Which type of ecological adaptations are present in plants those grow in conditions where temperature is 25°C and rainfall is less than 25 cm/year ?

(A) Reduced leaf lamina

(B) Deep rooted root system

(C) Thin cuticle

(D) Well developed mechanical tissue

(E) Root pockets present

(F) Well developed aerenchyma

(G) Single layered epidermis

The correct answer is (A) Reduced leaf lamina, (B) Deep rooted root system, (D) Well developed mechanical tissue.

Key Points

• Reduced leaf lamina: Plants in arid regions minimize water loss through transpiration by reducing the size of their leaves or modifying them into spines.
• Deep rooted root system: Deep roots allow plants to access water from deeper soil layers in environments with low rainfall.
• Well developed mechanical tissue: Mechanical tissues like sclerenchyma provide structural support to plants, helping them withstand extreme environmental conditions.
• These adaptations are characteristic of xerophytes, which thrive in hot and dry climates with minimal rainfall (less than 25 cm/year).
• Xerophytic plants include species like cacti, acacias, and succulents that have specialized adaptations to conserve water.

Additional Information

• Xerophytes: Plants adapted to grow in arid and semi-arid regions, characterized by features like thick cuticles, sunken stomata, and reduced leaf area.
• Transpiration reduction: Xerophytes minimize water loss through strategies like closing stomata during the day and storing CO₂ for photosynthesis at night (CAM pathway).
• Root adaptations: Xerophytes often have either deep tap roots for accessing groundwater or wide-spreading fibrous roots for capturing surface water quickly.
• Mechanical tissues: Enhanced sclerenchyma or collenchyma provide rigidity and protection to plants in harsh conditions.
• Examples of xerophytes: Cactus, Opuntia, Euphorbia, and Agave are common examples of xerophytic plants, demonstrating these ecological adaptations.