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1.
Morphological and histological changes during somatic embryo formation from coconut plumule explants
L. Sáenz A. Azpeitia B. Chuc-Armendariz J. L. Chan J. -L. Verdeil V. Hocher C. Oropeza 《In vitro cellular & developmental biology. Plant》2006,42(1):19-25
Summary Studies on the development of protocols for the clonal propagation, through somatic embryogenesis, of coconut have been reported
for the past three decades, mostly using inflorescence explants, but with low reproducibility and efficiency. Recent improvements
in these respects have been achieved using plumular explants. Here, we report a developmental study of embryogenesis in plumule
explants using histological techniques in order to extend our understanding of this process. Coconut plumule explants consisted
of the shoot meristem including leaf primordia. At day 15 of culture, the explants did not show any apparent growth; however,
a transverse section showed noticeable growth of the plumular leaves forming a ring around the inner leaves and the shoot
meristem, which did not show any apparent growth. At day 30, the shoot meristem started to grow and the plumular leaves continued
growing., At day 45, the explants were still compact and white in color, but showed partial dedifferentiation and meristematic
cell proliferation leading to the development of callus structures with a translucent appearance. After 60 d, these meristematic
cells evolved into nodular structures. At day 75, the nodular structures became pearly globular structures on the surface
of translucent structures, from which somatic embryos eventually formed and presented well-developed root and caulinar meristems.
These results allow better insights and an integrated view into the somatic embryogenesis process in coconut plumule explants,
which could be helpful for future studies that eventually could lead us to improved control of the process and greater efficiency
of somatic embryo and plantlet formation. 相似文献
2.
C. J. J. M. Raemakers J. J. E. Bessembinder G. Staritsky E. Jacobsen R. G. F. Visser 《Plant Cell, Tissue and Organ Culture》1993,33(2):151-156
Four Indonesian and two Latin-American cassava genotypes (Manihot esculenta Crantz), were evaluated for their ability to develop somatic embryos from young leaf lobes. All genotypes formed somatic embryos but they differed in the frequency of embryos induced. The best genotypes, M. Col 22 and Tjurug, produced germinating embryos (GE) on 81% (22.1 GE/initial leaf lobe) and 46% (4.3 GE/initial leaf lobe) of the cultured leaf lobes, respectively. Up to 57% of the germinating embryos of M. Col 22 and 12% of Tjurug produced either normal or malformed shoots. Most malformed shoots developed into shoots with normal morphology after prolonged culture. All shoots formed roots after transfer to medium without BAP. Roots of all normal and most malformed regenerants had the original ploidy level (2n=36). Regardless of whether the plants were multipliedin vitro (150 plants) or in the greenhouse (30 plants) there were no morphological differences compared to parent plants. 相似文献
3.
Carrot cells were cultured under various light spectra and intensities at different times following the initiation of suspension cultures from callus. The highest intensity white and blue light treatments were inhibitory to growth and somatic embryogenesis. Red and green light were not different from dark treatments which produced the highest total number of embryoids. After extended time in culture, carrot cells in blue light produced secondary embryoids and anthocyanin. Cultures in red light had multiple cotyledons and orange-pigmented radicles. Leafy cotyledons occurred in all light treatments. Abscisic acid production peaked at the heart stage of embryogenesis and synthesis was most pronounced in blue light. Red light enhanced development to the heart stage. Both the red and blue light spectra may be used to manipulate carrot cell cultures to optimize growth. 相似文献
4.
Embryogenic tissues have been initiated on cotyledon explants dissected from seedlings or emblings of hybrid firs. Cotyledons of seedling origin (Abies alba x A. cephalonica) gave a relatively low initiation frequency (1.94 percnt;). In embling-derived cotyledons (Abies alba x A. cephalonica, Abies alba x A. numidica), the initiation was cell-line dependent and reached values between 1.25 and 24.28 percnt;. The established embryogenic cell lines are being maintained in long-term cultures.The origin and development of the somatic embryos have been traced histologically. The early stages of somatic embryo development have been characterised by cell division activity (predominantly periclinal) in the epidermal and subepidermal layers of cotyledons and subsequently by development of nodular structures. Further differentiation led to the formation and emergence of somatic embryos on the surface of cotyledons.Somatic embryo development and plantlet regeneration occurred from proliferating tissues initiated from cotyledons of embling as well as seedling origin. 相似文献
5.
