Micropropagation Flashcards
What is meant by Micropropagation?
Micro-propagation is defined as the true-to type propagation of selected genotypes using in vitro culture techniques.
What is meant by Explant?
- It is the piece of plant tissue placed on culture
media. Potentially all living plant parts can be used as explant.
What is the explant source?
It may be obtained from field-grown plant or
plants growing under in vitro conditions.
Contamination rates of the explants increase in
Summer
Give reason: Larger explants have better response in Tissue culture?
Because they contain more nutrient reserves and plant growth regulators to sustain the culture.
What is meant by somaclonal variations?
Genetic variations that can arise among regenerated plantlets.
If Clonal propagation is the goal ……………. or ………….. are used.
lateral or terminal buds
………., ……………., and …………….. are excellent explants for callus induction.
Leaf segments, hypocotyl sections and cotyledons
Factors considered when selecting explants.
1- Explant age
2- Season in which the explant is obtained
3- Explant size and position in mother plant
4- Plant quality
5- Goal
The choice of explant depends on ………….
The choice of explant depends on what type of response required.
The used explant in the shoot apical meristem method is……….
meristematic tissues (apical meristems).
Apical meristems tend to be genetically stable because…………..
Because they are highly organized structure
Shoot apical meristems are located at………..
The apices of the main and lateral buds of plants.
…………….. has no connection to xylem and phloem.
Shoot apical meristem.
Meristem tip culture consists of………………
meristematic dome and one or two leaf primordia.
The shoot apical meristem method is rarely used…………
because of meristem low survival rate.
Plant meristem culture is a unique technique to
produce……………
plants free of pathogens including viruses, viroides, mycoplasma, bacteria and fungi.
The capacity of the meristem, however, should be enough to regenerate a full plant.
Explant size: As big as possible.
a……………. is required between successful virus elimination and the probability for plant development.
balance
Meristems are frequently devoid of systemic pathogen due to…………….
due to the absence of differentiated conducting tissues.
The rate of obtaining a virus-free plant is related to………
the size of the isolated meristem (Explant size: As small as possible)
Shoot and node culture depend on……………..
The stimulation of axillary shoot growth from lateral buds.
The axillary shoots produced are either subdivided into …………….. and……………
shoot tips and nodal segments
Shoot tips and nodal segments serve as secondary explants for……….
further proliferation or serve as microcuttings for rooting.
Node culture is………….
is a simplified form of shoot culture where shoot is cut into nodal segments (single elongated unbranched shoot consists of several nodes).
Adventitious origin regeneration includes:
1.Adventitious Shoot Proliferation
2. Adventitious shoot and root organogenesis
3. Adventitious somatic embryogenesis
What is meant by adventitious origin?
It is unusual sites of a cultured tissue such as the Internode, leaf blade, cotyledon, or root elongation zone (where
meristems do not naturally occur)
Adventitious origin/plant regeneration is often dependent upon……
the presence of organized explant tissue.
Produced/Regenerated organs are produced…..
directly such as
- Shoot and root
- or somatic embryo
………….is the most frequently used multiplication technique in micropropagation systems.
Adventitious shoot and root organogenesis
………is Utilized commercially in the ornamentals industry.
Adventitious shoot and root organogenesis
Used explant in Adventitious somatic embryogenesis is…………
The immature zygotic embryo.
Examples of plants cultured by Adventitious somatic embryogenesis are……….
Soybean, and maize, Zea mays
True or False: Zygotic and somatic embryos
share the same gross pattern of development?
True
What are the stages of embryogenesis?
Globular
Heart
Torpedo
Cotyledonary stages
Somatic embryogenesis formation steps involve:
- Initiation of embryogenic cell
Dramatic dedifferentiation and redetermination of explant or callus toward formation of an embryogenic cell type. Mostly immature zygotic embryos are used as explant. - Embryo development
Observable transition from non-embryogenic to embryogenic cell through unequal division - Embryo maturation phases
In somatic embryos: Complete maturation is not absolutely necessary to obtain plants from somatic embryos. It is required to achieve high rate of plant recovery. High sucrose concentration, ABA and polyethylene glycol are shown to enhance maturation of somatic embryos.
Callus can be produced from……… and many callus cells are……….
a single differentiated cell, and many callus cells are totipotent, being able to regenerate the whole plant body.
De novo (literally, “to arise new”) plant regeneration occurs from……….
callus and cell cultures in the absence of organized explant tissues.
Callus formed under in vitro culture condition and Callus induced at the wound site, these two types of callus are ………… in their molecular and physiological properties.
Different
Explant tissues generally show………….
distinct planes of cell division,
various specializations of cells,
and organization into specialized structures such as the vascular system.
……………. ratio of auxin and cytokinin promotes callus induction.
An intermediate ratio
Hormones, such as ……………….., also induce callus.
brassinosteroids or abscisic acid
………….. is Used in the propagation of economically important traits and the introduction of transgenes.
Indirect regeneration from callus culture.
Calli are very diverse and can be classified into subgroups based on their………………..
macroscopic characteristics
Calli without any obvious organ regeneration are typically called……………
friable or compact callus depending on their tissue characteristics.
Calli with some degrees of organ regeneration are often called……………
Rooty, shooty, or embryonic callus depending on the organs they form.
What is meant by callus?
Callus is defined as a mass of undifferentiated cells. It is naturally formed on plants in response to wounding.
Callus growth passes through:
1-Lag phase: Explant cells prepare to divide.
2-Exponential phase: The rate of cell division reaches its
maximum.
3-Linear phase: Cell division slows but rate of cell expansion
increases.
4-Deceleration phase: Rate of cell division and elongation decrease.
5-Stationary phase: Number and size of cells remain constant.
What is meant by suspension culture?
Suspension culture is a type of culture in which single cells or small groups of cells multiply while suspended in agitated liquid medium.
It is also referred as cell culture or cell suspension culture.
…………… is the first stage before moving to bioreactors.
suspension culture
Bioreactors are used to……….
produce mass production of callus for extracting of secondary metabolites.
The benefit of suspension culture is:
able to produce mass production of cells, however, it more sensitive to contamination.
Micropropagation has …………. stages, which are:
5 Stages:
Stage zero
Stage one
Stage Two
Stage three
Stage four
In Micropropagation, Stage zero is………….
Donor plant selection and preparation.
[Donor plants (Pathogen free, grown clean, low humidity) to
reduce contamination.]
In Micropropagation, Stage one is………….
Establishment of aseptic culture initiation step.
[- Affected with explant size, position, and time of explantation
- Requires cytokinins and auxins to enhance explant (conc. Genotype dependent)]
In Micropropagation, Stage two is………….
Proliferation of axillary shoots.
[-Repeated enhanced formation of axillary shoots from shoot tips or lateral buds cultured on a cytokinin rich medium.
- A subculture interval of 4 weeks]
In Micropropagation, Stage three is………….
Pretransplant (rooting).
[Included shoot elongation stage then rooting on basal or auxin contain media]
In Micropropagation, Stage four is………….
Transfer to natural environment.
[Ability to re-establish vigorously growing plants from in vitro to greenhouse conditions.]
