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1.
A reproducible system for somatic embryogenesis and plantlet formation of
sandalwood has been developed. A high frequency (100%) of somatic embryos
were induced directly from various explants in MS (Murashige and Skoog,
1962) medium with thidiazuron (1 or 2 M) or
indirectly in medium containing 2,4-D plus thidiazuron. Within 8 weeks,
white globular somatic embryos or friable embryogenic tissue developed on
cultured explants. In S. album the globular somatic
embryos were transferred to MS medium supplemented with IAA (6 M) and kinetin (1 and M) where they
developed further, multiplied and maintained friable embryogenic tissue.
After 15-30 d, mature somatic embryos (1-2 mm) with well-developed
cotyledons were separated and subcultured on to medium containing GA3 (6
M) for germination. Once germinated, elongated somatic embryos
(10-20 mm long) grew further in MS supplemented with lower GA3 (3
M). In S. spicatum, the addition of casein
hydrolysate and coconut milk was necessary for plantlet development from
somatic embryos. From histological studies, it appeared that primary
somatic embryos arose from single cells or had a multicellular origin from
the epidermis or cortical parenchyma. Secondary somatic embryos and friable
embryogenic tissue differentiated from groups of proembryogenic cells from
a superficial layer of the primary somatic embryos.Keywords:
Santalum album, Santalum spicatum, somatic
embryogenesis, histological studies.
相似文献
2.
Summary Regeneration of plants via somatic embryogenesis was achieved from zygotic embryo explants isolated from mature seeds of Schisandra chinensis. Merkle and Sommer's medium, fortified with 2,4-dichlorophenoxyacetic acid (2,4-D; 9.04 μM) and zeatin (0.09 μM), was effective for induction of embryogenic callus. The development of a proembryogenic mass and somatic embryos occurred
on Murashige and Skoog medium (MS) free of plant growth regulators. The embryogenic callus induced on Merkle and Sommer's
medium supplemented with 2,4-D (9.04 μM) and zeatin (0.09 μM) showed development of the maximum number of somatic embryos when transferred to MS medium free of plant growth regulators.
The maximum maturation and germination of cotyledonary somatic embryos (46.3%) occurred on MS medium supplemented with 2,4-D
(0.45 μM) and N6-benzyladenine (1.11 μM). The somatic embryo-derived plants were successfully hardned, with a survival rate of approximately 67%, and established
in the field. 相似文献
3.
Scott A. Merkle Margaret T. Hoey Beth A. Watson-Pauley Scott E. Schlarbaum 《Plant Cell, Tissue and Organ Culture》1993,34(2):191-198
Propagation of hybrids between the Chinese tuliptree (Liriodendron chinense) and the North American yellow-poplar (Liriodendron tulipiferea) could be greatly accelerated with a highly productive somatic embryogenesis system. Flowers were collected from a single Chinese tuliptree and the anthers used for controlled pollinations of 4 yellow-poplar mother trees. Aggregates of samaras resulting from the pollinations were harvested 8 weeks post-pollination. Following surface disinfestation, samaras were dissected and embryos and endosperm were cultured together on a semisolid induction medium containing 9.0 M 2,4-dichlorophenoxyacetic acid and 1.1 M benzyladenine. Following 2–3 months on induction medium, an average of 15.6 percent of the explants produced either somatic embryos or proembryogenic masses. Compared to pure yellow-poplar embryogenic cultures, putative hybrid cultures tended not to maintain growth as proembryogenic masses while exposed to auxin, instead proliferating via repetitive embryogenesis as globular-stage embryos. Four to six weeks following transfer of globular embryos to basal medium, mature embryos were produced from the putative hybrid lines. Mature embryos germinated following transfer to basal medium lacking casein hydrolysate. Plantlets survived transfer to potting mix and acclimatization to greenhouse conditions. Verification of the hybrid nature of the embryogenic lines and somatic embryo-derived plantlets was accomplished by Southern hybridization analysis with a species-specific DNA marker.Abbreviations BA
benzyladenine
- 2,4-d
2,4-dichlorophenoxyacetic acid
- PEM
proembryogenic mass
- CH
casein hydrolysate
- RFLP
restricted fragment length polymorphism
- CTAB
hexadecyltrimethylammonium bromide
- TBE
Tris-borate-EDTA
- SDS
sodium dodecylsufate
- SSC
sodium citrate/chloride 相似文献
4.
