Anthoceros: Anthoceros is a type of hornwort, a group of simple plants without vascular systems, found worldwide in damp, shaded areas of subtropical and temperate regions. These plants are small and do not have true roots, stems, or leaves. Instead, they have a flat, leaf-like structure called a thallus that is greenish in colour and lies on the ground. The thallus is often lobed or divided and contains chloroplasts with pyrenoids. The plant is anchored by root-like structures called ventral rhizoids, which also form partnerships with cyanobacteria (Nostoc). Anthoceros NEET Biology Notes are provided in the article below.
Anthoceros, a genus of hornworts, belongs to the Anthocerotaceae family. It is widely distributed around the world and is considered the largest genus of hornworts. Typically, it grows best in damp, shaded areas within sub-tropical and temperate climates. Its distinguishing feature is a small to medium-sized green body with lobed edges.
Anthoceros reproduces both asexually and sexually. Asexual reproduction happens through methods like fragmentation, tubers, and persistent growth points. Sexual reproduction involves oogamy, where male structures called antheridia produce sperm and female structures called archegonia contain egg cells. The sporophyte, emerging from the archegonium, is characterized by a horn-shaped structure.
Structural Organisation in Animals
Anthoceros is a type of hornwort belonging to the Anthocerotaceae family. It is the largest genus among hornworts and is distributed worldwide in damp and shaded areas of subtropical and temperate regions. The following is the classification of Anthoceros:
Anthoceros is a type of bryophyte. Let's explore where it lives and how widespread it is:
Distribution:
Habitat:
Sexual Reproduction in Flowering Plants
Anthoceros belongs to a group of plants called hornworts, which are non-vascular bryophytes. Unlike mosses and liverworts, hornworts lack the complex structures found in plants with vascular systems. However, they possess a distinct and well-defined structure both externally and internally.
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Embryo | Funaria | Selaginella | Malvaceae |
Polyembryony | Apomixis | Pinus | Pollen Grains |
Chara | Volvox | Endosperm | Equisetum |
Although Anthoceros primarily exists in its gametophyte (thallus) form, it also has a sporophyte generation, which is smaller and less prominent. The sporophyte develops from a fertilized egg and remains attached to the gametophyte. It consists of three main parts:
The internal structure of Anthoceros is relatively simple compared to vascular plants, yet it is well-suited for its habitat, enabling it to thrive in moist and shaded environments where it can reproduce effectively.
In Anthoceros, the spore is haploid, containing one nucleus, and is semicircular with a notable triradiate marking. It comprises two layers:
Between these two layers, there are oil droplets, colorless plastids, and stored food materials.
Anthoceros, a type of hornwort genus, reproduces through two primary methods: asexual and sexual reproduction.
Anthoceros have developed several adaptations for asexual reproduction, aiding in rapid propagation and survival during tough conditions. Here are the different ways Anthoceros achieve asexual reproduction:
Sexual reproduction in Anthoceros follows the oogamous type, involving the fusion of eggs and sperm. Anthoceros plants can be monoecious (having both male and female organs on the same plant) or dioecious (male and female organs on separate plants). The sex organs are:
Antheridia grow on the upper surface of the plant body in a sequence from base to tip within special chambers. They have a club-like shape with a long stalk made of multiple cells arranged in four vertical rows. The antheridium is covered by a sterile outer layer, inside of which are androcytes. These androcytes mature into sperm cells called biflagellated antherozoids.
Archegonia also grow sequentially on the upper surface of the plant body, without specialized chambers. They are flask-shaped structures consisting of a neck and a bulbous base (venter). The neck cells break down as the archegonium matures, turning into a sticky substance.
Unlike the antheridium, the archegonium lacks a sterile outer layer. Instead, it has four cover cells or lid cells at its tip.
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Plasma Membrane Structure | Pre-Fertilisation | Economic Importance of Algae |
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In the presence of water, antherozoids fertilize eggs within the archegonia, forming a diploid zygote. This zygote undergoes meiosis to produce haploid spores. These spores are released from the sporophyte—a slender capsule growing from the thallus—to germinate and form new gametophytes.
The sporophyte capsule matures and releases spores when ready.
This reproductive strategy ensures Anthoceros' survival and adaptation in various environments through both efficient asexual propagation and genetic diversity via sexual reproduction.
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Rhizopus | Fibrous root | Marchantia | Actinomycetes |
Nostoc | Spirogyra | Ribosomes | Liverworts |
The life cycle of Anthoceros, a type of hornwort, represents the alternation of generations. This means it includes a predominant haploid phase (gametophyte) and a shorter-lived diploid phase (sporophyte). Here's an overview of its life stages:
In summary, the life cycle of an Anthoceros involves:
This type of life cycle, characterized by alternation of generations with a dominant haploid phase, is termed diplontic.
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