Plant tissue culture glossary

Also called 2,4-D, 2,4-dichlorophenoxyacetic acid

A strong synthetic auxin, used mainly to start callus and somatic embryos rather than to grow shoots or roots. Long periods on it are associated with genetic variation in regenerated plants of some crops, so labs record how many subcultures a line spent on it.

Also called 2iP, 2-iP, isopentenyladenine, N6-(2-isopentenyl)adenine

A naturally occurring cytokinin, common in media for rhododendron, mountain laurel and other woody crops. Lloyd and McCown's 1980 mountain laurel cultures, the work that introduced Woody Plant Medium, multiplied on WPM with 2iP.

Also called ABA, abscisic acid

A plant hormone tied to stress, dormancy and seed maturation. In culture it turns up mostly in media that mature somatic embryos and in slow-growth storage, and rarely in routine multiplication.

Also called accession, accession ID

A unique number a collection assigns to each plant or lot when it is added, used by botanic gardens, gene banks and other collections to track it for life. Cultures started from an accessioned plant usually carry the number so they stay tied to it.

In xPlant Pro A cross's parent can be recorded by name or accession number.

Also called Stage IV, acclimatization, hardening off, weaning

Moving plantlets from the vessel into substrate and slowly lowering humidity and raising light until they manage water loss and photosynthesis on their own; many growers call it hardening off. Survival varies by species and batch, so it is logged per batch.

In xPlant Pro Shown as the Acclimation workflow step on the Stage Dashboard.

Also called AC, charcoal

Finely powdered charcoal added to a medium to soak up the browning compounds tissue releases and to darken the root zone. It also binds growth regulators and other components, so a recipe with charcoal and the same recipe without it are two different media.

Also called adventitious shoots, adventitious buds

A shoot that forms where shoots do not normally arise, such as on a leaf piece, a root or callus, rather than from an existing bud. It can give high numbers, but it is more likely than axillary growth to produce off-types.

Also called agar-agar

A gelling agent extracted from red seaweed, and the usual way to make a semi-solid medium. Gel strength and purity vary by brand and lot, and a low pH can leave it soft, so labs record the brand and lot with each batch.

Also called anti-browning agent

A compound such as ascorbic acid (vitamin C) or citric acid that slows the browning of cut tissue as its phenolic compounds oxidize. Labs add it to the medium or to a rinse for freshly cut explants, and record which, because ascorbic acid breaks down in solution.

Also called artificial propagation, source code A

A CITES term for plants that meet the definition in CITES Resolution Conf. 11.11. On CITES permits and in trade records such plants carry source code A, or code D for Appendix I plants propagated for commercial purposes.

Also called sterile technique

The working habits meant to keep microbes out of a culture while it is open: a cleaned work surface, sterilized tools, and vessels opened only in clean air. When a vessel turns later, a note of who worked, where and when is what lets a lab look back at technique.

In xPlant Pro A room can be given the category Aseptic Transfer.

Also called asymbiotic sowing

Germinating orchid seed on a sugar-containing medium in a flask with no fungus, so the medium supplies what a fungal partner would in the wild. It is how most commercial orchid flasks are sown, and the medium used belongs on the sowing record.

A pressure vessel that sterilizes media, tools and vessels with steam at high temperature and pressure. Media records usually note the run that sterilized them, so a contamination pattern can be traced back to a particular cycle.

In xPlant Pro Autoclaves are tracked as equipment, and the media form has a Sterilization field for autoclave time and temperature.

Also called auxins

A class of growth regulators that drive root formation, cell elongation and callus growth. IAA is the main one plants make; IBA, NAA and 2,4-D are the ones labs most often add, and auxin is the ingredient most often changed on a rooting recipe.

In xPlant Pro Inventory files auxins under the category "PGR — auxin".

Also called auxin:cytokinin ratio, hormone balance, PGR balance

The balance of auxin to cytokinin in a medium: relatively more auxin tends toward roots, relatively more cytokinin toward shoots, with callus in between. Responses differ by crop and cultivar, so labs tune the balance for each line and record both amounts.

Also called axillary branching, axillary bud proliferation

Multiplying a culture by getting the buds already present at each leaf joint to grow out as new shoots. Because those shoots come from existing buds, it is generally the route most likely to stay true-to-type.

Also called bacteria

Contamination by bacteria, often seen as a milky, cloudy or slimy patch in the medium, frequently around the base of the explant. Some bacteria grow slowly and show up only weeks after initiation or a transfer.

Also called BA, 6-BA, 6-BAP, benzyladenine, 6-benzylaminopurine

A synthetic cytokinin, and the one most widely used for shoot multiplication; it survives autoclaving and costs little. In some crops long runs on it are linked to glassy shoots, so labs note how many subcultures a line has spent on it.

Also called base medium, basal salt mixture

The salts, and usually the vitamins, of a named formula such as MS or WPM, before growth regulators and other additions go in. Many labs buy it as a premixed powder, so the supplier, product and lot belong in the batch record.

In xPlant Pro Inventory has a "Basal salts" category, and the new-recipe templates include a "Base medium".

A group of plants, explants or vessels handled together, such as cut on the same day or set up from the same media pour, and tracked as one. A batch number lets a problem be traced to everything that shared it.

In xPlant Pro The Batch Tracker groups plants or explants that are moved and tracked together.

Also called glass bead sterilizer, dry sterilizer

A small heated well of glass beads that sterilizes the tips of forceps and scalpels between cuts without an open flame. Only the part of the tool pushed into the beads is treated, and tools come out hot.

Also called phenolic browning, phenolic oxidation, blackening

Darkening of an explant and the medium around it as cut tissue releases phenolic compounds that oxidize. It is common at initiation and in woody plants, and heavy browning can slow or stop growth.