Direct somatic embryogenesis induced from cotyledons of mango immature zygotic embryos 总被引:3,自引:0,他引:3
Summary For the first time, regenerated plantlets were obtained from immature zygotic embryos of mango (Mangifera indica L.) through direct somatic embryogenesis. Pro-embryogenic mass (PEM)-like structures, which are differentiated as clusters
of globular structures, were easily induced directly from the abaxial side of cotyledons from immature fruits, 2.0–3.5 cm
diameter by a 2-wk culture period on a modified Murashige and Skoog medium with 5 mgl−1 (25μM) indole-3-butyric acid (IBA). Conversion of somatic embryos into plantlets was achieved after 4 wk of culture on the conversion
medium containing 5mgl−1 (23 μM) kinetin. Secondary somatic embryogenesis could also be obtained directly from the hypocotyls of mature primary somatic embryos
cultured on the conversion medium. In our experimental system, only minor problems were noted with browning of cultures. 相似文献
5.
Summary This paper investigates maintenance and proliferation of somatic embryogenesis systems for Ulmus minor and U. glabra. Proliferation occurred with subculture of embryogenic calluses. The calluses were mainly formed by friable nodules composed
of meristematic cells organized into proembryogenic cell masses (PEMs) and thin-walled vacuolated parenchymatic cells. Cotyledonary
embryos, with procambial strands and differentiation of their vascular tissues as well as visible root meristems, were identifiable
after 18d of culture on a proliferation medium with 0.44 μM benzyladenine (BA). The shoot meristem was only occasionally well developed. Somatic embryo multiplication from elm embryogenic
calluses is a clearly asynchronic system, and PEMs as well as embryos at all stages of development are observed simultaneously
at the end of subculture period. Factors affecting the proliferation of elm embryogenic callus, such as culture medium, carbon
source and genotype, were studied. Basal medium (MS) or medium supplemented with 0.44 μM BA produced the highest number of somatic embryos. Somatic embryo production was higher with sucrose or glucose than with
maltose, and significant differences were also found among the four embryogenic lines tested. The use of liquid medium with
filter paper support is an essential step for the survival of isolated somatic embryos during the germination stage. The addition
of 0.22 μM BA′ to liquid MS medium was the best treatment for germination and plantlet conversion of elm somatic embryos. 相似文献
6.
Myung Jin Oh Hye Ryun Na Hong-Keun Choi Jang Ryol Liu Suk Weon Kim 《Plant biotechnology reports》2008,2(1):87-92
An improved protocol for high frequency plant regeneration via somatic embryogenesis from zygotic embryo-derived cell suspension
cultures of watershield (Brasenia schreberi) was developed. Zygotic embryos formed pale-yellow globular structures and white friable callus at a frequency of 80% when
cultured on half-strength MS medium supplemented with 0.3 mg l−1 2,4-D. However, the frequency of formation of pale-yellow globular structures and white friable callus decreased slightly
with increasing concentrations of 2,4-D up to 3 mg l−1, where the frequency reached ~50% of the control. Cell suspension cultures from zygotic embryo-derived white friable callus
were established using half-strength MS medium supplemented with 0.3 mg l−1 2,4-D. Upon plating of cell aggregates on half-strength MS basal medium, approximately 8.3% gave rise to somatic embryos
and developed into plantlets. However, the frequency of plantlet development from cell aggregates was sharply increased (by
up to 55%) when activated charcoal and zeatin were applied. Regenerated plantlets were successfully transplanted to potting
soil and grown to normal plants in a growth chamber. The distinctive feature of this study is the establishment of a high
frequency plant regeneration system via somatic embryogenesis from zygotic embryo-derived cell suspension cultures of watershield,
which has not been previously reported. The protocol for plant regeneration of watershield through somatic embryogenesis could
be useful for the mass propagation and transformation of selected elite lines. 相似文献
7.
