A Comprehensive Introduction To Plant Tissue Culture

  • acclimatisation:

  • adventitious: developing from unusual points of origin, such as shoots or roots from callus or from leaf explants, or embryos from other sources than a zygote

  • androgenesis: senso stricto it means development from an anther; it is however most often used in a more restricted sense to indicate one obtained haploids or doubled haploids from these anthers

  • anther culture: culture of anthers in tissue culture

  • aneuploidy: the situation which exists when the nucleus of a cell does not contain an exact multiple of the haploid number of chromosomes

  • antioxidant: product which is preferably oxidised; mainly used in case of browning problems to avoid or to minimise the formation of polyphenolics

  • artificial seed: encapsulated somatic embryo

  • asepsis: without infection, avoiding contamination

  • autoclaving: the use of pressurised steam to sterilise ustensils and devices used in tissue culture

  • autotrophy: if an organism does not require a particular essential growth substrate or cofactor to be added exogenously

  • axenic: free from association with any foreign form of life (cannot been proven as we do not have appropriated tools)

  • axillary buds: formed in the axil of a leaf

  • bacteria free: the use of this term should be avoided and be replaced by "tested for a particular bacteria" (we do not have the adeqauate diagnostic tools at our disposal to prove cultures are completely bacteria free)

  • batch culture: discontinuous way of growing cell suspensions in a closed system in which the amount of nutrients becomes limiting as the growth progresses

  • binary vectors: the use of two compatible plasmids for genetic engeneering; one of them is a broad host-range vector containing the T-DNA border regions flanking selective markers and other foreign genes, the second plasmid carries the virulence genes (often called the helper plasmid) but has a large deletion in the T-DNA region

  • biotransformation: a process through which the functional groups of organic compounds are modified by living cells

  • browning: refers to colour change of medium or explant: most often associated with the formation of polyphenolics (melanines, quinones)

  • callogenesis: de novo formation of callus

  • callus: unorganised growth of cells, does occur in nature for healing wounds, does occur in tissue culture as a proliferative mass of differentiated cells

  • caulogenesis: de novo formation of buds

  • cell culture: the maintenance or cultivation of cells in vitro, including the culture of single cells; the cells are no longer organised into tissues

  • cell hybridisation: the fusion of two or more dissimilar cells leading to the formation of a synkaryon

  • cell suspension: culture of cells in a suspension; most often it is not really isolated cells but aggregates of up to 10 cells

  • cellulase: cellulose-degrading enzyme

  • chimera: in a chimeral plant not all the cells have the same genetic information; a distinction is made between sectorial, mericlinal and periclinal ones; such plants cannot be micropropagated by adventitious bud formation

  • clonal propagation: asexual propagation of plants that are considered to be genetically uniform and originated from a single individual or explant; a synonym for clonal propagation in vitro is micropropagation

  • clone: genetically identical organisms

  • competence: the possibility to manifest totipotentiality

  • conditioned medium: culture medium that has supported growth of cells; such a medium will contain a range of cell-derived molecules (e.g. amino acids, growth substances) that may enhance the growth of a subsequent batch of cells

  • contaminant: unwanted organism invading cultures; differs from a pathogen in the sense that a contaminant is not necessarily responsible for diseases

  • convection:

  • cryopreservation: ultra low temperature storage of cells, tissues, organs or seeds; it is usually carried out at temperatures below -1000C, as in liquid nitrogen (-1960C)

  • cybrid: cytoplasmic hybrid, viable cell containing cytoplasts from two different origins and the nucleus from one of them

  • de-differentiation: loss of specialised function, usually characterised by small isodiametric cells

  • differentiation: acquisition of specialised cell functions; the differentiated status is usually stable and in plant tissue culture the term is often taken to indicate the formation of shoots, roots or even other organs

  • diffusion:

  • dihaploid: having the number of chromosomes of the gametes of a plant which was originally a tetraploid

  • disinfectants: different products used to decontaminate plant material

  • double layer system: culture system where instead of subculturing a liquid medium is poured on top of the existing culture

  • electrofusion: fusion of protoplasts held in an appropriate electric field

  • electroporation: creation of transient pores in the plasmalemma, by means of an electrical current, for the purpose of introducing exogenous material, specially DNA, from the medium

  • elicitor: compound, often of pathogen origin, that can influence enzymes in biosynthetic pathways leading to increased or altered accumulation of secondary metabolites

  • embryo culture: culture of an isolated embryo from zygotic origin

  • embryogenesis: de novo formation of somatic embryos; syn. adventitious or asexual embryogenesis

  • embryoid: embryolike structure formed under in vitro conditions, this structure has the potential for further development into a plantlet

  • epigenetic: selective gene expression, any change in phenotype which does not result from an alteration in DNA sequence; is inheritable in the sense that there is no transmission of the change to meiotic progeny but is heritable in the sense that it can be passed from one cell generation to the next; an example is switching off of genes by base methylation

  • euploid: the situation which exists when the nucleus of a cell contains an exact multiple of the haploid number of chromosomes

  • evocator: product or environment that will enhance specific symptoms under certain conditions

  • explant: tissue or organ taken from its original site and transferred to an artificial medium for growth or maintenance

  • feeder culture:

  • friability: a term indicating the tendency for plant cells to separate from one another

  • gametoclone:

  • genetic variation: when the new characteristic can be passed sexually

  • genetic engineering: use of a vector (e.g. a plamid) or mechanical devices (shot gun) to transfer genetic information (DNA)

  • genotype: plants with the same genetic information (DNA)

  • haploid: having a single set of chromosomes

  • hardening: application of mild environmental stress to prepare the plant for more rigorous growing conditions

