Does Marchantia lack archegonium?
Asexual reproduction in Marchantia is by the gemmae which detach from gemmee cup and produce new plants. Sexual reproduction occurs by the formation of sex organs borne on special branches. The female reproductive organs are “archegonia”. They were born on special stalked branches called archegoniophores.
What is the shape of archegonium in bryophytes?
The female sex organ is usually a flask-shaped structure called the archegonium. The archegonium contains a single egg enclosed in a swollen lower portion that is more than one cell thick.
Is the gemma Cup stalked sessile?
Plants with air-chambers and pores, ventral surface with scales, capsule in involucres, Gemmae cup absent, male, receptacle sessile, archegonia stalked, terminal with a characteristic perianth. Fresh plants have a characteristic fishy smell.
How do marchantia polymorpha reproduce?
Marchantia can reproduce both sexually and asexually. Sexual reproduction involves sperm from antheridia on the male plant fertilizing an ovum (egg cell) in the archegonium of a female plant. The sporophyte produces spores which develop into free-living male and female gametophyte plants.
What happens in the archegonia?
archegonium, the female reproductive organ in ferns and mosses. Neck-canal cells, located above the egg, disappear as the archegonium matures, thus producing a passage for entry of the sperm. The sperm are produced in the corresponding male reproductive organ, the antheridium.
What does the archegonium produce?
An archegonium (pl: archegonia), from the ancient Greek ἀρχή (“beginning”) and γόνος (“offspring”), is a multicellular structure or organ of the gametophyte phase of certain plants, producing and containing the ovum or female gamete.
Which structure is the archegonium?
archegonium, the female reproductive organ in ferns and mosses. An archegonium also occurs in some gymnosperms, e.g., cycads and conifers. A flask-shaped structure, it consists of a neck, with one or more layers of cells, and a swollen base—the venter—which contains the egg.
Why is archegonia absent in angiosperms?
The term is not used for angiosperms or the gnetophytes Gnetum and Welwitschia because the megagametophyte is reduced to just a few cells, one of which differentiates into the egg cell. The function of surrounding the gamete is assumed in large part by diploid cells of the megasporangium (nucellus) inside the ovule.
What is Spore dissemination?
Spore dissemination in some liverworts is aided by elaters. Elater is a water attracting cell structure found in the capsule of liverworts. It is hygroscopic in nature. Due to its hygroscopic nature, it helps in dispersal of spores.
Is Plagiochasma a bryophyte?
Ethnotherapeutics of bryophyte Plagiochasma appendiculatum among the Gaddi tribes of Kangra Valley, Himachal Pradesh, India.
What is the difference between a Marchantia antheridia and a Marchantia archegonia?
Key Difference – Antheridia vs Archegonia Male sex organ of the male gametophyte is known as antheridium. Antheridia are found in the androecium, and they produced male gametes. Female sex organ of the female gametophyte is archegonium. Archegonia are found in the gynoecium, and they produce female gametes.
What reproductive cells develop from archegonia?
At maturity, archegonia each contain one egg, and antheridia produce many sperm cells. Because the egg is retained and fertilized within the archegonium, the early stages of the developing sporophyte are protected and nourished by the gametophytic tissue.
How does the Marchantia plant reproduce both sexually and asexually?
Marchantia can reproduce both sexually and asexually. Sexual reproduction involves sperm from antheridia on the male plant fertilizing an ovum (egg cell) in the archegonium of a female plant. The antheridia and archegonia are borne atop special gametophore stalks called antheridiophores and archegoniophores, respectively.
What kind of covering is the sporangium of Marchantia?
A ring of basal cells of archesporium forms a second one cell thick protective covering round the growing sporangium. It is called the perigynium or the pseudoperianth. Therefore, the sporangium of Marchantia develops within three gametophytic coverings viz., calyptra, perigynium and perichaetium (Fig. 6.18A-C).
Where are the antheridia and archegonia located on a plant?
The antheridia and archegonia are borne atop special gametophore stalks called antheridiophores and archegoniophores, respectively. These are borne on separate thalli and thus the plants are dioicous .
What is the dehiscence of antheridium in Marchantia?
The dehiscence of antheridium in Marchantia is similar to that of Riccia. The archegoniophore or the carpocephalum is comprised of a stalk and a disc that bears 9 rays (Fig. 6.14D) instead of lobes. In the early stage, the archegonia develop on the upper (dorsal) side of the disc (Fig. 6.14A, A’).