Asked by: Hassie Kronert
Asked in category: science, biological sciences
Last Updated: 1st Jul 2024

What is Protonema biology?

A protonema, plural: protonemata, is a thread-like string of cells that forms the earliest stage of the moss life cycle (the haploid). The protonema is an alga-like filamentous structure that moss spores form when they germinate. This is the juvenile gametophyte.



Afterwards, you might also wonder, "What does the Protonema do?"

The protonema is a proton, which grows from the germinatingspore. It is a branched system made up of multicellular filaments rich in chlorophyll. This stage triggers the formation of hormones which influence the growth of new cells.

Second, what are the structure of Protonema's? When a moss or liverwortspore germinates, a protonema is formed. It is usually composed of green, branching filaments in mosses. However, it can be thalloid (a flat or disc of cells) found in Andreaea and Sphagnum, as well as many liverworts.

People also ask: What is secondary Protonema?

The basic portion of the chain formed from the spore is called the primary protonema. The stem, or the primary pronema, gives rise to the many branches or rhizoids or leaves that are called secondary pronema. As part of vegetative reproduction, the secondary protonema develops into leafy gametophytes.

Are the Protonema and Sporophyte parts of the same gametophyte generation?

The gametophyte is a term that refers to all tissues and organs that belong to the haploid generation. The gametophyte has two developmental stages: the pronema and the gametophore. The protonema, which is the first component of the moss to develop from the germinatingspore, is the protonema.

17 Related Question Answers Found

What do the Protonemata produce?

When a moss first grows from the spore, it start as a germ tube which lengthens and branches into a filamentous complex known as a protonema, which develops into a leafy gametophore, the adult form of a gametophyte in bryophytes.

Is Archegonium haploid or diploid?

The male and female sex organs, the antheridia and the archegonia respectively, are produced on the gametophytic plants. Haploid sperm are released from the antheridia and when a haploid sperm reaches a haploid egg in an archegonium the egg is fertilized to produce a diploid cell.

Is Prothallus haploid or diploid?

The diploid sporophyte produces haploid spores by meiosis, the same process that produces eggs and sperm in animals and flowering plants. Each spore grows into a photosynthetic prothallus (gametophyte) via mitosis. Because mitosis maintains the number of chromosomes, each cell in the prothallus is haploid.

What do Elaters do?

Elaters come in a variety of forms, but are always associated with plant spores. In many plants that do not have seeds, they function in dispersing the spores to a new location.

Are Elaters haploid or diploid?

The product of these divisions in Marchantia are (haploid) spores. Some diploid cells in the sporangium expand and form elateres (tubular cells with spiral-like thickenings) that contribute to the dissemination of the spores.

What is the function of bryophytes?

Bryophytes are small, non-vascular land plants that require water for reproduction. Land plants fall into two categories: those that have special tissues to transport water and other materials, called vascular plants; and those that do not have specialized tissues, called non-vascular plants.

Where do Hornworts grow?

Hornworts may be found worldwide, though they tend to grow only in places that are damp or humid. Some species grow in large numbers as tiny weeds in the soil of gardens and cultivated fields. Large tropical and sub-tropical species of Dendroceros may be found growing on the bark of trees.

What are Gemmae cups?

The gemma cups are cup-like structures containing gemmae. The gemmae are small discs of haploid tissue, and they directly give rise to new gametophytes. They are dispersed from gemma cups by rainfall.

How does Moss Protonema reproduce?

Moss reproduces in two ways: sexually and asexually. Moss sexually reproduces by transmitting sperm (in the presence of water) from the male plant to the female. The zygote forms a stalk (called seta) which hold spores in a small pod at its top.

Do Ferns have Protonema?

A fern spore is a haploid reproductive cell, which unlike the seeds of higher plants, does not contain an embryo. Upon germination, a spore gives rise to a green, thread-like tissue, called a protonema. The protonema develops into a prothallus, a small, green, multicellular tissue that is rarely seen in nature.

What is Protonema and leafy stage?

The leafy stage in some mosses develops from a lateral bud in the secondary protonema. It is a small leafy structure consisting of rhizoid, leaves and stem. Whereas, Protonema is the gametophytic phase of mosses directly develops from haploid spores. It is thalloid, small, inconspicuous, often photosynthetic phase.

What is Calyptra botany?

In bryophytes, the calyptra (plural calyptrae) is an enlarged archegonial venter that protects the capsule containing the embryonic sporophyte. The calyptra is usually lost before the spores are released from the capsule. The shape of the calyptra can be used for identification purposes.

How is leafy stage formed in mosses how is it different from Protonema?

The leafy stage in some mosses develops from a lateral bud in the secondary protonema. It is a small leafy structure consisting of rhizoid, leaves and stem. It bears the sex organs antheridia and archegonia. Whereas, Protonema is the gametophytic phase of mosses directly develops from haploid spores.

What is Apospory?

Apospory is the development of 2n gametophytes, without meiosis and spores, from vegetative, or nonreproductive, cells of the sporophyte. In contrast, apogamy is the development of 1n sporophytes without gametes and syngamy from vegetative cells of the gametophyte.

What do you mean by alternation of generation?

Alternation of generations (also known as metagenesis) is the type of life cycle that occurs in those plants and algae in the Archaeplastida and the Heterokontophyta that have distinct haploid sexual and diploid asexual stages. The haploid spores germinate and grow into a haploid gametophyte.

What happens in the Antheridium?

Simply put, an antheridium is a structure that produces and holds sperm cells in bryophytes (non-vascular plants) and ferns. The antheridia of the organism will begin to open and allow the sperm to flow out. This occurs during a period when there are water droplets for the sperm to swim through.

What is the life cycle of moss?

Mosses have a unique life cycle in which the haploid stage (the gametophyte, n ) is the dominant generation. Once the egg is fertilized, a diploid sporophyte develops (2n) and produces spores which are dispersed into the surrounding environment.
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