  • head space: gaseous environment of a tissue culture container

  • heterokaryon: a cell possessing two or more genetically different nuclei in a common cytoplasm, usually as the result from cell to cell fusion

  • homokaryon: a cell possessing two or more genetically identical nuclei in a common cytoplasm, usually as the result from cell to cell fusion

  • hyperhydricity: physiological abnormality occuring in tissue culture; formerly the word vitrification was used

  • hypersensitivity reactions: upon wounding a cell will initiate its defence mechanisms, thereby influencing the neighbouring cells; phenolics are involved in this type of reactions and are quite often related to the browning problem

  • induction: initiation of a structure, organ or process

  • inoculum: tissues or organs taken from an established tissue culture and transferred to fresh medium for subculture

  • in vitro: literally it means under glass, to indicate cultures were kept in glass containers under aseptic conditions; glass can now eventually be replaced by plastic

  • in vivo: normal growing conditions (e.g. in a garden or a greenhouse)

  • isogenic lines:

  • juvenility: conceptual term to indicate the status of a plant that has not yet flowered and from which cuttings can easily be rooted

  • meristem culture: culture of a shoot apical meristem in view of avoiding contaminations, especially specific viruses and bacteria

  • micropropagation: term often used to indicate large scale clonal propagation

  • mixotrophy: an essential substrate for growth is partly provided exogenously and partly by the plant; often used to characterise the origin of carbon sources in a plant, part is provided by the carbon source in the culture medium and part by the photosynthetic activity of the plant in culture

  • morphogenesis: (a) the evolution of a structure from an undifferentiated to a differentiated state; (b) the process of development and of growth of differentiated structures

  • mother plant: plant from which a tissue culture is initiated

  • nurse culture:

  • organogenesis: de novo formation of organs (caulogenesis, embryogenesis, rhizogenesis)

  • packed cell volume: the volume of cells present at any time during the growth cycle

  • pectinase: an enzyme that hydrolyses pectin, a heterogeneous polysaccharide mainly found in the middle lamella between adjacent cell walls. Incubation of tissue with pectinase can produce individual, walled cells

  • permeability:

  • phenotype: physical appearance; visual perception of the interplay between the genotype and the environment

  • phytoalexin: a non-specific antibiotic substance produced by plant cells in response to infection by pathogens, or environmental stress or injury; it isoften phenolic substances

  • plasmolysis: the removal of water from a cell, with attendant shrinkage, resulting from hyperosmotic extracellular conditions

  • polarity:

  • primary metabolite: essential metabolites (e.g. carbohydrates, proteins, lipids), components of the essential metabolic pathways

  • propagules: units that can be considered for in vitro propation purposes

  • protoplast = cell - cell wall

  • protoplast fusion: technique in which protoplasts are fused into a single cell

  • regeneration: term used in plant cultures to indicate a morphogenic response that results in the neoformation of organs (roots, buds, embryos, ..)

  • rhizogenesis: de novo formation of roots

  • secondary metabolite: a metabolite that is not part of the primary metabolic network of the cells. Primary metabolites are components of fundamental biochemical pathways (e.g. glycolysis) that are present in all cells. Secondary metabolites only appear in cells that are specialised in some way e.g. in defence

  • shoot apical meristem: undifferentiated tissue, located within the shoot tip, generally appearing as a shiny dome-like structure distal from the youngest leaf primordia and measuring less than 0.1 mm in length when excised

  • somaclonal variation: genotypic or phenotypic variations occuring in tissue culture, the latter being either genetic or epigenetic in origin

  • somatic embryogenesis: see embryogenesis

  • somatic hybrid: the cell or plant resulting from the fusion of plant protoplasts (nuclear fusion must have taken place), respectively derived from somatic cells which differ genetically

  • stage 0: a step in in vitro propagation of plants, aiming to prepare the plant material for successful introduction in tissue culture

  • stage I: a step in in vitro propagation of plants characterised by the establishment of an aseptic culture

  • stage II: a step in in vitro propagation of plants characterised by the rapid numerical increase of propagules

  • stage III: a step in in vitro propagation of plants characterised by preparation of the propagules for successful transfer to soil, a process which can involve hardening off, elongation, rooting

  • stage IV: a step in in vitro propagation characterised by the establishment in soil of a tissue culture derived plant, in certain cases stage IV can follow stage II

  • sterilisation: sterile = without life; sterilisation are the procedures used to kill all germs

  • subculture: transfer of a part of a developed culture to fresh culture medium

  • suspension culture: a type of culture in which cells, or aggregates of cells, multiply while suspended in liquid medium

  • synkaryon: a hybrid cell which results from the fusion of the nuclei it carries

  • tissue culture: abbreviation for protoplast, cell, tissue, organ and plant culture under in vitro conditions

  • totipotentiality: a cell characteristic in which the potential for forming all the cell types in the adult organism is retained, theoretically it means that each cell can give rise to a complete plant (vs competence)

  • transgenic: possessing genes from a different organism

  • transformation: in plant cell culture it is used for the introduction and stable genomic integration of foreign DNA into a plant cell, resulting in a genetic modification

  • undifferentiated: not specialised, see dedifferentiation

  • vitrification: formation of amorphous ice during the process of cryopreservation; formerly also used to describe the process of hyperhydricity

  • virus free: the use of this term should be avoided and replaced by virus indexed (for a specific virus); the reason is that we cannot prove something is virus free


Last modified: Friday, 25 February 2011, 06:54 PM

This course covers the applied aspect of plant tissue culture. The content of the entire course can be used as a platform for interactive learning and supplementary teaching by the lecturer. Self learners will find this course a little too abstract unless they have some basic knowledge of chemistry and botany. This course was created by Dr. Chow Yong Neng and used by him for 2 batches of students from Beijing Normal University. It is at senior or professional level in terms of the rigour.

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