American Journal of Plant Sciences, 2011, 2, 727-732
doi :1 0.4236/ aj ps.2011 .26087 Publ i s hed Online December 2011 (http://www.SciRP.org/journal/ajps)
Copyright © 2011 SciRes. AJPS
727
Advances in Somatic Embryogenesis Research of
Horticultural Plants
Aiqing Ji1,6*, Xueqing Geng2*, Yan Zhang3, Hongyan Yang4, Guoliang Wu5,6#
1Department of Biology Science and Technology, Jinzhong College, Jinzhong, China; 2Department of Plant Cellular and Molecular
Biology, Ohio State University, Columbus, USA; 3Department of Horticultural Science, Xinyang Agricultural Junior College, Xin-
yang, China; 4Jinzhong City Meteorology Bureau of Shanxi Province, Jinzhong, China; 5College of Horticultural Science, Henan
Agricultural University, Zhengzhou, China;6Henan Key Laboratory of Fruit and Cucurbit Biology, Zhengzhou, China.
Email: #walnut-wu@126.com
Received August 8th, 2011; revised September 16th, 2011; accepte d November 10th, 2011.
ABSTRACT
Advances in horticulture plant biotechnologies provide new opportunities for researchers to study the field of vegetative
propagation and genetic engineering. Developments of clonal propagation methods, especially somatic embryogenesis
(SE), have numerous potential applications. This paper reviewed progress of research on SE in horticultural plants in
last decade; analyzed plant regeneration having both direct and indirect SE from the characteristics of occurrence
means, but mainly in an indirect way; and discussed the impact factors of SE, as well as reviewed the research in the
practical applications of horticulture plants SE in the practice.
Keywords: Horticultural Plants, Somatic Embryogenesis, Embryoid
1. Introduction
Plant somatic embryogenesis (SE) research has been in-
vestigated in plant tissue culture in recent years. The de-
finition of SE is that the plant somatic cell develops into a
new plant with the similar progress of zygotic embryo
development [1]. The origination of embryogenesis is di-
fferent between SE and zygotic embryogenesis; however,
both embryogenesis are close in structure and bio-chemi-
cal properties [2]. Plant SE is the expression of plant cell
totipotency, and the successful SE of different plants re-
quires specific cultural environments [3]. The SE research
progress of fruit trees is relativ ely slow compared wit h the
rapid development of vegetables and flowers. Whereas,
due to the nutrient and economic value of fruit trees in
agricultural production, SE of fruit trees has made rapid
progress in the past decade years. The author reviews the
factors that affect SE and its application to the field of
horticulture science in recent years, providing the refer-
ence for future embryogenesis research.
2. The SE Pathway of Horticultural Plants
2.1. The Direct SE Pathway
The definition of direct SE is that e xplants could directly
induce somatic embryos. For example, the immature em-
bryos and cotyledons of peach (Prunus persica L.) [4],
the young embryos of cherry (Prunus avium L.) [5], the
leaves of apple (Malus pumila Mill.) [6], the embryos of
sugar beet (Beta vulgaris L.) [7], the young leaves of
Bartlett (Pyrus communis L.) [8], the flowers of chry-
santhemu m (Dendranthema morifolium) [9], the leaves of
carnation (Dianthus caryophyllus L.) [10] (Yantcheva A.
et al., 1998), the scale leaves of lily (Lilium brownii var.
viridulum) [11], the tender leaf of Kalanchoe bloss-
feldiana [12], and the leaves of Alaenopsis orchid [13]
could all induce the somatic embryos to form regenera-
tion plants.
2.2. The Indirect SE Pathway
The definition of indirect SE is that explants ded ifferenti-
ate to form callus, from which cells differentiate to form
the somatic embryos. For example, the embryos of man-
go (Mangifera indica) [14], the male inflorescences of
banana (Musa paradisiaca) [15], the leaves of grape (Vi-
tis vinifera) [16], the bulb stems of garlic (Allium sati-
vum L.) [17], the cotyledons of cucumber (Cucumis sa-
tivus) [18], and the young stems of Poinsettia (Euphorbia
pulcherrima Willd) [19] and gypsophila (Gypsophila pa-
niculata L.) [20] all could form somatic embryos and de-
velop to regenerate plants by indirect SE.
In addition, some plants could induce somatic embryos
*These auth ors cont ribut ed equally to this work.
Advances in Somatic Embryogenesis Research of Horticultural Plants
728
by both direct and indirect SE. Examples include Chry-
santhemum morifo lium [21,22], cucumber [23], orchid [13],
and walnut [24].
