Organogenesis, in plant tissue cultureKAUSHAL SAHU
Introduction
Definition
Types of organogenesis
Organogenesis through callus formation (indirect organogenesis)
Growth regulators for indirect organogenesis
Organogenesis through adventitious organ (direct organogenesis)
Growth regulators for direct organogenesis
Factor affecting the soot bud differentiation
Organogenic differentiation
Application of organogenesis
Conclusion
References
A process where an embryo is derived from a single somatic cell or group of somatic cells. Somatic embryos (SEs) are formed from plant cells that are not normally involved in embryo formation.
Embryos formed by somatic embryogenesis are called Embryoids.
The process was discovered for the first time in Daucas carota L. (carrot) by Steward (1958), Reinert (1959).
Organogenesis, in plant tissue cultureKAUSHAL SAHU
Introduction
Definition
Types of organogenesis
Organogenesis through callus formation (indirect organogenesis)
Growth regulators for indirect organogenesis
Organogenesis through adventitious organ (direct organogenesis)
Growth regulators for direct organogenesis
Factor affecting the soot bud differentiation
Organogenic differentiation
Application of organogenesis
Conclusion
References
A process where an embryo is derived from a single somatic cell or group of somatic cells. Somatic embryos (SEs) are formed from plant cells that are not normally involved in embryo formation.
Embryos formed by somatic embryogenesis are called Embryoids.
The process was discovered for the first time in Daucas carota L. (carrot) by Steward (1958), Reinert (1959).
Embryo culture is a laboratory method for producing plant lets from a fertilized or unfertilized embryo in invitro condition. there are several advantages are associated with the embryo culture like production of haploid plants, making distant crosses successful, sometimes aborted embryos can be rescued from a unsuccessful hybridization.
Somaclonal Variation in Plant tissue culture - Variation in somaclones (somatic cells of plants)
Somaclonal variation # Basis of somaclonal variation # General feature of Somaclonal variations # Types and causes of somaclonal variation # Isolation procedure of somaclones via without in-vitro method and with in-vitro method with their limitations and advantages # Detection of isolated somaclonal variation # Application (with examples respectively related to crop improvement) # Advantages and disadvantages of somaclonal variations.
https://www.youtube.com/watch?v=IZwrkgADM3I
Also watch, Gametoclonal variation slides to understand, how to changes occur in gametoclones of plants.
https://www.slideshare.net/SharmasClasses/gametoclonal-variation
The presentation gives overview of production of secondary metabolites using callus culture as well as tissue culture techniques. Various batch and continuous culturing process are described on the basis of secondary metabolite to be synthesised.
A presentation covering the process of protoplast culture including protoplast isolation, protoplast fusion, culture of protoplast, its application, factors affecting protoplast culture and the future of protoplasts.
The isolation, culture and fusion of protoplasts is a fascinating field in plant research. Protoplast isolation and their cultures provide millions of single cells (comparable to microbial cells) for a variety of studies.
Embryo culture is a laboratory method for producing plant lets from a fertilized or unfertilized embryo in invitro condition. there are several advantages are associated with the embryo culture like production of haploid plants, making distant crosses successful, sometimes aborted embryos can be rescued from a unsuccessful hybridization.
Somaclonal Variation in Plant tissue culture - Variation in somaclones (somatic cells of plants)
Somaclonal variation # Basis of somaclonal variation # General feature of Somaclonal variations # Types and causes of somaclonal variation # Isolation procedure of somaclones via without in-vitro method and with in-vitro method with their limitations and advantages # Detection of isolated somaclonal variation # Application (with examples respectively related to crop improvement) # Advantages and disadvantages of somaclonal variations.
https://www.youtube.com/watch?v=IZwrkgADM3I
Also watch, Gametoclonal variation slides to understand, how to changes occur in gametoclones of plants.
https://www.slideshare.net/SharmasClasses/gametoclonal-variation
The presentation gives overview of production of secondary metabolites using callus culture as well as tissue culture techniques. Various batch and continuous culturing process are described on the basis of secondary metabolite to be synthesised.
A presentation covering the process of protoplast culture including protoplast isolation, protoplast fusion, culture of protoplast, its application, factors affecting protoplast culture and the future of protoplasts.
