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1.
Summary The influence of the gaseous composition of the atmosphere inside culturing vessels on somatic embryogenesis and on adventitious
root formation was investigated in the quince clone (Cydonia ablonga Mill.) BA29. Leaves taken from in vitro-grown shoots were cultured in glass Petri dishes and exposed to ventilation with atmospheric air (flow rate 25 ml min−1) for 0, 5, 10, 20, and 40 d. Twenty days of ventilation reduced the frequency of embryogenic leaves and a further decrease
was observed after 40d of treatment. Conversely, adventitious root formation in the ventilated dishes was never different
from the untreated cultures. In a second test, leaves were incubated in atmospheres containing different levels of oxygen
(0, 5.0, 10.0, and 21.0%) or carbon dioxide (0, 0.04, 0.15, 1.5, and 3.0%). Anoxia conditions almost completely inhibited
somatic embryo and adventitious root formation, but without compromising callus formation and explant viability. In contrast,
embryo and root regeneration occurred even in totally CO2-free atmosphere. Oxygen seemed to influence somatic embryogenesis according to a quadratic response; a similar relationship
was also observed for root regeneration. Instead, no clear trend could be inferred between embryo or root regeneration and
CO2 levels. Furthermore, in dishes flushed with gas mixtures containing oxygen or carbon dioxide somatic embryo formation was
almost always lower than in confined dishes. A different result was observed for root regeneration, since the number of roots
was never lower than in the control and increased appreciably with 3.0% CO2. These results demonstrate that atmosphere composition of the culture head-space can influence somatic embryogenesis in quince.
The finding that both vessel ventilation and atmosphere replacement with different gas mixtures reduced somatic embryo formation
suggests that gaseous compounds, different from O2 an CO2, present in the gaseous environment may promote embryogenesis in this species. 相似文献
2.
S. J. Ochatt C. Pontécaille M. Rancillac 《In vitro cellular & developmental biology. Plant》2000,36(3):188-193
Summary The production of whole plants from explants of protein pea (Pisum sativum L.) using an efficient, reliable and rapid strategy, while maintaining trueness to type, will be required before regeneration
can be exploited for genetic transformation. Seeds of the pea genotypes Terese, Solara, Frisson and P64 (a hypernodulating
mutant line of Frisson) were surface-sterilized and imbibed overnight, whereafter embryo axes were dissected and germinated
on hormone-free medium for 7–10 d. Hypocotyl sections lacking pre-existing meristems were harvested and cultured on a range
of media with various concentrations and combinations of growth regulators in order to induce either caulogenesis or somatic
embryogenesis. Differences in responsiveness were apparent between genotypes, but regeneration via caulogenesis was consistently
more reliable than via the induction of somatic embryos. Few explants underwent somatic embryo production and their conversion
into plants has remained elusive so far, irrespective of the genotype studied. Conversely, large numbers of buds were produced
within 10 d by organogenesis, and healthy, rootable shoots were obtained. A clear relationship was observed between the growth
regulators employed for bud regeneration and shoot rooting phases and the subsequent competence of the regenerated plants
for flowering, pod formation and viable seed production. 相似文献
3.
Laurent Bonneau Nicole Beranger-Novat Jeannine Monin Josette Martin-Tanguy 《Plant Growth Regulation》1967,16(1):5-10
In vitro formation of roots and somatic embryos is obtained from cotyledon explants of a Spindle tree (Euonymus europaeus L.) cultured on two different media: a medium inducing callus formation and the production of roots, and a medium inducing callus formation, root and somatic embryo production. We studied the effects of -difluoromethylornithine (DFMO), a specific, irreversible inhibitor of ornithine decarboxylase (ODC) on root and somatic embryo production, growth and titers of putrescine in Euonymus explants and explant-derived calli. Early changes in putrescine levels were detected in both cultures before the visible emergence of roots or somatic embryos. DFMO rapidly inhibited putrescine accumulation and growth in non-embryogenic calli and highly stimulated rooting activity. DFMO partially inhibited putrescine accumulation in embryogenic calli. This inhibition had no effects on callus growth but significantly reduced the time of emergence of roots and highly stimulated somatic embryo production. The relationship among putrescine, putrescine metabolism, growth, root and somatic embryo formation is discussed. 相似文献
4.