3. The Impact Factors for SE of
Horticultural Plants
3.1. Genotypes and Explants
The genotype is the key factor in affecting plant SE. The
frequency of SE has been shown to be quite diverse be-
cause of genotypic variation, even within the same genus.
Not all of the species of an induced genus can be induced
for SE. Because of the difference of genotypes, the extent
and frequency of SE of the same variety are distinct.
Yang et al.’s [25] research indicated that Yesanhan cu-
cumber is an ideal genotype for SE of cucumber. When
immature cotyledons from three sour cherry cultivars
were tested, the ability to induce SE under identical cul-
tural conditions and age of materials ranged from 41.43%
to only 14.88% [24]. Different Early varieties of walnuts
(Xiangling and Yuanfeng) have distinct frequencies of
inducing somatic embryos when using the same explants
[26]. There are only 5 species and 3 hybrids of walnut
that have been reported to induce SE successfully de-
pending on genotypes and explants [24]. Wang et al.’s
study indicated the frequencies of callus and SE of 8
vegetable soybeans (Phaseolus vulgaris Linn.) with im-
mature cotyledons were associated with their genotypes
[27]. Bian et al. [28] have shown that the distinct geno-
types of cyclamen (Cyclamen persicum Mill) play a very
important role in inducing SE. The different frequency of
SE, which is widely considered to pertain to their opti-
mal inducible conditions, leads to various results. How-
ever, the specific inducible conditions could not easily be
grasped by the researchers.
The status of physiology and development of explants
impacts the SE. In general, the tissue with the highest
level of metabolism and lowest level of differentiation
would promote the induction of SE [29]. The inner fila-
ment base of Spathiphyllum floribundum is relatively
easy to induce SE [30]. It has been shown that callus in-
duction varied in different Euphorbia pulcherrima tis-
sues, with the order of young stem > young inflorescen-
ces > young leaf [31]. The cotyledons of Citrtullus lana-
tus cv. Zhengkang No.4 placed facing down on the me-
dium have higher somatic callus induction rates than
when facing upwards [32]. It has been shown that the
shoot apexes of Clematis Multi-Blue (Clematis florida
Thunb) have the best ability to induce SE among young
leaves, stem tips, and young stems [33]. Xin et al.’s [34]
research indicated that the leaves of Anthuriuln andra-
eanum are much easier to induce SE than other explants.
The callus formed on the apical end of walnut petioles
exposed to the air is the real embryonic callus [35]. The
research already indicated that the SE of the immature
embryo of walnuts is better than that of mature embryo,
and 6 to 11-week-old cotyledons of walnut (J. regi a) after
pollination had a relatively high ability to induce SE [24],
while Eastern black walnut (J. nigra) needed 12 - 14
weeks after pollination. During the induction of SE from
inflorescence explants of Freesia ref racta, all soma tic em-
bryos appeared exclusively at the original morphological
lower end, while no embryo was formed at the morpho-
logical upper end; these results were irrespective of grav-
ity and the position of the explants on the medium [36].
Xin et al.’s [34] results indicated that the leaf sections of
Anthuriuln andraeanum were suitable explants and ex-
pressed higher embryogenic potential than other explants.
Therefore, selecting the distinct explants is the key factor
of inducing SE.
3.2. The Base Medium
The components of the base medium play a complex role
in SE. There are mainly 5 different media for the SE of
horticultural plants: MS, SH, B5, DKW and WPM. MS is
the basal media for the culture. Dewald and Wang [37]
indicated that the effect of improved B5 was better than
MS or WPM for the study of SE of mango. When ap-
plied on improved B5 media, it would induce normal
cotyledons, and most of the somatic embryos developed
normally at the early stage of heart-shape embryo. DKW
is the best media for inducing the SE of walnut, but the
effect of WPM is much better than DKW for the SE of
black walnut. Under the same conditions, the frequency
of SE of young embryos of walnuts in MS media is
higher than in DKW; nonetheless, the frequency of the
SE of cotyledons of walnuts in DKW media is higher
than in MS. WPM has no effect on SE of both young
embryos and cotyledons [24]. In summary, the SE of
horticultural plants has different requirement for the me-
dia depending on the variation of genotypes, explants,
and species of plants.
3.3. Plant Growth Regulators (PGR)
The effect of PGR is an important factor impacting SE
and plant regeneration. In most cases, successful plant SE
needs a mixture of the different concentration ratios of
auxin and cytokinin (CTK), both of which are neces- sary
for plant culture in vitro.