Sacco C. de Vries Hilbert Booij Peter Meyerink Gert Huisman H. Dayton Wilde Terry L. Thomas Ab van Kammen 《Planta》1988,176(2):196-204
Embryogenic suspension cultures of domesticated carrot (Daucus carota L.) are characterized by the presence of proembryogenic masses (PEMs) from which somatic embryos develop under conditions of low cell density in the absence of phytohormones. A culture system, referred to as starting cultures, was developed that allowed analysis of the emergence of PEMs in newly initiated hypocotyl-derived suspension cultures. Embryogenic potential, reflected by the number of FEMs present, slowly increased in starting cultures over a period of six weeks. Addition of excreted, high-molecular-weight, heat-labile cell factors from an established embryogenic culture considerably accelerated the acquisition of embryogenic potential in starting cultures. Analysis of [35S]methionine-labeled proteins excreted into the medium revealed distinct changes concomitant with the acquisition of embryogenic potential in these cultures. Analysis of the pattern of gene expression by in-vitro translation of total cellular mRNA from starting cultures with different embryogenic potential and subsequent separation of the [35S]methionine-labeled products by two-dimensional polyacrylamide gel electrophoresis demonstrated a small number of abundant in-vitro-translation products to be present in somatic embryos and in embryogenic cells but absent in nonembryogenic cells. Several other in-vitro-translation products were present in explants, non-embryogenic and embryogenic cells but were absent in somatic embryos. Hybridization of an embryoregulated complementary-DNA sequence, Dc3, to RNA extracted from starting cultures showed that the corresponding gene is expressed in somatic embryos and PEMs but not in non-embryogenic cells.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- cDNA
complementary DNA
- PAGE
polyacrylamide gel electrophoresis
- PEM
proembryogenic mass 相似文献
8.
Embryogenic callus was obtained from bulb segments of Iris
pseudacorus on Murashige and Skoog (MS) medium with 2,4-dichlorophenoxyacetic acid (2,4-D) alone or in combination with kinetin. When
early globular somatic embryos were subcultured onto MS medium with 4.52 μM 2,4-D, high frequency of somatic embryogenesis
was obtained. Deprivation of 2,4-D was required for maturation. Mature somatic embryos had an elongated scutellum with a notch
on the base of scutellum. Separation of embryos from embryo clusters was necessary to enhance the frequency of germination.
Germination was stimulated by separation of embryos from embryo clusters and transfer onto fresh half-strength MS medium with
3% sucrose. After acclimation in artificial soil in greenhouse for 2 months, 96.4% of plantlets survived. 相似文献
9.
Summary High-frequency embryogenesis systems were established for hybrid yellow-poplar (Liriodendron tulipifera×L. chinense) and hybrid sweetgum (Liquidambar styraciflua×L. formosana) by modifying a medium originally developed for embryogenic yellow-poplar cultures. Embryogenic cultures of both hybrids,
consisting of proembryogenic masses (PEMs), were initiated from immature hybrid seeds on an induction-maintenance medium (IMM)
supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D), benzyladenine (BA), and casein hydrolyzate (CH). For hybrid yellow-poplar,
as many as 2100 germinable somatic embryos per 4000 cells or cell clumps were produced when PEMs were grown in liquid IMM
lacking CH, at a pH that varied with genotype (3.5 or 5.6), followed by size fractionation and plating on semisolid embryo
development medium (DM; IMM lacking 2,4-D and BA) without CH, but supplemented with 4.0 mgl−1 (15 μM) abscisic acid. For hybrid sweetgum, up to 1650 germinable somatic embryos per 4000 cells or cell clumps were produced when
PEMs were grown in liquid IMM without CH, but with 550 mgl−1
l-glutamine, 510 mg l−1 asparagine, and 170 mg l−1 arginine at pH 5.6. Somatic embryos developed from cell clumps on DM without any plant growth regulators or other supplements.