Jorge M. Canhoto Sandra C. Rama Gil S. Cruz 《In vitro cellular & developmental biology. Plant》2006,42(6):514-519
Summary Somatic embryos of carob (Ceratonia siliqua L.) were induced from cotyledonary segments excised from immature seeds when cultured on Murashige and Skoog media supplemented
with several combinations of 6-benzylaminopurine (BA) and indole-3-butyric acid (IBA). The best frequencies of induction (33.8%)
were obtained when 4.4 μM BA and 0.5 μM IBA were used. Shoots were also sporadically formed in the same media. When IBA was replaced by other auxins in the induction
media, only α-naphthaleneacetic acid (NAA) and indole-3-acetic acid (IAA) could induce somatic embryogenesis, although at
lower rates than IBA. 2,4-Dichlorophenoxyacetic acid and 4-amino-3,5,6-trichloropicolinic acid were completely ineffective.
Besides culture media composition, the developmental stage of the explants at the time of culture showed a strong influence
on somatic embryogenesis induction, with cotyledons from stage II pods providing the highest levels of induction. By contrast,
the genotype of the explant did not determine a significant role in the induction process. Attempts to achieve somatic embryo
germination were mostly unsuccessful, since only shoot development was observed; the highest frequencies of development occurred
on media containing only gibberellic acid (3.0 μM). For plant regeneration, the developed shoots were further rooted on IBA-supplemented media, and the plantlets obtained
were transferred to soil, where c. 88% of them survived. Histological observations showed the presence of morphologically normal and abnormal somatic embryos,
the latter displaying an abnormal pattern of vascular bundles. Ultrastructural analysis showed that the cells of the globular
embryos had a dense cytoplasm, whereas those not involved in somatic embryo formation showed signs of senescence. Histological
studies were also used to distinguish between somatic embryos and shoots originated in the same media. 相似文献
5.
Summary The effects of increasing concentrations of NaCl and CaCl2 on quince (Cydonia oblonga Mill. BA 29 clone) somatic embryogenesis and adventitious root regeneration were investigated. Leaves collected from in vitro-grown shoots were used as explants and induced for 2d in liquid Murashige and Skoog medium containing 11.3 μM 2,4-dichlorophenoxyacetic acid. Explants were then cultured on semisolid Murashige and Skoog medium enriched with 4.7 μM kinetin and 0.5 μM naphthaleneacetic acid under red light for 25 d and under white light for another 25 d. Two experiments were performed: in
the first, NaCl was used at 0,25, 50, 100, and 200 mM in factorial combination with CaCl2 at 3, 9, and 27 mM; in the second, NaCl was applied at 0, 5, 10, 20, 40, and 80 mM in combination with CaCl2 at 0.3, 1.0, and 3.0 mM. Quince leaves revealed the capacity to regenerate somatic embryos and/or adventitious roots. Quantitative and qualitative
regeneration from leaves was affected by NaCl treatments: increasing NaCl concentrations, in combination with CaCl2 at 1 mM, led to an increase in the proportion of leaves producing somatic embryos only, and to a decrease of both leaves regenerating
roots only and leaves simultaneously producing somatic embryos and adventitious roots. This suggests a beneficial effect of
salt stress on the embryogenic process. The regeneration response decreased with increasing salt concentrations and was almost
totally inhibited above 50 mM NaCl and 9 mM CaCl2. The presence of CaCl2 in the culture medium apparently mitigated the effects of salt stress, but only when NaCl was applied at 40 mM. NaCl at 5 mM, in the presence of 0.3 or 1 mM CaCl2, was favorable both to somatic embryo and root production. No value of the ratio Na+/Ca2+ was found to be optimal for the regeneration processes. 相似文献
6.