In general, 2,4-dickorophenoxyacetic (2, 4-D), which
is one of the most important hormones inducing SE, has
been widely used in horticultural plants. For instance,
Papaya (Chaenomeles sinensis Koehne) [38], Grape (Vi-
tis vinifera) [16], Peach (Prunus persica L.) [4], Ameri-
can chestnut (Castanea dentata) [3 9], Mango (Mangifera
indica) [14], Rocket (Eruca Sativa Mill) [40], Lily [11].
Copyright © 2011 SciRes. AJPS
Advances in Somatic Embryogenesis Research of Horticultural Plants729
The other type of auxin instead of 2.4-D would inhibit the
SE. Nevertheless, the effect of 2.4-D was less than naph-
thaleneacetic acid (NAA) and indole-3-acetie acid (IAA)
at inducing the SE of Citrus (Citrus reticulata Banco.) [1]
and Gladiolus (Gladiolus hort.) [41], and 2, 4-D is inva-
lid and even hampers SE on Cherry [5] and Begonia
gracilis [42]. Depending on the different stage of devel-
opment of somatic embryos, 2,4-D would pro- mote in-
ducing the production of embryo callus, but in- hibiting
the embryoid differentiation stage. For instance, 2,4-D
could induce synthesis of the embryonic proteins during
SE of Lily, but it would inhibit the synthesis of protein
for the development of an embryoid. Therefore, it would
induce the somatic embryo of Lily scales when cultured
in media containing 2,4-D around 15 d following transfer
to the media without any PGR [11]. However, not all
plants requires 2,4-D for SE. IAA is necessary to induce
SE of Begonia cathayana Hemsl, but 2,4-D does not
have any effect on it [42]. Picloram would induce the
SE of banana rather than 2,4-D [43]. The somatic em-
bryo of Gladiolus could be induced in media containing
NAA but not in media containing other PGR [41].
The reasonable ratio of CTK and auxin is one of the
major factors to induce horticultural plant SE. The high
efficiency of SE in poinsettia depends on the ratio of
CTK to auxin [3 1]. The hi gh rat io of auxi n to CTK wo uld
promote the SE of American chestnut [39], Bego- nia
cathayana Hemsl [42] and Cyclamen [44], whereas a
high ratio of CTK to auxin would promote apple SE. It is
a requirement of two types of auxin and CTK to induce
direct SE for Chrysanthemum morifolium [22], but wal-
nut [45] and peach [4] require two types of CTK and IAA
to induce SE.
Gibberellic acid (GA) and Abscisic acid (ABA) are not
necessary for the induction of SE. GA has been shown to
promote SE for Apple, Pear, Garnetberry, and Cherry and
also plays an inhibition role in Citrus SE [2]. ABA has
promoting or inhibitory effects depending on the specific
plant. Wei et al. [43] had shown that ABA inhibited the
SE of banana embryogenic suspension callus (ESC), and
the extent of callus increased with increasing ABA con-
centration in the media. Different plants have specific re-
quirements for ABA concentration. For example, increased
concentrations of ABA (100 mmol·L–1) was re- quired for
high quality somatic embryos of cherry to induce forma-
tion [5]. However, the SE of Papaya would form in me-
dium containing only A BA [38].
In a word, different PGR have diverse specialties, and
a variety of explants have different requirements for these
hormones. Considering the specificity of PGR re- quire-
ment of explants, different types of PGR have to be ap-
plied in a reasonable ratio to promote the growth and
development of SE.
3.4. Nitrogen Source, Carbon Source, and
Natural Addition
The distinct types and amounts of nitrogen play a signi-
fica nt role i n SE. In general, the M S which cont ains hig h
amounts of NH4NO3 is always used in inducing SE. Dif-
ferent amino acids have distinct roles in plant SE. For
example, Serine, Glntamine, Asn, and Ala promote SE.
The effect of L-proline is the best one to promote petiole
SE of apple among these 4 amino acids [6]. It has been
shown that nitrogen-containing compounds could also
promote SE instead of NH+4, but the effects of these com-
pound s were less than that of NH+4.