Haoru Tang Zhenglong Ren Gari Krczal 《In vitro cellular & developmental biology. Plant》2000,36(1):47-50
Summary Well-developed somatic embryos were selected from a repetivively somatic embryo line derived from embryonic axes of immature
zygotic embryos of English walnut ‘No. 120’ (Juglans regia L.) for germination and conversion studies. In germinating dishes, somatic embryos germinated into only shoots, only roots,
or both shoots and roots. Without any pretreatment, 28% somatic embryos germinated, while those treated with 2.5–5.0 mg 1−1 (7.2–14.4 μmol) gibberellic acid (GA3) germinated at 25–28% and those receiving a cold treatment of 2–3 mo. at 3–4°C germinated at 30–43%. However, only 4–19%
of the germinating embryos showed both shoots and roots. Treated with desiccation, either with CaCl2·6H2O or Ca(NO3)2·4H2O at 20°C in the dark for 3 d, somatic embryos germinated at 85–91%, 57–69% of which had both shoots and roots. Treatment
with 2 mo. cold storage in combination with desiccation using Ca(NO3)2·4H2O resulted in 92% of somatic embryos germinating, 70% of which showed both shoots and roots. No significant differences were
observed between solid and liquid germination media. After transferring the germinating embryos to plantlet development media,
52–63% of those with both shoots and roots developed into plantlets while 11% with only shoots or 9% with only roots converted
into plantlets. Plantlet development was improved by using lower medium salts and sucrose concentrations. The addition of
activated charcoal enhanced root development, particularly root branching. Of 131 plants transplanted, 91 plants were acclimatized
to a greenhouse. 相似文献
6.
Plant regeneration via somatic embryogenesis in cotton 总被引:6,自引:0,他引:6
An efficient in vitro plant regeneration system characterized by rapid and continuous production of somatic embryos using leaf and stem explants
of abnormal seedling as an explant have been developed in Gossypium hirsutum L. Embryogenic callus and somatic embryos have been obtained directly from the explants of cotton abnormal seedlings. Plant
growth regulators influenced the induction of cotton somatic embryogenesis. The optimal medium for direct somatic embryogenesis
was modified MS medium supplemented with 0.1 mg l-1 ZT and 2 g l-1 activated carbon. On this medium, an average of 28.0 and 28.1 matured somatic embryos formed from per leaf and stem explants
respectively. The highest frequency of somatic embryogenesis was 100%. The somatic embryos were converted into normal plantlets
when cultured on modified MS medium supplemented with 0.1 mg l-1 ZT. Upon transfer to soil, plants grew well and appeared normal. Plants could be regenerated within 60–80 days. The system
of cotton somatic embryogenesis and plant regeneration described here will facilitate the application of plant tissue culture
and genetic engineering on cotton genetic improvement.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
7.
Ljubinka Ćulafić SneŽana Budimir Radmila Vujičić Mirjana Nešković 《Plant Cell, Tissue and Organ Culture》1987,11(2):133-139
Axillary buds of the dioecious plant Rumex acetosella L. were isolated and cultured in vitro. The callus tissue which developed at the basal parts of the explants displayed a high capacity for shoot formation. This morphogenetic pattern was predominant on Murashige and Skoog (MS) medium supplemented with 2% sucrose, 2.2 mgl-1 benzylaminopurine and 0.17 mgl-1 indole-3-acetic acid. Somatic embryogenesis was induced when the osmolality of the medium was increased by adding 6% sucrose instead of 2%, or hexitols in addition to 2% sucrose. Most of the embryogenic calli were formed on the basal parts of leaf laminae and bracts. Development and maturation was strongly promoted by transferring the tissue to a solid or liquid medium lacking benzylaminopurine and indole-3-acetic acid and supplemented with 10 mgl-1 gibberellic acid. The embryos germinated and developed into normal rosette plants when transferred to vermiculite moistened with hormone-free, half-strength MS salt solution. The histology of successive embryogenic stages is presented. 相似文献
8.
Plamen D. Denchev Alexander I. Kuklin Atanas I. Atanassov Alan H. Scragg 《Plant Cell, Tissue and Organ Culture》1993,33(1):67-73
A method for direct somatic embryogenesis in alfalfa (Medicago falcata) is described. The time course in the development phase has been followed for fresh weight, cell density, pH, sugar uptake and embryo number and type. The method of disrupting the explant material has also been shown to influence subsequent embryo formation. 相似文献
9.