Hundreds of somatic embryos of both hybrids were germinated on DM without CH, transferred to potting mix, and hardened off
in a humidifying chamber for transfer to the greenhouse. 相似文献
10.
Iris R. von Recklinghausen Anna Iwanowska Henk Kieft Andreas P. Mordhorst Jan H. N. Schel André A. M. van Lammeren 《Protoplasma》2000,211(3-4):217-224
Summary Seeds of theArabidopsis thaliana mutant primordia timing (pt) were germinated in 2,4-dichlorophenoxyacetic acidcontaining liquid medium. The seedlings formed somatic embryos and nonembryogenic and embryogenic callus in vitro in a time period of approximately two to three weeks. Embryogenesis and callus formation were monitored with respect to origin, structure, and development. Ten days after germination globular structures appeared in close vicinity of and on the shoot apical meristem (SAM). Somatic embryos formed either directly on the SAM region of the seedling or indirectly on embryogenic callus that developed at the SAM zone. Globular structures developed along the vascular tissue of the cotyledons as well, but only incidentally they formed embryos. Upon deterioration, the cotyledons formed callus. Regular subculture of the embryogenic callus gave rise to high numbers of somatic embryos. Such primary somatic embryos, grown on callus, originated from meristematic cell clusters located under the surface of the callus. Embryos at the globular and heart-shape stage were mostly hidden within the callus. Embryos at torpedo stage appeared at the surface of the callus because their axis elongated. Secondary somatic embryos frequently formed directly on primary ones. They preferentially emerged from the SAM region of the primary somatic embryos, from the edge of the cotyledons, and from the hypocotyl. We conclude that the strong regeneration capacity of thept mutant is based on both recurrent and indirect embryogenesis.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- DIC
days in culture
- SAM
shoot apical meristem 相似文献
11.
Summary Efficient in vitro propagation of Ceropegia candelabrum L. (Asclepidaceae) through somatic embryogenesis was established. Somatic embryogenesis depended on the type of plant growth
regulators in the callus-inducing medium. Friable callus, developed from leaf and internode explants grown on Murashige and
Skoog (MS) medium supplemented with 4.52μM2,4-dichlorophenoxyacetic acid (2,4-D), underwent somatic embryogenesis. Compared to solid media, suspension culture was superior
and gave rise to a higher number of somatic embryos. Transfer of the friable callus developed on MS medium containing 4.52μM 2,4-D to suspension cultures of half- or quarter-strength MS medium with lower levels of 2,4-D (0.23 or 0.45 μM) induced the highest number of somatic embryos, which developed up to the torpedo stage. Somatic embryogenesis was asynchronous
with the dominance of globular embryos. About 100 mg of callus induced more than 500 embryos. Upon transfer to quarter-strength
MS agar medium without growth regulators, 50% of the somatic embryos underwent maturation and developed into plantlets. Plantlets
acclimatized under field conditions with 90% survival. 相似文献
12.
B. A. Bergmann W. P. Hackett H. Pellett 《In vitro cellular & developmental biology. Plant》1996,32(3):161-164
Summary Somatic embryogenesis was observed with explants taken from four types ofAesculus tissue: (a) shoots of 4-wk-oldin vitro germinated excised embryos (seed fromA.×arnoldiana), (b) roots of 4-wk-oldin vitro germinated excised embryos (seed fromA.×arnoldiana), (c) shoots from newly forced 3-yr-old seedlings (A. glabra), and (d) newly forced shoots from a 30-yr-old tree (A.×arnoldiana “Autumn Splendor”). Shoots provided three types of explants, single node, shoot apex, and internodal section, and all exhibited
embryogenesis.
