Which charcter is not associated with plant where shull studies inbreeding depression while Miller and Letham extracted a hormone from its seeds ?

Options

A. Atactostele in stem
B. Bundle sheath in leaf
C. Chromosome number 30 in endosperm
D. Medulla absent in root

Answer

To solve the question regarding which character is not associated with the plant studied by Shull for inbreeding depression and from which Miller and Letham extracted a hormone, we will analyze the options provided and the characteristics of maize (Zea mays).

### Step-by-Step Solution:

1. **Identify the Plant**: The plant in question is maize (Zea mays). Shull studied inbreeding depression in maize, and Miller and Letham extracted a hormone from its seeds.

2. **Understand the Options**:
- **Option A: Atectoestrogen**: This is a type of estrogen hormone. While hormones can be extracted from maize, this specific term does not refer to a structural characteristic of the plant.
- **Option B: Bundle sheath in leaf**: Maize leaves do have a bundle sheath, which is a layer of cells surrounding the vascular bundles.
- **Option C: Chromosome number 13 endosperm**: Maize has a specific chromosome number and endosperm, which is a characteristic of its seed structure.
- **Option D: Medulla absent in root**: The term "medulla" typically refers to the innermost part of a structure. In the context of maize roots, the medulla is not a recognized structure.

3. **Analyze Each Option**:
- **Atectoestrogen**: Not a structural characteristic of maize.
- **Bundle sheath in leaf**: Present in maize.
- **Chromosome number 13 endosperm**: Present in maize.
- **Medulla absent in root**: Medulla is not a recognized structure in maize roots.

4. **Conclusion**: The character that is not associated with maize is **Option D: Medulla absent in root**. This is because maize does not have a medulla structure in its root anatomy.

### Final Answer:
The correct answer is **Option D: Medulla absent in root**.