Embryogenic cultures of pumpkin (Cucurbita pepo L.) were initiated from mechanically wounded mature zygotic embryos on 2,4-D-containing MS medium, and on hormone-free, semisolid modified MS medium containing NH4Cl as the sole source of nitrogen. The habituated line was derived from the embryogenic tissue induced with 2,4-D and maintained on medium without growth regulators. Sustained subculturing of the three embryogenic lines on a medium with NH4Cl as the sole source of nitrogen enabled the establishment of highly uniform cultures in which no further development into mature embryo stages occurred. The tissue consisting of proembryogenic globules or globular stage embryos was maintained, without decline, for over six years. Globular embryos proceeded to maturity when a combination of reduced (NH4) and unreduced (NO3) forms of nitrogen was provided in the medium. Different nitrogen sources in the medium caused changes of medium pH during subculture in the pH range of 4.0-6.5. The tissue growth and embryo development were blocked on medium with pH adjusted and stabilized at 4.0 or at 3.2. 相似文献
10.
High frequency somatic embryogenesis and plantlet regeneration from hypocotyl protoplast cultures of Brassica napus 总被引:1,自引:0,他引:1
Dwarkesh S. Parihar Satish C. Maheshwari Paramjit Khurana 《Plant Cell, Tissue and Organ Culture》1995,42(1):113-115
A simple protocol has been developed for high frequency protoplast regeneration via somatic embryogenesis in B. napus. Protoplasts isolated from hypocotyl tissue of 8–12 day old seedlings of Brassica napus ISN706 (AACC) when cultured in KM(A) medium resulted in divisions with a, frequency ranging from 30–35%. Regeneration of plantlets was possible by both organogenesis and embryogenesis. Nearly 80% of the call transferred on to MS medium supplemented with 5.0 mg l-1 2iP, 0.1 mg l-1 NAA, 0.001 mg l-1 GA3, 0.5 g l-1 PVP and 0.5 g l-1 MES displayed somatic embryogenesis. The somatic embryos developed into normal plantlets, and also displayed secondary, repetitive embryogenesis. 相似文献
11.
Immunomodulation of abscisic acid (ABA) function during somatic embryogenesis of Nicotiana plumbaginifolia has been used to demonstrate for the first time the effect of this phytohormone on early embryonic events. A homozygous transgenic
line constitutively expressing an anti-abscisic acid (ABA) single chain fragment variable antibody in the endoplasmic reticulum
was established. Development of somatic embryos from the transgenic line and the wild type was compared. The ABA biosynthesis
mutants aba1 and aba2 and wild type cultures treated with the ABA biosynthesis inhibitor fluridone were also used for the comparative investigations.
The development of embryonic structures was disturbed in the early stages of all cultures in which ABA function was blocked
or which were ABA-deficient. After ABA complementation of the in vitro cell cultures normal somatic embryo development was
restored.
Received: 23 May 2000 / Revision received: 1 September 2000 / Accepted: 4 September 2000 相似文献
12.
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
13.
Summary A method of clonal germplams preservation utilizing dehydrated somatic embryos and cool temperature storage conditions was
demonstrated. Somatic embryos of grapevine (Vitis vinifera L) Autumn Seedless and Chardonnay were produced from suspension cultures. After washing twice with sterile water mature somatic
embryos were blot-dried and placed on sterile filter paper in an open Petri dish in a laminar flow hood until they reached
about 25% of their initial weight. Approximately 300 dried embryos were placed in each sterile 90×15 mm Petri dish, which
was tightly sealed with two layers of ParafilmTM. Sealed dishes were stored in the dark at 4°C in a standard refrigerator. Samples of 25–60 individual dehydrated somatic
embryos were periodically tested for viability by placing them on solidified MS medium for germination and plant regeneration.
After 42 mo. of dehydrated storage, 90% of the somatic embryos regenerated into plants. To further test utility, of this storage
method dehydrated embryos stored for 12 and 26 mo. were shipped from Florida to Washington where 75 and 87.5% regenerated
into plants, respectively. Cool temperature storage of dehydrated somatic embryos is a simple and inexpensive method of clonal,
germplasm preservation when compared to alternatives such as cryopreservation. 相似文献
14.
Protolasts of Bupleurum scorzonerifolium were prepared from stem node-derived embryogenic calli with an enzyeme mixture, in which snailase was a necessary component. Follolwing cell wall regeneration protoplasts divided and directly formed somatic embryos which developed into plantlets. The conditions favorable to direct embryo formation were investigated, and the nature of the callus used for protoplast preparation was found to be a critical factor. The osmotic concentration and the composition of the culture medium including the phytohormone combinations were also important. 相似文献
15.