Carbon as the energy source of explants balances os-
motic pressure and plays an important role in plant SE. Li
et al. [46] have sho wn t hat ga r l ic SE co uld b e adj uste d b y
different concentrations of sucrose. In brief, the su- crose
of 10 - 30 g·Kg–1 could promote garlic SE, but su- crose
over 60 g·Kg–1 could inhibit the growth and deve- lop-
ment of garlic SE. The distinct sources of carbon also
impact embryogenesis. For instance, taking the cotyle-
don of melon “GT-1” as explants, indirect embryogene-
sis occurred when glucose was used as the carbon source,
while direct embryogenesis was observed when the me-
dium contained lactose [47]. Citrus SE efficiency in-
creases 6 - 12 times by combining lactose with galactose
insteading of sucrose alone [26]. Cucumber SE effici-
ency increases by combining mannitol with sucrose as
the source of carbon [25]. However, sucrose induced
cotyledon SE of Melon (Cucumis melo), but mannitol did
not [48]. The effect of white sugar with 10 - 40 g·L–1 as
the source of carbon is the best to induce the formation of
somatic embryos among sucrose, glucose, and maltose
when inducing Chinese chestnut SE; nevertheless, the
mortality of American chestnut explants increases with
increasing sugar concentration [39]. Longan (Dimocar-
pus longgana Lour) so matic e mbryos would fo rm mat ure
embryoids at high sugar concentration (50 g·L–1), but the
transparent somatic embryos would lead to immature
embryoids at low sugar concentration (20 g·L–1) [2].
The natural additions of hydrolyzed casein (CH), malt
wort (ME), and coconut wort (CW) as the cultural media
provide more reduction of N than inorganic N, which
plays a specific role in inducing SE. However, natural
additions play a variety of roles in specific species of
plants because of the complex assortments of compo-
nents in natural additions.
CH induces SE in many horticultural plants, such as
grape, peach, sweet cherry, walnut [2], garlic [17], and
celery [29]. In addition, CH promotes the formation of
mature embryoids of leechee and high quality SE of poin-
settia [49]. ME containing less P plays a specific role in
promoting citrus SE at the ME concentration of 500 -
1000 mg·L–1 without the addition of PGR in the medium
Copyright © 2011 SciRes. AJPS
Advances in Somatic Embryogenesis Research of Horticultural Plants
730
[2]. Some scientists consider that ME is necessary for
inducing SE of citrus. CW, which contains many compo-
nents, has the obvious effect of promoting SE of many
horticultural plants. For instance, the growth and deve-
lopment of the somatic embryoid of Papaya had been
promoted with the addition of 2% CW in the media [38].
The nucellus embryo SE efficiency of mango increased
18% and has a big volume of embryoids and very little
abnormal embr yoids with the additio n of 20% CW in the
media. In addition, CW also promotes the growth and
devel opment o f longan SE. On t he contra ry, CW i nhibits
SE of pear and apple [1].
4. Application of SE in Horticulture Plants
SE research has broad application prospects e.g., genetic
engineering, germplasm preservation, seedling fast breed-
ing, artificial seeds, hybrid zygotic embryo rescue, in-
duced culture of somatic cell hybrids, haploid, triploid,
and the individual choice of cell-induced mutations, and
breeding, which have high importance in scientific re-
search as well as great economic value in production.
Briefly, three main aspects of applications of SE of hor-
ticultural plants will be discussed.
4.1. Rapid Propagations of Horticultural Plants
by SE
The very high commercial value resulting from tissue
culture techniques (i.e., rapid multiplication of superior
cultivars and rootstock asexual reproduction) has already
been demonstrated. In comparison to organogenesis, the
advantage of SE is to generate the intact plant with the
apical meristem and the primary root, avoiding a series of
orga nogenesi s pro blems: se nesce nce, re juvena tion, r hizo-
genesis and difficult to transfer into soil. Therefore, SE
has developed into an important research field in recent
years. A typical example is to carry out embryonic callus
suspension culture by using grape; there are a number of
somatic embryos produced after 20 d by subculturing
grape [1].
4.2. The Transgenic Engineering of Horticultural
Plants with Somatic Embryos as the
Receptor
With the rapid development of modern molecular biolo-
gy techniques, molecular genetic breeding has become
the important complemental method of traditional breed-
ing to improve plant germplasms. In general, somatic
embryos are originated from single cells, and the chimera
frequency is very low; both of these advantages make it
easy for the application towards breeding transgenic plants.
Meanwhile, the simple operation, short cycle, and high
transformation efficiency are advantages inducing em-
bryo calluses as the receptors of transgenic plants. Cur-
rently, there ar e many s ucce ss ful plan t tra ns formatio ns ( e.g.,
Chrysa nthemu m [21] , Rose (Rosa rugosa) [ 50] , Eggp lant
(Solanum melongena Linn.), papaya [38], Walnut [51],
Peach [52], Cherry [53], and Litchi (Litchi chinensis) [54].
In addition, genes have been expressed on the level of
cell or calluses in some trees by transformation techni-
ques. Comparing the success ful transgenic engineering us-
ing somatic embryos as the recipients in foreign, our SE
research is at the beginning of stage, we could expect that
transgenic SE engineering would have a very broad ap-
plication in future.
