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In vitro Regeneration System for
Indirect Somatic Embryogenesis in
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ID. No:- PALB 3235
Sr. M.Sc. (Plant Biotech)
Definition of Somatic Embryogenesis.
Stages of Somatic Embryogenesis.
Process involved in formation of Somatic Embryos.
Types of Somatic Embryogenesis.
Factors affecting Somatic Embryogenesis.
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Stages of ZYGOTIC Embryogenesis:-
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Somatic embryogenesis is a process by which
somatic cells or tissues develops into differentiated
Embryos regenerate from somatic cells or tissues (
haploid or diploid etc) it is termed as Somatic
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Somatic embryogenesis was first induced in
suspension culture (Stewart et al, 1958) and in callus
culture (Reinert, 1959) of carrot, Umbelliferae and
Solanaceae dicotyledonous families have produced
SE occur most frequently in tissue culture as an
alternative organogenesis for regeneration of whole
Somatic embryos are referred to by many names such
as embryo like structures, adventitious or vegetative
embryos, Embryoids; and the process is termed as
adventitious , asexual or somatic embryogenesis.
Stages of Somatic Embryogenesis:-
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Development and Maturation
Germination and Conversion
• Globular stage: Embryo
is small and round
• Heart stage (Bilateral symmetry):
Shape changes to heart
shape with more
• Torpedo shaped stage:
Consists of initial cells
for the shoot/root
• Mature stage: Embryo
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Auxin required for induction
Pro embryonic masses are formed.
2,4-D are mostly used.
NAA, DICAMBA are also used.
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• Auxin must be removed for embryo development.
• Continuous use of Auxin inhibits embryogenesis.
• Stages are similar to those of Somatic embryogenesis:-
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Embryo are mature with apical meristem, radicle and
Often obtained repetitive embryony.
Storage protein production necessary.
Often require ABA for complete maturation.
ABA often required for normal morphology.
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Morphological Stages of Maize cv. Gaurav
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Types of Somatic Embryogenesis:-
Two types of somatic embryogenesis
Direct somatic embryogenesis
The embryos initiate directly from explants in the
absence of callus formation. Embryos are formed due
to PEDCs cell.
Indirect somatic embryogenesis
Callus from explants takes place from which embryos
are developed. Embryos are formed due to IEDCs cells.
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Examples of Direct Somatic Embryogenesis:-
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Figure :- Isolation of mature embryo from imbibed durum grain.
Isolated mature embryo which will be inoculated with abaxial
surface in contact with culture medium.
Ganeshan et al., 2006.
Mature embryos culture in the Murashige and Skoog,
1962 medium with supplements 1gm/l enzymatic
casein hydrolysate, 0.7 gm/l L-proline.
4.5 µM of TDZ and 4.4 µM of BAP are best combination
of growth regulators in which Durum Wheat produced
35 number of shoots per explant and Mature embryos
of CDC Dancer oat produced 16 shoots per explant.
Explants for direct embryogenesis include microspores,
ovules, scutellum, endosperm, embryos and seedlings.
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Indirect Somatic Embryogenesis:-
In Indirect SE, callus is produced from explants.
Embryoids are produced from callus tissue.
Explants are roots, shoots, leaf cells, anthers, seeds
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a) Formation of callus b) Greening of callus c) Embryo at globular stage
d) Torpedo stage of embryo e) Cotyledonary stage and regeneration
of embryo f-g) Multiple shoot regeneration h) Complete plantlets i)
Hardening of plantlets. (Rice Variety:- Swarna)
Mondal et al., 2011
(a) (b) (c) (d)
(e) (f) (g) (h)
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Steps involved in Plant regeneration of Rice variety through Indirect SE:-
Factors affecting Somatic Embryogenesis:-
Genetically engineered / transgenic plant does
not regenerate through SE.
Methylation occurs in the DNA during mitosis
then SE occurs. If Methylation occur in the
cytosine bases or H3 protein then SE get stop.
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Totipotent somatic cell are used.
Immature inflorescence and Scutellar tissue of
immature seeds are used for the research. Ex:-
Triticum aestivum .