Anzidei M. Bennici A. Schiff S. Tani C. Mori B. 《Plant Cell, Tissue and Organ Culture》2000,61(1):69-79
Different NAA plus kinetin or BA combinations were tested on Francia Pernod fennel seedlings for callus induction and plant
regeneration. Callogenesis from hypocotyls was obtained in all auxin/cytokinin-containing media. The organogenic response
was observed especially in presence of NAA plus kinetin. The highest frequency of shoot regeneration was found when the auxin
and kinetin were used at a 1:1 ratio. Moreover, a prolonged culture period increased shoot formation. Somatic embryogenesis
was tested on several fennel populations. The results gave evidence of the genotypic importance. Two different protocols were
used for somatic embryo induction. Using the first protocol among the different fennel genotypes tested, only Francia Pernod
showed embryogenic capacity. In this case, from a primary non-embryogenic callus cultured for 12 months in presence of 2,4-D,
an embryogenic secondary callus was produced. When transferred to the medium without 2,4-D (agarized or liquid), this gave
embryogenic plants in high frequency. As far as the second embryogenic method is concerned, secondary embryogenic callus developed
only in the presence of 2,4-D plus kinetin in Francia Pernod genotype. Thereafter, the replacement of those growth regulators
by GA3 into the medium greatly increased the somatic embryo development, especially in `Francia Pernod', but also in `Aboca erbe'
callus, a population with a very poor embryogenic capacity. In Francia Pernod, the primary and secondary (embryogenic) calli
showed different morphological and histological responses, either when the secondary callus was induced by 2,4-D alone or
by 2,4-D plus kinetin. Ontogenetic processes leading to somatic embryo formation are described in this context.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
7.
Arzu Ucar Turker Esra Cansever Mutlu Arzu Birinci Yıldırım 《Acta Physiologiae Plantarum》2008,30(4):421-426
Epilobium angustifolium L. (fireweed) is a medicinal plant that has been used to treat diarrhea, mucous colitis, irritable-bowel syndrome, skin problems,
prostate problems, menstrual disorders, asthma, whooping cough, and hiccups. A highly efficient and rapid regeneration system
via multiple shoot formation was developed for fireweed. Explants (leaf, petiole, root, and stem segments) excised from sterile
seedlings were cultured on medium supplemented with different concentrations and combinations of various plant growth regulators.
Explant browning, a major problem for regeneration, was overcome by adding 100 mg/l ascorbic acid to all prepared media containing
growth regulator combinations. Root explants formed more shoots than other explants. Best shoot proliferation was obtained
from root explants cultured on media with 0.1 mg/l BA and 0.5 mg/l IAA. Regenerated shoots were transferred to rooting media
containing different concentrations of IAA, IBA, NAA or 2,4-D. Most shoots developed roots on medium with 0.5 mg/l IAA. Rooted
explants were transferred to vermiculate in Magenta containers for acclimatization and after 3 weeks they were planted in
to plastic pots containing potting soil and maintained in the plant growth room. 相似文献
8.
Callus cultures of Encephalartos cycadifolius were established from zygotic embryo explants on a modified B5 medium containing 1 mg l–1 2,4-D and 1 mg l–1 kinetin. Callus was transferred to media containing various combinations of 2,4-D and kinetin for improvement of somatic embryogenesis. Somatic embryos were produced on media with several growth regulator combinations. The somatic embryos developed from proembryos, which developed long suspensors. A dicotyledonary embryo formed at the distal end of the suspensor. The embryos turned green in light. When transferred to a medium containing 1 mg l–1 ABA the somatic embryos matured. The suspensors desiccated and these embryos rooted when transferred to a medium without phytohormones.Abbreviations ABA
abscisic acid
- 2,4-D
2,4-dichlorophenoxyacetic acid 相似文献
9.
A. H. McKently 《Plant Cell, Tissue and Organ Culture》1995,42(3):251-254
Genotypes representing the three botanical varieties of peanut (Arachis hypogaea L.) were assessed for somatic embryogenesis and subsequent plant conversion from mature zygotic embryo axes. Explants were initially cultured on Murashige and Skoog medium supplemented with 12.42 M 4-amino-3,5,6-trichloropicolinic acid. Individual somatic embryos wer isolated from explant tissue and used to initiate repetitive liquid cultures. There were significant differences among genotypes and varieties for somatic embryo formation and plant regeneration using a single media sequence. Botanical variety fastigiata had a lower embryogenic frequency and produced significantly fewer embryos than either hypogaea or vulgaris, which were similar in response.Abbreviations EA
zygotic embryo axes
- MS
Murashige and Skoog (1962) medium
- picloram
4-amino-3,5
- 6
trichloropicolinic acid 相似文献
10.
