共查询到20条相似文献,搜索用时 953 毫秒
1.
Summary Immature zygotic embryos of sunflower constitute an experimental system where the change of a single key factor (sucrose concentration) conditions the in vitro morphogenesis to either organogenesis (87 mM sucrose) or somatic embryogenesis (350 mM sucrose). Experiments with a variety of culture media differing in the sugar type and concentration, as well as osmotic pressure, indicate that a minimal threshold level of both, sugar supply and osmotic pressure, are required for somatic embryogenesis, but not organogenesis, to occur. The nature of the sugar used, though, was less important.Abbreviations IZE
immature zygotic embryo 相似文献
2.
High-frequency plant regeneration via somatic embryogenesis and organogenesis and in vitro flowering of regenerated plantlets in Panax ginseng 总被引:4,自引:0,他引:4
W. Tang 《Plant cell reports》2000,19(7):727-732
The morphogenesis ability of light yellowish globular callus derived from cotyledons of mature zygotic embryos of Panax ginseng was investigated. The optimal media for somatic embryogenesis and shoot organogenesis were MS medium containing 0.5 mg l–1 2,4-dichlorophenoxyacetic acid, 0.1 mg l–1 6-benzyladenine (BA), and 500 mg l–1 lactoalbumin hydrolysate, and SH medium supplemented with 0.5 mg l–1 α-naphthaleneacetic acid, 0.1 mg l–1 BA, and 500 mg l–1casein hydrolysate. The influences of glucose, mannose, fructose, and sorbose in the media on somatic embryogenesis and shoot
organogenesis were revealed as differences in the numbers of somatic embryos and adventitious shoots per gram of morphogenic
callus. The best regeneration of somatic embryos was obtained on medium containing glucose, with a mean of 8.7 somatic embryos
per gram of callus. The best regeneration of shoots was observed on medium containing fructose, with an average of 12.2 adventitious
shoots per gram of callus. Of the somatic embryos 95% were converted into regenerated plantlets, and 100% of adventitious
shoots rooted to form regenerated plantlets. Regenerated plants were successfully established in soil. Flowering was observed
in 5.7% of the regenerated plants derived from shoot organogenesis and in 1.4% of the regenerated plants derived from somatic
embryogenesis.
Received: 1 December 1998 / Revision received: 13 September 1999 / Accepted: 20 September 1999 相似文献
3.
The aim of this study was to improve the direct somatic embryogenesis and initiate embryogenic callus formation in camphor
tree (Cinnamomum camphora L.) on hormone-free medium. The influence of osmotic stress pretreatment of immature zygotic embryos (0.5 and 1.0 M solution
of sucrose for 12, 24, 48, 72, 96, 120, and 144 h at 4 or 25°C) before cultured on hormone-free medium, on embryogenesis efficiency
was assessed. The embryogenesis frequency was improved from 16.29 to 93.27%, while the average number of somatic embryos per
explant increased from 3 to 12.57. Activated charcoal (AC), medium renewal, basal medium, light conditions and sucrose concentration
in culture medium were also evaluated for their effect on somatic embryogenesis. AC addition and 10-day medium renewal did
not increase embryogenesis efficiency significantly, and Murashige and Skoog (MS) medium proved to be more beneficial for
somatic embryo formation than others. No differences were found between embryogenesis frequencies when cultured in darkness
or under light, but culturing under light yielded more embryos. After the sucrose solution pretreatment, high level concentration
of sucrose in induction medium was not needed for somatic embryogenesis, for it had a negative effect on somatic embryo formation
when the concentration of sucrose was higher than 50 g l−1. The derived embryogenic lines were maintained via repetitive embryogenesis on hormone-free medium. Low ratio formation of
embryogenic callus was observed on the surface of somatic embryos both on induction and proliferation medium. Plantlets derived
from somatic embryos grew vigorously with normal appearance similar to germinated zygotic embryos. 相似文献
4.
