Monoecious Plant of Chara

Monoecious plants have both male and female reproductive structures on the same plant. Chara is a genus of green algae that includes some species of monoecious plants. In monoecious Chara plants, the occurrence of upper oogonium and lower antheridium on the same plant is observed.

Explanation:

Chara is a genus of green algae that belongs to the division Charophyta. It is commonly known as stonewort and is found in freshwater habitats. Chara plants are multicellular and have a complex body structure. They are commonly found in shallow water bodies like ponds and lakes.

Monoecious Chara plants have both male and female reproductive structures on the same plant. This means that the plant can produce both male and female gametes, allowing for self-fertilization. In Chara, the male reproductive structure is called an antheridium, and the female reproductive structure is called an oogonium.

Occurrence of upper oogonium and lower antheridium refers to the positioning of these reproductive structures on the plant body. In Chara, the upper part of the plant contains the oogonium, which produces female gametes or eggs. The lower part of the plant contains the antheridium, which produces male gametes or sperm.

When the plant is in the reproductive stage, the upper part of the plant develops a cluster of oogonia, which are flask-shaped structures containing the eggs. These oogonia are usually larger in size compared to the lower reproductive structures.

In contrast, the lower part of the plant develops antheridia, which are smaller and cylindrical structures that produce sperm. The antheridia are positioned below the oogonia on the same plant.

This arrangement allows for the release of sperm from the antheridia, which can then swim upwards towards the oogonia. The sperm fertilizes the eggs present in the oogonia, resulting in the formation of zygotes.

Conclusion:

In monoecious Chara plants, the occurrence of upper oogonium and lower antheridium on the same plant allows for the production of both male and female gametes. This positioning facilitates self-fertilization and the formation of zygotes.