4.3. Other Applications of SE in Horticultural
Plants
In addition to the application of rapid breeding and trans-
genic engineering, the application of SE of horticultural
plants has also shown to be applicable towards breed
improvement, like germplasm resource preservation, and
protoplast culture. The plant somatic embryos provide a
model experimental system studying plant cell develop-
ment and differentiation, the expression of plant totipo-
tency, crop improvement, and mutant screening. All of
these is very important in both in theory and practical
application. Endangered plant species could be preserved
by the application of embryonic callus techniques under
specific conditions. There are so many asexual cell lines
produced during SE, which provide the material for scr-
eening mutants, cell fusing, protoplast regeneration, cell
differentiation, and plant regeneration.
5. The End
Currently, there are problems which still need to be so-
lved in the research of embryogenesis even though some
research achievements have been employed in horticul-
ture and forestry industries. For instances, both the tissue
culture co nditions and e mbryo transitio n efficiency should
be further studied in order to improve the quality and
quantity of embryogenesis; the inheritance stability and
the molecular mechanism of embryogenesis should also
be continued to study in detail. There are mainly two as-
pects on which we should focus in future. On the one
hand, the model system of embryogenesis of horticultu-
ral plants, especially for fruit trees, should be built based
on pr evio us wor ks i n re se nt ye ar s. O n the o the r hand, it i s
really important to carry out systemic research on the
mechanisms of embryogenesis growth and developmental
regulation, regeneration study of genetic variability. All
of this research would promote researchers to further un-
derstand the embryogenesis mechanism, in essence, im-
proving the application of embryogenesis research achieve-
ments in agricu ltural practices.
REFERENCES
[1] K. R. Cui and R. L. Dai, “Molecular Biology of Plant
Copyright © 2011 SciRes. AJPS
Advances in Somatic Embryogenesis Research of Horticultural Plants731
Somatic Embryogenesis,” Science Press, Beijing, 2000,
pp. 48-54.
[2] Y. J. Chen and Z. X. Lai, “Researches and Utilization of
Somatic Embryogenesis in Fruits and Trees,” Journal of
Fujian Agricultural University, Vol. 30, No. 3, 2001, pp.
420-426.
[3] X. L. Huang and Y. J. Li, “Morpho genesis and Regu lat ion
of Higher Plant Organ Culture in Vitro,” Science Press,
Beijing, 1995, pp. 46-72.
[4] G. H. Yan and Y. Zhou, “Plant Regeneration from Ex-
cised Immaturate Embryos of Peach (Prunus persica L.), ”
Acta Horticulturae Sinica, Vol. 29, No. 5, 2002, pp. 480-
482.
[5] G. March, E. Grenier, N. Miannay, G. Sulmont, H. David
and A. David, “Potential of Somatic Embryogenesis in
Prunus avium Immature Zygotic Embryos,” Plant Cell, Ti-
ssue and Organ Culture, Vol. 34, 1993, pp. 209- 21 5.
doi:10.1007/BF00036104
[6] K. D. Da, S. Zhang, Y. Z. Li and Z. J. Qi, “Direct Somatic
Embryogenesis from in Vitro Leaves of Apple,” Acta
Horticulturae Sinica, Vol. 23, No. 3, 1996, pp. 241-245.
[7] C. L. Zhan g, D. F. Chen , M. Kubalako va, J. Z han g, N. W.
Scott, M. C. Elliott and A. Slater, “Efficient Somatic Em-
bryogenesis in Sugar Beet (Beta vulgaris L.) Breeding
Lines,” Plant Cell, Tissue and Organ Culture, Vol. 93,
2008, pp . 209-221. doi:10.1007/s11240-008-9364-2
[8] Q. R. Sun, Q. Z. Liu and R. H. Zhao, “Somatic Embryo
Genesis from in Vitro Leaves of P ear, ” Acta Horticulturae
Sinica, Vol. 30, No. 1, 200 3 , pp. 85-86.
[9] A. K. A. Mandal and S. K. Datta, “Direct Somatic Em-
bryogenesis and Plant Regeneration from Ray Florets of
Chrysanthemum,” Biologia Plantarum, Vol. 49, No. 1,
2005, pp. 29- 3 31 1. doi:10.1007/s10535-005-0033-6
[10] X. M. Liu, P. H. Zhou, S. C. Qu, X. Y. Lu and Z. M. Luo,
In Vitro Induction of Indefinite Bubs and Somatic Em-
bryos from Scale Leave of Tetraploid ‘Longya Lily’,”
Acta Horticulturae Sinica, Vol. 24, No. 4, 1997 , p. 353.