The soluble acid invertase (β-D-fructofuranoside fructohydrolase, EC 3.2.1.26) from potato (Solanum tuberosum L. cv. Kennebec) tubers was located in the vacuoles. Although the functionality of this invertase in the vacuoles has been
assumed, the activity of the enzyme has never been shown within isolated vacuoles. Vacuoles were prepared by gentle osmotic
shock from free protoplasts obtained by enzymic digestion of tuber tissues. The mean volume of these vacuoles, (0.26 ± 0.05) × 10−2 μl, was estimated by optical microscopy. Sucrose, glucose and fructose concentrations were calculated to be 100 mM, 20 mM
and 40 mM, respectively, in the vacuoles. Sucrose hydrolysis and the increase in glucose and fructose concentrations within
the vacuoles were measured during vacuolar incubations. An almost identical pattern of sucrose hydrolysis by invertase was
found by an in-vitro assay reproducing the vacuolar conditions. In view of the determinations of internal vacuolar pH (5.2),
the possibility of spontaneous hydrolysis of sucrose was disregarded. Vacuoles were shown to be free from proteinaceous inhibitors,
confirming the extravacuolar location of these inhibitors. The vacuolar hydrolytic pattern of sucrose confirms the regulatory
role of the reaction products previously proposed for in-vitro assays.
Received: 21 July 1997 / Accepted: 31 August 1997 相似文献
5.
Callus induction and somatic embryogenesis of Phalaenopsis 总被引:23,自引:0,他引:23
Callus induction and plant regeneration through somatic embryogenesis in Phalaenopsis Richard Shaffer `Santa Cruz' were examined. Protocorm-like body (PLB) segments formed calli in Vacin and Went medium with
sucrose. The optimal concentration of sucrose was 40 g ⋅ l–1. Medium containing 200 ml ⋅ l–1 coconut water together with 40 g ⋅ l–1 sucrose was effective for callus induction. Gellan gum was suitable than agar as a gelling agent for callus induction. The
calli easily formed PLBs after being transferred to a medium without sucrose. Histological observation suggested that the
PLBs were somatic embryos. No variation was observed in the flowering plants regenerated through somatic embryogenesis.
Received: 11 June 1997 / Revision received: 6 October 1997 / Accepted: 18 October 1997 相似文献
6.
Regeneration of Acacia mangium through somatic embryogenesis 总被引:2,自引:0,他引:2
Somatic embryogenesis and whole plant regeneration were achieved in callus cultures derived from immature zygotic embryos
of Acacia mangium. Embryogenic callus was induced on MS medium containing combinations of TDZ (1–2 mg/l), IAA (0.25–2 mg/l) and a mixture of
amino acids. Globular embryos developed on embryogenic callus cultured on the induction medium. Nearly 42% of embryogenic
cultures with globular embryos produced torpedo- and cotyledonary-stage embryos by a two-step maturation phase. The first
stage occurred on 1/2-strength MS basal medium containing 30 g/l sucrose and 5 mg/l GA3 followed by the second stage on 1/2-strength MS basal medium containing 50 g/l sucrose. Of the cotyledonary-stage somatic
embryos, 11% germinated into seedlings that could be successfully transferred to pots. Light- and scanning electron microscopy
showed that the somatic embryos originated from single cells of the embryogenic callus. Further, a single cell layer could
be detected beneath the developing somatic embryos that appeared to be a demarcation layer isolating the somatic proembryonic
structure from the rest of the maternal callus. A suspensor-like structure connected the globular embryos to the demarcation
layer. This is the first successful report of plant regeneration through somatic embryogenesis for this economically important
tropical forest species.
Received: 20 January 2000 / Revision received: 28 September 2000 / Accepted: 29 September 相似文献
7.
Pascal Montoro Hervé Etienne Nicole Michaux-Ferrière Marc-Philippe Carron 《Plant Cell, Tissue and Organ Culture》1993,33(3):331-338
The influence of plant growth regulators, sucrose, calcium and various macronutrient media on callus friability and somatic
embryogenesis was investigated inHevea brasiliensis Müll. Arg. Friable and embryogenic calli were spontaneously formed in two rubber tree clones (PR 107 and RRIM 600) on the
Medium for Hevea (MH), with 3,4-dichlorophenoxyacetic acid (3,4-d), kinetin and sucrose, while compact embryogenic calli were enhanced in three other clones (PB 260, PB 235 and GT1). Callus
friability was enhanced in clone PB 260 when the concentration of one growth factor (3,4-d or kinetin) was reduced from 4.5 μLM to 0.45 μM during the first culture, or when high sucrose or calcium levels 351 mM and
12 mM, respectively) were maintained during subcultures. The different macronutrient media did not alter callus texture but
only use of MH and Murashige and Skoog (MS) media led to somatic embryogenesis. Friable calli obtained by modifying the auxin/cytokinin
balance lost their embryogenic potential. In contrast, those obtained on media with high sucrose or calcium concentrations
were mainly composed of embryogenic cells embedded in a mucilaginous matrix. Such calli could be of potential interest for
establishing embryogenic cell suspension cultures. 相似文献
8.
