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1.
Anthers of snapmelon (Cucumis melo L. var. momordica) were irradiated with varied doses of gamma rays (150, 200, 250, 300 and 350 Gray). Then pollen from irradiated anthers was
used for pollinating female flowers. Results revealed that 250 Gray of gamma-irradiation was successful in inducing parthenogenesis
and fruit development, whereas, low (150 and 200 Gray) or high (300 and 350 Gray) irradiation doses were not effective in
inducing haploid embryos. Embryos at a range of developmental stages were dissected from fruits harvested after 21 days of
pollination and cultured on E20A medium. Among these embryos cultured, only cotyledonary embryos germinated into plantlets.
Chromosome counting, performed on the roots of regenerated plants, showed the haploid level (n = 12). Ploidy analysis using flow cytometer, measurement of stomatal cells and counting of chloroplast in the guard cells
also corroborated the haploid nature of regenerated plants. 相似文献
2.
In this study, the effect of spraying mother plants with various levels of putrescine, spermidine, and cycocel (each at 0, 50, 500, and 5000 mg/l) were assessed on the frequency of haploid embryos produced from unfertilized ovaries and subsequent regeneration of derived embryos. Significantly higher haploid embryos were obtained when mother plants were sprayed with putrescine at 500 mg/l (5.2 embryos/fruit), spermidine at 50 mg/l (4.8 embryos/fruit), and cycocel at 50 mg/l (5.2 embryos/fruit) as compared to the control (without spraying, 3.2 embryos/fruit). However, embryogenesis induction was decreased drastically as the concentration of all the three compounds tested was increased and the lowest haploid embryos were observed when 5000 mg/l of spermidine (0.4 embryos/fruit) or cycocel (2.0 embryos/fruit) were applied. Only spermidine at 50 mg/l led to 100% regeneration into fully developed plantlets. The seed setting and size of fruits were also affected by polyamines and cycocel applications. Ploidy analysis using a flow cytometer indicated that all regenerated plantlets contain the gametic chromosome number (n?=?x?=?7) of parental plants and the results of chromosome counting also confirmed the haploid nature of regenerated plantlets. It can be concluded that the induction of haploid embryogenesis from unfertilized ovaries after pollination with irradiated pollen and subsequent conversion of derived embryos into the plantlets could be improved in Cucumis sativus L. by applying appropriate levels of putrescine, spermidine, and cycocel. 相似文献
3.
Janine S. Croser Monika M. Lulsdorf Ravinder K. Grewal Kayley M. Usher Kadambot H. M. Siddique 《In vitro cellular & developmental biology. Plant》2011,47(3):357-368
Routine production of haploid plants has not been reported for any legume, despite the major role these species play in sustainable
farming systems and human nutrition. It is within this context that we report a protocol for the induction of haploid development
in chickpea (Cicer arietinum L.) using isolated microspore culture. The cultivars “Rupali”, “Narayen”, and “Kimberley Large” were identified as responsive
to isolated microspore culture. Flower bud length and microspore developmental stage were correlated for these cultivars.
Depending on the cultivar, buds 2.85–3.5 mm in length contained uninucleate microspores. Microspores from donor plants grown
in winter and spring were more responsive than those grown in summer. A cold treatment (4°C) of between 24 and 48 h enhanced
microspore response in winter- and spring-grown material but was not effective in summer-grown material. A medium developed
by the authors was effective for microspore induction and early-stage embryo development. The addition of hormones to this
medium was promotive of microspore induction in winter- and spring-grown material, but not in summer-grown material. The initial
haploid division predominantly occurred via symmetrical division of the vegetative nucleus. Further research is under way
to convert pro-embryos into plants. 相似文献
4.
Najat Mustafa Faris Vesselina Nikolova Katarzyna Niemirowicz-Szczytt 《Acta Physiologiae Plantarum》1999,21(4):391-396
Pollination with irradiated pollen was the only effective way for the induction of haploid embryo in cucurbits. The possibility
of using lower doses of γ rays (Co60 source) was studied. The effect of 0.2 and 0.3 kGy of rays was tested on five cucumber lines and three hybrids in the first
experiment. It was found that there was hardly any difference between the total number of embryos produced by all studied
forms. The highest number of isolated embryos was obtained from hybrids Gy-3 M and BxOg (111 and 188 respectively). The plant
regeneration was estimated at 3.3 %.
