共查询到20条相似文献,搜索用时 15 毫秒
1.
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
2.
Summary The influence of donor plant growth environment, microspore development stage, culture media and incubation conditions on
microspore embryogenesis was studied in three Indian B. juncea varieties. The donor plants were grown under varying environments: field conditions, controlled conditions, or a combination
of the two. The correlation analysis between the bud size and microspore development stage revealed that the bud size is an
accurate marker for donor plants grown under controlled conditions, however, the same does not hold true for the field-grown
plants. The buds containing late uninucleate microspores collected from plants grown under normal field conditions up to bolting
stage and then transferred to controlled environment were observed to be most responsive with genotypic variability ranging
from 10 to 35 embryos per Petri dish, irrespective of the other factors. NLN medium containing 13% sucrose was found to be
most suitable for induction of embryogenesis The fortification of this medium with activated charcoal, polyvinylpyrrolidone,
colchicine, or growth regulators (6-benzylaminopurine and 1-naphthaleneacetic acid) was observed to be antagonistic for microspore
embryogenesis, while silver nitrate (10 μM) had a significant synergistic effect. A post-culture high-temperature incubation of microspores at 32.5±1°C for 10–15 d
was found most suitable for high-frequency production of microspore embryos. The highest frequency of microspore embryogenesis
(78 embryos per Petri dish) was observed from the late uninucleate microspores (contained in bud sizes 3.1–3.5 nm irrespective
of genotype) cultured on NLN medium containing 13% sucrose and silver nitrate (10 μM), and incubated at 32.5°C for 10–15 d. 相似文献
3.
Summary Plantlets of Capsicum annuum L. ev. Sweet Banana regenerated via somatic embryogenesis from immature zygotic embryos were capable of producing flower,
fruit, and seed when cultured in small tissue culture containers. In vitro floral buds were first formed on plantlets that grew on plantlet development medium [agar-gelled Murashige and Skoog (MS)
basal medium containing 1 mgl−1 (5.3 μM) α-naphthaleneacetic acid (NAA)] in a growth room at 22°C and continuous illumination. However, floral buds rarely developed
further into mature flowers. This problem was overcome using the vented autoclavable plant tissue culture containers. In vitro fruit formation and ripening was observed when liquid half-strength MS basal medium supplemented with 5 μg ml−1 silver thiosulfate, 1 mg l−1 (5.3 μM) NAA, and 3% sucrose was added to the surface of the plantlet development medium. Hand-pollination improved fruit set. Further
research in needed to determine why the pepper seeds formed in vitro failed to germinate. 相似文献
4.
Pradeep K. Agarwal Parinita Agarwal Jan B. M. Custers Chun-ming Liu S. S. Bhojwani 《Plant Cell, Tissue and Organ Culture》2006,86(2):201-210
An efficient protocol to improve microspore embryogenesis is established in an important oleiferous crop, Brassica juncea (Indian mustard). Colchicine was used for enhancing microspore embryogenesis and also to obtain doubled haploid embryos. Colchicine at high concentrations (>10 mg l−1), for 24 h, proved convenient for direct recovery of diploid embryos. Higher temperature treatment and an antiauxin PCIB (p-chlorophenoxyisobutyric acid) enhanced microspore embryogenesis significantly as compared to colchicine. An increase in temperature from 32°C to 35°C proved very efficient in increasing embryogenesis by 10-fold. The highest embryogenesis rate was obtained when PCIB was added at 35°C in the culture after 1 day of culture initiation. 20 μM PCIB could enhance microspore embryogenesis by 5-fold. Different abnormal shapes of embryos like lemon, banana, flask and fused cotyledons were observed. Both normal and fused cotyledonous embryos showed normal germination when transferred on the B5 basal medium. 相似文献
5.
Factors affecting microspore embryogenesis of cow cockle (Saponaria vaccaria) were evaluated including donor plant growing conditions, genotype, bud size, density, medium composition, and culture conditions.
Of the two donor plant (day/night) temperature regimes evaluated (10/5°C and 20/15°C), plants grown at 20/15°C were the most
embryogenic. An embryogenic frequency of greater than 350 embryos/100 buds was observed in the most embryogenic genotype,
cv. ‘White Beauty’. Buds from 3–9 mm in length were evaluated for their embryogenic potential; buds that were 4–7.9 mm produced
the most embryos/100 buds. Of all the media compositions evaluated, NLN medium with 15% sucrose resulted in the most embryos.
Cow cockle microspores required an initial period of 32°C for 3 days for production of microspore-derived embryos (MDEs). 相似文献
6.
