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1.
Veronique Troch Stefaan Werbrouck Danny Geelen Marie-Christine Van Labeke 《Plant Cell, Tissue and Organ Culture》2009,98(1):115-123
Factors affecting conversion of horse chestnut (A. hippocastanum L.) somatic embryos into plantlets were evaluated. Anther filament derived embryogenic tissue developed bipolar structures
with two cotyledons and a well-developed shoot and root apical meristem upon auxin omittance from the culturing medium. The
impact of carbohydrate type (glucose, fructose, sucrose and maltose) and concentration (3 and 6%) on somatic embryo maturation
and conversion were evaluated. Although conversion frequencies were high for all treatments, overall quality of regenerated
plantlets was poor. Increasing the carbohydrate concentration in the maturation medium did not increase conversion of somatic
embryos or quality of regenerated plantlets in terms of shoot height. On the contrary, addition of PEG (polyethylene glycol)
in maturation media had a beneficial effect on shoot quality of regenerated plantlets. Sucrose was a superior carbon source
when PEG was included in the maturation medium, in terms of conversion rate (65.7%) as well as of shoot quality of plantlets
(43.8% of plantlets had shoots >2 cm). Clonal fidelity of the different development stages of somatic embryogenesis and of
converted plantlets was assessed by flow cytometry and no major ploidy changes were found. 相似文献
2.
Sánchez MC Martínez MT Valladares S Ferro E Viéitez AM 《Journal of plant physiology》2003,160(6):699-707
Experiments were performed to determine the influence of maturation medium carbohydrate content on the rates of germination and plantlet conversion (root and shoot growth) of somatic embryos from four embryogenic lines derived from leaf or internode explants of Quercus robur L. seedlings. The conversion rate was favoured by high carbohydrate content as long as the maturation medium contained at least 2% sucrose, which was necessary for healthy embryo development. Given this, sorbitol and mannitol favoured the conversion rate more efficiently than sucrose, the highest rate, 32%, being achieved by medium with 6% sorbitol and 3% sucrose. Maturation treatment did not affect the root or shoot lengths of converted embryos. In supplementary experiments, 2 weeks of gibberellic acid treatment between maturation and germination treatments did not improve germination rates, but did reduce root length and the number of leaves per regenerated plantlet. In the four embryogenic lines tested, plant recovery rate was enhanced by inclusion of benzyladenine into the germination medium following culture of the embryos on maturation medium with 6% sorbitol and 2-3% sucrose. In embryogenic systems it is important to assess the uniformity of the regenerants. Random amplified polymorphic DNA (RAPD) analysis using 32 arbitrary oligonucleotide primers was performed to study variability in DNA sequences within and between four embryogenic lines. No intraclonal nor interclonal polymorphism was detected between embryogenic lines originating from different types of explant from the same seedling, but every one of the primers detected enough polymorphism among clones originating from different plants to allow these three origins to be distinguished. No differences in DNA sequences between regenerated plantlets and their somatic embryos of origin were detected, but a nodular callus line that had lost its embryogenic capacity was found to be mutant with respect to three other clones originating from the same plantlet. This study shows that high carbohydrate levels in the maturation medium significantly increase plant conversion of oak somatic embryos, which exhibit no variation in DNA sequences when proliferated by secondary embryogenesis. 相似文献
3.
Summary The effect of abscisic acid (ABA) was evaluated during the maturation and germination of holm oak (Quercus ilex L.) somatic embryos. The addition of ABA to the culture medium significantly reduced unwanted recurrent embryogenesis in
mature somatic embryos without affecting the germination of embryos subjected to stratification at 4°C. Stratification at
4°C for 2 mo. was the most efficient for stimulating somatic embryo germination of holm oak. The addition of 90 and 450 mM sucrose also improved germination, while higher sucrose concentrations were inhibitory. 相似文献
4.