We established a plant regeneration system for Hinoki cypress (Chamaecyparis obtusa) via somatic embryogenesis. Embryogenic tissues were successfully induced on three kinds of Smith media from megagametophyte explants containing pre-cotyledonary embryos of C. obtusa plus-trees. Factors affecting somatic embryo maturation were examined. The concentration of polyethylene glycol 4000 in the medium was a critical factor for embryo maturation and its effective concentration was 150 g/l. The addition of 30 g/l maltose to the medium had a positive effect on embryo maturation, but sucrose was ineffective. The mature somatic embryos germinated at a germination frequency of approximately 60%, and the presence of activated charcoal was effective in stimulating plantlet growth. The plantlets acclimatized successfully in a greenhouse. To our knowledge, this is first report describing details of a plant regeneration method for C. obtusa via somatic embryogenesis.Abbreviations ABA
Abscisic acid
- PEG
Polyethylene glycol 4000
- SM1
Smith Standard Embryonic Tissue Capture Medium
- SM2
Smith Standard Embryogenesis Medium
- SM3
Smith Embryo Develop Medium 相似文献
11.
Rapid propagation of Eleutherococcus senticosus via direct somatic embryogenesis from explants of seedlings 总被引:5,自引:0,他引:5
Explants from three different parts (cotyledon, hypocotyl or root) of one week-old seedlings of Eleutherococcus senticosus were cultured on Murashige and Skoog (MS) medium with 1.0 mg l-1 2,4-D. Somatic embryos were formed directly from the surfaces of explants. The frequency of direct somatic embryo formation
was the highest in the hypocotyl segments (75%) as compared to cotyledon (56%) or root segments (12%). When hypocotyl explants
from 3 different stages of seedlings (zero, one or three week-old) were cultured on MS medium with 1.0 mg l-1 2,4-D, the frequency of somatic embryo formation rapidly declined as the zygotic embryos germinated. However most somatic
embryos (93%) from explants of zygotic embryos developed as fused state (multiple embryo), whereas somatic embryos (over 89%)
from more developed seedlings developed into single state (single embryo). Single embryos germinated and regenerated into
plantlets with both shoots and roots, while multiple embryos only regenerated into only multiple shoots. Plantlets that regenerated
from single embryos of E. senticosus were acclimatized in a greenhouse.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
12.
Kourosh Vahdati Shima Bayat Hassan Ebrahimzadeh Maryam Jariteh Masoud Mirmasoumi 《Plant Cell, Tissue and Organ Culture》2008,93(2):163-171
Low efficiency of embryo maturation, germination and conversion to plantlets is a major problem in many species including
Persian walnut. We studied the effects of abscisic acid (ABA) and sucrose, on the maturation and germination of Persian walnut
(Juglans regia) somatic embryos. Individual globular somatic embryos were grown on a maturation medium supplemented with different combinations
of ABA and sucrose for ca. 1 month, until shoot meristems and radicles had developed. White and opaque embryos in late cotyledonary
stage were subjected to desiccation after the culture period on maturation media. The number of germinated somatic embryos
was influenced by the concentrations of ABA in the maturation medium. The best treatment for germination, in which both shoot
and root were developed contained 2 mg l−1 ABA and resulted in 41% conversion of embryos into plantlets. Regeneration was reduced at higher levels of ABA. While ABA
always reduced the rate of secondary embryogenesis, treatments containing 4.0% sucrose significantly increased the number
of secondary embryos. On the other hand, sucrose had little influence on maturation. Normal and abnormal embryos were verified
anatomically. 相似文献
13.
Summary Methods of plant regeneration from callus and protoplasts of Helianthus giganteus L. are described. Embryogenic callus was obtained from leaf explants and plants were regenerated from these calli on MS media with different combinations of benzyladenine and naphtaleneacetic acid. Leaf protoplasts isolated from in vitro grown plants formed somatic embryos when cultured in agarose solidified droplets of V-KM medium containing benzyladenine and naphtaleneacetic acid. Embryos developed into plantlets on media with reduced auxin contents. Regenerated plants were successfully planted in soil.Abbreviations BA
benzyladenine
- IAA
indoleacetic acid
- MS
Murashige and Skoog medium
- NAA
naphtaleneacetic acid
- V-KM
protoplast culture medium of Binding and Nehls 相似文献
14.