The best two lines and one hybrid were used in the second experiment to find the lowest possible dose of irradiation. The
dose 0.05 kGy produced only diploid embryos and was rejected as too low. Other three doses (0.1; 0.2; and 0.3 kGy) effected
embryo development in relation to the irradiation applied with the highest number obtained at the lowest dose. However the
number of plants regenerated from each combination was similar. The plant regeneration in this experiment was 7.7 %. The effect
of 0.1 and 0.3 kGy was tested during the next two years on one highly vigorous variety. It was confirmed that 0.1 kGy stimulated
the development of higher number of haploid embryos. 相似文献
5.
Recovery of doubled haploid (DH) progeny from haploid melon plants for use in breeding programs requires efficient chromosome
doubling procedures. We describe improved procedures for recovery of fruits and viable seeds from parthenogenetic melon plants.
Plant regeneration from nodal explants treated with 500 mg/L colchicine for 12 h was increased from 40 to 88% by transferring
the treated explants to medium supplemented with a combination of growth regulators [5 μM IAA; 5 μM BA; 1 μM ABA; 30 μM AgNO3). Prolonged exposure (2–7 days) to colchicine inhibited regeneration from nodal explants but had less effect on shoot tip
explants. Many colchicine-treated plantlets flowered in vitro, allowing early assessment of their male fertility. Production
of stained pollen in plants from nodal explants was highest after 0.5–2 days of colchicine treatment and on plants from shoot
tips after 1–2 days. In vitro pollen counts correlated well with counts from greenhouse grown plants and with fruit set. The
fruit set rate for colchicine-treated plants with a high pollen number was 47%. Appropriate colchicine treatment and culture
of nodal explants as well as tip explants can substantially increase the number of fertile plants and DH lines recovered from
parthenogenetic melons. 相似文献
6.
X. XuHan H. -C. Jing X. -F. Cheng A. Iwanowska H. Kieft J. H. W. Bergervoet S. P. C. Groot R. J. Bino A. A. M. van Lammeren 《Protoplasma》1999,208(1-4):240-247
Summary Embryogenic microspore and pollen culture followed by subculture of microspore-derived plantlets enabled the production of clones ofBrassica napus cv. Topas. Flow-cytometric analysis revealed that most microspore- and pollen-derived embryos (pEMs) were haploid initially. Spontaneous diploidization occurred at the globular stage of the pEMs, and was expressed as the relative increase of the 2C and 4C nuclear DNA content. Diploidization occurred throughout various organs of the pEMs and resulted in the formation of haploid and doubled haploid chimerics. In some embryos, nearly all cells were doubled haploid. From early cotyledon stage onward, pure haploid embryos were not observed anymore. At late cotyledon and germination stages, pure doubled haploid embryos and plantlets increased in number. Tetraploid pEMs were found occasionally. A culture regime was established to induce somatic embryos on the pEM-derived young plantlets. The ploidy of the somatic embryos varied highly and tended to be the same as that of the tissue at the initiation site on the pEM-plant. The results show that during the embryogenic development ofB. napus microspores, spontaneous diploidization occurs at globular stage, and increases progressively, resulting in the formation of chimerical haploid and doubled haploid plants as well as pure doubled haploid plants; ploidy neither affects pEM development at embryo developmental stages nor somatic embryogenesis, that starts on young pEM-derived plantlets; doubled haploid somatic embryos can be cloned from single pEM-derived plantlets; and doubled haploid embryos develop to fertile plants. 相似文献
7.
Deepak Prem Kadambari Gupta Gautam Sarkar Abha Agnihotri 《Plant Cell, Tissue and Organ Culture》2008,93(3):269-282
Three Indian Brassica juncea cultivars were studied for embryogenic response of microspores, microspore embryo regeneration, ploidy assessment of microspore-derived
plants and their diploidization. Genotype dependence for microspore totipotency was observed and a significant effect of genotype
by bud size selection was established. The addition of activated charcoal in NLN medium containing 13% (w/v) sucrose and 10 μM
silver nitrate resulted in a fourfold increase in microspore embryogenesis, ranging from 100 to 405 embryos per Petri dish
corresponding to 2,700–10,935 embryos per 100 buds. Conversion/germination of embryos produced in presence or absence of activated
charcoal was similar but air-drying of microspore embryos was essential. Incubation of microspore embryos at 4 ± 1°C for 10 days
in dark resulted in 82.3% conversion. The majority of plants produced from these embryos was haploid. Treating microspore-derived
plants at the 3–4 leaf growth stage with 0.34% colchicine for 2–3 h resulted in greatest survival (70%) and chromosome doubling
(75%) frequencies. Doubled haploid plants were self-pollinated and grown to maturity under field conditions. 相似文献
8.