[11] A. Yantcheva, M. Vlahova and A. Antanassov, “Direct
Somatic Embryogenesis and Plant Regeneration of Carna-
tion (Dianthus caryophyllus L.), ” Plant Cell Reports, Vol.
18, 1998, pp. 14 3- 1 53 . doi:10.1007/s002990050548
[12] X. M. Liu, P. H. Zhou, S. C. Qu, X. Y. Lu and Z. M. Luo,
In Vitro Induction of Indefinite Bubs and Somatic Em-
bryos from Scale Leave of Tetraploid ‘Longya Lily’,”
Acta Horticulturae Sinica, Vol. 24, No. 4, 1997 , p. 353.
[13] G. H. Ma and N. Liu, “Direct Somatic Embryogenesis and
Shoot Formation from Cultured Young Leaf of Kalanchoe
blossfeldiana,” Plant Physiology Communications, Vol. 39,
No. 6, 2003, p. 625.
[14] W. P. Gow, J. T. Chen and W. C. Chang, “Effects of
Genotype, Light Regime, Explant Position and Orienta-
tion on Direct Somatic Embryogenesis from Leaf Ex-
plants of Alaenopsis Orchid,” Acta Physiologiae Planta-
rum, Vol. 31, No. 2, 2009, pp. 263-269.
do i:10.1007/s11738-008-0243-6
[15] M. Rivera-Domínguez, M. A. Manzanilla-Ramírez, M.
Robles-González and M. A. Gómez-Lim, “Induction of
Somatic Embryogenesis and Plant Regeneration of
‘Ataulfo’ Mango (Mangifera indica),” Plant Cell, Tissue
and Organ Culture, Vol. 79 , No. 1, 2004, pp. 101-104.
[16] A. Grapin, J. Schwendiman and C. Teisson, “Somatic
Embryogenesis in Plantain Banana,” In Vitro Cellular &
Developmen tal BiologyPlant, Vol. 32, No. 2, 19 96, pp.
66-71. doi:10.1007/BF02823133
[17] C. Robacher, “Somatic Embryogenesis and Plant Regen-
eration from Muscadine Grape Leaf Explant,” Hort Sci-
ence, Vol. 28, No. 1, 1993, pp. 53 - 55.
[18] L. Fereol, V. Chovelon and S. Causse, “Evidence of a
Somatic Embryogenesis Process for Plant Regeneration in
Garlic (Allium sativum L.),” Plant Cell Reports, Vol. 21,
No. 3, 2002, pp. 197-203.
do i:10.1007/s00299-002-0498-0
[19] K. M. S. Elmeer and M. J. Hennerty, “Observations on the
Combined Effects of Light, NAA and 2,4-D on Soma-
ticembryogenesis of Cucumber (Cucumis sativus) Hy-
brids,” Plant Cell, Tissue and Organ Culture, Vol. 95, No.
3, 2008, pp. 381-384. doi:10.1007/s11240-008-9439-0
[20] L. P. Chen, B. L. Wang and M. F. Chen, “Studies on So-
matic Embryogenesis of Euphorbia pulcherrima in Vitro
Culture,” Plant Physiology Communications, Vol. 35, No.
6, 1999, pp. 463-465.
[21] J. J. Zamorano-Mendoza and J. M. Mejia-Munoz, “In
Vitro Propagation of Gypsophila (Gypsophila paniculata
L.) cv. Perfecta.-Revista-Chapingo,” Horticultural Ser-
vices, Vol. 1, 1994, pp. 67-71.
[22] X. W. Jiang and Q. X. Zhang, “Studies on Transgenic
Acceptor System of Ground-Cover Chrysanthemum via
Indirect Somatic Embryogenesis,” Forest Research, Vol.
20, No. 3, 2007 , pp. 328-333 .
[23] X. W. Jiang, F. J. Chen, M. Lu, M. Cai and Q. X. Zhang,
“Direct Somatic Embryogenesis in Ground-Cover Chry-
san-Themum,” Journal of Beijing Forestry University,
Vol. 30, No. 2, 2008, pp. 65-70.
[24] K. H. G. Ashok, H. N. Murthy and K. Y. Pack, (2003).