Yantree Devi Sankar-Thomas Katja Saare-Surminski Reinhard Lieberei 《Plant Cell, Tissue and Organ Culture》2008,95(2):163-173
The present study describes a protocol for plant regeneration via somatic embryogenesis in temporary immersion system (TIS)
for Camptotheca acuminata. Somatic embryos were induced by culturing hypocotyl segments from 14-day-old in vitro grown C. acuminata seedlings in TIS. Hypocotyl segments were placed in culture vessels modified with a mechanical device to support the fixation
of explants. Cultures were maintained under a 16 h photoperiod with a light intensity of 60 μmol m−2 s−1 PPF at 25 ± 1°C. After 16 weeks of incubation embryogenic calli were formed above the edge of the mechanical device in the
basal Murashige and Skoog (MS) medium containing 35 g l−1 sucrose and without hormonal supplementation. For plantlet regeneration, somatic embryos at cotyledonary stage were cultured
in three different concentrations of 6-benzylamino-purine (0.5, 1.0 and 1.5 mg l−1 BAP) and in plant growth regulator (PGR) free medium. In general, 0.5 mg l−1 BAP was found to be the most effective concentration for growth and development of Camptotheca embryos in TIS. Conversion of somatic embryos into plantlets was also successfully achieved on sterile substrates moistened
with 0.5 mg l−1 BAP. Plantlets derived from cotyledonary embryos were rooted in vitro with 0.5 mg l−1 indole-3-butyric acid (IBA) before transfer to ex vitro conditions. 相似文献
7.
A new moderately halophilic, strictly aerobic, Gram-negative bacterium, strain SX15T, was isolated from hypersaline surface sediment of the southern arm of Great Salt Lake (Utah, USA). The strain grew on a
number of carbohydrates and carbohydrate polymers such as xylan, starch, carboxymethyl cellulose and galactomannan. The strain
grew at salinities ranging from 2 to 22% NaCl (w/v). Optimal growth occurred in the presence of 7–11% NaCl (w/v) at a temperature
of 35°C and a pH of 6.7–8.2. Major whole-cell fatty acids were C16:0 (30.5%), C18:0 (14.8%), C18:1ω7c (13.1%) and C12:0 (7.8%). The G+C content of the DNA was 60 ± 0.5 mol%. By 16S rRNA gene sequence analysis, strain SX15T was shown to be affiliated to members of the gammaproteobacterial genus Marinimicrobium with pair wise identity values of 92.9–94.6%. The pheno- and genotypic properties suggest that strain SX15T represents a novel species of the genus Marinimicrobium for which the name Marinimicrobium haloxylanilyticum is proposed. The type strain is SX15T (= DSM 23100T = CCUG 59572T). 相似文献
8.
Dong-Mei Kong John E. Preece Hai-Long Shen 《Plant Cell, Tissue and Organ Culture》2012,108(3):485-492
Somatic embryogenesis was obtained from immature cotyledon explants that were cultured on half-strength Murashige and Skoog
(MS) salts and vitamins with 5.4 μM naphthaleneacetic acid (NAA) and 0.2 μM thidiazuron (TDZ) plus a 4 × 4 factorial combination
of 0, 9.8, 24.6, or 49.2 μM indole-3-butyric acid (IBA) and 0, 8.9, 22.2, or 44.4 μM 6-benzyladenine (BA). The addition of
44.4 μM BA improved the percentage of cotyledon explants that produced somatic embryos to >20%, if 9.8 or 24.6 μM IBA was
also present. Somatic embryogenesis was >30% when seeds were harvested on 31 July or 15 August. The addition of 50 or 70 g l−1 sucrose enhanced embryogenesis. Histological examination showed that somatic embryos originated from epidermis cells of zygotic
embryos. A peak germination rate (69%) was attained when somatic embryos were desiccated for 10 min before they produced green
cotyledons and elongating shoot tips. Of the germinated embryos from this desiccation treatment, 65.6% also grew roots and
therefore converted into plants. Chilling somatic embryos at 4°C for 15 days resulted in the highest germination rate (69.4%),
which was significantly higher than those without chilling treatment (27.6%). However <10% of the chilled germinated embryos
formed roots and grew into plants. Plantlets from somatic embryos were transplanted into a 2 vermiculite: 1 sphagnum peat
medium, where they had a survival rate of 80.8%, and had no morphological abnormalities. 相似文献
9.