Ravinder Kaur Grewal Monika Lulsdorf Janine Croser Sergio Ochatt Albert Vandenberg Thomas D. Warkentin 《Plant cell reports》2009,28(8):1289-1299
This is the first report on the production of double-haploid chickpea embryos and regenerated plants through anther culture
using Canadian cultivar CDC Xena (kabuli) and Australian cultivar Sonali (desi). Maximum anther induction rates were 69% for
Sonali and 63% for CDC Xena. Under optimal conditions, embryo formation occurred within 15–20 days of culture initiation with
2.3 embryos produced per anther for CDC Xena and 2.0 embryos per anther for Sonali. For anther induction, the following stress
treatments were used: (1) flower clusters were treated at 4°C for 4 days, (2) anthers were subjected to electric shock treatment
of three exponentially decaying pulses of 50–400 V with 25 μF capacitance and 25 Ω resistance, (3) anthers were centrifuged
at 168–1,509g for 2–15 min, and finally (4) anthers were cultured for 4 days in high-osmotic pressure (563 mmol) liquid medium. Anthers
were then transferred to a solid embryo development medium and, 15–20 days later, embryo development was observed concomitant
with a small amount of callus growth of 0.1–3 mm. Anther-derived embryos were regenerated on plant regeneration medium. Electroporation
treatment of anthers enhanced root formation, which is often a major hurdle in legume regeneration protocols. Cytological
studies using DAPI staining showed a wide range of ploidy levels from haploid to tetraploid in 10–30-day-old calli. Flow cytometric
analysis of calli, embryos and regenerated plants showed haploid profiles and/or spontaneous doubling of the chromosomes during
early regeneration stages. 相似文献
9.
Payam Pour Mohammadi Ahmad Moieni Asa Ebrahimi Farzad Javidfar 《Plant Cell, Tissue and Organ Culture》2012,108(2):251-256
An efficient method for producing doubled haploid plants of oilseed rape (Brassica
napus L.) was established using in vitro colchicine treatment of haploid embryos. Haploid embryos in the cotyledonary stage were
treated with one of four colchicine concentrations (125, 250, 500 and 1,000 mg/L); for one of three treatment durations (12,
24 and 36 h) at one of the two temperatures (8 and 25°C) and were compared to control embryos (without colchicine treatment).
The number of chromosomes, seed recovery, size and density of leaf stomata, and pollen grain size from regenerated plants
were determined. No doubled haploid plants were regenerated from control embryos; however, the doubled haploid plants were
regenerated from colchicine-treated embryos. A high doubling efficiency, 64.29 and 66.66% of regenerated plants, was obtained
from 250 mg/L colchicine treatment for 24 h and 500 mg/L colchicine treatment for 36 h, respectively, at 8°C. Following 500 mg/L
colchicine treatment for 36 h, a few plants regenerated (9 plants). At the higher colchicine concentration (1,000 mg/L), no
plant regenerated. These results indicate that the colchicine treatment of embryos derived from microspores can induce efficient
chromosome doubling for the production of doubled haploid lines of oilseed rape. 相似文献
10.
Haploids (monoploids) can be produced in cultivated barley (Hordeum vulgare) by pollination with Hordeum bulbosum and the subsequent elimination of H. bulbosum chromosomes [13]. Pollen of H. bulbosum was gamma-irradiated at doses of 1 to 8 kR to determine if it would lead to a more rapid chromosome elimination and subsequently a higher frequency of haploid barley seedlings. Early embryo development was slower following low dosages of irradiation than at higher dosages and there was no significant improvement in haploid production. At higher dosages, the frequencies of seed set, embryos and haploid seedlings declined. Double fertilization is an apparent pre-requisite of haploid formation and the “intrinsic vigour” of the bulbosum nucleus after fertilization appears to be an important factor in this system of haploid formation. 相似文献
11.