“Embryogenesis and Plant Regeneration from Anther Cul-
ture of Cucumis sativus L. ,” Scientia Hoticulture, Vol. 98,
No. 2, 2003, pp. 213-222.
doi:10.1016/S0304-4238(03)00003-7
[25] H. R. Tang, Y. Q. Wang and Z. L. Ren, “An Overview of
Progress on Somatic Embryogenesis and Transformation
in Walnut,” Scientia Silvae Sinicae, Vol. 36, No. 3, 2000,
pp. 102-110.
[26] A. F. Yang, Y. M. Zhu and A. J. Hou, “Several Factors
Affecting Somatic Embryos Derived from Cotyledons of
Cucumber (Cucumis sativus), ” Plant Physiology Commu-
nications, Vol. 39, No. 3, 20 03, pp. 206-208.
[27] W. S. Chen and S. C. Su, “The Di fference and Occurrence
of Somatic Embryogenesis in Early Varieties of Walnut,”
Science & Technology Information, Vol. 16, 2006, pp.
176-177.
[28] P. Wang, G. Wang and J. Ji, “Embryogenesis and Regen-
eration from Different of Vegetable Soybean,” Soybean
Science, Vol . 24, No. 4, 2005, pp. 314-316.
Copyright © 2011 SciRes. AJPS
Advances in Somatic Embryogenesis Research of Horticultural Plants
Copyright © 2011 SciRes. AJPS
732
[29] F. H. Bian, F. N. Qu, C. X. Zheng, C. R. You and X. Q.
Gong, “Recen t Advances in Cyclamen persicum Mill. So-
matic Embryogenesis,” Northern Horticulture, Vol. 8,
2007, pp. 70- 7 2.
[30] H. Cui, Z. C. Guo and Y. L. Gui, “Studies on Somatic Em-
bryogenesis and Desiccation Somatic embryos in Celery,”
Acta Botanica Si nic a, Supple m e nt A00, 1993, pp. 94- 100.
[31] S. Werbrouck, T. Eeekhaut and P. Deber, “Induction and
Conversion of Somatic Embryogenesis on the Anther
Filament of spathiphyllum Schott.,” Acta Hort, Vol. 520,
2000, pp . 263-269 .
[32] G. F. Zhu, F. B. Lu, M. L. Chen and B. Q. Wang, (2004).
“Somatic Embryogenesis and Plantlet Regeneration of
Euphorbia pulcherrima,” Subtropical Plant Science, Vol.
33, No. 4, 2004 , pp. 37-38.
[33] S. S. Niu, S. W. Song, F. Yan and H. X. Miao, “Somatic
Embryogenesis and Plantlet Regeneration in Citrullus
lanatus cv. Zhengkang No. 4,” Journal of Fruit Science,
Vol. 23, No. 3, 2006, pp. 406-410.
[34] Q. X. Zhang, Y. M. Fang, M. Lü and N. Chen, “A Pre-
liminary Study on Induction of Adventitious Buds and
Embryogenesis in Clematis Multi-Blue,” Acta Horticul-
tura e Si nica, Vol. 34, No. 2, 2007, pp. 465-468.
[35] W. J. Xin, B. Xu, G. D. Wang, W. M. Guo, F. D. Wen
and J. P. Jin, “Somatic Embryogenesis and Plant Regen-
eration of Anthurium andraeanum,” Acta Horticulturae
Sinica, Vol. 33, No. 6, 2006 , pp. 128 1-1286.
[36] S. L. Liu, B. W. Han and H. Z. Chen, “Somatic Em-
bryogenesis and Cytological Observation from Petiole of
Walnut (Juglans regia L.),” Journal of China Agri c ul t ur a l
University, Vol. 18, 1992, pp. 29-32.
[37] L. Wang, X. M. Bao, B. Q. Huang and S. Hao, “Somatic
Embryogenic Potential Determined by the Morphological
Polarity of the Explant in Tissue Cultures of Freesia Re-
fracta,” Acta Botanica Sinica, Vol. 40, No. 2, 1998, pp.
138-143.
[38] S. G. Dewald and X. F. Wang, “Optimization of Mango
Somatic Embryogenesis,” Tropical Crops Translation Se-
ries, Vol. 1, pp. 25-2 9.
[39] M. M. M. Fitch, “High Frequeacy Somatic Embryogene-
sis and Plant Regeneration from Papaya Hypocotyl Cal-
lus,” Plant Cell, Tissue and Organ Culture, Vol. 32, No. 2,
1993, pp . 205-212.
doi:10.1007/BF00029844
[40] D. T. Carraway, H. D. Wilde and S. A. Merkle, “Somatic
Embryogenesis and Gene Transfer in American Chest-
nut,” Journal of American Chestnut Found, Vol. 8, 1994,
pp. 29-33.
