A homogamous tall pistilltate plant (TT) is crossed with homogamous dwarf staminate plant (tt). What is the genotype of endosperm?

Options

A. TTT
B. TTt
C. Ttt
D. ttt.

Answer

To determine the genotype of the endosperm when a homogamous tall pistillate plant (TT) is crossed with a homogamous dwarf staminate plant (tt), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Genotypes of the Parent Plants:**
- The tall pistillate plant is homozygous dominant, represented as TT.
- The dwarf staminate plant is homozygous recessive, represented as tt.

2. **Understand the Role of Each Parent in Fertilization:**
- The pistillate plant (female) contributes its genotype to the endosperm through the egg cell.
- The staminate plant (male) contributes its genotype through the pollen.

3. **Determine the Gametes Produced by Each Parent:**
- The tall pistillate plant (TT) can only produce gametes with the genotype T (since both alleles are T).
- The dwarf staminate plant (tt) can only produce gametes with the genotype t (since both alleles are t).

4. **Fertilization Process:**
- During fertilization, the egg cell from the pistillate plant (T) fuses with the pollen from the staminate plant (t).
- This results in the formation of the zygote, which will develop into the embryo.

5. **Formation of the Endosperm:**
- The endosperm is formed through a process called triple fusion, where one sperm cell fuses with the egg cell (T) and another sperm cell fuses with two polar nuclei.
- The genotype of the endosperm will be a combination of the contributions from both parents.

6. **Genotype of the Endosperm:**
- The endosperm will have one allele from the female (T) and two alleles from the male (t).
- Therefore, the genotype of the endosperm is Tt.

### Final Answer:
The genotype of the endosperm is Tt.

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