Question:
The seedling of which plants are thorny during juvenile phase
A. Apple
B. Pear
C. Citrus
D. Guava
E. Mango
Choose the correct answer from the options given below:
The seedling of which plants are thorny during juvenile phase
A. Apple
B. Pear
C. Citrus
D. Guava
E. Mango
Choose the correct answer from the options given below:
A. Apple
B. Pear
C. Citrus
D. Guava
E. Mango
Choose the correct answer from the options given below:
Show Hint
Juvenility markers:
Citrus = Thorns
Ivy = Creeping habit
Eucalyptus = Different leaf shape.
Citrus = Thorns
Ivy = Creeping habit
Eucalyptus = Different leaf shape.
Updated On: Aug 13, 2026
- A, B and D only
- A, B and C only
- C only
- A and C only
Show Solution
Verified By Collegedunia
The Correct Option is B
Solution and Explanation
Step 1: Understanding the Concept:
Juvenility is the initial stage of a plant's life during which it cannot be induced to flower. This phase is often marked by distinct morphological features such as different leaf shapes, vigorous vegetative growth, and in some species, the presence of thorns. This phenomenon is known as "heteroblastic development."
Step 2: Detailed Explanation:
Thorniness is an evolutionary defense mechanism to protect young, tender seedlings from herbivory during their vulnerable juvenile stage.
A. Apple and B. Pear: Seedlings of these temperate fruits frequently show thorn-like structures or sharp, modified spurs during their first few years of growth. These thorns disappear as the tree reaches the "adult" or reproductive phase. Grafted commercial trees usually skip this because the scion is taken from an adult tree.
C. Citrus: Citrus is the most classic example of juvenile thorniness. Almost all Citrus seedlings (Acid lime, Sweet orange, etc.) are extremely thorny. As the tree matures and begins to fruit, the newer branches produced from the canopy's outer parts are either less thorny or completely thornless.
D. Guava and E. Mango: Seedlings of these tropical/subtropical fruits do not typically exhibit thorniness as a juvenile characteristic. Their juvenile phase is instead characterized by rapid vertical growth and a lack of flowering regardless of environmental cues.
Therefore, thorniness as a marker of juvenility is characteristic of Apple, Pear, and Citrus.
Step 3: Final Answer:
The correct grouping of plants showing juvenile thorniness is A, B, and C.
Juvenility is the initial stage of a plant's life during which it cannot be induced to flower. This phase is often marked by distinct morphological features such as different leaf shapes, vigorous vegetative growth, and in some species, the presence of thorns. This phenomenon is known as "heteroblastic development."
Step 2: Detailed Explanation:
Thorniness is an evolutionary defense mechanism to protect young, tender seedlings from herbivory during their vulnerable juvenile stage.
A. Apple and B. Pear: Seedlings of these temperate fruits frequently show thorn-like structures or sharp, modified spurs during their first few years of growth. These thorns disappear as the tree reaches the "adult" or reproductive phase. Grafted commercial trees usually skip this because the scion is taken from an adult tree.
C. Citrus: Citrus is the most classic example of juvenile thorniness. Almost all Citrus seedlings (Acid lime, Sweet orange, etc.) are extremely thorny. As the tree matures and begins to fruit, the newer branches produced from the canopy's outer parts are either less thorny or completely thornless.
D. Guava and E. Mango: Seedlings of these tropical/subtropical fruits do not typically exhibit thorniness as a juvenile characteristic. Their juvenile phase is instead characterized by rapid vertical growth and a lack of flowering regardless of environmental cues.
Therefore, thorniness as a marker of juvenility is characteristic of Apple, Pear, and Citrus.
Step 3: Final Answer:
The correct grouping of plants showing juvenile thorniness is A, B, and C.
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