An unorganized mass of dividing cells that grows from cut or wounded tissue in culture. Some lines are grown through callus on purpose to regenerate shoots or embryos; in others it is unwanted growth worth noting, since callus stages are linked to off-types.

Also called seed pod, pod, seed capsule

The orchid seed pod that swells on the seed parent after a successful pollination, holding thousands to millions of dust-like seeds. Record the harvest date and whether it was taken green or dry, since that changes how the seed is handled.

In xPlant Pro Recorded on a cross as Capsule harvested on, with Harvested as Green pod or Dry seed.

Also called chimeral

A plant made of cell layers or sectors with different genetics; many variegated plants are chimeras. The pattern can be lost in culture when new shoots grow from only one layer, so labs check variegated lines for plants that came out plain.

Also called Convention on International Trade in Endangered Species of Wild Fauna and Flora, CITES Appendices

An international convention regulating trade in species threatened, or potentially threatened, by that trade. Listed species sit in one of three Appendices, each regulated differently, and each member country's Management Authority issues the permits.

In xPlant Pro A plant's acquisition record keeps the parent-stock details that an application to export CITES-listed plants asks for.

A plant, or a group of plants, propagated without seed from one individual, so they all share its genotype. Every plant from a clone traces back to the same mother plant and keeps the same name.

Also called coconut milk, CW

The liquid endosperm of the coconut, called coconut milk in older papers but not the canned cooking product, added to some media, orchid media especially, for its sugars, amino acids and natural cytokinins. Its makeup varies with the nut and the supplier, so labs record its source alongside the recipe.

Also called compot, community tray

A single pot or tray where many small seedlings from one flask are planted together after deflasking. Growers use it to carry them through acclimation before individual pots, and its label keeps the flask's cross details.

Also called contam, contaminated culture

Unwanted microbes, usually bacteria, fungi or yeast, growing in a culture vessel. Logging each case with the date, vessel, stage and what it looked like is what lets a pattern show across media, rooms or operators.

In xPlant Pro Contaminations logs each event and which plants and explants it touched.

Also called contamination log, contamination report

A dated record of contamination seen in a vessel: what it looked like, where, and which culture it was in. It describes what was seen; it does not identify the organism or prove where it came from.

In xPlant Pro Log Contamination records the contamination type, its severity and the date it was detected.

The share of vessels or cultures found contaminated, over a period or for a stage, batch, medium or operator, usually given as a percentage. It means little without its denominator, so a rate says what was counted and over what span.

In xPlant Pro A lab can set the contamination rate at which it wants an alert; with no figure set, no alert is sent.

Also called custom propagation, contract lab

Tissue culture production that a propagation lab carries out for a client, who supplies or names the starting stock and takes the plants. The lab's records tie each order to the client's material, the lines started and the counts delivered.

In xPlant Pro The Order Book shows whether what is running will land on an order, and what more to start.

Also called crossing, hybrid cross

A deliberate pollination between two plants, written seed parent × pollen parent. Record it the day you pollinate, then add the capsule harvest, the sowing and the grex name as they happen.

In xPlant Pro Recorded with Record a cross: “Each cross records a seed parent and a pollen parent, the day they were pollinated, the capsule harvest and the grex.”

Also called cryostorage, cryo

Storing shoot tips, embryos, seeds or cells at ultra-low temperature, usually in or above liquid nitrogen, so they can be kept long term without subculture. Regrowth after thawing varies by species and method, so labs test it and record the result.

Also called cv., cultivated variety, clonal name

A named plant, or group of plants, selected and kept in cultivation for traits that stay distinct when it is propagated, often a single clone. Its name goes in single quotation marks, not italics, with a capital first letter, and should match the label exactly.

Also called line decline, loss of vigor

A line growing steadily weaker across subcultures: slower growth, lower multiplication, more abnormal shoots. Labs often restart a declining line from fresh explants, and the cycle count shows how far along a line is.

In xPlant Pro A banner appears as a line nears its usual restart point, counting the replate cycles it has completed.

Also called medium, media, growth medium, nutrient medium

The gelled or liquid mix of water, mineral salts, sugar, vitamins and often growth regulators that cultures grow on; media is the plural. Which medium a culture is on is part of its record, as much as the plant itself.

In xPlant Pro Linking a media recipe to a plant or explant "records which medium this culture is growing on."

Also called shelf temperature

The air temperature a growth room is held at, usually kept steady within a narrow range. Shelves near lights or on upper racks can run warmer than the set point, so readings are logged at the shelf as well as for the room.

In xPlant Pro Connected sensors report live readings, temperature among them.

Also called vessel, jar, container, culture container

Any closed container a culture grows in: a jar, tube, box, flask, bag or dish. Vessel counts are the basic unit of most tissue culture records, so a jar or vessel usually means one counted culture unit.

In xPlant Pro Each lab can set its own word for the vessel, such as jar, test tube or Magenta box, and the app uses it wherever it counts them.

Also called subculture cycle, passage, transfer cycle

One round of growth between transfers, or the count of how many transfers a line has been through. Labs track the count because many restart a line from fresh explants after a set number of cycles.

In xPlant Pro Transfers show which cycle a line is at and how many cycles remain before the usual restart point.

Also called cytokinins

A class of growth regulators that drive cell division and shoot formation and loosen the main shoot tip's hold, letting side shoots grow. BAP, kinetin, zeatin, 2iP and the cytokinin-like TDZ are the ones labs meet most, and the choice is usually tuned for each crop.

In xPlant Pro Inventory files cytokinins under the category "PGR — cytokinin".