Onay A. Jeffree C.E. Theobald C. Yeoman M.M. 《Plant Cell, Tissue and Organ Culture》2000,60(2):121-129
Embryogenic masses (EMSes) of pistachio (Pistacia vera L.) were proliferated in liquid Murashige and Skoog (MS) medium without growth regulators. To determine the effects of benzylaminopurine
(BAP), racemic (±) abscisic acid (ABA) and sucrose treatments during maturation on the subsequent germination and plantlet
regeneration, clusters of mature somatic embryos were transferred from maturation medium onto the surface of 0.7% agar-solidified
Murashige and Skoog medium. Neither germination nor plantlet development medium contained BAP or ABA. Germination studies
were carried out using 80 somatic embryos at every combination of four sucrose concentrations, three maturation periods and
either five concentrations of BAP or four of ABA, and the numbers germinating were recorded after four durations of culture.
A similar experimental plan was used to study plantlet regeneration. The number of germinated somatic embryos increased markedly
with duration of the culture on germination medium, and was influenced by the concentrations of BAP or ABA in the maturation
medium; the concentration of sucrose in this medium had little influence. Plantlet regeneration also increased with culture
duration and was reduced at the highest levels of BAP or ABA; with ABA, the probability of plantlet regeneration was lower
for longer maturation periods. ABA and BAP have similar effects on somatic embryo germination (except at the highest levels
used), but BAP is superior to ABA for promoting subsequent plantlet regeneration. Linear logistic models were used to investigate
the significance of the treatments, and to estimate the optimum conditions for germination and plantlet regeneration.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
5.
Experiments were performed to determine the influence of proliferation medium on the maintenance of embryogenic competence and on repetitive embryogenesis in Castanea sativa Mill. somatic embryos derived from leaf explants. Somatic embryo proliferation was carried out by both direct secondary embryogenesis and by the culture of nodular callus tissue originated from cotyledons of somatic embryos. Both systems led to the production of cotyledonary somatic embryos on Murashige and Skoog proliferation medium supplemented with 0.1 mg l-1 benzyladenine and 0.1 mg l-1 naphthaleneacetic acid. Carbon source and concentration had a marked influence on maturation and subsequent germination ability of chestnut somatic embryos. Plantlet conversion was achieved in embryos matured on media with 6 % sucrose, and on 3 or 6 % maltose, whereas mean shoot length, root length and leaf number of produced plants were not significantly affected by these maturation media. Overall, the best results were obtained with 3 % maltose-matured somatic embryos, giving rise to 6 % plant recovery in addition to 33 % of embryos exhibiting only shoot development. The application of a 2-month cold treatment at 4 degrees C to somatic embryos matured on medium with 3 % maltose was necessary for achieving plant conversion, while partial desiccation did not appear to influence this response. A total of 39 % of embryos eventually produced plants either through conversion to plantlets or indirectly through rooting of shoots. Shoots formed by somatic embryos could be excised, multiplied and rooted following the micropropagation procedures previously developed for chestnut. 相似文献
6.