Proembryogenic masses developed in a few cases after 6 wk in culture but were more commonly seen after 3 mo. The yellow, friable
proembryogenic masses emerged from proximal cut ends of explants. Almost all cultures that formed embryos possessed leaves,
either from developing apical or axillary buds or from adventitious buds, prior to the emergence of proembryogenic masses.
Only tissues that had begun to senesce and had been exposed to cytokinin (benzyladenine at 5 or 25 μM) formed somatic embryos. Embryos with distinct cotyledonlike structures and root/shoot axes developed during the 10 to 16
wk following the inital emergence of proembryogenic masses. Enhanced frequency of embryogenesis was obtained by dark culture
of root and shoot explants from 4-wk-old germinated embryos (A.×arnoldiana) and by dark and cold (5°C) treatment of shoot tissue cultures derived from 3-yr-old seedlings (A. glabra). Embryogenic potential was greatest in the most juvenile tissue and least in the mature tissue. Five percent of shoot explants
taken from the 30-yr-old select treeA.×arnoldiana “Autumn Splendor” produced somatic embryos. 相似文献
13.
S. A. Merkle A. T. Wiecko R. J. Sotak H. E. Sommer 《In vitro cellular & developmental biology. Plant》1990,26(11):1086-1093
Summary Embryogenic suspension cultures of the hardwood forest tree yellow-poplar (Liriodendron tulipifera) have the potential to produce millions of plantlets. However, low conversion frequencies limit the realization of this potential.
Using 4 embryogenic yellow-poplar lines, we first tested the ability of somatic embryos, selected for their similarity to
mature zygotic embryos, to convert to plantlets, then tested physical and chemical treatments for their effects on promoting
maturation of somatic embryos and subsequent plantlet production. Embryos selected based on resemblance to mature zygotic
embryos and transferred to a hormone-free basal medium without casein hydrolysate (CH) produced plantlets at a frequency of
63%. Populations of synchronized somatic embryos were obtained by repeated fractionation of liquid medium-cultured proembryogenic
masses (PEMs) on stainless steel sieves. These fractionated embryos failed to mature properly when cultured in liquid basal
medium, however. Development of embryos cultured in basal medium supplemented with 5×10−7
M abscisic acid (ABA) was slowed and embryos appeared to mature properly, with separated cotyledons and little precocious germination.
However, ABA-treated embryos only rarely converted to plantlets, possibly due to residual effects of the ABA. PEMs fractionated
on sieves, transferred to filter paper and placed on solidified basal medium gave a 60–70% synchronous population of mature
embryos 10–12 days following plating. Mature embryos transferred to basal medium without CH converted at a frequency of 72%.
The percentage of all embryos differentiating from PEMs on filter paper that formed plantlets was 32%.
This material is based upon work supported by the U. S. Department of Agriculture Cooperative State Research Service under
Agreement No. 85-FSTY-9-0117. 相似文献
14.
Somatic embryogenesis from leaf explants of Scaevola aemula R. Br. was achieved. Somatic embryos were induced from explants cultured on MS medium supplemented with 0.2 mg/ 2,4-dichlorophenoxyacetic acid and 0.2–0.5 mg/l 6-benzylaminopurine (BAP). Various developmental stages of somatic embryos were found on this medium—from globular embryos to germinated embryos. The transfer of globular embryos to MS medium containing 0.5 mg/l BAP resulted in a high frequency of shoot regeneration. Leaf explants cultured on MS medium containing different combinations of BAP and -naphthaleneacetic acid formed adventitious shoots and roots. Histological examination confirmed the process of somatic embryogenesis. Induction of somatic embryogenesis in Scaevola provides a system for studying embryogenesis in Australian native plants and will facilitate the improvement of these plants using genetic transformation techniques.Abbreviations
ABA
Abscisic acid
-
BAP
6-Benzylaminopurine
-
2,4-D
2,4-Dichlorophenoxyacetic acid
-
NAA
-Naphthaleneacetic acid
-
PIPES
Piperazine-N, N-(2-ethanesulfonic acid)
Communicated by R.J. Rose 相似文献
15.