Role of exogenous reduced nitrogen and sucrose in rapid high frequency somatic embryogenesis in Medicago sativa 总被引:1,自引:0,他引:1
The effect of exogenously supplied reduced nitrogen and sucrose on high-frequency somatic embryogenesis in petiole-derived tissue cultures of a diploid and a tetraploid regenerable clone of Medicago sativa ssp. falcata was investigated. There was an absolute requirement for ammonium during embryo induction and differentiation, with 5mM being the optimum for induction and 10–20 mM the optimum for differentiation of somatic embryos. Exogenous amino acids were not essential for differentiation and often even inhibitory, except 1 or 2 g/l casein hydrolysate or 4.4 mM glutamine with 3.1 mM proline which, under certain conditions, resulted in increases of 20–30% in the number of embryos obtained. High and low sucrose concentrations inhibited somatic embryogenesis and there was no reason to deviate from the 3% (0.088 M) sucrose level commonly used in plant tissue culture media. Selected clones from three M. sativa cultivars showed a response similar to the highly regenerable ssp. falcata clone F1.1. 相似文献
9.
Trabelsi El Bahri Bouzid Sadok Bouzid Monji Elloumi Nedra Belfeleh Zina Benabdallah Abdallah Ghezel Rachida 《Journal of Plant Biology》2003,46(3):173-180
We induced somatic embryogenesis from the cotyledon segments ofOlea europaea (L) cvs. ‘Chetoui’, ‘Chemleli’, and ‘Arbequina’. Calli were established from all three cultvars on OMc media supplemented
with IBA and 2i-R The greatest success was obtained with media that contained zero or low concentrations of growth regulators.
High levels of hormones (i.e.,>0.5 mgL-1 IBA and 2i-P) inhibited embryogenesis. Embryos at different maturation stages were observed with continuously proliferating
secondary embryogenesis. Abnormally shaped embryos and teratoma were also noted. Four weeks was the optimal incubation period
for inducing embryogenesis on the auxin-containing medium. In addition, 30 to 40 gL-1 sucrose was more effective than glucose in stimulating the growth and maturation of somatic embryos. Embryogeic efficiency
was also higher when multivariate combinations of nitrogen sources (inorganic and organic nitrogen forms) were used. The plantlets
that were derived from our germinating somatic embryos were similar to those obtained from axillary buds. 相似文献
10.
Oxidative events during in vitro regeneration of sunflower 总被引:1,自引:0,他引:1
Robert Konieczny Marta Libik Monika Tuleja Ewa Niewiadomska Zbigniew Miszalski 《Acta Physiologiae Plantarum》2008,30(1):71-79
The changes in the activity of some antioxidant enzymes and endogenous H2O2 level in zygotic sunflower embryos during organogenesis and somatic embryogenesis were monitored. Pathways of regeneration
were induced on media differing with sucrose concentration 87 mmol dm−3 for shoot [shoot induction medium (SIM) medium] and 350 mmol dm−3 [embryo induction medium (EIM) medium] for somatic embryo induction. Water potential of the explants cultured on SIM increased,
while the embryos maintained on EIM showed middle water deficit stress. The pattern of superoxide dismutase (SOD) isoforms
was similar in organogenic and embryogenic culture; however, the intensity of MnSOD bands was higher on SIM than on EIM. Differences
in catalase activity were observed: high activity on SIM predominated, whereas on EIM it was reduced. The activity of guaiacol
peroxidase in the explants producing shoots and somatic embryos differed at the beginning of culture, but became comparable
at the time of shoot and somatic embryo formation (day 5). H2O2 content was unchanged in organogenic culture, but on EIM it increased on day 1 followed by significant decrease. The results
indicate that sugar concentration per se, or via induction of different developmental pathways influences the activity of
antioxidant enzymes and also H2O2 level in cultured sunflower embryos. 相似文献
11.