Decai Cui J. R. Myers G. B. Collins P. A. Lazzeri 《Plant Cell, Tissue and Organ Culture》1988,15(1):33-45
The origin and development of zygotic and somatic embryos of Trifolium rubens L. was studied with the aid of paraffin sections and light microscopy. Zygotic embryos were collected, fixed and prepared daily from one to ten days after cross-pollination. Somatic embryos were obtained by plating petiole sections on modified L2 medium with 0.015 mgl-1 picloram and 0.1 mgl-1 6-BAP. Cultured petioles were collected and fixed daily from one to 25 days after plating. Two regions in the vascular bundle sheath of cultured petioles gave rise to callus. The first region was adjacent to the phloem fibers and produced friable callus. The second region gave rise to compact callus that was connected to the fascicular cambium. Somatic embryos originated from single cells in the cortex directly without intervening callus formation and from single cells in the friable callus. In addition, embryos arose from meristematic regions in compact callus. Many early stages of embryogenesis (one, two and four-celled stages) were observed in the cortex and friable callus. Zygotic embryogenesis in Trifolium differs from other legumes in that the suspensor is short and has a broad attachment. This arrangement was observed in zygotic embryos of T. rubens and in many somatic embryos. However, a continuum of somatic embryogenesis was observed where some young embryos had a Trifolium suspensor-like arrangement while others were attached to a long narrow suspensor-like structure more characteristic of Medicago. 相似文献
16.
David I. Dunstan Stephanie Berry Cheryl A. Bock 《In vitro cellular & developmental biology. Plant》1994,30(3):156-159
Summary We investigated abscisic acid (ABA) metabolism among Norway and white spruce somatic embryo cultures which exhibited differences
in maturation response when placed on racemic abscisic acid [(±)-ABA]. Differences in metabolic rate among the spruce genotypes
could affect the ABA pool available for the maturation process, and might therefore be responsible for the differences in
maturation response. The production of cotyledonary (stage 3) somatic embryos in cultures (genotypes) of Norway spruce (PA86:26A
and PA88:25B) and of white spruce (WS1F cryoD and WS46) was compared. In each species pair one of the two genotypes failed
to show stage 3 embryo development (respectively, PA88:25B and WS46). The investigation of ABA metabolism of each species
pair showed that no substantial differences in ABA consumption or in the production of metabolites occurred. In each case
ABA was metabolized to phaseic acid and dihydrophaseic acid over the 42-day culture period, metabolites were recoverable from
the agar-solidified medium, and the sum of residual ABA and metabolites were equivalent to the ABA initially supplied. The
results indicate that the process of ABA metabolism occurs essentially independently of somatic embryo maturation.
NRCC no. 37345. 相似文献
17.
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
18.
Some features of somatic embryo maturation of algerian fir 总被引:1,自引:0,他引:1
Summary Maturation of Abies numidica De Lann. somatic embryos was tested on media with abseisic acid and various maltose and polyethylene glycol-4000 concentrations.
The effect of basal medium and subculture period on maturation was also examined. The maturation of somatic embryos was promoted
by polyethylene glycol-4000, at 7.5–10%. Three to 6% maltose significantly enhanced the yield of mature embryos. The most
effective somatic embryo maturation occurred when embryogenictissue was transferred to maturation medium after 14–21 d cultivation
on proliferation medium. The ability for A. numidica cultures to form cotyledonary somatic embryos was assessed over a period of 3 yr. Plantlets germinated on half-strength SH
(Schenk and Hildebrandt) medium with charcoal and survived transfer to the soil. 相似文献
19.
H. Brittain-Loucas S. R. Bowley B. D. McKersie 《In vitro cellular & developmental biology. Plant》1998,34(4):281-284
Summary The effects of callus inoculation concentration and culture duration on somatic embryogenesis of orchardgrass,Dactylis glomerata L., were evaluated in suspension cultures of an embryogenic genotype Embryogen-P. Somatic embryo formation was induced in
liquid SH medium containing 30 μM dicamba (SH-30 and 1.5% casein hydrolysate; embryo development was in liquid SH medium without plant growth regulators (SH-0);
and embryo maturation and germination occurred on solid SH-0 medium. Callus proliferation in SH-30 suspension cultures was
greatest when callus was inoculated into the liquid medium at a relatively high concentration of 4% (4 g callus/100 ml medium),
but the induction of somatic embryos was highest in this medium if the callus was inoculated at a lower concentration (<2%).
In a second experiment, somatic embryo yield was highest when SH-0 development medium was inoculated with suspension culture
callus at 0.1% concentration and declined markedly as inoculation concentration increased. Cell concentration is a critical
factor in regulating the somatic embryogenesis response in orchardgrass suspension cultures. 相似文献