The effects of ancymidol,abscisic acid,uniconazole and paclobutrazol on somatic embryogenesis of asparagus 总被引:1,自引:0,他引:1
Summary The effects of ancymidol, abscisic acid (ABA), uniconazole, and paclobutrazol on asparagus somatic embryogenesis were evaluated. Calli induced from seedlings of genotype G447 were transferred to embryo induction medium (MS plus 3% sucrose, 0.1 mg L–1 NAA, 0.5 mg L–1 kinetin and 3% gelrite), with different concentrations of these compounds. After 8 weeks, the recovered bipolar or globular embryos were placed on germination medium (MS plus 6% sucrose, 0.1 mg L–1 NAA, 0.1 mg L–1 kinetin, 0.75 mg L–1 ancymidol, 40 mg L–1 adenine sulphate dihydrate, 0.17 mg L–1 sodium phosphate monobasic and 3% gelrite) for conversion to plantlets. Inclusion of ancymidol, ABA, uniconazole and paclobutrazol in the embryo induction medium did not affect the total number of somatic embryos produced relative to the control without these compounds. However, ancymidol, ABA and uniconazole significantly improved embryo development by increasing the production of bipolar embryos 250–750% and decreasing that of globular embryos 8–35% relative to the control. The bipolar embryos produced with any of the four compounds in the embryo induction medium converted to plantlets at rates 700–1100% greater than the control. None of the globular embryos converted to plantlets. Ancymidol (0.75 mg L–1) and ABA (0.05 mg L–1) were the most effective treatments; 61 and 46 bipolar embryos g–1 callus were produced, and 38% and 37% of the bipolar embryos converted to plantlets, respectively. These results indicated that ancymidol, ABA, uniconazole and paclobutrazol significantly enhanced the production of asparagus somatic embryos and their conversion to plantlets, and ancymidol and ABA were more effective than uniconazole and paclobutrazol.Abbreviations Ancymidol
a-cyclopropyl-a(4-methoxyphenyi)-5-pyrimidine methanol
- NAA
1-naphthaleneacetic acid
- Paclobutrazol
I-(4-chlorophenyl)-4,4-dimethyl-2(1H-1,2,4-triazol-1-yl)-pentan-3-ol
- Uniconazole
(E)-(p-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-pentan-3-ol
- ABA
abscisic acid
- GA
gibberellic acid 相似文献
7.
High-frequency plant regeneration through cyclic secondary somatic embryogenesis in black pepper (Piper nigrum L.) 总被引:5,自引:0,他引:5
A high-frequency plantlet regeneration protocol was developed for black pepper (Piper nigrum L.) through cyclic secondary somatic embryogenesis. Secondary embryos formed from the radicular end of the primary somatic embryos which were originally derived from micropylar tissues of germinating seeds on growth regulator-free SH medium in the absence of light. The process of secondary embryogenesis continued in a cyclic manner from the root pole of newly formed embryos resulting in clumps of somatic embryos. Strength of the medium and sucrose concentration influenced the process of secondary embryogenesis and fresh weight of somatic embryo clumps. Full-strength SH medium supplemented with 1.5% sucrose produced significantly higher fresh weight and numbers of secondary somatic embryos while 3.0 and 4.5% sucrose in the medium favored further development of proliferated embryos into plantlets. Ontogeny of secondary embryos was established by histological analysis. Secondary embryogenic potential was influenced by the developmental stage of the explanted somatic embryo and stages up to “torpedo” were more suitable. A single-flask system was standardized for proliferation, maturation, germination and conversion of secondary somatic embryos in suspension cultures. The system of cyclic secondary somatic embryogenesis in black pepper described here represents a permanent source of embryogenic material that can be used for genetic manipulations of this crop species. 相似文献
8.
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
9.
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
10.
Jing Li Yang Yu Da Niu Chuan Ping Yang Gui Feng Liu Cheng Hao Li 《Plant Cell, Tissue and Organ Culture》2011,106(3):391-399
Somatic embryogenesis (SE) was induced in female flower buds from mature Schisandra chinensis cultivar ‘Hongzhenzhu’. Somatic embryo structures were induced at a low frequency from unopened female flower buds and excised
unopened on Murashige and Skoog (MS) agar medium containing 4.0 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D). Friable embryogenic calli were induced from somatic embryo structures after three
to four subcultures on initiation medium. The frequencies of mature somatic embryo germination and plantlet conversion were
low, but increased in the presence of gibberellic acid (GA3). Some germinated somatic embryos could form friable embryogenic calli on medium without plant growth regulators (PGRs).
The germination and conversion frequencies of somatic embryos from embryogenic calli induced using PGR-free medium were higher
than for somatic embryos from embryogenic calli induced on medium containing 2,4-D. Most somatic embryos from 2,4-D-induced
embryogenic calli had trumpet-shaped embryos, and most somatic embryos from PGR-free medium–induced embryogenic calli had
two or three cotyledons. Histological observation indicated that two- and three-cotyledon embryos had defined shoot primordia,
but most of the trumpet-shaped embryos yielded plantlets that lacked or had poorly developed meristem tissue. Cytological
and random amplification of polymorphic DNA (RAPD) analyses indicated no evidence of genetic variation in the plantlets of
somatic embryo origin. 相似文献
11.
