Multicellular filaments forming the early gametophyte of bryophytes
Protonematal cells of the moss Physcomitrella patens
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. When a moss first grows from a spore, it starts 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.[1]
Moss spores germinate to form an alga-like filamentous structure called the protonema. It represents the juvenile gametophyte. While the protonema is growing by apical cell division, at some stage, under the influence of the phytohormone cytokinin, buds are induced which grow by three-faced apical cells. These give rise to gametophores, stems and leaf like structures. Bryophytes do not have true leaves (megaphylls). [2] Protonemata are characteristic of all mosses and some liverworts but are absent from hornworts.[citation needed]
Protonemata of mosses are composed of two cell types: chloronemata, which form upon germination, and caulonemata, which later differentiate from chloronemata and on which buds are formed, which then differentiate to gametophores.[3]
^Life Cycle - in a nutshell - bryophyte
^Reski, R. (1998). "Development, Genetics and Molecular Biology of Mosses". Botanica Acta. 111 (1): 1–15. doi:10.1111/j.1438-8677.1998.tb00670.x.
^Batschauer, Alfred (31 October 2007). Photoreceptors and Light Signalling. Royal Society of Chemistry. p. 335. ISBN 978-1-84755-166-5.
A protonema (plural: protonemata) is a thread-like chain of cells that forms the earliest stage of development of the gametophyte (the haploid phase)...
moss life-cycle starts with a haploid spore that germinates to produce a protonema (pl. protonemata), which is either a mass of thread-like filaments or...
its juvenile form, the protonema, under the influence of phytohormones (mainly cytokinins). Whereas the filamentous protonema grows by apical cell division...
become thalloid, and can produce a few rhizoids. Soon afterwards, the protonema develops buds and these differentiate into its characteristic, erect,...
emerging from the opposite end. The germ tube develops into the hypha, protonema or thallus of the gametophyte. In seedless vascular plants such as ferns...
haploid spore to produce a protonema, which is either a mass of thread-like filaments or a flattened thallus. The protonema is a transitory stage in the...
growing on potato dextrose agar Knop agar is used to axenically culture protonema and whole moss plants, such as those of Physcomitrella patens, a model...
spore germinates. In either case, the protonema is a transitory stage in the life of a hornwort. From the protonema grows the adult gametophyte, which is...
viridis is microscopic, existing mostly as non-competitive, slow-growing protonema. It is not desiccation-tolerant. B. viridis is dioicus, with its antheridia...
adapted to grow in low light conditions by utilizing spherical cells in the protonema that act as lenses, collecting and concentrating even the faintest light...
haploid spore that germinates to produce a protonema, which are thread-like filaments or thalloid. Protonema is a combination of chloronema, caulonema...
corresponding organs in other algae. As a result of fertilization, a protonema is formed, from which the sexually reproducing algae develops. A new terrestrial...
of the family Mitteniaceae in the order Pottiales. It has luminescent protonema. Goffinet, B.; Buck, W. R.; Shaw, A. J. (2008). "Morphology and Classification...
transition from apical growth to growth via a three-faced apical cell in moss protonema. This bud induction can be pinpointed to differentiation of a specific...
stages: juvenile and adult. The juvenile stage is represented by "primary protonema" (thread-like structures formed directly by spore germination). The adult...
of the moss. To ensure a maximum growth rate, the moss is kept at the protonema stage by continuous mechanical disruption, e.g. by using rotating blades...
regeneration. Instead, they regenerate directly into the filamentous protonema, mimicking a germinating moss spore. Protoplasts may also be used for...
spore germinates it grows to produce a filament of cells (called the protonema). The mature gametophyte of mosses develops into leafy shoots that produce...
with the haploid spore, which then germinates into a thalloid protonema. The protonema then gives rise to the leafy gametophyte which houses the male...
called protonema, composed of two types of cells – chloronema with large and numerous chloroplasts and caulonema with very fast growth. Protonema filaments...
After being dispersed as a haploid spore, it develops protonema. The first stage of protonema is chloronema which consists of irregular branching, transverse...
carried hemisphere-wide by the jet streams. They germinate to algae-like protonema, which then convert to more robust gametophytes. Species are suited to...
changes and new moss record in Australia: including a description of the protonema of Calomnion. Journal of Bryology 16, 261-273. Vitt DH (1995) The genus...
germinate and grow into a narrow long rhizoid-like form named a protonema. This protonema develops buds which grow to become either a male or female gametophyte...
into the sea through papillae. After fertilisation, the zygote becomes a protonema and this in turn develops into a new thallus. Guiry, M.D. & Guiry, G.M...
He directly observed the germination of spores and formation of the protonema. He was less successful with other sporophytes, being unable to determine...
polyethylene glycol. As mosses are haploid organisms, moss filaments (protonema) can be directly screened for the target, either by treatment with antibiotics...
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