Also called deflask, deflasked

Taking plantlets out of their flask or vessel, rinsing the medium off the roots and setting them into substrate. It starts acclimation, so labs note the date and how many came out, which is the baseline for later survival counts.

Organogenesis is the forming of new shoots or roots; direct means they grow straight from the explant's own tissue, with no callus stage in between. Because it skips callus, labs usually expect fewer off-types from it than from indirect routes.

Reducing the number of microbes on a surface without killing all of them; spores in particular can survive it. Wiping the hood, gloves and the outsides of vessels with 70% ethanol is disinfection; autoclaving a jar is sterilization.

Seed from a ripe capsule that has started to split, collected dry and sown now or stored for later. Because it has been open to the air, it is surface-cleaned before sowing, and labs note its age and storage, which affect germination.

In xPlant Pro Recorded on a cross as Harvested as Dry seed.

Also called embryo rescue

Growing an embryo on medium after taking it out of its seed. Breeders use it as embryo rescue for crosses whose embryos would not develop in a normal seed, and it can get around dormancy in seed that is slow to germinate.

Also called endophytic microbe

A microbe that lives inside plant tissue, often without visible harm to the plant. Surface sterilization cannot reach it, so it can appear in culture weeks or several subcultures after initiation.

Also called 70% ethanol, 70% alcohol, EtOH

Ethyl alcohol diluted with water to about 70%, the usual strength for wiping hoods, gloves, tools and the outsides of vessels. It is flammable, which matters wherever a flame or a hot bead sterilizer is nearby.

Also called ethene

A gaseous plant hormone that cultures give off, more so when wounded, and that builds up in tightly sealed vessels. It is associated with yellowing, leaf drop and glassy shoots, so labs record the closure and venting along with the medium.

Outside the culture vessel: in substrate, in a greenhouse or a growth room. Ex vitro rooting means shoots root straight in potting mix rather than on medium, which some labs use to fold rooting into acclimation.

A piece of plant tissue cut from a source plant to start a culture, such as a shoot tip, a node, a leaf piece or a seed. Record which plant and which part it came from, and when, so every jar can be traced back to its mother plant.

In xPlant Pro Each explant has its own record in the Explant Logbook.

Passing a tool, or the mouth of a vessel, through a flame to sterilize it, often after dipping it in alcohol. Alcohol and an open flame together are a fire risk inside a hood, which is one reason many labs use a bead sterilizer instead.

Also called orchid flask

A sealed culture vessel holding orchid seedlings or plantlets, and the usual unit that orchid growers buy, sell and count. A flask label carries the cross or clone, the sowing or replate date and the medium.

In xPlant Pro A sowing recorded from a cross becomes a plant record, where “its flasks, transfers and stages are recorded”.

Also called tweezers

Long tweezers for handling explants and shoots inside the hood without touching them by hand. They are sterilized before work and between cultures, so many labs keep several pairs in rotation.

Also called mold, mould, fungus

Contamination by molds, usually seen as fuzzy or cottony growth, white, gray, green or black, on the medium or the tissue. Fungal spores travel in air, so a fungal case is often logged with the room and hood that were used.

Also called B5, B5 medium, Gamborg's B5

A basal medium Gamborg, Miller and Ojima published in 1968 for soybean root cell suspensions, much lower in ammonium than MS. Its vitamin set is often borrowed on its own, so a recipe reading "MS salts with B5 vitamins" combines two formulas.

Also called Gelrite, Phytagel, gellan

A gelling agent made by bacterial fermentation and sold under names such as Gelrite and Phytagel; it sets clearer than agar and needs the medium's calcium and magnesium to gel. Roots and contamination are easier to see in it, though some crops turn glassy more often on it.

Also called solidifying agent, gel

Whatever turns a liquid medium into a semi-solid one, most often agar or gellan gum. Gel firmness changes how much water and nutrient tissue can reach, so the product and its amount are part of the recipe, not a detail.

In xPlant Pro Inventory has a "Gelling agent" category.

A plant's genetic makeup, as distinct from how it looks. Culture response is often genotype-specific: a medium or timing that works for one cultivar may not work for a close relative, so labs record results per line.

Also called genetic resources

Living genetic material kept for breeding, research or conservation, as seeds, plants, cultures or frozen tissue. Each sample, or accession, needs its origin and identity recorded, or it cannot be used with confidence.

Also called GA3, GA₃, gibberellic acid, gibberellins

A class of plant hormones that drive stem elongation and break some kinds of dormancy; gibberellic acid, GA3, is the one most often added to media. Heat breaks much of it down, so it is usually filter-sterilized and added after autoclaving, and the recipe says so.

Also called green pod, green capsule sowing, immature seed sowing

Sowing seed from a capsule harvested before it splits: the outside of the closed pod is cleaned and the seed inside is sown without separate treatment. Labs record the days from pollination to harvest, since the right timing differs by genus.

In xPlant Pro Recorded on a cross as Harvested as Green pod.

Also called gx, grexes, greges

The group, and its name, for all the seedlings of a cross between two named parents, whichever way round the cross was made. Seedlings in one grex can vary widely, so a standout plant can be given its own cultivar name after the grex name.

In xPlant Pro Recorded on a cross as Grex name, “The name for all seedlings of this pairing”.

Also called culture room, grow room, incubation room

The room or chamber where cultures sit on shelves under controlled light and temperature between transfers. Recording which room and shelf a culture was on lets a lab compare results between spaces.

In xPlant Pro The Rooms page lists growth rooms and their current conditions.

Also called auxin habituation, cytokinin habituation

When a culture stops needing a growth regulator it once required, usually an auxin or a cytokinin, and keeps growing without it. It tends to appear after long periods in culture and shows when a line keeps growing on a medium without the regulator, so labs note the subculture at which it was first seen.