S. A. Webster S. A. Mitchell W. A. Gallimore L. A. D. Williams M. H. Ahmad 《In vitro cellular & developmental biology. Plant》2008,44(2):112-118
A procedure for producing somatic embryos enriched with dibenzyl trisulfide (DTS) using a hormone-dependent culture system
is reported for Petiveria alliacea L. (Guinea hen weed). Leaf explants were cultured on a Murashige and Skoog medium supplemented with a range of naphthaleneacetic
acid (NAA) concentrations and a fixed concentration of benzyladenine (BAP) at 11.0 μM and sucrose or glucose at 30 g l−1. Leaf explants cultured on all media types started to form callus at the cut surfaces of the discs 10–14 d after initiation.
The type of sugar used influenced average fresh weight, the propensity to form roots, as well as the embryogenic response.
The highest mean fresh weight (337.7 ± 26.18 mg) and mean root number (23.7 ± 1.69) was produced on media enriched with sucrose
and supplemented with 53.7 μM NAA and 11.0 μM BAP. An ethanol extract of rhizogenic/embryogenic callus or somatic embryos
was subjected to high-performance liquid chromatography analysis, which revealed the presence of DTS in both extracts. UV
spectral analysis and the use of standard quantitation procedures showed that the quantity of DTS in the somatic embryo extract,
at 0.16% (w/v), was approximately 30-fold higher than in rhizogenic/embryogenic callus (0.0055% w/v) of similar fresh weight. These results indicate that it is possible to biosynthesize approximately 6 mg of natural DTS from
3,808 mg of fresh somatic embryos within 10 wk from less than three leaf explants. 相似文献
12.
In the present investigation, nutritional requirements for induction of a high frequency of well formed somatic embryos (SEs)
from zygotic embryos (ZEs) of sunflower were assessed. Variables like genotype, embryo size (0.5–10 mm), sucrose concentration
(30–240 g l−1), carbohydrate source (sucrose, glucose, maltose), agar strength (0.2–1.0%), basal media (MS, Gamborg, Nitsch, White), photoperiod
(light/dark) and temperature (20–36°C) were tested. All these variables except photoperiod had significant effect on the frequency
of embryogenesis. Highest frequency of embryogenesis was facilitated by Gamborg basal salt media, 120–210 g l−1 sucrose, 0.8–1.0% agar, smaller sized embryos (0.5–2 mm) and incubation temperature of 28–32°C. In addition to these, growth
regulator combinations (2,4-D, 2,4-D+kinetin, BA+NAA) in varying concentrations were tried. Media supplemented with 2,4-D promoted direct embryogenesis, BA+NAA facilitated formation of single/multiple shoots while there was no response on 2,4-D+kinetin supplemented media. Zygotic embryos with well differentiated embryos were transferred to growth regulator free half
strength MS medium for whole plantlet development.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
13.
Improved microspore culture and doubled-haploid plant regeneration in the brown condiment mustard (Brassica juncea) 总被引:11,自引:0,他引:11
The availability of doubled haploids could greatly contribute to improving seed quality in condiment mustard (Brassica juncea). We have developed an efficient and reliable protocol of microspore culture, modified from that of Baillie et al. (1992),
based on a modification of the sucrose concentration of culture media. A comparison of microspore culture media differing
in their sucrose content showed that a decrease from 17% (w/v) sucrose during the first 48 h to 10% (w/v) thereafter favoured
an increase in the production of embryos whatever the responding genotype tested. Thus, out of the 13 B. juncea genotypes studied, 12 gave rise to embryos, and seven of these embryos could be converted into plants. Doubled-haploid plants
were produced after treatment with colchicine.
Received: 16 January 2000 / Revision received: 8 August 2000 / Accepted: 20 September 2000 相似文献
14.
Improved formation of regenerable callus in isolated microspore culture of maize: impact of carbohydrates, plating density and time of transfer 总被引:4,自引:0,他引:4
Pure fractions of maize (Zea mays L.) microspores at various densities were exposed to defined media containing different concentrations of maltose and sucrose.
