Module: | Embryo, Seed, Fruit & Apomixis
Q90: Consider the following statements regarding the endosperm of the Orchidaceae family:
1. While typical angiosperms develop a nutritive triploid endosperm, mature seeds of the orchid family completely lack an endosperm.
2. Because they lack this stored food, the microscopic, dust-like seeds of orchids rely obligately on a symbiotic relationship with mycorrhizal fungi for germination.
3. The primary endosperm nucleus (PEN) in orchids survives and differentiates into a massive, woody cotyledon that protects the embryo.
Which of the above statements is/are correct?
2. Because they lack this stored food, the microscopic, dust-like seeds of orchids rely obligately on a symbiotic relationship with mycorrhizal fungi for germination.
3. The primary endosperm nucleus (PEN) in orchids survives and differentiates into a massive, woody cotyledon that protects the embryo.
Which of the above statements is/are correct?
✅ Correct Answer: A
The correct option is A. Statements 1 and 2 are correct, but Statement 3 is entirely incorrect.
The Orchidaceae family is famous for producing some of the smallest seeds in the plant kingdom, often described as dust-like.
Structurally, double fertilization does occur in orchids, but the primary endosperm nucleus (PEN) typically degenerates early, or if it divides, the resulting endosperm fails to develop and is absent in the mature seed.
This makes the seeds exalbuminous to an extreme degree.
Causally, without an endosperm to provide sugars, a dormant orchid embryo cannot germinate on its own in nature.
It must be infected by a specific mycorrhizal fungus, which digests organic matter in the soil and physically pumps the necessary carbohydrates directly into the seed.
Statement 3 is a fictional distractor; the PEN degenerates and never forms a protective cotyledon.
The Orchidaceae family is famous for producing some of the smallest seeds in the plant kingdom, often described as dust-like.
Structurally, double fertilization does occur in orchids, but the primary endosperm nucleus (PEN) typically degenerates early, or if it divides, the resulting endosperm fails to develop and is absent in the mature seed.
This makes the seeds exalbuminous to an extreme degree.
Causally, without an endosperm to provide sugars, a dormant orchid embryo cannot germinate on its own in nature.
It must be infected by a specific mycorrhizal fungus, which digests organic matter in the soil and physically pumps the necessary carbohydrates directly into the seed.
Statement 3 is a fictional distractor; the PEN degenerates and never forms a protective cotyledon.