Epidermis, Procambial tissue are also produced
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Polar transport of auxin produces somatic embryo.
Auxin concentration will be more then somatic
embryogenesis get stop. Ex:- Maize.
Auxin induces indirect somatic embryogenesis in monocots.
During Proembryonic phase, 2,4-D generates DNA Hyper
methylation so that cells in a highly active mitotic stage.
High concentration of auxin produces root in somatic
2,4-D is one of the growth regulator that produces callus
from cereals and conc. of 2,4-D 0.1-10µM
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Cytokinin promote axial growth.
Cytokinin produces globular embryo from initial
Cytokinin combination with auxin, induces somatic
embryogenesis and produce callus in cereals.
Cytokinin ratio more than auxin then it produces
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5) Gibberellic acid:-
GA promote elongations of embryo axis, cell division.
It synthesized of photosynthetic pigments in developing
It improve photosynthetic activity, Extra storage reserves in
Hypo cotyledon are used as explant then GA inhibit somatic
GA higher in suspensory embryo than the proper embryo.
Addition of Uniconazole, Paclobutrazol inhibit somatic
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6) Abscisic acid (ABA):-
ABA control tolerance and seed dormancy during later
stage of embryogenesis.
ABA induced somatic embryogenesis in high osmotic
stress and high temperature in auxin free medium.
Primary embryo contain more conc. of ABA than
Treatment of Fluridone inhibit ABA synthesis and
primary embryo does not produce secondary embryo.
Spermidine, Spermine and Putrescine are added as
growth regulators and secondary messenger.
Polyamines serve as nitrogen source for plants.
It act as a free radical scavengers by protecting
senescing membranes against lipid per oxidation.
In Maize, Putrescine are most effective with varying
concentration of GA3.
Spermine act as a antioxidant in a medium.
It help in vegetative growth, pollen development,
regulation of DNA duplication, transcription of genes,
cell division, development of organs.
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It modulate the culture media.
It promote cell division of embryogenic cells, in
Phytosulfokine increases the cell through
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9) Phenolic compounds:-
Phenolic compounds are inhibit somatic
4hydroxy benzyl alcohol inhibits the globular stages.
Vanillyl benzyl ether are inhibit the suspensor
Recently identification of 4 [(phenyl methoxy) methyl]
phenol involves in seed development stills
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Advantages and Disadvantages of Somatic
Higher propagation rate.
Suitable in Suspension culture.
Artificial seed production.
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Response tissue specific (explants).
Low frequency embryo production.
Incomplete embryo production.
May create unwanted genetic variation (Somaclonal
Inability to generate large numbers of normal, free
Plantlets are weaker.
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Rice is the staple diet for two billion people world wide .
It is feared that world population would be around 10
billion by 2050.
Diminishing of cultivated land.
Attack of pests and insects are responsible for decrease in
There is a constant need to improve crops to overcome all
Somatic embryogenesis in rice has been reported culture of
leaf tissue, root tissue, inflorescence and protoplast.
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Materials and method:-
Explant material for this research were rice seeds.
Variety APMS-6B obtained from DRR (Hyderabad).
Rice caryopses containing Scutellar region of
embryo, were isolated by removing lemma and
palea from the seeds .
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Surface sterilization of Seeds:-
Sterilization of rice caryopses using 70% alcohol for
Followed by shaking in 30% Chlorox containing 2-3
drops of Tween-20 on an orbital shaker at 120 rpm
Explants were rinsed with sterile with sterile double
sterilization water for 6 times.
Cultured onto the medium with different treatment.
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Preparation of Media:-
Two basic media used in this study:-
First one was:- half MS (Murashige & Skoog, 1962)
supplements with 500mg/l glutamine, 100 mg/l
Second one was:- N6 media supplemented with
Both media were solidified with 0.2% agar.
pH adjusted with 5.8.
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Callus Induction Media:-
Different concentrations of 2, 4-D [0.1, 1.5, 2.5,3.5
and 5 mgL-1 (w/v)] were used as the treatments for
embryogenic callus induction.
Media were kept in dark condition for 1 week, 25±2°C
at room temperature.