In general, lower carbohydrate concentrations (60, 90 g/l) yielded higher frequencies of embryo-like structures than a high
concentration (120 g/l). Optimum cell density seemed to depend on the genotype, but densities above 80,000 microspores/ml
led to reduced embryogenesis in all genotypes tested. Direct comparison of maltose and sucrose as carbohydrate source in the
induction medium clearly demonstrated the superiority of maltose with regard to the regeneration frequency. For two out of
three genotypes tested, maltose also enhanced the formation of embryo-like structures. The time of embryo transfer to callus
induction media had a significant effect on regeneration frequency.
Received: 26 September 1997 / Revision received: 5 November 1998 / Accepted 24 March 1999 相似文献
15.
An efficient method of repetitive somatic embryogenesis and plant regeneration of two carnation cultivars (Sagres and Impulse)
was established using a two-step protocol. In the first step, embryogenic tissue were induced from petal explants on MS culture
medium containing 9% sucrose (w/v), 9 μM 2,4-D and 0.8 μM BA. In the second step, embryogenic tissue transferred onto the
MS medium containing 3% sucrose supplemented with different concentrations of picloram (0.8, 2, 4, 8 and 16 μM) to produce
primary somatic embryos. Precotyledonary clumps and cotyledonary somatic embryos were then isolated and subcultured onto the
same media as the second step where they formed secondary somatic embryos in repetitive cycles. Cotyledony somatic embryos
were converted into plantlets when they transferred onto the growth regulator-free half-strength MS medium followed by being
acclimated to the greenhouse conditions. 相似文献
16.
S. J. Murch J. M. R. Victor S. Krishnaraj P. K. Saxena 《In vitro cellular & developmental biology. Plant》1999,35(1):102-105
Summary Peanut seeds germinated on media supplemented with thidiazuron [TDZ: N-phenyl-N′-(1,2,3-thiadiazol-yl)urea], formed somatic embryos at the hypocotyledonary notch region by Day 35 of the culture period.
Supplementation of the culture media with proline, thioproline, or glutamine reduced the total number of embryos formed, but
the resulting embryos were larger, greener and had a more synchronous development than the regenerants formed on media containing
TDZ alone. Analysis of the endogenous amino acid content of the germinating seeds during the induction phase of somatic embryogenesis
revealed accumulation of proline to 6% of the dry seed weight. Concurrent with the emergence of the radicle, the proline concentration
remained significantly elevated throughout the expression phase of embryogenesis. Several other amino acids including alanine,
aspartate, asparagine, glutamate, glutamine, γ-aminobutyrate (GABA), hydroxyproline, isoleucine, threonine and valine accumulated
to peak values approximately 10-fold higher than those of the controls. These results indicate that proline plays a key role
in directing the route of TDZ-induced somatic embryogenesis and that TDZ effectively stimulates a cascade of metabolic events
resulting in the production of specific metabolites, including amino acids, required for the regenerative process. 相似文献
17.
Maturation of black spruce somatic embryos: Sucrose hydrolysis and resulting osmotic pressure of the medium 总被引:1,自引:0,他引:1
The physiological and osmotic roles of sucrose during black spruce (Picea mariana (Mill.) B.S.P.) embryo maturation were investigated. The results showed that when both sucrose and mannitol were present in the medium, the optimum sucrose concentration varied between 4% and 6%. From these data, mannitol does not apparently replace sucrose during the maturation of somatic embryos and therefore it might not be a suitable osmoticum. For the media supplemented with 4% to 12% sucrose and various concentrations of mannitol, the osmotic pressure of the medium rose during maturation, particularly for the highest sucrose concentrations (7% to 12%). Medium containing 3% each of fructose and glucose produced fewer mature embryos compared to the medium with 6% sucrose. An increment in the osmotic potential was observed in medium with 6% sucrose in contrast to that containing 3% each of fructose and glucose. Sugar analysis revealed that the sucrose hydrolysis in the medium was detectable within 1 week of incubation and continued throughout the maturation period. Moreover, no significant uptake of the sugars was detected, since the total amount of fructose, glucose and sucrose remained constant. Our results indicate that the action of sucrose on embryo maturation is mostly achieved through an osmotic control. 相似文献
18.