Theoretically, complete rejuvenation of mature trees should occur through somatic embryogenesis, however, this has not been
extensively studied. The main objective of the present study was to increase the efficiency of in vitro clonal propagation
for mature Quercus robur (100–300 years old), by induction of somatic embryogenesis as rejuvenation step prior to establishment of shoot culture through
micropropagation of somatic embryo-derived plantlets. Shoot culture lines of “mature” origin were established from epicormic
shoots of two centenarian oak genotypes (Sainza and CR-0) and maintained by axillary shoot proliferation. Embryogenic lines
were also initiated from epicormic leaf explants of the same genotypes and maintained by secondary somatic embryogenesis.
Although the frequency of somatic embryo conversion into plantlets was low in pedunculate oak, shoot culture lines could be
established and maintained by axillary branching from several germinated somatic embryos. For each genotype and shoot culture
line of the two origins (mature tree and somatic plantlets), shoot multiplication rate and elongation as well as rooting ability
parameters were compared. Compared with “mature-origin” shoot cultures and after more than one year propagation in vitro,
shoot lines established from somatic plantlets produced a significantly higher proportion of elongated, rootable shoots (from
26.0–31.6 to 36.8–40.5%) with increased rooting ability (from 3.3–45.6% to 23.2–89.8%). In the case of 300-year-old Sainza
genotype such a high organogenic capacity was similar to shoot cultures initiated from basal sprouts. Basal sprouts are considered
as “mature” material that retains juvenile characteristics compared with epicormic shoots forced from crown branches. Somatic
embryogenesis only slightly improved plant regeneration of shoot cultures from basal sprouts, thus validating their use as
“juvenile control”. The present results provide evidence that some rejuvenation occurred during the process of somatic embryogenesis
and resulted in improved shoot growth and rooting of somatic embryo-derived culture compared with “mature” shoot culture.
The results reported in this study might be useful in embryogenic systems with low plant conversion rates. The proposed experimental
model might also be useful in finding molecular markers of plant ontogeny. 相似文献
12.
Induced parthenogenesis in mandarin for haploid production: induction procedures and genetic analysis of plantlets 总被引:1,自引:0,他引:1
Froelicher Y Bassene JB Jedidi-Neji E Dambier D Morillon R Bernardini G Costantino G Ollitrault P 《Plant cell reports》2007,26(7):937-944
This study focused on haploid induction in mandarin through in situ gynogenesis by pollination with irradiated pollen of ‘Meyer’
lemon. Pollination was carried out for three genotypes of mandarin with four levels of gamma-ray-irradiated pollen (150, 300,
600, and 900 Gy). The resulting seeds were characterised by a small size. Embryos were rescued in vitro and the ploidy level
of the plantlets was determined by flow cytometry analysis. Haploid, diploid, triploid plantlets were obtained. The haploid
parthenogenetic origin was confirmed using microsatellite marker analysis and chromosome count. Diploid and triploid plants
were the result of crosses between mandarin and lemon. The induction of gynogenetic haploids of ‘Fortune’ (Citrus clementina Hort ex Tan. × Citrus tangerina Hort ex Tan.) and ‘Ellendale’ (Citrus reticulata Blanco × Citrus sinensis L. Osb) is reported here for the first time. 相似文献
13.
Immature embryos culture in Italian red chicory 总被引:3,自引:0,他引:3
Varotto Serena Lucchin Margherita Parrini Paolo 《Plant Cell, Tissue and Organ Culture》2000,62(1):75-77
Chicory (Cichorium intybus L.) embryo maturation in vitro was achieved in B5 medium without growth regulators. Immature embryos were collected at different developmental stages 4–168
h after pollination. Only a few plantlets were obtained from ovules collected shortly after pollination since the embryos
at these early stages developed abnormal leaves and roots which regenerated shoots ‘via’ organogenesis. Zygotic embryos collected
24–72 h after pollination needed one month of culture in vitro before acclimation. Embryos collected at the heart or early torpedo stage of development (three days after pollination) produced
green plantlets after two weeks of in vitro culture and thus they could be transferred to the greenhouse for acclimation. Culture of zygotic embryos in vitro has shown to be a suitable technique to accelerate the breeding process in biennial cultivated Italian red chicory. In fact
it is possible to obtain plantlets ready for performing the selection for the desired agronomic traits one month after pollination.