After 1 week transferred the cultures under 16 hrs
lighting , provided by fluorescent bulbs with 15.75
µmolm-²s-¹ for eight weeks.
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Somatic Embryo Germination Media:-
MS medium containing different concentrations of
BAP (0, 1, 2, 3, 4and 5 mg/l), in combination with
different concentrations of NAA (0, 0.5, 1.0, 1.5, 2.5
and 4.0 mgL-1) were used as treatments for the
germination of somatic embryos.
Media were kept in the incubation room 25±2°C with
16 hrs of light provided by fluorescent bulbs and a
light intensity of 16.75 µmolm-²s-¹ for eight weeks.
Calculate the Callus induction frequency(%) and
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After 3 days of culture callus started to grow from
Embryo derived callus subsequently started to enlarge
and some yellowish to greenish nodules grew around
explants after ten days.
After 2 months of culture calli almost covered the
For callus induction MS medium supplemented with
different concentration of 2,4-D(0, 1.0, 1.5, 2.5, 3.5
and 5 mg/l) was used in which 3.5 , 5 mg/l 2,4-D
showed high callus induction percentage. It can be
observed from Table 1
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Table 1. Callus induction percent of rice in Somatic
S. No Conc. Of 2,4-D (mgL-¹) Callus Induction Frequency % from rice
1. 0 No callus
2. 1.0 76±35
3. 1.5 80±40
4. 2.5 88±45
5. 3.5 95±30
6. 5.0 86±45
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The result showed that the increased concentration of
2,4 –D more than 3.5 mgL-¹ decreased the callus
MS media supplemented with 0.8% agar, 70gm/l
sucrose, 4gm/l Casein, 3mg/l BAP and 4 mg/l NAA
was used for derived calli. 3 mg/l BAP concentration
showed good results in Shoot induction, it can be
observed from Table 3.
4 mg/l NAA concentration showed good results in
Shoot induction, it can be observed from Table 2.
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MS medium supplements with different concentrations
of NAA (0, 0.5, 1.0, 1.5, 2.0 mg/l) in combination with
different concentrations of BAP (0, 1, 2, 3, 4, and 5
mg/l). Result showed that combination of 3mg/l BAP +
1.5 mg/l NAA showed highest result.
Further combination increases cause the decrement of
percent of Shoot induction. It can be observed from
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APMS -6B Variety Seeds Regenerate through
Indirect Somatic Embryogenesis
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Fig 1. Seed inoculation in MS medium Fig 2. Callus formation by 2, 4-D
Fig 3. Shoot induction by differ. Conc. Of
BAP and NAA
Fig -4 Transplantation
Somatic embryogenesis is an efficient plant
It is potentially useful tool for genetic transformation.
Cross linking between hormone and transcription
factors is likely to play an important part in SE.
But mechanism of plant embryogenesis is unclear and
comphrensive work in future is necessary to be studied
with the interaction of various factors for entire picture
of regulatory mechanism of embryogenesis to be
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Indirect Somatic embryogenesis reduces the breeding
Indirect somatic embryogenesis are used in the crop
Indirect somatic embryogenesis are produce virus free
Indirect somatic embryogenesis are better than the
Direct somatic embryogenesis.
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Joshi, R., KUMAR, P., 2013, Regulation of Somatic
Embryogenesis in Crops: A Review, Agri. Reviews, 34
(1): 1-21, 2013.
DHLLION, N. K., GOSAL, S. S., 2013, Analysis of
Maize Inbred Lines for their response to Somatic
Embryogenesis, J. Cell and Tiss. Res, 13(1): 3557-
SAH, SK., KAUR, A., SANDHU, J,S., 2014, High
Frequency Embryogenic Callus Induction and Whole
Plant Regeneration in Japonica Rice Cv. Kitaake, J.
Rice Res., 2: 125.
ANAND, P., TIWARI, A., SAXENA, A., ARNOLD, R.,
TIWARI, S., 2014, Studies on Optimization OF
Protocol for Somatic Embryogenesis and Regeneration
of Rice (APMS – 6B), Euro. J. Mol. Biol. Biochem.,
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