The isolation, culture and fusion of protoplasts is a fascinating field in plant research. Protoplast isolation and their cultures provide millions of single cells (comparable to microbial cells) for a variety of studies.
Clonal Propagation: Introduction, Techniques, Factors, Applications and Disadvantages
Multiplication of Apical or Axillary bud, Shoot tip or meristem culture
Production of Disease free plants by Micropropagation techniques: their Advantages and Disadvantages
Clonal propagation invitro is called micropropagation.In micropropagation, apical meristem is cultivated. so this technique is also known as meristem culture or mericlones.Webber used the word ‘clone’for first time to apply for cultivated plants that were propagated vegetatively.It indicates that plants grown from such vegetative parts are not individuals in the ordinary sense, but are simply transplanted parts of the same individual and such plants are identical.
Plant tissue culture is a collection of techniques used to maintain or grow plant cells, tissues or organs under sterile conditions on a nutrient culture medium of known composition. It is widely used to produce clones of a plant in a method known as micropropagation.
Crude drugs and their classification. Crude drugs, organized and unorganized. Introduction to crude drugs and their classification. Classification of crude drugs. JNTUA, Crude drugs and their classification as per PCI syllabus. For B Pharmacy and Pharm D II year Students.
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
2. Micropropagation
Plants can be propagated by sexual (through generation of
seeds) or asexual (through multiplication of vegetative parts)
means.
Clonal propagation refers to the process of asexual
reproduction by multiplication of genetically identical copies
of individual plants, where the term clone is used to
represent a plant population derived from a single individual
by asexual reproduction.
In vitro clonal propagation through tissue culture is referred
to as micro propagation.
Micropropagation is the practice of rapidly multiplying
stock plant material to produce a large number of progeny
plants, using modern plant tissue culture methods.
3. Micropropagation is used to multiply noble plants such as
those that have been genetically modified or bred through
conventional plant breeding methods. It is also used to
provide a sufficient number of plantlets for planting from a
stock plant which does not produce seeds, or does not
respond well to vegetative reproduction.
Technique of Micropropagation:
Micro propagation is a complicated process and mainly
involves 5 stages (stage 0 and IV) for more comprehensive
representation of micro- propagation.
Stage 0:This is the initial step in micropropagation, and
involves the selection and growth of stock plants for
about 3 months under controlled conditions.
Stage I: In this stage, the initiation and establishment of
culture in a suitable medium is achieved. Selection of
appropriate explants is important.The most commonly
used explants are organs, shoot tips and axillary buds.
4. Stage II: In this stage, the major activity of micro
propagation occurs in a defined culture medium. Stage II
mainly involves multiplication of shoots or rapid embryo
formation from the explant.
Stage III:This stage involves the transfer of shoots to a
medium for rapid development into shoots. Sometimes,
the shoots are directly planted in soil to develop roots. In
vitro rooting of shoots is preferred while simultaneously
handling a large number of species.
Stage IV:This stage involves the establishment of
plantlets in soil.This is done by transferring the plantlets
of stage III from the laboratory to the environment of
greenhouse. For some plant species, stage III is skipped,
and un-rooted stage II shoots are planted in pots or in
suitable compost mixture.
5. StageV: In this stage, the major activity of micro
propagation occurs in a defined culture medium. Stage II
mainly involves multiplication of shoots or rapid embryo
formation from the explant.
7. Approaches involved in Micropropagation
1. Multiplication by axillary buds/apical shoots.
2. Multiplication by adventitious shoots.
Besides the above two approaches, the plant regeneration
processes namely organogenesis and somatic embryo-
genesis may also be treated as micro propagation.
3. Organogenesis:The formation of individual organs such
as shoots, roots, directly from an explant or from the
callus and cell culture induced from the explant.
4. Somatic embryogenesis:The regeneration of embryos
from somatic cells, tissues or organs.
8. 1 Multiplication by axillary buds/apical shoots.
Actively dividing meristems are present at the axillary
buds and apical shoots (shoot tips).
The axillary buds located in the axils of leaves are capable
of developing into shoots.
By means of induced in vitro multiplication in micro
propagation, it is possible to develop plants from
meristem and shoot tip cultures and from bud cultures.
9. Shoot tip cultures-
Apical meristem is a dome of tissue located at the
extreme tip of a shoot.The apical meristem along with the
young leaf primordia constitutes the shoot apex.
