Question:

Name three groups of plants that bear archegonia. Briefly describe the life cycle of any one of them.

Updated On: Jul 12, 2024
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Solution and Explanation

Archegonium is the female sex organ that produces the female gamete or egg. It is present in the life cycles of bryophytes, pteridophytes, and gymnosperms.
Life cycle of a fern (Dryopteris)
Dryopterisis a common fern with pinnately-compound leaves. The main plant-body is sporophytic. Many sporangia are borne on the lower surfaces of its mature leaves. Each sporangium has spore mother cells which undergo meiosis to produce haploid spores. On maturing, these spores dehisce and germinate to give rise to a heart-shaped gametophyte called prothallus.
Theprothallus bears the male and female sex organs called antheridia and archegonia respectively. The antheridia produce sperms that swim in water to reach the archegonia. The egg is produced by the archegonia. As a result of fertilisation, a zygote is formed. The zygote forms an embryo, which in turn develops into a new sporophyte. The young plant comes out of the archegonium of the parent gametophyte.Dryopteris
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Concepts Used:

Bryophytes

Bryophyta is a taxonomic division under Kingdom Plantae comprising of three non-vascular land plants namely:

  • Liverwarts
  • Hornwarts 
  • Mosses

Characteristics of Bryophytes:

  • Plants in this category do not have roots but have crude stems and leaves.
  • They have “rhizoids” instead of roots which helps the plant to anchor to surface.
  • These roots or rhizoids do not absorb nutrients like other usual plant roots.
  • Mosses release spores from their leaves which travels by water and make new mosses in new locations.
  • Water is very essential for mosses to grow and spread. They can entirely dry out and survive. When in contact with water, they again revive and continue growing.

Classification of Bryophytes:

According to the newest classification, Bryophyta is split into three classes:

Hepaticopsida (Liverworts): The classification of Bryophytes is incomplete without Hepaticopsida.

Anthocerotopsida (Hornworts): Containing more than 300 species, Anthocerotopsida exhibit the following salient features – 

  • Thallus shows no signs of scales.
  • The gametophytic body comprises of a thalloid, without any internal tissue differentiation.
  • Seta is meristematic.
  • Sporophyte is cylindrically shaped. It only partially depends on the gametophyte to derive its nutrition.

Bryopsida (Mosses): This class of Bryophytes contains nearly 1500 species, making it the largest class among the three. Also known as mosses, common examples of Bryopsida include polytrichum and funaria, among others.