Also found in: Thesaurus, Medical, Legal, Encyclopedia, Wikipedia.


A cell of a plant, fungus, bacterium, or archaeon from which the cell wall has been removed, leaving the protoplasm and plasma membrane.

[French protoplaste, from Old French, the first man, from Late Latin prōtoplastus, from Greek prōtoplastos : prōto-, proto- + plastos, formed, molded; see -plast.]

pro′to·plas′tic adj.


(Biology) a unit consisting of the living parts of a cell, including the protoplasm and cell membrane but not the vacuoles or (in plants) the cell wall
[C16: from Late Latin prōtoplastus the first-formed, from Greek prōtoplastos, from proto- + plassein to shape]
ˌprotoˈplastic adj


(ˈproʊ təˌplæst)

a. the contents of a cell within the cell membrane, considered as a fundamental entity.
b. the primordial living unit or cell.
2. a person or thing that is formed first; original; prototype.
3. the hypothetical first individual or one of the supposed first pair of a species or the like.
[1525–35; < Late Latin prōtoplastus the first man, n. use of Greek prōtóplastos formed first]
pro`to•plas′tic, adj.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.protoplast - a biological unit consisting of a nucleus and the body of cytoplasm with which it interacts
cell - (biology) the basic structural and functional unit of all organisms; they may exist as independent units of life (as in monads) or may form colonies or tissues as in higher plants and animals
body part - any part of an organism such as an organ or extremity


A first form from which varieties arise or imitations are made:


n (Bot) → Protoplast m
References in periodicals archive ?
In the third stage, the stream of newly activated spores is exposed to alpha particle bombardment via a small, safe, self- contained, low-level polonium source that damages the spores' DNA containing protoplast -- effectively killing the spore and making it incapable of germinating or producing infection.
Leaf and petiole segments from in vitro raised young plantlets were used for protoplast isolation and electroporation.
The team is relying on a technique called protoplast fusion to move the insect-resistance trait, explains Eash.
Cells are spherical or hemispherical after division and pale blue-green, but they appear brownish due to aerotopes that mask the blue-green color of the protoplast.
Examining various aspects of fungal diversity, biologists, botanists, plant pathologists, and related scientists discuss phylogeny, fungi from little-explored and extreme habitats, endophytes in tropical forests and their diversity and ecology; the degradation of organo-pollutants by ligninolytic basidiomycetes, ectomychorrizal fungi, aquatic fungi, and other fungi; the exploitation of filamentous fungi as edible crops and in health care for such conditions as cancer and immunodeficiency states, and the biotechnology of Neosartorya; the evolution of fungal diseases in ornamental crops and the exploitation of fungi for organic dyes; and universally primed PCR and fungal protoplast technologies and their possible application in developing new anti-fungal targets.
Work is in progress to determine if cell wall synthesis or some other aspect of protoplast biology is affected.
Ohtani (1987), noting the evidence for vestures (warts) in septate fibers and parenchyma cells, stated that vestures have no function associated specifically with pits of conductive elements, but are simply "formed by an oversupply of wall material from the protoplast at the final stage of secondary wall formation process.
Other wild species are so genetically different that they can't be crossed with cultivated potatoes, so Brown and colleague Sandra Austin-Phillips, at the University of Wisconsin, are using protoplast fusion to make hybrids of the two.
The growth of full plants from genetically altered protoplast, reported in the April 8 issue of SCIENCE, was the logical combination of these results.
Similar processes of chromosome elimination occur either in a spontaneous or in an induced manner during protoplast fusion (Liu et al.
This hypothesis posits that the entire protoplast acts as the gravity sensor with the cell sensing the relative buoyancy of the protoplast within the cell wall.
But results have been promising: The four Pioneer elm trees, now about three feet tall, may be the first woody plants grown using the protoplast method, according to the January AGRICULTURAL RESEARCH.