10. Meristem or shoot tip is isolated from a stem by aV-
shaped cut.The size (frequently 0.2 to 0.5 mm) of the tip
is critical for culture. In general, the larger the explant
(shoot tip), the better are the chances for culture survival.
For good results of micro propagation, explants should be
taken from the actively growing shoot tips, and the ideal
timing is at the end of the plants dormancy period.
The most widely used media for meristem culture are
MS medium andWhite’s medium.
11.
12. In stage I, the culture of meristem is established. Addition
of growth regulators namely cytokinins (kinetin, BA) and
auxins (NAA or IBA) will support the growth and
development.
In stage II, shoot development along with axillary shoot
proliferation occurs. High levels of cytokinins are required
for this purpose.
Stage III is associated with rooting of shoots and further
growth of plantlet.
Consequently, stage II medium and stage III medium should
be different in composition.The optimal temperature for
culture is in the range of 20-28°C (for majority 24-26°C).
Lower light intensity is more appropriate for good micro
propagation.
13. Bud Cultures-
The plant buds possess quiescent or active meristems
depending on the physiological state of the plant.Two types
of bud cultures are used— single node culture and axillary
bud culture.
Single node culture:This is a natural method for vegetative
propagation of plants both in vivo and in vitro conditions. A
bud along with a piece of stem is isolated and cultured to
develop into a plantlet. Closed buds are used to reduce the
chances of infections. In single node culture, no cytokinin is
added.
14.
15. A). Shoot initiation from nodal part. (B). Multiplication & elongation of
shoots. (C). Rooting of in vitro formed shoots (D & E). In vitro hardening of
rooted shoots. (F). Ex vitro hardening. (G). 1 year old plant in pot.
16. Axillary bud culture: In this method, a shoot tip along with
axillary bud is isolated.The cultures are carried out with high
cytokinin concentration. As a result of this, apical dominance
stops and axillary buds develop. A schematic representation
of axillary bud culture for a rosette plant and an elongate
plant is given as follows.
17. For a good axillary bud culture, the cytokinin/ auxin ratio is
around 10: 1.This is however, variable and depends on the
nature of the plant species and the developmental stage
of the explant used. In general, juvenile explants require
less cytokinin compared to adult explants. Sometimes,
the presence of apical meristem may interfere with
axillary shoot development. In such a case, it has to be
removed.
18. 2 Multiplication by adventitious shoots .
The stem and leaf structures that are naturally formed
on plant tissues located in sites other than the normal
leaf axil regions are regarded as adventitious shoots.
There are many adventitious shoots which include
stems, bulbs, tubers and rhizomes.The adventitious
shoots are useful for in vivo and in vitro clonal
propagation.
The meristematic regions of adventitious shoots can be
induced in a suitable medium to regenerate to plants.
19. Adventitious shoots and roots developed from an immature leaf explant on
induction medium containing IAA (a) NAA (b).Adventitious shoots developed
from an immature leaf explant on induction medium containing BA (c)
20. 3 Organogenesis
Organogenesis is the process of morphogenesis
involving the formation of plant organs i.e. shoots,
roots, flowers, buds from explant or cultured plant
tissues. It is of two types i.e direct organogenesis and
indirect organogenesis.
Direct organogenesis-Tissues from leaves, stems, roots
and inflorescences can be directly cultured to produce
plant organs. In direct organogenesis, the tissue
undergoes morphogenesis without going through a callus
or suspension cell culture stage.
Indirect organogenesis-When the organogenesis occurs
through callus or suspension cell culture formation, it is
regarded as indirect organogenesis. Callus growth can be
established from many explants (leaves, roots,
cotyledons, stems, flower petals etc.) for subsequent
organogenesis.
21. Micro Propagation of plant by organogenesis-a) Direct organogenesis
b) Indirect organogenesis through callus c) Indirect organogenesis
through suspension culture
22.
23. In general, the bigger the explant the better the chances for
obtaining viable callus/cell suspension cultures. It is
advantageous to select meristematic tissues (shoot tip, leaf,
and petiole) for efficient indirect organogenesis.This is
because their growth rate and survival rate are much better.
