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PLANT & TISSUE CULTURE - C1 (Plant Tissue Culture) Cheat Sheet (DRAFT) by

Brief summary of Chapter 1 (Plant Tissue Culture) of Plant and Tissue Culture Subject

This is a draft cheat sheet. It is a work in progress and is not finished yet.


plant cells re-dif­fer­entiate
plant tissues can be regene­rated from explants


increase crop yield (devel­oping countries)
produce consistent yield quality (private at-home grower)
produce exact replicas of species for profit (busin­esses)


-plant's ability to adapt and cope with changes in the enviro­nment
-plant's ability to different develo­pmental pathways (alter their phenotype) in response to a particular stimul­i/c­hanges in the enviro­nment
-alter its metabo­lism, growth, and develo­pment which suit the current enviro­nment the best
Plant cells and tissues with high plasticity is needed for plant tissue culture.
EXAMPLE: Fanwort (aquatic weed)
1. feathery underwater leaves
2. floating surface leaves
-both leaf types are geneti­cally identical cells, but the dissimilar enviro­nments cause certain genes involved in leaf formation to be expressed or unexpr­essed in different enviro­nments

Plant Adapta­tio­n/R­esponse

plastic structural responses to specific enviro­nment
etc. growth of plant towards sunlight source and growth of root towards source of water
morpho­logical adapta­tions in specific enviro­nment
etc. cactus's leaves are reduced to spines and a stem to reduce water lost in desert

Fundam­ental Abilities of Plants

1. Totipo­tency
potential of a cell/group of cells to develop into an entire organism if suitably stimulated
2. Dediff­ere­nti­ation
develo­pment of differ­ent­iated explant into a undiff­ere­ntiated callus (mature cells return to merist­ematic condition)
3. Compet­ency??
endogenous potential of a given cells or tissue to develop in a particular way
physio­logical and morpho­logical changes that occur in a cell, tissue or organ during develo­pment
*Meris­tematic Condition
unmatured plant which does not have specific differ­ent­iated merist­ematic tissues (etc. apical meristem, lateral meristem) and all meristem tissues function for the 'simple growth' of the plants
develo­pment of undiff­ere­ntiated callus into planta differ­ent­iated

Plant Regene­ration Pathway Image

Plant Regene­ration Pathway

1. Organo­genesis
-initi­ation and develo­pment of tissues and organ from cells which is not meristems
a) Dediff­ere­nti­ation
-starts shortly after the isolation of explant
-rapid cell division and formation of undiff­ere­ntiated cells (callus)
b) Rediff­ere­nti­ation (budding)
-starts after the first callus cell forms
-tissue named organ primordia is differ­ent­iated from callus cells
-organ primordia will give rise to small meristems (cells densely filled with protoplasm and strikingly large nuclei)
-different types of specia­lized cells will further differ­entiate
-vascular system formed will connect new organs with the parent explan­t/c­allus mass
2. Somatic Embryo­genesis
-dedif­fer­ent­iation of plant somatic cell into totipotent embryonic stem cell then to differ­ent­iated embryos
-embryonic stem cell need to have the ability to give rise to an embryo which can further develop into a whole new plant without sexual fertil­ization of zygotic embryos
a) initiated directly
from explants
b) initiated indirectly
from callus
1) induction of embryo­genic cultures from zygotic seed, leaf or stem segment
2) further multip­lic­ation of embryos
3) mature embryos are then cultured for germin­ation and plantlet develo­pment
4) transf­erred to soil
3. Histog­enesis
-diffe­ren­tiation of undiff­ere­ntiated cells and their component cell types into specific tissues and organ
*Somatic embryos - embryos form from ordinary plant cells(2n) which normally are not involved in embryo develo­pment

Plant Tissue Culture

collection of techniques used to maintain or grow plant cells, tissues or organs under sterile conditions on a nutrient culture medium of known compos­ition
1. Approp­riate tissue
2. Sterile conditions with aseptic techniques
3. Suitable growth medium

