Crassinucellate ovule shows:

Options

A. Developed nucellus
B. Partically development nucellus
C. Well developed nucellus
D. No nucellus

Answer

To answer the question "Crassinucellate ovule shows:", we will break down the concept of crassinucellate ovules and their characteristics step by step.

### Step-by-Step Solution:

1. **Definition of Crassinucellate Ovule**:
- A crassinucellate ovule is a type of ovule characterized by a thick nucellus. The term "crassinucellate" comes from the Latin words "crassus" meaning thick and "nucellus" referring to the central part of the ovule.

2. **Structure of Crassinucellate Ovule**:
- In a crassinucellate ovule, the structure includes integuments that surround the nucellus. The nucellus is the tissue that contains the megasporangium and is crucial for the development of the female gametophyte.

3. **Arche Sporeal Cell**:
- The ovule contains an arche sporeal cell, which is the initial cell that undergoes division. This cell divides to form two cells: the primary parietal cell and the megasporangium.

4. **Formation of Megasporangium**:
- The primary parietal cell undergoes meiosis to form a megas mother cell (MMC), which is a diploid (2n) structure. This MMC is significant as it will eventually give rise to the megaspores.

5. **Meiosis and Megaspores**:
- The MMC undergoes meiosis, resulting in the formation of four megaspores. Typically, in crassinucellate ovules, one of these megaspores survives and undergoes mitotic divisions to develop into the female gametophyte.

6. **Characteristics of Nucellus**:
- The crassinucellate ovule is characterized by a well-developed nucellus, which is thicker compared to other types of ovules (like tenuinucellate ovules). This thick nucellus provides nourishment to the developing female gametophyte.

7. **Conclusion**:
- Therefore, the crassinucellate ovule shows a well-developed nucellus, which is a key feature distinguishing it from other ovule types.

### Final Answer:
Crassinucellate ovule shows a well-developed nucellus.

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