[41] T. Zhang, Z. Y. Cao and X. Y. Wang, “Induction of So-
matic Embryogenesis and Plant Regeneration from Coty-
ledon and Hypocotyls Explants of Eruca Sativa Mill,” In
Vitro Cellular Developmental Biology—Plant. Vol. 41, No.
5, 2005, pp. 65 5- 65 7.
doi:10.1079/IVP2005653
[42] B. Stefaniak, “Somatic Embryogenesis and Plant Regen-
eration of Gladiolus (Gladiolus ho rt.),” Plant Cell Reports,
Vol. 13, No. 7, 1994, pp. 386-389.
doi:10.1007/BF00234143
[43] B. Castillo and M. A. L. Smith, “Direct Somatic Em-
bryogenesis from Begonia gracilis Explants,” Plant Cell
Reports, Vol. 16, No. 6, 19 97, pp. 385- 388.
[44] Y. R. Wei, H. Yang, B. Z. Huang, X. Huang, X. L. Huang,
J. S. Qiu and L. B. Xu, “Effects of Picloram, ABA and
TDZ on Somatic Embryogenesis of Banana,” Acta Hor-
ticulturae Sinica, Vol. 34, No. 1, 2007, pp. 81- 86.
[45] T. Takejiro, M. Ikuo and M. Eisuke, “Somatic Embryo-
genesis of Cyclamen Persicum Mill. ‘Anneke’ from
Aseptic Seedlings,” Plant Cell Reports, Vol. 15, No, 1-2,
1995, pp. 22-25.
[46] W. Tulecke and G. Mcgranahan, “Somatic Embryoge-
nesis and Plant Regeneration from Cotyledons of Wal-
nut,” Juglans regia L. Plant Science, Vol. 40, No. 1, 1985,
pp. 57-6 3. doi:10.1016/0168-9452(85)90163-3
[47] X. Q. Li, S. F. Krasnyanski an d S. S. Ko rban, “Optimiza-
tion of the UidA Gene Transfer into Somatic Embryos of
Rose via Agrobacterium Tumefaciens,” Plant Physiology
and Biochemistry, Vol. 40, No. 5, 2002, pp. 453-459.
doi:10.1016/S0981-9428(02)01394-3
[48] Y. T. Zeng, C. Z. Zhao and L. Lu, “Establishment of Plant
Regeneration System through Somatic Embryogenesis of
Cotyledons of Cucumis melo ‘GT-1’,” Journal of Gansu
Agricultural University, Vol. 42, No. 2, 2007, pp. 39-42.
[49] H. Nakagawa and T. Saijyo, “Effect Sugar and ABA on
Somatic Embryo Formation with Cotyledon Culture of
Melon,” Foreign Crop Breeding, Vol. 21, No. 3, 2002, p.
75.
[50] Y. Xiao and G. Wang, “Studies on High Quality Somatic
Embryogenesis Applied to Artificial Seed of Euphorbia
Pulcherrima Willd,” Acta Horticulturae Sinica, Vol. 33,
No. 1, 2006, pp. 175-178.
[51] B. X. Li and Z. H. Cheng, “Studies on the Induction Fac-
tors of Somatic Embryogenesis in Garlic (Allium sativum
L.),” Journal of Northwest Sci-Tech University of Agri-
culture and Forestry, Vol. 30, No. 5, 2002, pp. 31-34.
[52] H. R. Tang, M. Wallbraun, Z. L. Ren, G. M. Reustle and
G. Krczal, “Genetic Transformation of the Trichoderma
Endochitinase Gene ThEn 42 to Somatic Embryos of
English Walnut,” Acta Horticulturae Sinica, Vo l. 28 , No.
1, 2001, pp. 12-18.
[53] R. Scorza, P. H. Morgens, J. M. Cordts, S. Mante and A.
M. Callahan, “Agrobacterium-Mediated Transformation
of Peach (Prunus persica L. Batch) Leaf Segments, Im-
mature Embryos and Long Term Embryogenic Callus,” In
Vitro Cellular & Developmental Biology, Vol. 26, 1990,
pp. 829- 834. doi:10.1007/BF02623625
[54] G. Q. Song and K. C. Sink, “Transformation of Mont-
morency Sour Cherry (Prunus cerasus L.) a n d Gi se la 6 ( P.
cerasus × P. canescens) Cherry Rootstock Mediated by
Agrobacteri um Tumefaciens,” Plant Cell Report, Vol . 25,
No. 2, 2006, pp. 117-123.
do i:10.1007/s00299-005-0038-9