What is plant tissue culture?
The culture of plant seeds, organs, explants, tissues, cells, or protoplasts on nutrient media under sterile conditions.
What do in vitro culture and micropropagation have in common?
They involve growing plant material on artificial nutrient media under aseptic and controlled conditions.
What is plant tissue culture used for by commercial growers?
Asexual propagation to produce large quantities of clones of a particular plant.
Who is recognized as the father of plant tissue culture?
Gottlieb Haberlandt.
Which plant parts can be cultured using plant tissue culture?
Stems, leaves, roots, flowers, tissues, cells, and protoplasts.
Who proposed culturing isolated plant cells in vitro in 1902?
Haberlandt proposed culturing isolated plant cells in vitro in 1902.
What is totipotency in plant cells?
Totipotency is the capacity to grow complete plants from separated plant cells or tissues.
What significant event happened with carrot explants in 1939?
Carrot explants produced an undifferentiated callus mass capable of repeated subculture in 1939.
What did Steward discover in 1950 using carrot culture?
Steward discovered embryogenesis in vitro through carrot culture in 1950.
What was produced by Morel and Martin in 1952 using shoot-tip culture?
They produced the first virus-free plant through Dahlia shoot-tip culture in 1952.
What effect does a high kinetin level have according to Skoog and Miller in 1957?
A high kinetin level promotes shoot formation.
What tissue culture medium did Murashige and Skoog develop in 1962?
They developed the MS medium for tobacco tissue culture in 1962.
What was achieved by Guha and Maheshwari in 1964 and Niizeki and Oono in 1968?
They obtained haploid plants from Datura anther culture and rice plants, respectively.
What is a culture medium in plant tissue culture?
An artificially prepared nutrient medium for in vitro plant tissue growth.
What components does a general culture medium contain?
Inorganic salts, iron source, vitamins, amino acids, growth substances, and carbohydrates.
How do macronutrients differ from micronutrients in culture media?
Macronutrients are needed in higher amounts; micronutrients in smaller amounts.
How is iron commonly supplied in culture media?
As ferric-sodium ethylenediaminetetraacetate (Fe-EDTA).
Which vitamins are common in culture media?
Meso-inositol, nicotinic acid, pyridoxine, and thiamine.
What is the most commonly used amino acid in culture media?
Glycine.
Which carbohydrate is usually supplied in plant tissue culture media?
Sucrose.
Name common auxins and cytokinins used in culture media.
Auxins: IAA, 2,4-D, NAA, IBA; Cytokinins: kinetin, BAP, zeatin.
What defines a chemically defined medium?
It has known composition and concentration for every constituent.
What characterizes a chemically undefined medium?
It contains natural products with unknown exact composition and concentration.
Why must the most suitable culture medium be determined by trial and error?
No single medium supports optimum growth for every plant tissue.
Name some complex additives used in culture media.
Coconut milk, casein hydrolysate, yeast extract, watermelon juice, malt extract, potato extract, ripe tomato extract, and orange juice.
Why is coconut milk added at 10–15% v/v in media?
Because diphenylurea in it produces cytokinin-like responses.
How do solid, semisolid, and liquid media differ in agar content?
Solid has 6–8% agar, semisolid has less agar, liquid has no agar.
For what cultures are solid and semisolid media broadly prepared?
Callus culture.
For what cultures are liquid media broadly used?
Cell suspension cultures.
Why are concentrated stock solutions prepared for MS medium components?
Because weighing every constituent before preparation is time-consuming and inaccurate for small quantities.
At what concentrations are MS nutrient salts and vitamins stock solutions prepared?
They are commonly prepared as 20X or 200X stock solutions.
Where are MS stock solutions stored before use?
They are stored at 4°C.
Name three macro salts included in MS medium.
NH4NO3, KNO3, and CaCl2·2H2O are three MS macro salts.
Name three micro salts included in MS medium.
H3BO3, MnSO4·4H2O, and ZnSO4·4H2O are three MS micro salts.
How much sucrose is in one litre of MS medium?
MS medium contains 30,000 mg sucrose per litre.
What amount of agar agar is added for solid MS medium?
Agar agar is added fresh at 8,000 mg per litre.
To what pH is MS medium adjusted and with which reagents?
The pH is adjusted to 5.8 using 0.1 N NaOH or 0.1 N HCl.
What is the first step in sterilizing glassware and equipment?
Soaking in detergent.
At what pressure and temperature is autoclaving done for glassware sterilization?
15 lb/in² and 121°C.
How long should glassware be autoclaved for sterilization?
15–20 minutes.
What is an alternative method to autoclaving glass goods?
Heating in an oven at 150°C for 3–4 hours.
How is prepared medium closed before autoclaving?
With non-adsorbent cotton plugs covered by paper or foil.
What are the autoclaving conditions for prepared medium?
15 lb/in² and 121°C for 15–20 minutes.
Why must screw-capped glass vials not be closed too tightly during autoclaving?
To prevent explosion risk from expanding gases.
What is the first step in surface sterilization of explants?
Explants are washed and treated with 5% liquid detergent for 10–15 minutes.
Where are detergent washing steps for explants performed?
In the general laboratory.
Where are alcohol, sterilant, and sterile-water steps performed during explant sterilization?
Inside a laminar-air-flow cabinet or pre-sterilized inoculation chamber.
Name one common sterilant used for explants and its concentration range.
Sodium hypochlorite at 1–1.4%.
Why must surface sterilants be removed by rinsing with autoclaved distilled water?
Because sterilants are toxic chemicals that can damage plant tissues.
What environmental factors must be controlled in plant tissue cultures?
Temperature, illumination, photoperiod, humidity, and air circulation must be controlled.
Name three equipment types found in culture rooms.
Air conditioning, fluorescent tubes, and bioreactors are found in culture rooms.
What temperature range should culture conditions maintain?
Approximately 25 ± 2°C should be maintained.
How is photon flux density for photosynthetically active radiation expressed?
It is expressed as μmol photons per square meter per second.
How is irradiance expressed?
Irradiance is expressed in watts per square meter (W/m²).
What role do greenhouses play in plant acclimatization?
They provide a transition allowing plants to harden and develop field-ready root and leaf systems.
What is the purpose of surface sterilizing seeds before culturing?
To produce aseptic seedlings for explant culture without further sterilization.
Why do seed coats help seeds during surface sterilization?
They protect seeds from toxic effects of sterilants better than exposed tissues.
What is aseptic inoculation in plant tissue culture?
Placing sterilized plant material onto culture medium under sterile conditions.
Test your knowledge with 27 questions on Plant Tissue Culture.
1. Which description best defines plant tissue culture?
2. Which statement best distinguishes plant tissue culture from micropropagation?
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