Also called ½ MS, 1/2 MS, half MS, MS/2

MS medium with its salts at half the usual amount, common for rooting and for crops that do poorly on full-strength salts. Labs differ on whether "half" covers only the macronutrients or every salt, so the recipe should say which.

A plant with half the usual number of chromosome sets, often raised in culture from pollen or egg cells. Doubling its chromosomes gives a doubled haploid (DH), a uniform, true-breeding line that breeders use to shorten their programs.

Also called high-efficiency particulate air filter

A high-efficiency particulate air filter: a dense, pleated filter that traps very fine airborne particles, bacteria and fungal spores among them. It is what makes the air in a flow hood clean, and it stops doing so when damaged or clogged, so labs log its checks and replacement.

Also called PGR-free medium, growth-regulator-free medium, hormone-free

A medium with no added growth regulators, used for elongation, for rooting in some crops, and to let cultures shed regulators carried over from earlier stages. Tissue still makes its own hormones and additives like coconut water bring some, so "free" means nothing added.

Also called parentage, pedigree

The parents of a hybrid, written seed parent × pollen parent, and through them its line back to the original species. A grex is defined by its parentage, so the record should spell each parent the way the register does.

In xPlant Pro Recorded on a plant under Accepted name and parentage, with Is it a hybrid? and Parent species; a sowing from a cross offers Record the hybrid parentage.

Also called vitrification, hyperhydration, glassiness

A disorder in which shoots turn glassy, swollen, brittle and water-soaked, and often grow poorly from then on. It is linked to conditions inside the vessel, such as humidity and the gelling agent, so those are noted with the observation. Vitrification also names a cryopreservation method.

Also called IAA, indole-3-acetic acid, indoleacetic acid

The main auxin plants make themselves. It breaks down in light and in culture, which is why many labs use the steadier IBA or NAA, and why IAA stock solutions are kept dark.

Also called IBA, indole-3-butyric acid, indolebutyric acid

An auxin used above all for rooting, both in culture and on cuttings, and steadier in the medium than IAA. Labs record whether it went into the rooting medium or was given as a short pulse, since the same compound is used both ways.

Also called PPQ 587, plants for planting permit

A permit from the importing country that lets specified plants enter and sets the conditions; it is not the CITES permit, which is a separate document. In the United States USDA APHIS issues it: most plants for planting need a PPQ 587 permit, though APHIS lists sterile orchid cultures among the exceptions.

Latin for “in glass”: growing in a closed vessel on medium, under controlled light and temperature. Plants in vitro live in near-saturated humidity, which is why they need acclimation before they can cope outside.

Shoots or roots forming from callus that grew first on the explant, rather than from the explant itself. The callus step can raise the chance of off-types, so labs note it on the line's record.

Also called Stage I, establishment, culture initiation

The first stage in culture: explants are surface-cleaned, trimmed and set on medium, and the ones that stay clean and start growing become a new line. It is often the costliest stage, especially for a plant new to the lab, so losses and contamination are recorded per batch.

In xPlant Pro Shown as the Initiation workflow step on the Stage Dashboard.

Also called Fe-EDTA, NaFeEDTA, chelated iron, iron stock

Iron bound to EDTA so it stays dissolved and available instead of settling out at the pH of a medium. Many labs make it as its own stock and keep it dark, and a stock that has clouded or dropped a deposit is remade rather than used.

Also called juvenile phase, juvenile tissue

The young growth phase before a plant can flower, which in many woody plants also differs in leaf form and rooting ability. Explants from juvenile growth often establish and root more readily than mature growth, so labs note the age and position of source material.

Also called keikis

Hawaiian for “child”: a small plantlet that grows on an orchid's flower stem or cane, common on Phalaenopsis and Dendrobium. It is a clone of its parent, so its record links back to that plant once it is removed and potted.

Also called KIN, 6-furfurylaminopurine, N6-furfuryladenine

A cytokinin, 6-furfurylaminopurine, and the first one identified, in the 1950s. Many crops respond to it more mildly than to BAP, which is why some recipes use it for gentler multiplication or alongside an auxin for callus.

Also called QR label, jar label, vessel label

The identifier on a vessel, tray or plant, often a printed QR code with a short ID, sometimes with species, date and stage. Reading or scanning it ties the physical jar to its record, and an unlabeled jar has no record to tie back to.

In xPlant Pro QR labels can be printed for jars, plants and batches, and scanning one opens its record.

Also called flow hood, laminar air flow cabinet, LAF hood, clean bench

A cabinet that pushes HEPA-filtered air across the work surface in a steady, even stream, to keep the space in front of the filter clean while cultures are open. It protects the culture, not the worker: the air flows out toward the person at the bench.

In xPlant Pro Laminar flow hood is an equipment category, and a transfer can record the workstation it was done at, so contamination rates can be read by station.

Also called hidden contamination, covert contamination, cryptic contamination

Contamination that is present but not yet visible, often from slow-growing microbes or ones inside the tissue. A line can look clean for several transfers and then show growth, which is why records keep each culture's lineage back to its starting explant.

Also called PPFD, photosynthetic photon flux density

How much light reaches the cultures, usually measured as PPFD (photosynthetic photon flux density) in micromoles per square meter per second. It drops with distance from the lamp and changes across a shelf, so a reading is logged with where it was taken.

Also called laboratory information management system

A laboratory information management system: software that holds a lab's samples, records, procedures and results in one place instead of on paper and spreadsheets. In a tissue culture lab that means plants, cultures, transfers, media and contamination records.