We identified and isolated a monoclonal antibody (MAb 3G2) raised against extracellular proteins from microcluster cells of
orchard grass (Dactylis glomerata L.) embryogenic suspension culture. MAb 3G2 recognized with high specificity an antigen ionically bound within the primary
cell wall and in the culture medium of microcluster cells. Two-dimensional polyacrylamide gel analysis and blotting of proteins
on PVDF membrane showed that MAb 3G2 detected a single polypeptide of apparent molecular mass of 48 kDa and an isoelectric
point (pI) of 5.2, designated EP48. A transient expression during somatic embryogenesis was observed for EP48. Indirect immunofluorescence
showed that this protein highly accumulated in the cell walls of some single cells, microclusters and partly in proembryogenic
masses (PEMs), but not in globular embryos of the embryogenic cell line and microclusters from the non-embryogenic cell line.
Signal intensity varied between individual cells of the same population and in successive stages of somatic embryo development.
Screening of several D. glomerata L. embryogenic and non-embryogenic cell lines with MAb 3G2 indicated the presence of ECP48 in only embryogenic suspension
cultures at early stages of embryo development long before morphological changes have taken place and thus it could serve
as an early marker for embryogenic potential in D. glomerata L. suspension cultures. 相似文献
16.
Gloria Pinto Yill-Sung Park Sónia Silva Lucinda Neves Clara Araújo Conceição Santos 《Plant Cell, Tissue and Organ Culture》2008,95(1):69-78
The described protocol for repetitive somatic embryogenesis (SE) in Eucalyptus globulus produced more somatic embryos than the primary SE protocol. Primary somatic embryos (induced on MS3NAA) were transferred to the same medium, leading to new cycles of somatic embryos, for at least 2 years. The influence of medium
(MS and B5), plant growth regulators (auxins and cytokinins), and light on secondary SE was tested. The MS medium without
growth regulators (MSWH) was more efficient for cotyledonary embryo formation and germination than the B5 medium. Reducing auxin (NAA) levels increased
the proliferation of globular somatic embryos and allowed SE competence to be maintained on medium free of plant growth regulators.
The addition of two cytokinins (BAP and KIN) to the MS medium did not improve proliferation of globular secondary embryos,
but was crucial during later stages of the SE process (germination and conversion). Data also show that light may influence
the quality of the process, depending on its stage. Darkness should be maintained until the cotyledonary stage is reached,
after which exposure to light is recommended. 相似文献
17.
Summary The effects of abscisic acid (ABA) (0, 0.09 μM, 0.19 μM, 0.28 μM, and 0.38 μM) or ancymidol (0, 0.98 μM, 1.95 μM, 2.93 μM, 3.90 μM) in embryo germination medium on the conversion of primary embryos to plantlets and secondary embryogenesis were evaluated
for asparagus. ABA and ancymidol each significantly enhanced both responses. ABA was more effective than ancymidol in promoting
the conversion of primary embryos to plantlets, while the converse was true for the production of secondary embryos. The most
effective treatments for embryo conversion were 0.19 and 0.28 μM ABA; 75–77% bipolar and 55–57% globular embryos converted to plantlets. For secondary embryogenesis, the most effective treatments
were 1.95 and 2.93 μM ancymidol; 99–101 and 84–86 somatic embryos were produced from 10 globular and 10 bipolar embryos, respectively. Bipolar
embryos generally converted to plantlets better than globular embryos, but more secondary embryos were produced from globular
embryos than from bipolar embryos in all treatments. ABA and ancymidol also affected the morphology of the plantlets produced.
The plantlets from the embryos incubated on the medium with ancymidol had strong and thick shoots and roots, while those on
the medium with ABA had long, thin shoots and short thin roots. 相似文献
18.
