A protonema (plural: protonemata) is a thread-like chain of cells that forms the earliest stage of development of the gametophyte (the haploid phase) in the life cycle of mosses. … Moss spores germinate to form an alga-like filamentous structure called the protonema.
What is the protonema stage of mosses?
Hint: Protonema is a creeping, green, branched, and often filamentous stage of the growth process. It is a haploid, autonomous, gametophytic stage of the moss life cycle. Complete answer: A protonema is a thread-like chain of cells that forms the gametophyte’s earliest stage of growth in the life cycle of mosses.
What is leafy stage?
Leafy stage is a long lived stage arises from proteneaml stage. Small adventitious buds appear on protenema which develops into leafy shoots. It is macroscopic and bear reproductive organs such as antheridia and archegonia.
What is the difference between primary protonema and secondary protonema?
Primary protonema is the basic part of this chain which is formed from a spore. Secondary protonema develops from any of the parts of the adult which may include stems, leaves and rhizoids.
What is protonema and leafy stage?
Leafy stage develops from secondary protonema as a lateral bud. Protonema is creeping green branched frequently filamentous stage whereas leafy stage is upright with spirally arranged leaves.
What is protonema example?
(i) Protonema – It is a creeping, green, branched and frequently filamentous stage. It is a haploid, independent, gametophytic stage in the life cycle of mosses. It is produced from the spores and gives rise to new plants. Examples – Funaria, polytrichum and sphagnum.
What is a protonema stage?
The protonema, which grows directly from the germinating spore, is in most mosses an extensive, branched system of multicellular filaments that are rich in chlorophyll. This stage initiates the accumulation of hormones that influence the further growth of newly formed cells.
What are the two stages of mosses?
Similar to plants, the moss lifecycle is completed in two distinct stages – the gametophyte and the sporophyte. The term that describes this type of life history is called alternation of heteromorphic generations.
What is protonema Funaria?
Hint: A protonema is a thread-like chain of cells that forms the earliest stage of the life cycle of mosses. Complete answer: Protonema can be seen in Funaria as it is a type of moss. … When it grows from the spore, it starts as a germinate tube that lengthens and branches off to form filamentous form called protonema.
Is protonema free living?
Protonema is not dependent on sporophyte.
What is antheridium with example?
An antheridium is a haploid structure or organ producing and containing male gametes (called antherozoids or sperm). … Many algae and some fungi, for example ascomycetes and water moulds, also have antheridia during their reproductive stages.
How secondary protonema is formed?
Under favourable conditions of moisture, the secondary protonemata are formed from any detached or injured portion of the gametophore as from stem, leaves, antheridium, paraphyses and archegonium. The rhizoids of a leafy gametophore when exposed to light in a moist atmosphere also form secondary protonema.
Is secondary protonema haploid or diploid?
It is composed of upward, slender axes carrying spirally arranged leaves linked to the soil via multicellular and threadlike rhizoids. This stage carries the sex organs. Thus, the correct option is A. i.e. haploid and is found in mosses.
Do all plants have rhizoids?
Root hairs are found only on the roots of the sporophytes of vascular plants. The lycophytes and monilophytes develop both rhizoids on their gametophytes and root hairs on their sporophytes. Rhizoids are multicellular in the mosses. All other land plants develop unicellular rhizoids and root hairs.
What is protonema what is its ploidy?
Mention the ploidy of the following protonemal cell of a moss; primary endosperm nucleus in dicot, leaf cell of a moss; prothallus cell of a fern; gemma cell in Marchantia; meristem cell of monocot, ovum of a liverwort and zygote of a fern. Answer: … (vi) Ovum of a liverwort-haploid.
What is protonema Toppr?
The protonema is an elongated and thread-like structure. This structure develops from the germinated spore of mosses and some liverworts. This structure forms the earliest stage in the life cycle of the bryophytes . The protonema then grows and developes to form the leafy gametophytic structure. Example, Funaria.
Where does protonema stage occur?
protonema An early stage in the development of a moss or liverwort. A protonema is produced when a moss or liverwort spore germinates. In mosses it usually consists of green, branching filaments; but it is thalloid (a flat sheet or disc of cells) in Sphagnum and Andreaea, for example, and in many liverworts.
What is Antheridium and Archegonium Class 11?
(ii) Antheridium – It is the male sex organ present in bryophytes and pteridophytes and is surrounded by a jacket of sterile cells. It encloses the sperm mother cells, which give rise to the male gametes. (iii) Archegonium – It is the female sex organ present in bryophytes, pteridophytes, and gymnosperms.
Do ferns have protonema?
Fern spores are often dispersed by the wind. 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 Archegonium means?
: the flask-shaped female sex organ of bryophytes, lower vascular plants (such as ferns), and some gymnosperms.
What is meant by gametophore?
gametophore in American English
(gəˈmitəˌfɔr ) noun. that part of a plant bearing the organs that produce gametes.
Can protonema of Mosses reproduce?
Organisms reproduce by asexualmeans also. Fungi multiply and spread easily due to the millions of asexualspores they produce. In lower organisms like yeast and hydra, we observe budding. … The fungi, the filamentous algae, the protonema of mosses, all easily multiply by fragmentation.
Why is Funaria called leafy gametophyte?
The leafy gametophyte is the prevailing period of Funaria as the vegetative assortment of itself is spoken to by these leafy gametophores. It has two unmistakable development arranges, a prostrate filamentous alga-like protonema, and an upstanding gametophore. Hence, correct option is B.