The type of embryo sac discovered by Strassburger in Polygonum plant ,

Options

A. Has seven called seven nucleated structure and is bisporic.
B. Has seven called seven nucleated structure and is monosporic.
C. Has seven called eight nucleated structure and is bisporic.
D. Has seven called eight nucleated structure and is monosporic.

Answer

**Step-by-Step Solution:**

1. **Identify the Type of Embryo Sac**: The question asks for the type of embryo sac discovered by Strassburger in the Polygonum plant. The key term here is "embryo sac."

2. **Understand the Embryo Sac Development**: In Polygonum, the embryo sac is developed from a single megaspore mother cell. This indicates that it is a monosporic embryo sac.

3. **Determine the Cell and Nucleus Count**: In the case of a monosporic embryo sac, the development begins with one megaspore. As the megaspore undergoes mitotic divisions, it results in the formation of multiple nuclei. Specifically, in the Polygonum plant, after several rounds of mitosis, the embryo sac reaches an 8-nucleated stage.

4. **Count the Cells**: After the nuclei are formed, the embryo sac organizes into cells. In Polygonum, the final structure consists of 7 cells, which contain 8 nuclei. This is a characteristic feature of the embryo sac in this plant.

5. **Select the Correct Option**: Based on the analysis, the correct description of the embryo sac in Polygonum is that it is a "7-celled, 8-nucleated structure" and is classified as monosporic.

**Final Answer**: The type of embryo sac discovered by Strassburger in the Polygonum plant is a **7-celled, 8-nucleated structure and is monosporic**.

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