Plant Physiology

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 :

[amp_mcq option1=”2 and 3 only” option2=”2 only” option3=”3 only” option4=”1, 2 and 3″ correct=”option4″]

All three listed leaf modifications are adaptations found in plants in desert areas to minimize water loss through transpiration.
1. Hard and waxy leaves: A thick, waxy cuticle on the leaf surface reduces evaporation of water.
2. Tiny leaves: Reducing the surface area of leaves directly reduces the total surface area available for transpiration.
3. Thorns instead of leaves: Thorns are often modified leaves or branches. If they are modified leaves (e.g., in cacti), they drastically reduce the surface area for transpiration. Thorns also deter herbivores, protecting the plant.

– Desert plants (xerophytes) have adaptations to conserve water.
– Adaptations include reducing leaf surface area and preventing water loss through barriers.
– Waxy cuticle, reduced leaf size, and modifications like thorns are common water-conserving adaptations.

Other adaptations in desert plants include sunken stomata, fleshy stems for water storage, and extensive root systems.

Which of the following leaf modifications occurs/occur in desert areas to inhibit water loss?

• 1. Hard and waxy leaves
• 2. Tiny leaves or no leaves
• 3. Thorns instead of leaves

Select the correct answer using the codes given below.

[amp_mcq option1=”1 and 2 only” option2=”2 only” option3=”1 and 3 only” option4=”1, 2 and 3″ correct=”option4″]

All the listed leaf modifications occur in desert areas to inhibit water loss: hard and waxy leaves, tiny leaves or no leaves, and thorns instead of leaves.

Desert plants (xerophytes) have evolved various adaptations to survive in arid environments with limited water availability. 1. Hard and waxy leaves (with thick cuticles) reduce cuticular transpiration. 2. Having tiny leaves or shedding leaves during dry periods minimizes the surface area for transpiration. Some plants have modified stems that photosynthesize instead of leaves. 3. Thorns are often modified leaves or stipules; they drastically reduce the surface area for transpiration and also deter herbivores, preventing tissue damage that could lead to water loss.

Other adaptations in desert plants include sunken stomata, fleshy stems or leaves for water storage (succulence), extensive root systems, and C4 or CAM photosynthesis pathways which are more water-efficient.

Many transplanted seedlings do not grow because

[amp_mcq option1=”the new soil does not contain favourable minerals” option2=”most of the root hairs grip the new soil too hard” option3=”most of the root hairs are lost during transplantation” option4=”leaves get damaged during transplantation” correct=”option3″]

Many transplanted seedlings do not grow because most of their root hairs are lost during the transplantation process.

Root hairs are fine, delicate extensions of root epidermal cells that greatly increase the surface area for absorption of water and mineral nutrients from the soil. When a seedling is dug up for transplantation, the soil around the roots is disturbed, and a large number of these fragile root hairs are broken or stripped off. The plant’s ability to absorb water is severely reduced until new root hairs can grow, leading to ‘transplant shock’, wilting, and potentially death if sufficient water uptake cannot be re-established quickly.

While factors like unfavorable soil conditions or leaf damage can also affect transplant success, the primary and most immediate challenge for a transplanted seedling is the drastic reduction in its water absorption capacity due to root hair loss. Proper watering and minimizing root disturbance during transplantation are crucial for survival.

Fruits stored in a cold chamber exhibit longer storage life because

[amp_mcq option1=”exposure to sunlight is prevented” option2=”concentration of carbon dioxide in the environment is increased” option3=”rate of respiration is decreased” option4=”there is an increase in humidity” correct=”option3″]

Fruits stored in a cold chamber exhibit longer storage life because the low temperature significantly reduces the rate of respiration in the fruits.

Respiration is a metabolic process in fruits that consumes stored sugars and leads to ripening and senescence. By lowering the temperature, this process is slowed down, thereby extending the time before the fruit spoils.

Other factors like preventing sunlight exposure and managing humidity are also important for fruit storage, but reducing the respiration rate through low temperature is the primary mechanism by which cold storage extends shelf life. Controlled atmosphere storage (modifying CO2 and Oxygen levels) is another technique used to further extend storage life by also impacting respiration and other metabolic processes.