UPSC Prelims 2018 Question:

Which of the following leaf modifications occur(s) in the desert areas to inhibit water loss?

1. Hard and waxy leaves
2. Tiny leaves
3. Thorns instead of leaves
   
   

Select the correct answer using the code given below:

Explanation:

• The plants growing in extremely dry conditions like desert areas throughout the year are called ‘Xerophytes’. For example, plants growing in deserts (psammophytes), on rock (lithophytes) or alpine plants growing above 14000 feet altitude.
  
  
• The leaves are modified in such a way that water loss due to transpiration reduces to a minimum. They are stiff and hard and are covered with hair. They are smaller in size. They are soft and fleshy. A waxy layer is present on the epidermis for the reflection of light. So, points 1 and 2 are correct.
  
  
• Some plants have thorns instead of leaves. Thorns lose less water than leaves so are very efficient in a hot climate. They also prevent animals from eating the plant. So, point 3 is correct.
  
  

Therefore, option (4) is the correct answer.

Subject: Environment | Terrestrial and Aquatic Ecosystem