Factors Affecting Plant Tissue Culture

1. Growth Media
-minerals, growth factors, carbon source, hormones
2. Enviro­nmental Factors
-light, temper­ature, photop­eriod, sterility, media
3. Explant Source
-usually, younger, less differ­ent­iated explant is a better explant source
4. Genetics
-different species show difference in amenab­ility to tissue culture
-different genotype within a species will have variable response to tissue culture


-small pieces of plant parts or tissues that are asepti­cally cut from a matured plant and used to initiate a culture in a nutrient medium
-almost all parts of plant are amenable to in vitro plant regene­ration provided that they are able to dediff­ere­ntiate into totipotent cells
-to grow, it require a nutrient medium consisting of mineral salts mixture, a carbon source, (usually sucrose) and vitamins
-to initiate and maintain cell division, it need phytoh­ormones (auxins and cytokines) in the nutrient medium
-occas­ion­ally, to ensure the prolonged growth of the excised tissue to give an establ­ished callus, other organic supple­ments (amino acids or hexitols) is also needed
correct choice of explant material can have an important effect on the success of a tissue culture experiment

Explants used in Microp­rop­agation

shoot tip
leaf tip
axillary bud
shoot tip
inflor­escence segment
nodal segment
lateral bud
flower stalk segment
leaf base
root tips

Plant Explant Selection

-correct choice of explant material can have an important effect on the success of a tissue culture experiment
1. Season in which the explant is obtained
season of the year can affect on the contam­ination and response in culture
2. Positi­on/part of plant
explants of various organs of a same parent plant vary in their rate of growth & regene­ration
in certain plants some organs may be more regene­rative than the others
3. Quality of the source plant
best to obtain explants from healthy plants compared to plants under nutrit­ional or water stress or plants which are exhibiting disease symptoms
4. Size of explant (commonly: 1-1.5 x 104 cells/ml)
minimum inocul­ation size of explant varies according to the genotype of the plant being cultured and the cultural conditions
-large explants generally survive more frequently and grow more rapidly at the outset than very small ones
-large explants probably contain more nutrient reserves and plant growth regulators to sustain the culture
-smaller explant harder to culture where the medium of culture has to have additional components
-smaller explant increase the chance of virus elimin­ation from subsequent cultures
5. The purpose/ goal of the proposed culture
choice of explant tissue will vary depending on what type of a response is desired from the cell culture
a) clonal propag­ation
lateral or terminal shoot or bud
b) callus induction
cotyledon, hypocotyl, stem, leaf, or embryo
c) protoplast isolation
leaf tissue from asepti­cally germinated seed
6. The kind of culture to be initiated
choice of explant material also determines if the plantlets developed via tissue culture are
a) haploi­d/d­iploid
b) cell/organ
7. Physio­logical condit­ion/age of the explant source
younger tissue is more responsive in vitro, usually the newest formed and is easier to surface disinfect and establish clean cultures
older tissue will not form callus that is capable of regene­ration


practice of rapidly multip­lying stock plant material to produce a large number of progeny plants, using modern plant tissue culture methods

Advantage of Plant Tissue Culture

In plants prone to virus diseases, virus free explants (new meristem tissue is usually virus free) can be cultivated to provide virus free plants
Plant “tissue banks” can be frozen, the regene­rated through tissue culture
Plant culture in approved media are easier to export than soil-grown plants, as they are pathogen free and take up little space (most current plant export is now done in this manner
Tissue culture allows fast selections for crop improv­ement – explants are chosen from superior plants then cloned
High degree of uniformity (true type plants) when compared to conven­tio­nally produced plants

Disadv­antage of Plant Tissue Culture

It is a labor intensive & expensive process.
There is a chance that the propagated plants will be less resilient to diseases due to the type of enviro­nment they are grown in.
It is imperative that, before being cultured, the material is screened; failure to pick up any abnorm­alities could lead to the new plants being infected.
While the success rate is high if the correct procedures are followed, success with the tissue culture is not a guarantee. There is still a chance that the process triggers a secondary metabolic chemical reaction, and the new explants or cells' growth gets stunted, or even die off