Cyclic somatic embryogenesis and efficient plant regeneration from callus of safflower 总被引:2,自引:1,他引:1
Efficient plant regeneration through somatic embryogenesis was established for safflower (Carthamus tinctorius L.) cv. NARI-6. Embryogenic calli were induced from 10 to 17-d-old cotyledon and leaf explants from in vitro seedlings. High frequency (94.3 %) embryogenic callus was obtained from cotyledon explants cultured on Murashige and Skoog’s
germination (MSG) basal medium supplemented with thidiazuron, 2-isopentenyladenine and indole-3-butyric acid. Primary, secondary
and cyclic somatic embryos were formed from embryogenic calli in a different media free of plant growth regulators, however,
100 % cyclic somatic embryogenesis was obtained from cotyledon derived embryogenic calli cultured on MSG. Somatic embryos
matured and germinated in quarter-strength MSG medium supplemented with gibberellic acid. Cotyledons with root poles or non
root poles were converted to normal plantlets and produced adventitious roots in rooting medium. Rooted plants were acclimatized
and successfully transferred to the field. 相似文献
15.
Panax japonicus is one of the important medicinal plants. Here, we established the protocol for plant regeneration of P. japonicus via direct somatic embryogenesis. Somatic embryos were directly obtained from the segments of zygotic embryos on MS medium
with 4.4 μM 2,4-D. Thereafter, somatic embryos were produced by repetitive secondary somatic embryogenesis. The secondary
somatic embryo formation was enhanced by plasmolyzing pretreatment (1.0 M mannitol for 10 h). Frequency of secondary somatic
embryo formation from cotyledon segments was lowered by plasmolyzing pretreatment, but the number of somatic embryos per explants
was greatly increased. Plasmolyzing pretreatment resulted in retardation of embryo growth and required subculture to fresh
medium for further growth of embryos into cotyledonary stage. Without plasmolyzing pretreatment, cotyledonary embryos were
obtained after 8 weeks of culture. All the cotyledonary somatic embryos germinated by 5 μM GA3 treatment, but only 15.3% were germinated on hormone-free medium. After 2 months of culture on 1/2 strength WPM medium, plantlets
produced flowers spontaneously. In the anthers of in vitro flowers, microsporogenesis occurred normally with low number of
pollen grains. 相似文献
16.
Response of stem explants to screening and explant source as a basis for methodical advancing of regeneration protocols for chrysanthemum 总被引:3,自引:0,他引:3
Annadana Seetharam Rademaker Wim Ramanna M. Udayakumar M. Jong Jan de 《Plant Cell, Tissue and Organ Culture》2000,63(1):47-55
The effects of 2,4-dichlorophenoxyacetic acid (2,4-D) concentration, length of induction period and light quality on leaf
regeneration of quince clone BA 29 were investigated. After 2, 4 or 6 days of induction with 2.5 mg l−1 or 5.0 mg l−1 2,4-D, leaves were cultured under red, blue, red+blue, far-red+blue, white, far-red light or darkness conditions. Leaves
thereby treated showed different responses, with respect to somatic embryogenesis, callus, red-nodular structures or roots.
Callus production increased with increasing 2,4-D concentration and induction period, although it was not influenced by light
quality; the only exception was far-red+blue light, which reduced callusing response. This result suggested involvement of
the blue-absorbing photoreceptor system in the callus formation processes. A high regeneration of red-nodular structures with
a meristematic appearance was also observed; from some histological characterizations, we presumed they were adventitious
buds that were arrested at an early developmental stage. Red-nodular structures increased with decreasing 2,4-D concentration
and induction period. In the regeneration of such structures, the blue-absorbing photoreceptor system appeared to have a negative
effect but only at a low photoequilibrium value. In contrast, light quality which activated phytochrome induced an increment
in regeneration, but the response did not vary for photoequilibrium values ranging from 0.43 to 0.86. For root regeneration,
phytochrome seemed to be the only photoreceptor involved.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
17.
Duong Tan Nhut Bui Van Le K. Tran Thanh Van 《In vitro cellular & developmental biology. Plant》2001,37(1):44-49
Summary Excised tissues from transverse young stem sections of Lilium longiflorum were cultured on Murashige and Skoog medium supplemented with growth regulators at various concentrations. After 45 d in
culture, the presence of α-naphthaleneacetic acid (NAA) in the culture medium at 5.4 μM resulted in bulblet formation while 2,4-dichlorophenoxyacetic acid (2,4-D) at 2.2 μM resulted in root formation. The presence of IBA (indole-3-butyric acid) in the culture medium at 1.0 μM resulted in shoot formation while plantlet formation occurred when IBA was added at a concentration of 2.0 μM. When 1-phenyl-3-(1,2,3-thiadiazol-5-yl)-urea (TDZ) was added to the culture medium at 1.1 μM, protocorm-like bodies (PLBs) formed, while 2.2 μM resulted in shoot formation (on abaxial and adaxial surfaces). The presence of NAA and TDZ in the culture medium at 5.4 μM and 0.4, 1.1 or 2.2 μM, respectively, resulted in somatic embryo formation while NAA- and 6-benzylaminopurine-(BA) containing culture medium formed
callus or bulblets. The establishment of different regeneration systems when explants are exposed to various growth regulators
demonstrates that the choice of growth regulator combinations and concentrations are of significance in determining the morphogenetic
response and plant regeneration capacity. 相似文献
18.