In xPlant Pro Settings can read an export file from another LIMS.

Also called culture lineage, line of descent

The line of descent of a culture: the plant it came from, the explant taken, and each subculture since. It answers where a jar came from and what else came from the same source.

In xPlant Pro A plant record shows the plant it was propagated from and any plants propagated from it.

Also called plug, TC liner, plug liner

A young plant sold or passed on for growing into a finished plant, such as a plug grown in one cell of a tray. Labs often ship acclimated plants as liners, with the tray size and count recorded on the order.

Also called liquid culture

A medium with no gelling agent, used still, shaken, on a support such as a paper bridge, or in temporary immersion systems. Tissue in liquid takes up more water and some crops turn glassy in it, so the vessel and how it was agitated belong in the record.

Also called failed culture, lost culture, discard

A culture or vessel that ended without going on, because it was contaminated, died or was discarded. Recording each loss with its reason keeps a failed jar in the count instead of letting it disappear.

In xPlant Pro Batches and cultures can carry a Lost status, and a task can be closed as culture lost.

Also called plant-loss rate, vessel loss rate

The share of plants, vessels or cultures lost over a stage or period, whether to contamination, death or discard. It is calculated from counted losses against what went in, and a rate counted in vessels does not compare with one counted in plants.

In xPlant Pro Contamination rates are counted in cultures, while vessel and plant-loss rates are counted separately on the control grid.

Also called lot number

A quantity of material treated as one unit for production and traceability, such as plants cut in the same week or a reagent from one manufacturing run. Lot numbers on supplies and media pours link a result back to what went into it.

In xPlant Pro Lab Operations shows lots in process, when they are expected to move and what was lost, and inventory keeps lot numbers for supplies.

Also called macroelements, major salts, macros

The mineral elements a medium supplies in the largest amounts: nitrogen, phosphorus, potassium, calcium, magnesium and sulfur. Named formulas differ most in these, including how much of the nitrogen comes as nitrate and how much as ammonium.

Also called Magenta vessel, GA-7

A square, clear plastic culture box with a fitted lid, common for shoot cultures that need more headroom than a tube or dish. Magenta is a brand name that many labs use for the style in general.

Also called pour, media pour, prep batch

One preparation of a recipe, made and poured on a given day, with its own component lots and sterilization run. Recording which batch each culture went onto is what lets a lab trace a problem back to a pour.

In xPlant Pro Linking a recipe or recording a transfer offers a "Media batch" picker: "Which prep batch this culture went onto."

Also called media formulation, media formula, recipe, formulation

The written formulation for a medium: each component and amount, the target pH, the gelling agent, and how it is sterilized and stored. Editing a recipe in place breaks the link to what earlier cultures grew on, so labs save a new version instead.

In xPlant Pro Media recipes are versioned: "Write a recipe, revise it, and keep the old version intact."

Also called meristem clone, mericloned

An orchid propagated in culture from the tissue of one named plant, usually a shoot tip, so it carries the parent's cultivar name. Most match the parent, but off-types do appear, so labs keep the source plant and batch on every mericlone's record.

Also called meristem-tip culture, meristemming

Culturing the tiny dome of dividing cells at a shoot tip, cut out under a microscope with little or no surrounding tissue. Labs use it when working toward virus-tested stock, and plants from it are still indexed before anyone treats them as tested.

In xPlant Pro Shown as the work type Meristem initiation on new work in the active queue.

Also called microelements, minor salts, trace elements, micros

The mineral elements needed only in trace amounts, chiefly iron, manganese, zinc, boron, copper, molybdenum and, in some formulas, cobalt and iodine. Because the amounts are so small, labs measure them from a concentrated stock rather than weighing them into each batch.

Also called tissue culture propagation, TC propagation

Producing many plants from small pieces of tissue grown on medium in closed vessels, usually as clones of one source plant. Most commercial work runs it as a sequence of numbered stages, from mother plant preparation through acclimation.

Also called stock plant, source plant, donor plant

The plant that explants or cuttings are taken from. Its identity, health notes and history sit at the top of every line's record, so a problem in a jar can be traced back to the plant it started from.

In xPlant Pro Kept as a plant record, and counted as Mother plants in the lab's culture figures.

Also called Murashige and Skoog medium, MS, MS basal medium, Murashige & Skoog

The basal medium Toshio Murashige and Folke Skoog published in 1962 for tobacco tissue cultures, high in nitrogen and salts, and the most widely used starting point today. Most lab recipes are MS with changes, so the record says what was changed.

Also called Stage II, shoot multiplication, proliferation

The stage where established cultures are divided and moved to fresh medium again and again to build numbers, usually as shoot clusters. Labs adjust the medium and timing per line, and record vessel and plantlet counts at each subculture to follow the rate.

In xPlant Pro Shown as the Multiplication workflow step on the Stage Dashboard.

Also called Stage II medium, proliferation medium, shoot multiplication medium

The medium a line is subcultured onto to make more shoots, usually with a cytokinin and sometimes a little auxin. Labs track each line's multiplication on it and record any change to it as a new recipe version.

In xPlant Pro The new-recipe templates are grouped by stage, one of which is "Multiplication".

Also called multiplication factor, multiplication ratio

How many usable shoots or vessels one vessel gives at a subculture; a jar divided into four new jars is a rate of four. Comparing it across subcultures, media and staff is how labs plan output and spot a line that is slowing down.

In xPlant Pro Shown on the Multiplication & survival chart, built from the vessel and plantlet counts logged on a transfer.

Also called inositol, meso-inositol

A sugar alcohol listed with the vitamins in most formulas, though it is not strictly a vitamin, and used by plants in building cell walls and membranes. Most labs add it with the vitamin stock, and a recipe without it is a different recipe.

