Q.68 The characters that define family Amborellaceae
A. flowers unisexual, tricolpate pollen, endosperm triploid
B. flowers unisexual, monoaperturate pollen, single ovule
C. flowers unisexual, tricolpate pollen, single ovule
D. flowers unisexual, monoaperturate pollen, endosperm triploid
Choose the correct answer from the options given below:
(A) A and B only
(B) B and C only
(C) A and C only
(D) B and D only
The correct answer is (C) A and C only.
Character Analysis for Amborellaceae
Amborellaceae (single species: Amborella trichopoda) defines the most basal angiosperm lineage. Key diagnostic traits:
A. Flowers unisexual, tricolpate pollen, endosperm triploid: Correct—Dioecious (unisexual flowers); primitive tricolpate pollen (eudicot-like); standard double fertilization → 3n endosperm.
B. Flowers unisexual, monoaperturate pollen, single ovule: Wrong—Monoaperturate = monocot pollen; Amborella has tricolpate.
C. Flowers unisexual, tricolpate pollen, single ovule: Correct—Unisexual + tricolpate + 1 ovule/carpel (apocarpous gynoecium).
D. Flowers unisexual, monoaperturate pollen, endosperm triploid: Wrong—Again, monoaperturate incorrect.
Option Breakdown
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(A) A,B only: Wrong—B has wrong pollen type.
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(B) B,C only: Wrong—Both B,D share monoaperturate error.
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(C) A,C only: Correct—Both combine unisexual flowers + tricolpate pollen (A) or + single ovule (C).
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(D) B,D only: Wrong—monoaperturate in both.
Introduction: Amborellaceae Family Characters
Amborellaceae family characters include unisexual flowers, tricolpate pollen, single ovules per carpel, and triploid endosperm—marking Amborella trichopoda as the most basal living angiosperm from New Caledonia. These primitive traits help NEET students solve MCQs distinguishing A-D options from derived eudicot/monocot features.
Defining Amborellaceae Diagnostic Features
1. Unisexual flowers: Dioecious shrub—separate male (staminate) + female (carpellate) flowers in cymes.
2. Tricolpate pollen: 3-groove pollen (ancestral eudicot state), not monocot monoaperturate.
3. Single ovule: Apocarpous gynoecium (4-8 free carpels), 1 ovule/carpel → red drupe.
4. Triploid endosperm: Double fertilization (standard angiosperm).
Other primitives: No vessels (tracheids only), spiral tepals, laminar stamens.
MCQ Solution: Amborellaceae Characters A B C D
Question: Characters defining Amborellaceae: A. unisexual+tricolpate+3n B. unisexual+monoaperturate+1ovule C. unisexual+tricolpate+1ovule D. unisexual+monoaperturate+3n.
| Option | Evaluation |
|---|---|
| (A) A,B | Wrong—B monoaperturate (monocot) |
| (B) B,C | Wrong—B wrong pollen |
| (C) A,C | Correct—tricolpate + single ovule diagnostic |
| (D) B,D | Wrong—both monoaperturate |
Answer: (C)
Taxonomic Significance
Amborellales → Amborellaceae → Amborella trichopoda: Sister to all other angiosperms. Tricolpate pollen + vessels absent = pre-eudicot. Single ovule/carpel = pre-syncarpous. Phylogenomic position confirmed 1990s onward.
Exam Strategy
Key distractor: Monoaperturate = monocots (B,D wrong). Tricolpate = basal/eudicots (A,C correct). Single ovule + apocarpy = primitive gynoecium. NEET tests Amborella as “most basal angiosperm.”