Elena Corredoira Silvia Valladares Ana M. Vieitez Antonio Ballester 《In vitro cellular & developmental biology. Plant》2008,44(4):307-315
For the mass production of chestnut trees with selected, hybrid, or genetically engineered genotypes, one potentially desirable
propagation strategy is based on somatic embryogenesis. Although methods exist for the initiation of embryogenic cultures
of Castanea sativa from immature zygotic embryos or leaf explants, the embryos produced have had low rates of conversion into plantlets. This
study explored the possible benefits for somatic embryos that have already undergone maturation and cold treatments, of (a)
partial slow or fast desiccation, and (b) of the addition of plant growth regulators or glutamine to the germination medium.
Germination response was evaluated in terms of both conversions to plantlets and through embryos developing only shoots (shoot
germination) that could be rooted following the micropropagation protocols developed for chestnut. Two or 3 wk slow desiccation
in sealed empty Petri dishes resulted in a slight reduction in water content that nevertheless increased total potential plant
recovery, shoot length, and the number of leaves per plantlet. However, best results were achieved by 2 h fast drying in a
laminar flow hood, which reduced embryo moisture content to 57–58% and enhanced the potential plant recovery and quality of
regenerated plantlets. Plant yield was also promoted by addition of 0.44 μM benzyladenine and 200–438 mg/l of glutamine to
the germination medium, and plantlet quality (as evidenced by root, shoot, and leaf growth) by the further addition of 0.49 μM
indole-3-butyric acid. 相似文献
12.
Direct somatic embryogenesis and synthetic seed production from<Emphasis Type="Italic"> Paulownia elongata</Emphasis> 总被引:8,自引:0,他引:8
We have developed a reproducible system for efficient direct somatic embryogenesis from leaf and internodal explants of Paulownia elongata. The somatic embryos obtained were subsequently encapsulated as single embryos to produce synthetic seeds. Several plant growth regulators [6-benzylaminopurine, indole-3-acetic acid, -naphthaleneacetic acid, kinetin and thidiazuron (TDZ)] alone or in combination were tested for their capacity to induce somatic embryogenesis. The highest induction frequencies of somatic embryos were obtained on Murashige and Skoog (MS) medium supplemented with 3% sucrose, 0.6% Phytagel, 500 mg l-1 casein hydrolysate and 10 mg l-1 TDZ (medium MS10). Somatic embryos were induced from leaf (69.8%) and internode (58.5%) explants on MS10 medium after 7 days. Subsequent withdrawal of TDZ from the induction medium resulted in the maturation and growth of the embryos into plantlets on MS basal media. The maturation frequency of somatic embryos from leaf and internodal explants was 50.8% and 45.8%, respectively. Subculturing of mature embryos led to their germination on the same medium with a germination frequency of 50.1% and 29.8% from leaf and internode explants, respectively. Somatic embryos obtained directly on leaf explants were used for encapsulation in liquid MS medium containing different concentrations of sodium alginate with a 30-min exposure to 50 mM CaCl2. A 3% sodium alginate concentration provided a uniform encapsulation of the embryos with survival and germination frequencies of 73.7% and 53.3%, respectively. Storage at 4°C for 30 days or 60 days significantly reduced the survival and complete germination frequencies of both encapsulated and non-encapsulated embryos relative to those of non-stored somatic embryos. However, the survival and germination rates of encapsulated embryos increased following storage at 4°C. After 30 days or 60 days of storage, the survival rates of encapsulated embryos were 67.8% and 53.5% and the germination frequencies were 43.2% and 32.4%, respectively. These systems could be useful for the rapid clonal propagation and dissemination of synthetic seed material of Paulownia elongata.Abbreviations BAP 6-Benzylaminopurine - IAA Indole-3-acetic acid - NAA -Naphthaleneacetic acid - TDZ ThidiazuronCommunicated by H. Lörz 相似文献
13.
