelles responsible for photosynthesis, not secretory structures.
- Hydathodes: Specialized secretory structures located primarily along the margins and tips of leaves. They are involved in guttation, the discharge of liquid water under positive root pressure when transpiration is low. In some plants, especially those growing in saline or mineral-rich soils, hydathodes and associated salt glands actively excrete excess dissolved salts (such as calcium, sodium, and chloride) alongside the water, forming salt crusts on the leaf margins.
Thus, hydathodes are the specialized structures from this list used by plants to excrete absorbed salts.

Step 2: Final Answer:
The correct answer is B only, which corresponds to Option (C).