Since flowering occurs after vernalization, the selection can be performed in the correct season before flowering.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
14.
Dormancy removal in apple embryos by nitric oxide or cyanide involves modifications in ethylene biosynthetic pathway 总被引:1,自引:0,他引:1
The connection between classical phytohormone-ethylene and two signaling molecules, nitric oxide (NO) and hydrogen cyanide
(HCN), was investigated in dormancy removal and germination “sensu stricto” of apple (Malus domestica Borkh.) embryos. Deep dormancy of apple embryos was removed by short-term (3–6 h) pre-treatment with NO or HCN. NO- or HCN-mediated
stimulation of germination was associated with enhanced emission of ethylene by the embryos, coupled with transient increase
in ROS concentration in embryos. Ethylene vapors stimulated germination of dormant apple embryos and eliminated morphological
anomalies characteristic for young seedlings developed from dormant embryos. Inhibitors of ethylene receptors completely impeded
beneficial effect of NO and HCN on embryo germination. NO- and HCN-induced ethylene emission by apple embryo was only slightly
reduced by inhibitor of 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase activity during first 4 days of germination. Short-term pre-treatment of
the embryos with NO and HCN modified activity of both key enzymes of ethylene biosynthetic pathway: ACC synthase and ACC oxidase.
Activity of ACC synthase declined during first 4 days of germination, while activity of ACC oxidase increased markedly at
that time. Additional experiments point to non-enzymatic conversion of ACC to ethylene in the presence of ROS (H2O2). The results indicate that NO and HCN may alleviate dormancy of apple embryos “via” transient accumulation of ROS, leading
to enhanced ethylene emission which is required to terminate germination “sensu stricto”. Therefore, ethylene seems to be
a trigger factor in control of apple embryo dormancy removal and germination. 相似文献
15.
Pradeep C. Deo Robert M. Harding Mary Taylor Anand P. Tyagi Douglas K. Becker 《Plant Cell, Tissue and Organ Culture》2009,99(1):61-71
Callus was initiated in three different “esculenta” taro cultivars by culturing corm slices in the dark on half-strength MS
medium supplemented with 2.0 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D) for 20 days followed by subculture of all corm slices
to half-strength MS medium containing 1.0 mg/l thidiazuron (TDZ). Depending on the cultivar, 20–30% of corm slices produced
compact, yellow, nodular callus on media containing TDZ. Histological studies revealed the presence of typical embryogenic
cells which were small, isodiametric with dense cytoplasms. Somatic embryos formed when callus was transferred to hormone-free
medium and ~72% of the embryos germinated into plantlets on this medium. Simultaneous formation of roots and shoots during
germination, and the presence of shoot and root poles revealed by histology, confirmed that these structures were true somatic
embryos. Plants derived from somatic embryos appeared phenotypically normal following 2 months growth in a glasshouse. This
method is a significant advance on those previously reported for the esculenta cultivars of taro due to its efficiency and reproducibility. 相似文献
16.
Short-term (3 or 6 h) pre-treatment of apple (Malus domestica Borkh.) embryos with nitric oxide (NO) or hydrogen cyanide (HCN) induces transient accumulation of reactive oxygen species
(ROS) leading to dormancy removal and germination. We demonstrated that enhanced NO emission by apple embryos during early
phase of germination “sensu stricto” is required for seed transition from dormant into non-dormant state, and may be described
by the model of “nitrosative door”, analogous to “oxidative window”. Cellular ROS concentration, resulting from NO or HCN
embryo pre-treatment, seems to be under severe control of antioxidant system. Activity of superoxide dismutase (SOD), catalase
(CAT), glutathione reductase (GR), glutathione peroxidase (GPX) and total peroxidases (Prxs) was determined during NO and
HCN-mediated germination “sensu stricto” of embryos. CAT and SOD activity increased transiently 24 h after embryos pre-treatment,
while GR and Prx activity was stimulated mainly after 96 h. The most evident alterations were detected in GPX activity, being
more than threefold stimulated by NO or HCN. Based on this results, we conclude that these reactive molecules act simultaneously
crossing their signaling pathways and we propose that ROS, reactive nitrogen species, HCN at accurate level are essential
during seed germination as signaling factors. 相似文献
17.