Manoj Kumar Harpal Singh Anoop Kumar Shukla Praveen Chandra Verma Pradhyumna Kumar Singh 《Plant signaling & behavior》2013,8(10)
Embryogenesis in cotton is a difficult task due its genome dependency. We used 3 cotton cultivars (Khandwa-2, G. Cot. 10, and BC-68–2) and Coker-312 as control for regeneration. Efficient somatic embryogenesis was induced in agronomically important Indian cotton cultivars, Khandwa-2 and G. Cot. 10. For callusing in all the cultivars, different media combinations were tried. Embryogenesis was initiated on a hormone-free MS medium (MSB). For embryo maturation and recovery excess of L-glutamine and l-asparagine were used. Khandwa-2 somatic embryos were successfully regenerated into plants. However, no plantlet was obtained in case of G. Cot. 10. Callus induction was also observed in BC-68–2 but there was no embryogenesis observed. The study indicated that the medium and genotype significantly effects embryogenesis. An efficient protocol is described here for regenerating plants via somatic embryogenesis in an elite Indian cotton cultivar Khandwa-2. 相似文献
19.
M. A. Bailey H. R. Boerma W. A. Parrott 《In vitro cellular & developmental biology. Plant》1993,29(3):102-108
Summary Proliferative somatic embryogenesis is a regeneration system suitable for mass propagation and genetic transformation of soybean
[Glycine max (L.) Merr.]. The objective of this study was to examine genotypic effects on induction and maintenance of proliferative embryogenic
cultures, and on yield, germination, and conversion of mature somatic embryos. Somatic embryos were induced from eight genotypes
by explanting 100 immature cotyledons per genotype on induction medium. Differences in frequency of induction were observed
among genotypes. However, this step was not limiting for plant regeneration because induction frequency in the least responding
genotype was sufficient to initiate and maintain proliferative embryogenic cultures. Six genotypes selected for further study
were used to initiate embryogenic cultures in liquid medium. Cultures were evaluated for propagation of globular-stage tissue
in liquid medium, yield of cotyledon-stage somatic embryos on differentiation medium, and plant recovery of cotyledon-stage
embryos. Genotypes also differed for weight and volume increase of embryogenic tissue in liquid cultures, for yield of cotyledon-stage
embryos on differentiation medium, and for plant recovery from cotyledon-stage embryos. Rigorous selection for a proliferative
culture phenotype consisting of nodular, compact, green spheres increased embryo yield over that of unselected cultures, but
did not affect the relative ranking of genotypes. In summary, the genotypes used in this study differed at each stage of plant
regeneration from proliferative embryogenic cultures, but genotypic effects were partially overcome by protocol modifications. 相似文献
20.
Ishizaki Takuma Komai Fuminori Masuda Kiyoshi 《Plant Cell, Tissue and Organ Culture》2001,67(3):251-255
A system for subculture of spinach (Spinacia oleracea L.) roots was established, and differences in regeneration; namely, embryogenic competence, among individuals of the `Nippon' cultivar were examined. Root tissues, excised from seedlings, were grown on medium without growth regulators and subcultured on the same medium and then on medium that contained 10 M naphthaleneacetic acid and 0.1 M gibberellic acid to induce callus formation. Calli were transferred to medium without growth regulators. All explants formed calli. However, the frequency of embryo formation varied among lines. Higher concentrations of gibberellic acid in the callus-induction medium had limited effects on somatic embryogenesis from poorly embryogenic lines. These results indicate that inherent factors are important for somatic embryogenesis in spinach and that the root subculture system is useful for identifying strongly regenerative genotypes among individuals of a single cultivar. 相似文献