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Callus is a ______ and amorphous tissue
Callus is a ______ and amorphous tissue
coherent
Callus is often induced in or upon parts of an intact plant by ______, by the presence of insects or microorganisms, or as a result of stress.
Callus is often induced in or upon parts of an intact plant by ______, by the presence of insects or microorganisms, or as a result of stress.
wounding
Callus can be initiated ______ by placing small pieces of the whole plant (explants) onto a growth-supporting medium under sterile conditions.
Callus can be initiated ______ by placing small pieces of the whole plant (explants) onto a growth-supporting medium under sterile conditions.
in vitro
During this process, cell ______ and specialization, which may have been occurring in the intact plant, are reversed
During this process, cell ______ and specialization, which may have been occurring in the intact plant, are reversed
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Although most experiments have been conducted with the tissues of higher plants, callus cultures can be established from ______, ferns, and mosses.
Although most experiments have been conducted with the tissues of higher plants, callus cultures can be established from ______, ferns, and mosses.
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Young ______ tissues are most suitable, but meristematic areas in older parts of a plant, such as the cambium, can give rise to callus.
Young ______ tissues are most suitable, but meristematic areas in older parts of a plant, such as the cambium, can give rise to callus.
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The choice of tissues from which cultures can be started is greatest in ______ species.
The choice of tissues from which cultures can be started is greatest in ______ species.
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The callus formed on an original explant is called ‘______ callus’.
The callus formed on an original explant is called ‘______ callus’.
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The type of ______ obtained can depend upon the origin and age of the tissue chosen.
The type of ______ obtained can depend upon the origin and age of the tissue chosen.
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Compact ______ shows as large, densely aggregated cells, while friable ______ shows more loosely associated cells.
Compact ______ shows as large, densely aggregated cells, while friable ______ shows more loosely associated cells.
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A ______ culture is mostly used to start cell suspension cultures.
A ______ culture is mostly used to start cell suspension cultures.
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The ______ phase of callus culture involves rapid cell division.
The ______ phase of callus culture involves rapid cell division.
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The ______ phase of callus culture involves cells dedifferentiating and beginning to divide.
The ______ phase of callus culture involves cells dedifferentiating and beginning to divide.
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The ______ phase of callus culture involves differentiation and formation of organized structure.
The ______ phase of callus culture involves differentiation and formation of organized structure.
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Explants grown in agar medium with appropriate nutrients and a suitable proportion of auxin and cytokinin exhibit ______ at the cut ends.
Explants grown in agar medium with appropriate nutrients and a suitable proportion of auxin and cytokinin exhibit ______ at the cut ends.
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The process of transferring cultures with or without dilution from one culture vessel to another is called ______.
The process of transferring cultures with or without dilution from one culture vessel to another is called ______.
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Study Notes
Callus Culture in Plant Tissue Culture
- Callus is a tissue that forms when plant cells multiply in a disorganized way.
- It can be induced naturally in plants by wounding, insects, microorganisms, or stress.
- Callus can be initiated in a lab setting (in vitro) by placing small pieces of a plant (explant) on a growth-supporting medium under sterile conditions.
- Cell differentiation and specialization that occurred in the intact plant are reversed during the process, and the explant produces new tissue composed of meristematic and unspecialized cells.
- The process of callus induction and organ formation is significant.
- Applications and challenges of callus culture are discussed.
- During dedifferentiation, the storage products found in resting cells tend to disappear.
- Callus cultures can be generated from gymnosperms, ferns, and mosses.
- Callus cultures are more easily established from some organs than others; young meristematic tissues are best, but even areas in older parts of a plant, like the cambium, can form callus.
- The choice of tissues to start a callus culture is most effective in dicotyledonous species.
- In cereals, callus growth is only achieved from specific parts of the plant like embryos, germinating seeds, seed endosperm and seedling mesocotyl, and very young leaves; the mature leaf tissue cannot.
- Primary callus is the callus tissue formed from an original explant.
- Secondary callus cultures arise from parts of the primary callus tissue.
- Callus culture is best performed in the dark; light encourages differentiation of the callus.
Types of Callus
- Callus tissues come in various types.
- They differ in appearance, color, compaction level, and morphogenetic potential.
- The type of callus, its differentiation level, and plant regeneration ability depend on the origin and age of the explant tissue, which is selected.
- Callus variability is higher when the selected explant contains multiple cell types.
Types of Callus
- Compact callus shows densely aggregated cells.
- Friable callus shows loosely associated cells that can easily break apart.
- Friable callus is often used in cell suspension cultures.
Stages of Callus Culture
- Induction phase: Cells in the explant dedifferentiate and start dividing.
- Division phase: Rapid cell division. Long-term culture requires reduced auxin and cytokinin requirements.
- Differentiation phase: Differentiation and formation of organized structures (including organogenesis and somatic embryogenesis).
Notes on Callus Culture
- Explants cultivated on an agar medium with appropriate nutrition and auxin/cytokinin ratios show callus formation, starting from cut ends and expanding to the whole tissue.
- Callus cultures need regular subculturing (every 3-5 weeks).
- Repeated subculturing improves callus friability.
- Subculturing is transferring a culture to a fresh culture medium in a new vessel; this is also known as passage.
- Callus tissue may lose its ability to form organs as subculturing continues.
- Callus cultures may show chromosomal changes (e.g., aneuploidy, polyploidy).
Current Applications of Callus Culture
- Manipulating auxin/cytokinin ratios in the culture medium can produce shoots, roots, or somatic embryos, leading to whole plant regeneration.
- Callus cultures can be used to establish cell suspensions.
- Callus cultures are used for studying plant nutrition requirements.
- Callus cultures are used to examine cell and organ differentiation, morphogenesis, somaclonal variations, genetic transformation, and production of secondary metabolites.
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Description
This quiz explores the process of callus culture within plant tissue culture, focusing on the mechanisms of callus formation, its applications, and challenges. Understand how callus is induced both naturally and in vitro, and learn about dedifferentiation and cell specialization in plant tissues. Join us in discovering the significance of callus cultures for various plant types.