For indirect organogenesis, the cultures may be grown in
liquid medium or solid medium. Many culture media (MS, B5
White’s etc.) can be used in organogenesis.The
concentration of growth regulators in the medium is critical
for organo- genesis.
24. 4. Embryogenesis.
The process of regeneration of embryos from somatic
cells, tissues or organs is regarded as somatic (or asexual)
embryogenesis.
Somatic embryos are structurally similar to zygotic
(sexually formed) embryos, and they can be excised from
the parent tissues and induced to germinate in tissue
culture media.
Two routes of somatic embryogenesis are known — direct
and indirect.
Direct Somatic Embryogenesis-When the somatic
embryos develop directly on the excised plant (explant)
without undergoing callus formation, it is referred to as
direct somatic embryogenesis .This is possible due to the
presence of pre-embryonic determined cells (PEDQ found
in certain tissues of plants.
25. Indirect Somatic Embryogenesis- In indirect
embryogenesis, the cells from explant (excised plant
tissues) are made to proliferate and form callus, from
which cell suspension cultures can be raised. Certain cells
referred to as induced embryo genic determined cells
(IEDC) from the cell suspension can form somatic
embryos.
Embryogenesis is made possible by the presence of
growth regulators (in appropriate concentration) and
under suitable environmental conditions.
26.
27. Somatic embryogenesis (direct or indirect) can be
carried on a wide range of media (e.g. MS,White’s).The
addition of the amino acid L-glutamine promotes
embryogenesis.The presence of auxin such as 2, 4-
dichlorophenoxy acetic acid is essential for embryo
initiation. On a low auxin or no auxin medium, the
embryo genic clumps develop into mature embryos.
Indirect somatic embryogenesis is commercially very
attractive since a large number of embryos can be
generated in a small volume of culture medium.The
somatic embryos so formed are synchronous and with
good regeneration capability.
28. Applications of Micro propagation
Micro propagation has become a suitable alternative to
conventional methods of vegetative propagation of
plants.There are several advantages of micro
propagation.
High Rate of Plant Propagation- Through micro
propagation, a large number of plants can be grown from
a piece of plant tissue within a short period. Another
advantage is that micro propagation can be carried out
throughout the year, irrespective of the seasonal
variations.
Production of Disease-free Plants- It is possible to
produce disease-free plants through micro propagation.
Meristem tip cultures are generally employed to develop
pathogen-free plants .
29. Cost-effective Process- Micro propagation requires
minimum growing space.Thus, millions of plant species
can be maintained inside culture vials in a small room in
a nursery.
Production of seeds in some crops- Micro
propagation, through axillary bud prolife- ration
method, is suitable for seed production in some plants.
This is required in certain plants where the limitation for
seed production is high degree of genetic conservation
e.g. cauliflower, onion.
It is the only viable method of regenerating genetically
modified cells after protoplast fusion.
Micropropagation often produces more robust plants,
leading to accelerated growth compared to similar plants
produced by conventional methods - like seeds or
cuttings.
30. Disadvantages of Micropropagation
Contamination of Cultures- During the course of micro
propagation, several slow-growing microorganisms (e.g.
Eswinia sp, Bacillus sp) contaminate and grow in cultures.
The microbial infection can be controlled by addition of
antibiotics or fungicides.
Brewing of Medium- Micro propagation of certain plants
(e.g. woody perennials) is often associated with
accumulation of growth inhibitory substances in the
medium. Chemically, these substances are phenolic
compounds, which can turn the medium into dark colour.
Phenolic compounds are toxic and can inhibit the growth
of tissues. Brewing of the medium can be prevented by
the addition of ascorbic acid or citric acid or polyvinyl
pyrrolidone to the medium.
31. Disadvantages of Micropropagation
GeneticVariability -When micro propagation is carried
out through shoot tip cultures, genetic variability is very
low. However, use of adventitious shoots is often
associated with pronounced genetic variability.
Vitrification-During the course of repeated in vitro shoot
multiplication, the cultures exhibit water soaked or almost
translucent leaves. Such shoots cannot grow and even
may die.This phenomenon is referred to as vitrification.
This can be be prevented by increasing the agar
concentration (from 0.6 to 1%) in the medium. However,
increased agar concentration reduces the growth rate of
tissues.
For some micro propagation techniques, expensive
equipment, sophisticated facilities and trained manpower
are needed.This limits its use.