Also called NAA, 1-naphthaleneacetic acid, α-naphthaleneacetic acid, naphthaleneacetic acid

A synthetic auxin, steadier in the medium than IAA, used for rooting and callus and alongside a cytokinin in some multiplication media. Shoots on it can callus at the base as they root, so labs note root quality, not just whether roots formed.

Death of cells or tissue, seen as brown or black, dry or water-soaked areas. In a record it describes what was seen, not why it happened.

Also called node culture, single-node culture

Culturing stem pieces that each carry a node, the point where a leaf and its bud join the stem, so the bud grows out into a new shoot. It is a common way to start and multiply plants that grow long single stems rather than tight clusters.

Also called off-types, variant

A plant that does not match what its line should produce, in leaf shape, color, variegation, vigor or flower. Labs remove or set aside off-types and record how many turned up in which batch, since a rising count can point to a problem in the line.

Also called grex registration, RHS orchid register, International Orchid Register

Entering a new grex name and its parentage in the International Orchid Register, kept by the Royal Horticultural Society. The register lists the seed parent, pollen parent, registrant, originator and registration date for each registered grex.

In xPlant Pro Recorded on a cross as Grex registration: Not registered, Registration applied for or Registered, with a Registration reference.

Also called complex additive, undefined additive

A natural ingredient of variable makeup, such as coconut water, banana, potato, peptone or casein hydrolysate, added for nutrients a defined formula lacks; banana is common in orchid media. No two lots are quite alike, so labs record the source and lot.

How strongly a medium's dissolved sugar and salts hold onto water, which sets how easily tissue can draw it in; the more that is dissolved, the lower (more negative) the potential. Sugar is usually the largest single contributor, and labs that lower it on purpose with mannitol or sorbitol record that in the recipe.

Also called virus-tested stock, tested stock, indexed stock

Plant material that tested negative for a named list of pathogens, by named methods, when it was sampled; it says what was looked for, not that nothing is there. In the US, the USDA's National Clean Plant Network keeps tested source plants for several crops.

Also called Petri plate, plate

A shallow, round dish with a loose-fitting lid, used for seed germination, callus and other short cultures. The lid does not seal by itself, so dishes are usually wrapped with sealing film.

Also called acidity, medium pH

How acidic a medium is, which affects nutrient availability and how firmly agar sets. It is adjusted before autoclaving, usually before the gelling agent goes in, and shifts in the autoclave and in culture, so labs record the target and the meter reading.

In xPlant Pro Each media recipe has a "Target pH" field under "Preparation".

Also called photoautotrophic micropropagation, sugar-free culture

Growing plantlets in vitro with little or no sugar in the medium, so they feed themselves by photosynthesis, usually with more light and ventilated vessels that let in more carbon dioxide. Labs try it to ease acclimation; results vary by species.

Also called day length, light cycle

The daily schedule of light and dark a culture gets, written as hours of light over hours of dark, such as 16/8. It can differ by stage and species, so labs log it per room or shelf.

Also called phyto, phyto certificate, plant health certificate

An official document stating that a consignment of plants or plant products meets the importing country's plant health requirements. It is issued by the national plant protection organization of the exporting country, in the format set by the IPPC standard ISPM 12.

In xPlant Pro An acquisition record can hold the phytosanitary certificate that came with an import.

Also called PGR, PGRs, growth regulator, plant growth substance

Any compound, natural or synthetic, added to a medium to steer growth; auxins, cytokinins, gibberellins and abscisic acid are the main groups. The compound and amount are written exactly in the record, since tissue responds to small differences.

In xPlant Pro A culture line on a medium has a "Growth regulator" field, written the way the lab writes it.

Also called phytohormone, hormone

A compound a plant makes itself, in tiny amounts, that controls growth and development, such as IAA, zeatin, gibberellins, abscisic acid and ethylene. Growers often say hormone for anything in the PGR column, but synthetics like NAA, 2,4-D and TDZ are growth regulators.

Also called EU plant passport

An official label that goes with certain plants, plant products and other objects that can carry quarantine pests when they move within the European Union, once they have passed EU checks. It is issued by the competent authority, or by a professional operator authorized to issue plant passports.

The record for one plant or stock plant: its name, source, location, stage and history, with the cultures taken from it. It is the anchor that explant, transfer and contamination records hang from.

In xPlant Pro Plants lists every plant record a lab tracks, from cutting to finished stock.

A small, complete plant with shoots and roots, produced in culture and ready, or nearly ready, to leave the vessel. Plantlet counts at each transfer are how a lab measures its output.

In xPlant Pro Counted on a transfer; the app asks you to “Record vessel and plantlet counts at your next transfer”.

The number of complete chromosome sets in a plant's cells; a polyploid carries more than two, such as a tetraploid with four. Ploidy can shift in culture or be changed on purpose by breeders, and labs confirm it with a lab test such as flow cytometry or a chromosome count.

Also called male parent, pollen donor

The plant the pollen came from, in orchids the waxy pollen packets called pollinia; it is written second in a cross. Note which plant and which flower, especially when the pollen was stored or came from another grower.

In xPlant Pro Recorded on a cross as Pollen parent, “The plant the pollen came from.”

A kitchen or canning pressure cooker used in place of an autoclave in home and small labs. It sterilizes the same way, with steam under pressure, at a smaller scale and usually without the readouts and cycle record of a lab autoclave.

In xPlant Pro Equipment has an Autoclave / pressure cooker category.

A hybrid between two species, rather than between hybrids; most in cultivation were made by hand. Its grex name covers every seedling from those two species, whichever was the seed parent and whichever forms of each were used.