“Fairmount 1 thorny” (“FM1 thorny”) (a Rosa multiflora Thunb ex. J. Murr.) and a thornless sport of “FM1 thorny” (“Fairmount 1” (“FM1”)) were established in vitro to investigate
chimeral segregation under various levels of BA and to obtain a pure thornless rose. While the chimeral thornless sport was
expected to segregate in vitro and yield both thorny and thornless plantlets, “FM1 thorny” was to yield only thorny plants.
“FM1” segregated in vitro into its constituent genotypes and yielded thorny and thornless plantlets, suggesting that “FM1”
is chimeral. “FM1 thorny” produced only thorny plants in vitro. These results indicate that the “FM1 thorny” clone was not chimeral (pure thorny) and that the thornless regenerates of “FM1”
did not develop via somaclonal variation. There was a significant linear relationship between increasing BA concentration
and the percentage of thorny plants. Among a population of 690 tissue culture derived plants from all the BA experiments,
6 plants were classified as pure thornless plants 1 year later. 相似文献
18.
Jatropha curcas L. (Physic nut) is a commercially important non-edible oil seed crop known for its use as an alternate source of biodiesel.
In order to investigate the morphogenic potential of immature embryo, explants from four developmental stages were cultured
on medium supplemented with combinations of auxins and cytokinins. It was found that the size of embryo is critical for the
establishment of callus. Immature embryos (1.1–1.5 cm) obtained from the fruits 6 weeks after pollination showed a good response
of morphogenic callus induction (85.7%) and subsequent plant regeneration (70%) with the maximum number of plantlets (4.7/explant)
on Murashige and Skoog’s (MS) medium supplemented with IBA (0.5 mg l−1) and BA (1.0 mg l−1). The above medium when supplemented with growth adjuvants such as 100 mg l−1 casein hydrolysate + 200 mg l−1
l-glutamine + 8.0 mg l−1 CuSO4 resulted in an even higher frequency of callus induction (100%). Plant regeneration (90%) with the maximum number of plantlets
(10/explant) was achieved on MS medium supplemented with 500 mg l−1 polyvinyl pyrrolidone + 30 mg l−1 citric acid + 1 mg l−1 BA + 0.5 mg l−1 Kn + 0.25 mg l−1 IBA. It was observed that plantlet regeneration could occur either through organogenesis of morphogenic callus or via multiplication
of pre-existing meristem in immature embryos. The age of immature embryos and addition of a combination of growth adjuvants
to the culture medium appear to be critical for obtaining high regeneration rates. Well-developed shoots rooted on half-strength
MS medium supplemented with 0.5 mg l−1 IBA and 342 mg l−1 trehalose. The rooted plants after acclimatization were successfully transferred to the field in different agro-climatic
zones in India. This protocol has been successfully evaluated on five elite lines of J. curcas. 相似文献
19.
J. L. Yang E. S. Seong M. J. Kim B. K. Ghimire W. H. Kang Chang Yeon Yu Cheng Hao Li 《Plant Cell, Tissue and Organ Culture》2010,100(1):49-58
Cotyledon, hypocotyl or root explants of 7-day-old broccoli seedlings were cultured on Murashige and Skoog (MS) agar or liquid
medium supplemented with 1.0 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D). The frequency of direct somatic embryo formation was 100% when root explants were
cultured in liquid medium. Histological analysis indicated that somatic embryos were initiated directly from the pericycle
cell layers of root explants as early as 1 day after liquid culture. Genotype did not affect the frequency of somatic embryo
formation or the number of somatic embryos per explant. All broccoli genotypes examined had 100% somatic embryo induction
efficiency, and the number of somatic embryos per 0.8 mm root segment ranged from 22.9 in ‘Luhui’ to 26.0 in ‘Haizi’. The
number of normally developed somatic embryos in culture increased with increasing 2,4-D concentration. Plantlet regeneration
frequency was the highest (73.3%) when germinated plantlets were transferred to 1/2 strength MS agar medium containing 1.0 mg l−1 6-benzyladenine (BA). When regenerated plantlets were transferred to a greenhouse, approximately 75% survived and there were
no morphological differences between regenerated plants and seed-derived controls. The protocols established in this study
will benefit large-scale vegetative propagation and transformation-based genetic improvement of broccoli. 相似文献
20.
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