What is the Difference Between Polyandrous and Polyadelphous

The main difference between polyandrous and polyadelphous is that polyandrous is the presence of many free stamens, whereas polyadelphous is the presence of many groups of stamens whose anthers are free.

Polyandrous and polyadelphous are two occurrences of androecium in the flower. The androecium is collectively the stamens of the flower that produce pollen grains. 

Key Areas Covered

1. What is Stamen
– Definition, Structure, Function
2. What is Polyandrous
– Definition, Structure, Examples
3. What is Polyadelphous
– Definition, Structure, Examples
4. Similarities Between Polyandrous and Polyadelphous
– Outline of Common Features
5. Difference Between Polyandrous and Polyadelphous
– Comparison of Key Differences

Key Terms 

Polyadelphous, Polyandrous, Stamen

What is Stamen

The stamen is the male reproductive structure of the flower. Also, androecium is another name for the stamen.

Structure

The two structural components of a stamen are the anthers and filaments. Here, anthers bear pollen sacs, which produce pollen grains. On the other hand, filaments hold anthers away from the flower, facilitating the dispersal of pollen grains as required by the plant’s pollination. The number of anthers with filaments per flower depends on the species. In general, flowers have 5-6 stamens in a ring surrounding the female reproductive structures.

Figure 1: Mature Flower

Furthermore, each anther consists of four pollen sacs, occurring inside the two lobes of the anther. Inside the pollen sacs, the microsporangia or thecae occur. Also, microsporocytes are the cells that undergo meiosis and then mitosis to produce microspores, which develop into pollen grains. These pollen grains disperse during pollination, and when captured by the stigma, they germinate to produce three cells: one tube cell and two male gametes.

Function

Moreover, the primary function of the stamen is to produce and disperse pollen. It is a powdery substance consisting of pollen grains. Also, there are two methods of pollination in plants: self-pollination and cross-pollination. Self-pollination is the deposition of pollen grains from the anther of a flower on the stigma of the same flower or the stigma of a different flower in the same plant. In comparison, cross-pollination is the deposition of pollen grains of the anther of one flower on the stigma of a flower of a different plant of the same species.

What is Polyandrous

Polyandrous is the presence of many free stamens. Therefore, both the anther and the filament of the stamen are free. Some examples of polyandrous flowers are lotus, rose, and Corchorus.

Figure 2: Corchorus Flower

What is Polyadelphous

Polyadelphous is the presence of groped filaments. But the anthers of the stamen are free in polyadelphous flowers. It occurs in citrus and Ricinus.

Figure 3: Citrus Flower

Similarities Between Polyandrous and Polyadelphous

• Polyandrous and polyadelphous are two arrangements of the stamens of the flower.
• Stamens are the male reproductive parts of the flower, and they produce pollens. 

Difference Between Polyandrous and Polyadelphous

Definition

Polyandrous refers to when the flower’s stamens are free, while polyadelphous refers to plants in which the stamen or anthers are present in three or more bundles.

Stamens 

Polyandrous plants contain many free stamens, while polyadelphous plants contain many groups of filaments where their anthers are free.

Anthers and Filaments

Both anthers and filaments are free in polyandrous flowers, while filaments are fused, and anthers are free in polyadelphous plants. 

Examples

The corchorus plant is polyandrous, while Ricinus and citrus plants are polyadelphous. 

Conclusion

In brief, polyandrous and polyadelphous plants are two arrangements of stamens. Stamens are the male reproductive part of the flower, producing pollen. The details of the stamen are anthers and filaments. Polyandrous plants contain many free stamens. The flower of the corchorus plant is an example of polyandrous. In comparison, polyadelphous is the presence of grouped filaments and free anthers in the flower. Examples of polyadelphous plants are citrus and Ricinus. Therefore, the main difference between polyandrous and polyadelphous is the type of arrangement of the stamens. 

References:

1. Components of androecium in plants (with diagram). Biology Discussion. (2016, May 27). https://www.biologydiscussion.com/plants/components-of-androecium-in-plants-with-diagram/34006

Image Courtesy:

1. “Mature flower diagram” By Mariana Ruiz LadyofHats – Own work (Public Domain) via Commons Wikimedia
2. “Corchorus cunninghamii with flowers” By Poyt448, Peter Woodard – Own Work (CC-BY SA 4.0) via Commons Wikimedia
3. “Citrus flower 2019-06-13 09-54-06 (C)-PSD” By Ermell – Own Work (CC-BY SA 4.0) via Commons Wikimedia