Also called protocorms

The small, rounded body an orchid seed swells into after it germinates, before it forms its first leaf and root. Protocorm counts per flask are an early read on how a sowing went.

Also called PLB, PLBs

A growth shaped like a protocorm that forms from cultured tissue, such as a shoot tip or leaf base, rather than from seed. Cutting and subculturing PLBs is a common way to multiply an orchid clone, including mericlones.

Also called recalcitrant

Poor response in culture: a species, genotype or tissue that will not establish, multiply, root or regenerate under conditions that work for others. It describes how material has behaved so far, so a record of what was tried is what gives the label meaning. In seed banking, recalcitrant seed is seed that cannot survive drying.

Growing new shoots, embryos or whole plants from cultured tissue such as callus, leaf pieces or single cells. A regeneration rate in the record is the share of pieces that went on to form shoots or embryos.

Also called replating, reflask, reflasking

Moving protocorms or young seedlings from a crowded sowing flask into fresh flasks with more room and new medium. Each replate is a transfer, so the date, the number moved and the number of new flasks go on the record.

In xPlant Pro Replates that are due are listed in the Replate queue.

Also called Stage III, root initiation, pretransplant stage

The stage where shoots are moved to a medium that encourages roots, or are rooted straight in potting mix outside the vessel. Record which route each batch took, since rooting ex vitro folds into acclimation and is scheduled and counted differently.

In xPlant Pro Shown as the Rooting workflow step on the Stage Dashboard.

Also called Stage III medium, root induction medium

The medium shoots go onto to form roots before leaving the lab, usually with an auxin, often at reduced salt strength, sometimes with charcoal or no regulators at all. Rooting varies by species and cultivar, so labs record the medium beside the roots they saw.

In xPlant Pro The new-recipe templates are grouped by stage, one of which is "Rooting".

Also called blade, surgical blade

A small knife with a replaceable blade, used to cut explants and divide shoot clusters. Blades are changed when they dull, and blades and handles are sterilized like other tools.

Also called Parafilm, plastic wrap, cling film

A stretchy film wrapped around the join between a vessel and its lid to hold it closed and slow drying out. Parafilm is a brand name; labs also use cling or PVC wrap, and the choice changes how much air the vessel exchanges.

Also called pod parent, female parent

The plant that receives the pollen and carries the capsule; it is written first in a cross. Record which plant it was and the pollination date, since the capsule can take months to ripen.

In xPlant Pro Recorded on a cross as Seed parent (pod parent), “The plant that carries the capsule.”

Also called selfing, self, selfed

Pollinating a flower with pollen from the same plant or the same clone, so one plant is both seed parent and pollen parent. Seedlings from a self can still vary, because the parent's genes recombine.

In xPlant Pro A plant recorded as both parents of a cross is shown as self-pollinated on its Crosses panel.

Also called solid medium, gelled medium, agar medium

A medium set with a gelling agent, the standard form for most shoot cultures. How firmly it sets changes how much water tissue takes up, so the gelling agent and its lot go in each batch record.

Also called storage life, use-by, media expiry

How long poured medium stays usable before it dries, pulls away from the vessel wall or loses components to light and time. Labs set their own window, store poured medium cool and dark, and record the pour date so old batches stand out.

In xPlant Pro Each media recipe has a "Storage" field: "How prepared medium is stored, and how long it stays usable".

Also called shoot-tip culture

Culturing the growing tip of a shoot, larger than a meristem and with a few young leaves still attached. It usually establishes more easily than a meristem and is a common starting point for multiplying a clone.

Also called STN, tip necrosis

Death of the growing tip of shoots in culture, after which they stop extending from the top and may branch lower down. It has been linked to calcium supply among other factors, and it shows up more in some species and media than in others.

Also called sibling cross, sib, sibbing

A cross between two different plants raised from the same seed batch, such as two seedlings of one grex or one species sowing. Breeders make sib crosses to combine good traits from siblings while keeping the line's background.

Also called minimal-growth storage, cold storage

Holding cultures under conditions that slow their growth, such as lower temperature or light, so they need subculture far less often. Stored lines still change, so they are checked on a schedule and the review dates are kept on record.

In xPlant Pro Tracked on the Cold Storage page, with a review date for each item.

Also called bleach, NaOCl

The active chemical in household bleach, widely used to surface-sterilize explants and to wipe down surfaces. Its strength differs between products and drops as a bottle ages, so labs record the product used, not just the word bleach.

Changes that arise in plants while they are in culture and show up as off-types in leaf, color, variegation, growth habit or flowering. It is linked to callus stages and to long periods in culture, so labs keep each line's subculture count on record.

In xPlant Pro The cycle tracker shows each line's count against the usual restart point, under Restarting from fresh explants.

Also called SE, somatic embryos

Body cells, rather than a fertilized egg, developing into embryos that grow both a shoot end and a root end, much like the embryo in a seed. It can happen straight from the explant or by way of callus, and labs record the embryos' development as cultures mature.

Also called standard operating procedure

A standard operating procedure: a written, versioned set of steps for a routine task, such as pouring media, surface sterilization or a transfer, so it is done the same way each time. Records can note which version was followed and who is trained on it.

In xPlant Pro SOPs holds the lab's step-by-step procedures, with a training matrix of who is signed off on each.

Also called Stage 0, stock plant preparation, donor plant selection

The work before anything goes into culture: choosing source plants and keeping them clean, labeled and well grown so explants start in good shape. Notes on how the mother plant was kept can help explain contamination or slow starts later.

Killing or removing all microbial life, spores included, from media, tools or vessels, usually by steam, dry heat or filtration. Living explants cannot be treated that way, which is why cleaning them is a separate step, surface sterilization.