D. H. Tejavathi M. D. Rajanna R. Sowmya K. Gayathramma 《In vitro cellular & developmental biology. Plant》2007,43(5):423-428
Somatic embryogenesis from cultures of shoot apices, cotyledon and young leaves of in vitro shoots of Agave vera-cruz Mill. was studied. Embryogenic callus was obtained when explants were cultured on Murashige and Skoog’s (MS) medium (1962)
supplemented with L2 vitamins, 4.52 μM 2,4-dichlorophenoxyacetic acid (2,4-d) or 5.37 μM ∝-naphthalene acetic acid (NAA). Somatic embryos differentiated from this embryogenic callus upon subculture
to maturation/conversion medium containing cytokinin either alone or with auxin and l-glutamine. The best combination of growth regulators for development of somatic embryos was found to be 5.37 μM naphthalene
acetic acid plus 0.91 μM zeatin and 40 g/l sucrose. The conversion frequency of somatic embryos to plantlets varied from 46–50%.
Rooted plantlets were transferred directly to pots containing a soil, sand, and manure mixture without any hardening phase
with 96–98% survival of the plantlets. Based on the histological observations, the potential origin of the somatic embryo
is discussed. 相似文献
14.
Jing Li Yang Bo Zhao Eun Soo Seong Myong Jo Kim Won Hee Kang Na Young Kim Chang Yeon Yu Cheng Hao Li 《Plant biotechnology reports》2010,4(4):261-267
We describe culture conditions for a high-efficiency in vitro regeneration system of Papaver
nudicaule through somatic embryogenesis and secondary somatic embryogenesis. The embryogenic callus induction rate was highest when
petiole explants were cultured on Murashige and Skoog (MS) medium containing 1.0 mg l−1 α-naphthaleneacetic acid (NAA) and 0.1 mg l−1 6-benzyladenine (BA) (36.7%). When transferred to plant growth regulator (PGR)-free medium, 430 somatic embryos formed asynchronously
from 90 mg of embryogenic callus in each 100-ml flask. Early-stage somatic embryos were transferred to MS medium containing
1.0 mg l−1 BA and 1.0 mg l−1 NAA to germinate at high frequency (97.6%). One-third-strength MS medium with 1.0% sucrose and 1.0 mg l−1 GA3 had the highest frequency of plantlet conversion from somatic embryos (91.2%). Over 90% of regenerated plantlets were successfully
acclimated in the greenhouse. Secondary somatic embryos were frequently induced directly when the excised hypocotyls of the
primary somatic embryos were cultured on MS medium without PGRs. Sucrose concentration significantly affected the induction
of secondary embryos. The highest induction rate (89.5) and number of secondary somatic embryos per explant (9.3) were obtained
by 1% sucrose. Most secondary embryos (87.2–94.3%) developed into the cotyledonary stage on induction medium. All cotyledonary
secondary embryos were converted into plantlets both in liquid and on semisolid 1/3-strength MS medium with 1.0% sucrose. 相似文献
15.
Sandra Correia Ana Estefânia Cunha Lígia Salgueiro Jorge M. Canhoto 《Plant Cell, Tissue and Organ Culture》2012,109(1):143-152
Somatic embryogenesis induction and somatic embryo development of the solanaceous tamarillo tree were previously established
and successfully used for plant regeneration from different explants and varieties. Somatic embryogenesis was induced in Murashige
and Skoog medium containing 2,4-dichlorophenoxyacetic acid (2,4-D) or picloram and high sucrose concentrations (0.25 M). The
embryogenic tissues were transferred to an auxin-free medium, with reduced sucrose levels, to permit embryo development and
conversion into plantlets. This two-step protocol is often impaired by an ineffective transition from the proembryogenic masses
to embryo development. In this work, attempts to optimize the somatic embryogenesis system of tamarillo by improving the quality
of somatic embryo and embryo conversion were carried out. The results showed that the presence of a high number of abnormal
somatic embryos did not significantly inhibit plant conversion, hence indicating that shoot apical meristem development was
not affected in abnormal somatic embryos. It was also shown that the manipulation of sucrose concentration in the development
medium (0.11 M) and dark conditions before conversion increased the number of morphologically normal somatic embryos. The
comparison between mature cotyledonary zygotic and somatic embryos showed an inefficient accumulation of storage compounds,
mainly lipids, in somatic embryos. These reduced levels of lipid storage could be responsible for the abnormal patterns of
embryo development found in tamarillo somatic embryos. 相似文献
16.
