Why Bryophytes are Called Amphibians of Plant Kingdom

Bryophytes are the most primitive members found in the kingdom of Plantae. They are non-vascular land plants. They grow in moist, shady places, which are in between the land and water. Therefore, they are called the amphibians of the plant kingdom. Bryophytes are autotrophs that produce their own food by photosynthesis. Asexual reproduction is the main method of reproduction in bryophytes. It occurs through the production of spores. Though bryophytes live on the land, they require water for the fertilization. The sperms of bryophytes swim through water to the eggs with the help of their flagella.

Key Areas Covered

1. What are Bryophytes
     – Definition, Characteristics
2. Why Bryophytes are Called Amphibians of Plant Kingdom
     – Habitat of Bryophytes

Key Terms: Bryophytes, Cuticle Layer, Fertilization, Moist and Shady Environments, Sexual Reproduction

What are Bryophytes

Bryophytes are the most primitive land plants, which are classified under the kingdom of Plantae. They are neither vascular nor seed plants. Bryophytes undergo alteration of generations where the gametophyte is dominant over the sporophyte. The haploid gametophyte produces spores. Bryophytes may grow from one millimeter to long strands of about one meter long. The plant body of bryophytes is not differentiated into root, stem, and leaves. The root-like structures are called rhizoids and they allow the plant to anchor onto a surface. However, rhizoids do not absorb water. The plant body itself absorbs water. Moreover, Bryophytes are mostly autotrophs.

Figure 1: Bryophytes

The most prominent method of reproduction in bryophytes is asexual reproduction, which occurs through the production of spores. These spores spread through the wind. Fragmentation and small aggregations called gemmae are other methods of vegetative reproduction in bryophytes.

Why Bryophytes are Called Amphibians of Plant Kingdom

Though bryophytes are land plants, they require water for the fertilization of gametes. Water carries sperms to the eggs during sexual reproduction. Hence, the sperms of bryophytes are always flagellated. Since bryophytes require water for their sexual reproduction, they tend to grow in moist, shady habitats. Given that they grow in moist places, bryophytes are considered as amphibians of the plant kingdom. Generally, amphibians are the animals that live on land but, move to water during reproduction. Gametes of amphibians are fused in the water. The following image shows the requirement of water for the reproduction of bryophytes.

Figure 2: Bryophytes Reproduction

Both bryophytes and amphibians do not contain cuticle layers in order to protect themselves from dehydration. Hence, they live in moist environments. In addition, bryophytes do not have a vascular system for the efficient transfer of water through the plant body. Therefore, bryophytes continuously require moisture from their surroundings.

Conclusion

Bryophytes live in moist, shady places since they require water for the fertilization of gametes. Therefore, they are considered as the amphibians of the plant kingdom. Bryophytes are primitive types of plants whose body is not differentiated into stem, root, and leaves.

Reference:

1. “BRYOPHYTES.” What Are Bryophytes, Available here.

Image Courtesy:

1. “Moss alternation of generations 03-2012” By Htpaul – own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Thallose liverwort (Marchantia and Lunularia spp.) showing clonal plantlets in gemma cups” By Avenue – Own work, GFDL) via Commons Wikimedia