Also called SAB

A clear, closed plastic box with armholes, used to keep the air still while a culture is open. It is a low-cost alternative to a flow hood in home and small labs: it calms the air rather than filtering it, so the box itself is wiped down before work.

In xPlant Pro Still-air box is one of the equipment categories, next to Laminar flow hood.

Also called stock, concentrated stock

A concentrated solution of one or more components, made ahead and measured into each batch so small amounts need not be weighed every time. Components that react, like calcium with sulfate or phosphate, go in separate stocks, and each bottle is labeled with contents and date.

Also called subculturing, passage

Moving a culture, or pieces of it, onto fresh medium in a new vessel before the old medium runs down or growth crowds the jar. Each subculture is one cycle, so the count shows how long a line has been in culture.

In xPlant Pro Each plant and explant shows its Transfer cycle, “Subcultures to date”.

Also called sugar, table sugar

The usual carbon source in a medium, since cultures in a closed vessel cannot photosynthesize enough to feed themselves. It is also the largest single contributor to the medium's osmotic strength, and autoclaving splits some into glucose and fructose; some labs use table sugar, so the grade belongs in the recipe.

In xPlant Pro Inventory has a "Sugar" category.

Also called surface disinfestation, explant sterilization

Treating the outside of an explant with disinfectants and sterile rinses before it goes onto medium, meant to clear the microbes from its surface. It cannot reach microbes living inside the tissue, so a culture that starts clean can still show contamination later.

In xPlant Pro Sterilization is one of the SOP templates, described as autoclave, laminar-flow and surface-sterilization protocols.

Also called mycorrhizal germination, symbiotic sowing

Germinating orchid seed together with a compatible mycorrhizal fungus, the partner that feeds orchid seedlings in the wild. It is used often for terrestrial orchids and conservation work, and the fungus strain is recorded with the sowing.

Also called TDZ, thidiazuron

A synthetic phenylurea with strong cytokinin-like activity at far lower amounts than BAP, used for difficult woody crops and for regeneration. Its effects can carry into later subcultures, so labs record how long a line was on it.

Also called TIS, temporary immersion bioreactor

A bioreactor that floods cultures with liquid medium for short periods at set intervals, then drains it so the tissue sits in air in between. It is meant to limit the glassy, waterlogged growth that constant immersion can cause, and labs record the immersion schedule with each run.

Also called culture tube, tube

A narrow glass or plastic tube used as a culture vessel, often holding one explant each at initiation. Keeping explants apart means one contaminated tube does not take its neighbors with it.

Also called vitamin B1, thiamine HCl, thiamine hydrochloride

Vitamin B1, the one vitamin most cultures are thought to need from the medium. In most formulas it goes into the vitamin stock with pyridoxine and nicotinic acid, and formulas differ widely in how much they carry.

Being able to follow a plant or vessel back through its records to its source, inputs and handling, and forward to where it went. In a tissue culture lab it rests on labels, lineage, and batch and lot numbers being recorded at each step.

In xPlant Pro Inventory keeps lot numbers so a media batch can be traced later.

Any move of culture material at the bench: a subculture onto fresh medium, a change of vessel, or a move to the next stage. The transfer record is where the date, the counts, the medium and who did the work are written down.

In xPlant Pro Logged on the Transfer Dashboard: “Record a subculture, vessel change, or stage move for a plant.”

Also called subculture record, replate record, transfer log

The record of moving a culture onto fresh medium: the date, who did it, what moved, onto which medium, and how many vessels came out. Multiplication and loss figures are calculated from these counts.

In xPlant Pro A transfer logs what moved, onto which medium and how many vessels came out.

Also called true to type, trueness-to-type

Matching the source plant in form, growth and flowering, with no unexpected changes. Labs check it by growing out and inspecting samples, and note which batches were checked and what was found.

Also called filter patch, filter disc, breathable lid, vent membrane

A lid or closure fitted with a membrane patch that lets gases pass while keeping out dust and spores. Venting changes humidity and gas buildup inside the vessel, so labs note the closure type alongside how cultures grew.

Also called virus testing, indexing

Testing a plant for specific viruses, with lab tests such as ELISA or PCR, or on indicator plants that show symptoms. A result covers only the viruses and the test named, on the date sampled, so the record should list all three.

Also called vitamin stock, MS vitamins, B5 vitamins

The small set of organic compounds a formula adds, usually thiamine, pyridoxine, nicotinic acid and myo-inositol, often with glycine. Many labs keep them as a cold stock, and "MS vitamins" and "B5 vitamins" are different sets, so the recipe names which.

In xPlant Pro Inventory has a "Vitamin / additive" category.

Also called WPM, Lloyd and McCown medium, Lloyd & McCown

A basal medium Gregory Lloyd and Brent McCown published in 1980 for shoot cultures of woody ornamentals such as mountain laurel, rhododendron and birch. It carries less total salt and nitrogen than MS, and labs often turn to it when a woody crop struggles on MS.

Single-celled fungi that grow as smooth, creamy or shiny colonies on or in the medium. At a glance yeast can look like bacterial growth, so many labs log it as its own contamination type.

What a batch or culture actually produced, such as shoots, rooted plantlets or plants surviving acclimation, counted against what went in. Yield figures come from counts recorded at each stage.

In xPlant Pro An explant record's Culture yield panel shows the vessel, plantlet and survival counts recorded on stage updates.

Also called trans-zeatin, ZEA

A natural cytokinin, first isolated from maize kernels, used in media for some woody crops, blueberry among them. It costs far more than BAP, so labs tend to keep it for the lines that respond to it.