Summary Somatic embryogenesis and plant regeneration have been achieved in Nothapodytes foetida, which is known for its rich source of anti-cancer and anti-AIDS alkaloids. Callus cultures were initiated from immature
zygotic embryos cultured on Murashige and Skoog's (MS) medium supplemented with 2,4-dichlorophenoxyacetic acid, 6-benzyladenine
(BA), and kinetin. MS medium devoid of plant growth regulators favored the development of globular somatic embryos that differentiated
further into plantlets. Plantlet regeneration efficiency was effectively increased on MS medium supplemented with BA. Over
90% of the in vitro plantlets survived when transferred to the soil. Alkaloids were detected in different stages of somatic embryos, regenerated
plantlets, and different parts of the 2-yr-old regenerated plants. The somatic embryos contains camptothecin (0.011% dry weight.
DW) and 9-methoxycamptothecin (0.0028% DW). Two-yearold field-grown plants obtained from somatic embryos were analyzed and
contained higher levels of camptothecin (0.20% DW) and 9-methoxycamptothecin. (0.097% DW) accumulated in roots, followed by
stem and leaves. Alkaloids were quantified and identified by TLC and HPLC. 相似文献
19.
Françoise Cailloux Josiane Julien-Guerrier Laurent Linossier Alain Coudret 《Plant science》1996,120(2):2028-196
A high frequency of secondary embryogenesis was induced from isolated early cotyledonary-stage somatic embryos of Hevea brasiliensis. A long-term embryogenic line was established by the use of recurrent embryogenesis and maintained for 3 years on hormone-free medium by the transfer of selected proembryogenic masses every 10 days.
The addition of 234 mM sucrose as stress with sucrose and 10−5 M abscisic acid (ABA) to the culture medium enhanced the maturation of somatic embryos. Under these culture conditions, the embryo population was composed of 45% globular, 18% oblong and 37% torpedo-stage embryos. These somatic embryos had well-formed tissue structure, a well-defined epidermis, protein storage bodies, and a high accumulation of starch. The triglyceride content was five times as high in the torpedo-stage embryos that developed on medium supplemented with 234 mM sucrose and 10−5 M ABA as in embryos obtained on basal medium with 58 mM sucrose. 相似文献
20.
Nucellar-derived cell cultures of sour orange (Citrus aurantium L.) proliferate as proembryogenic masses. By a change in the carbon source of the medium from sucrose to glycerol they are induced to undergo synchronous embryogenesis forming embryo initials that develop into globular embryos. The proembryogenic masses released glycoproteins to the medium. Exogenous addition of the glycoproteins to cells in glycerol-containing medium modified the course of embryo development in a dose-dependent manner. Addition of 20 g · ml–1 of glycoproteins blocked embryogenesis and resulted in an accumulation of embryo initials. When glycoproteins were added to cultures containing advanced globularstage embryos further development was suppressed. The inhibitory component of the glycoproteins was found to be a family of polypeptides with apparent molecular masses of 53–57 kDa. While these proteins normally accumulated only in cultures of proembryogenic masses, they could be induced to accumulate in glycerol-containing medium by the addition of the glycoproteins. Thus, their accumulation was not a direct consequence of the type of growth medium used or the developmental state of the cultures. The results indicate that the 53-to 57 kDa glycoproteins could play a regulatory role in in-vitro embryogenesis in sour orange. The normal progression of embryo development appears to depend, in an obligatory manner, on the absence of these glycosylated extracellular proteins from the medium.Abbreviations kDa
kilodalton
- PEM
proembryogenic masses
- SDS-PAGE
sodium dodecyl sulphate-polyacrylamide gel electrophoresis
- 2D-PAGE
Two-dimensional polyacrylamide gel electrophoresis
We thank Dr. S. Satoh (Institute of Biological Sciences, Tsukuba, Japan) for sending protein samples of the purified 57-kDa glycoprotein. This research was supported by a grant from the Charles H. Revson Foundation for Basic Research in the Life Sciences of the Israel Academy of Sciences. R.F. is a recipient of the Jack and Florence Goodman Career Development Chair. 相似文献