Module: | Pollination & Outbreeding Devices
Q38: Consider the following statements regarding the helobial type of endosperm development:
1. Helobial endosperm development is an intermediate morphological type bridging the nuclear and cellular types.
2. It is predominantly observed in monocotyledonous plants belonging to the order Helobiae.
3. In this type, the first division of the primary endosperm nucleus is free-nuclear, completely lacking any cell wall formation.
Which of the above statements is/are correct?
2. It is predominantly observed in monocotyledonous plants belonging to the order Helobiae.
3. In this type, the first division of the primary endosperm nucleus is free-nuclear, completely lacking any cell wall formation.
Which of the above statements is/are correct?
✅ Correct Answer: A
The correct option is A. Statements 1 and 2 are correct, while Statement 3 is incorrect.
Endosperm development manifests in three primary modes: nuclear, cellular, and helobial.
Structurally, the helobial type is an evolutionary intermediate.
It is heavily restricted botanically, found almost exclusively in the monocot order Helobiae.
Statement 3 incorrectly describes its defining causal mechanism.
In helobial development, the very first mitotic division of the Primary Endosperm Nucleus (PEN) is actually followed by immediate, unequal cytokinesis (cell wall formation). This splits the embryo sac into a large micropylar chamber and a small chalazal chamber.
Only after this initial cellular division do the nuclei in both chambers undergo successive free-nuclear divisions.
Thus, it begins like the cellular type but proceeds like the nuclear type, contradicting the claim that the first division lacks a cell wall.
Endosperm development manifests in three primary modes: nuclear, cellular, and helobial.
Structurally, the helobial type is an evolutionary intermediate.
It is heavily restricted botanically, found almost exclusively in the monocot order Helobiae.
Statement 3 incorrectly describes its defining causal mechanism.
In helobial development, the very first mitotic division of the Primary Endosperm Nucleus (PEN) is actually followed by immediate, unequal cytokinesis (cell wall formation). This splits the embryo sac into a large micropylar chamber and a small chalazal chamber.
Only after this initial cellular division do the nuclei in both chambers undergo successive free-nuclear divisions.
Thus, it begins like the cellular type but proceeds like the nuclear type, contradicting the claim that the first division lacks a cell wall.