Control of hyperhydricity of mango somatic embryos 总被引:3,自引:0,他引:3
Mary-Joy Monsalud Helena Mathews Richard E. Litz Dennis J. Gray 《Plant Cell, Tissue and Organ Culture》1995,42(2):195-206
Hyperhydricity of immature somatic embryos has been a limiting factor for the development of highly embryogenic suspension cultures of many important mango cultivars. Reversion of hyperhydricity was achieved in two ways: 1) heart-stage somatic embryos (2–3 mm length) were partially dehydrated under controlled conditions at high relative humidity (RH) for 24–48 h and 2) the gelling agent (Gel-Gro) concentration of the plant growth medium was increased from 2.0 to 6.0 g l-1. Partially dehydrated immature somatic embryos were normal in appearance. Somatic embryos that were partially dehydrated germinated precociously when cultured on maturation medium. Although abscisic acid (ABA) did not reverse hyperhydricity of primary somatic embryos, ABA did stimulate the reversal of this abnormal pattern of development among secondary embryos. ABA (500 M) inhibited precocious germination and permitted somatic embryo maturation. Partially dehydrated, immature somatic embryos (4–7 mm long) remained viable for up to 32 days in the absence of maturation medium under high RH.Abbreviations 2,4-d
2,4-dichlorophenoxyacetic acid
- ABA
abscisic acid
- BA
6-benzyladenine
- RH
relative humidity 相似文献
17.
Summary
In vitro propagation of Quassia amara L. (Simaroubaceae) was attempted using mature and juvenile explants. Attempts to establish in vitro culture using leaf and internode explants from a plant more than 15yr old were unsuccessful due to severe phenolic exudation.
Plant regeneration through direct and indirect somatic embryogenesis was established from cotyledon explants. Murashige and
Skoog (MS) medium with 8.9 μM N6-benzyladenine (BA) and 11.7 μM silver nitrate induced the highest number (mean of 32.4 embryos per cotyledon) of somatic embryos. Direct somatic embryogenesis
as well as callus formation was observed on medium with BA (8.9–13.3 μM). Semi-mature pale green cotyledons were superior for the induction of somatic embryos. Embryos developed from the adaxial
side as well as from the point of excision of the embryonic axis. More embryos were developed on the proximal end compared
to mid and distal regions of the cotyledons. Subculture of callus (developed along with the somatic embryos on medium with
BA alone) onto medium containing 8.9 μM BA and 11.7 μM silver nitrate produced a mean of 17.1 somatic embryos. Primary somatic embryos cultured on MS medium with 8.9 μM BA and 11.7μM silver nitrate produced a mean of 9.4 secondary somatic embryos. Most of the embryos developed up to early cotyledonary stage.
Reduced concentration of BA (2.2 or 4.4 μM) improved maturation and conversion of embryos to plantlets. Ninety percent of the embryos converted to plantlets. The optimized
protocol facilitated recovery of 30 plantlets per cotyledon explant within 80d. Plantlets transferred to small cups were subsequently
transferred to field conditions with a survival rate of 90%. 相似文献
18.