Etienne H.; Lartaud M.; Carron M.P.; Michaux-Ferrire N. 《Journal of experimental botany》1997,48(1):129-137
In Hevea brasiliensis (Mll. Arg.), increasing the calcium contentof the friable callus maintenance medium from 3 to 9 mM stimulatedregeneration potential through somatic embryogenesis. This stimulationcould be attributed to the homogeneous cytological structureof calluses, which were formed of undifferentiated cells capableof somatic embryogenesis in optimal culture conditions. Thevery marked increase in the active cell population was sufficientto cause a decrease and a stabilization of water and osmoticpotentials of the calluses, whereas their water content increased.The regeneration capacity of calluses cultured on a medium withadditional CaCl2 was greater in terms of both quantity (numberof somatic embryos produced was increased 2-fold) and quality(germination efficiency trebled). High CaCl2 concentrations (9 mM CaCl2) in the embryogenesisinduction medium favoured somatic embryo development when calluseswere maintained 2 months on the same medium. In this case, additionof benzylaminopurine (BAP) and 3,4-dichlorophenoxy- acetic acid(3,4-D) increased the number of embryos produced (243 embryosg1 FW callus) and their germination capacity (27%). These culture conditions were used to determine the optimumembryogenesis induction period. The length of the period affectedboth the intensity of embryogenesis (maximum 5677 d)and somatic embryo quality (maximum 4970 d). The bestresults were obtained with a 70 d embryogenesis induction period,within which 355 embryos g1 FW callus were obtained,with 35% germination. Key words: Calcium, somatic embryogenesis, long-term culture, water status, histology 相似文献
19.
An efficient plant regeneration procedure has been established from hypocotyl explants of the common ice plant, Mesembryanthemum crystallinum L, a halophytic leaf succulent that exhibits a stress-induced switch from C3 photosynthesis to crassulacean acid metabolism
(CAM). Somatic embryos were initiated and developed up to globular and heart stages in Murashige and Skoog (MS) media supplemented
with 3% sucrose, 0.6% bacto-agar, 80 mM NaCl, 5 μM 2,4-D and 1 μM kinetin. High frequency regeneration occurred when somatic
embryos were germinated on media that lacked 2,4-D. High cytokinin treatment suppressed normal growth of embryos and favored
abnormal embryo proliferation. Without growth regulators, regenerated plants rooted on MS medium with 100% efficiency. Mature,
regenerated plants were fertile and morphologically identical to seed-derived plants.
Received: 29 April 1999 / Revision received: 2 July 1999 · Accepted: 12 July 1999 相似文献
20.
Emile Minyaka Nicolas Niemenak Fotso Abdourahamane Sangare Denis Ndoumou Omokolo 《Plant Cell, Tissue and Organ Culture》2008,94(2):149-160
Somatic embryogenesis in cacao is difficult and this species is considered as recalcitrant. Therefore, reformulation of culture
media might be a breakthrough to improve its somatic embryogenesis. In cacao, acquisition of somatic embryogenesis competence
involves three main stages: induction of primary callus, induction of secondary callus and embryo development. Screening for
MgSO4 and K2SO4 concentrations for somatic embryo differentiation was conducted on three genotypes (Sca6, IMC67 and C151-61) at the three
stages. The effect of these two salts in culture media appears to be most efficient at the embryo development stage. At this
stage, high MgSO4 (24 mM) and K2SO4 (71.568 mM) in the culture media induced direct somatic embryos on staminodes and petals of the Sca6 and IMC67 genotypes.
Media supplemented with 6.0 mM and 12.0 mM MgSO4 enabled high responsive of explants and produced high proportion of embryos. The positive effect of MgSO4 and K2SO4 on the acquisition of embryogenesis competence was further tested on seven cacao genotypes reputed as non embryogenic: SNK12,
ICS40, POR, IMC67, PA121, SNK64 and SNK10. All these genotypes were able to produce somatic embryos depending on the MgSO4 concentration. Thus, our results showed that the recalcitrance of cacao to somatic embryo differentiation can be overcome
by screening for the suitable MgSO4 or K2SO4 concentration. Studies of the influence of different K+/Mg2+ ratios (at normal sulphate concentration) on somatic embryo differentiation revealed that sulphate supply was the main factor
promoting responsive explants and the proportion of embryos. Cysteine synthase isoforms showed patterns related to morphogenetic
structures sustaining that sulphur supply and its assimilation improve somatic embryogenesis in cacao. 相似文献