Commercial deployment of clonal trees via somatic embryogenesis (SE) could increase forest productivity over conventional
tree breeding techniques. However, some technical advances need to be made to use SE in clonal forestry with Pinus radiata. For example, the conversion of embryonal mass (EM) into plants is at present a major bottleneck. For this reason, maturation
experiments were carried out to determine the effect of the initial amount of EM, activated charcoal (AC) and the best combination
of abscisic acid (ABA), sucrose and amino acid concentration in the maturation medium. Germination was evaluated on different
media formulations with and without AC. When 100 mg of EM were suspended in liquid medium without AC, cotyledonary somatic
embryos were obtained in all the maturation media tested. Maturation medium supplemented with 60 μM ABA, 6% sucrose, and embryo
development medium amino acid mixture produced the highest number of cotyledonary somatic embryos, between 10 and 1,550 embryos
per gram of EM fresh weight. Approximately half of the tested 25 lines produced more than 600 embryos per gFW. Embryo development
was the best when somatic embryos were germinated in half strength modified Quoirin and Lepoivre medium supplemented with
2 g L−1 AC. This protocol simplified and improved SE maturation and germination due to the elimination of subcultures, the large
number of somatic embryos obtained from a very low amount of EM, and the elimination of pre-germination treatments, resulting
in a significant saving of cost and labor. 相似文献
19.
Effects of Desiccation, Medium Osmolarity and Abscisic acid on the Maturation of Hevea brasiliensis Somatic Embryos 总被引:3,自引:0,他引:3
ETIENNE H.; MONTORO P.; MICHAUX-FERRIERE N.; CARRON M. P. 《Journal of experimental botany》1993,44(10):1613-1619
The effects of desiccation of Hevea somatic embryos and of sucroseand ABA concentrations in the maturation medium on their germinabilitywere investigated. Conversion into plant, water and histochemicalstatus of somatic embryos were compared systematically to thoseof the zygotic embryos used as reference. Slow desiccation ormaturation on 351 mol m3 sucrose supplemented with 1mmol m3 ABA strongly improved germinability and conversionof embryos into plants. The combination of the two treatmentswas the most effective, increasing the germination frequencyby 3·7 and plant conversion by 6·6 in clone PR107. Each of these two treatments increased the vigour of somaticembryos, stimulated the formation of root and shoot meristemsand the synthesis and accumulation of starch and protein reserves.At the end of maturation, the Hevea somatic embryos bore ananatomical and histochemical resemblance to mature zygotic embryos.Likewise, the two treatments brought the water status of somaticembryos closer to that of the mature zygotic embryos, but withoutachieving a perfect match. Optimization of the successful conversioninto plants may require full acquisition of this water status. Key words: ABA, embryo maturation, Hevea, somatic embryogenesis, water status 相似文献
20.
Development and germination of American chestnut somatic embryos 总被引:8,自引:0,他引:8
Zizhuo Xing William A. Powell Charles A. Maynard 《Plant Cell, Tissue and Organ Culture》1999,57(1):47-55
American chestnut (Castanea dentata (Marsh.) Borkh.) plants were regenerated from developing ovules through somatic embryogenesis.
On an initiation medium containing 18.18 μM 2,4-dichlorophenoxyacetic acid and 1.11 μM 6-benzyladenine (BA), 25 out of 1,576
ovules were induced to form proembryogenic masses (PEMs). These PEMs were cultivated on a development medium for 4 weeks.
Individual somatic embryos were then grown on a maturation medium for at least one month, until shoot meristems and radicles
were developed. Both development and maturation media consisted of Gamborg's B-5 basal medium, 0.5 μM BA, and 0.5 μM α-naphthaleneacetic
acid, but the former contained 20 g l−1 sucrose and the later contained 60 g l−1 sucrose. A range of 86 to 586 embryos per gram PEMs was observed beyond the cotyledonary stage. These embryos then germinated,
resulting in plantlets with a 3.3% conversion rate. An additional 6.3% of the mature embryos produced shoots, which could
also result in plantlets by rooting of microcuttings. Proembryogenic masses that were established in continuous culture and
maintained on initiation medium for 17 months retained regenerability, though the embryo yield decreased over time. Twenty
plantlets were acclimatized and grown in potting mix in a greenhouse. The largest 6 were transplanted, along with seedling
controls, into a nursery bed in 1997. As of July, 1999, 4 out of the 6 were surviving.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献