Chen C Shi R Liu BB Zhang YJ Sun HZ Li CT Tang SK Zhang LL Li WJ 《Antonie van Leeuwenhoek》2011,100(3):365-373
Two moderately halophilic, Gram-negative, rod-shaped bacteria, designated YIM 93003T and YIM 94343T, were isolated from a salt lake in Xinjiang province, north-west China. The two strains YIM 93003T and YIM 94343T grew at 20–40°C, pH 6–9, 0.5–24% (w/v) NaCl and at 20–40°C, pH 6–9, 0.5–23% (w/v) NaCl, respectively. No growth occurred
in absence of NaCl. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains YIM 93003T and YIM 94343T were phylogenetically affiliated to the genus Halomonas and exhibited sequence similarity of 97.5% and 97.4% to the type strain Halomonas anticariensis DSM 16096T, respectively. The strains possessed chemotaxonomic markers that were consistent with their classification in the genus Halomonas (Q-9 as predominant respiratory quinine; C18:1ω7c, C16:0 and C16:1 ω7c/iso-C15:02-OH as the major fatty acids). The DNA–DNA hybridization values for strains YIM 93003T and YIM 94343T, YIM 93003T and DSM 16096T, YIM 94343T and DSM 16096T were 38.1 ± 3.0, 18.3 ± 4.7, and 20.8 ± 4.6%, respectively. The G+C contents of the strains YIM 93003T and YIM 94343T were 63.4 and 64.0 mol%, respectively. Based on comparative analysis of physiological, biochemical and chemotaxonomic data,
including low DNA–DNA hybridization results, two novel species, Halomonas qijiaojingensis sp. nov., and Halomonas
flava sp. nov., are proposed. The type strains are YIM 93003T (=CCTCC AB 208133T =KCTC 22228T) and YIM 94343T (=CCTCC AB 2010382T =KCTC 23356T), respectively. 相似文献
10.
Embryogenic calli of Dioscorea bulbifera L. were successfully cryopreserved using an encapsulation-vitrification method. Embryogenic calli were cooled at 6°C for
5 days on solid MS medium (Murashige and Skoog 1962) containing 2 mg L−1 Kinetin (Kn), 0.5 mg L−1 α-naphthalene acetic acid (NAA) and 0.5 mg L−1 2,4-dichlorophenoxy-acetic acid (2,4-D). These were prior precultured on liquid basal MS medium enriched with 0.75 M sucrose
at 25 ± 1°C for 7 days. Embryogenic calli were osmoprotected with a mixture of 2 M glycerol and 1 M sucrose for 80 min at
25°C and dropped in a 0.1 M CaCl2 solution containing 0.4 M sucrose at 25 ± 1°C. After 15 min of polymerization, Ca-alginate beads (about 4 mm in diameter)
were dehydrated for 150 min at 0°C in a PVS2 solution [30% glycerol, 15% ethylene glycol, and 15% dimethyl sulfoxide (w/v)] containing 0.5 M sucrose. The encapsulated
embryogenic calli were then plunged directly into LN (liquid nitrogen) for 1 h. After rapid thawing in a water bath (37°C;
2 min), the beads were washed 3 times at 10-min intervals in liquid basal MS medium containing 1.2 M sucrose. Following thawing,
the embryogenic calli were transferred to fresh solid basal MS media supplemented with Kn 2 mg L−1, 0.09 M sucrose and 0.75% (w/v) agar (embryoid induction medium) and cultured under light conditions of 12-h photoperiod
with a light intensity of 36 μmol m−2 s−1 provided by white cool fluorescent tubes after a 2-day dark period at 25 ± 1°C. After 30 days, the embryoids developed from
embryogenic calli were transferred to fresh solid basal MS media supplemented with Kn 2 mg L−1, NAA 0.5 mg L−1, 3% (w/v) sucrose and 0.75% (w/v) agar (regeneration medium). After 60 days, the embryogenic calli developed normal shoots
and roots. No morphological abnormalities were observed after plating on the regeneration medium. The survival rate of encapsulated
vitrified embryogenic callus reached over 70%. This encapsulation-vitrification method appears promising as a routine and
simple method for the cryopreservation of Dioscorea bulbifera embryogenic callus. 相似文献
11.
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
12.
Shelake Rahul Mahadev Angappan Kathithachalam Murugan Marimuthu 《In vitro cellular & developmental biology. Plant》2011,47(5):611-617
In vitro propagation has played a key role for obtaining large numbers of virus free, homogenous plants, and for breeding of plantains
and bananas (Musa spp.). Explant sources utilized for banana micropropagation include suckers, shoot tips, and floral buds. The present study
employed male floral meristems as explant material for micropropagation of hill banana ecotypes (AAB) ‘Virupakshi’ and ‘Sirumalai.’
Immature male floral buds were collected from healthy plants from hill banana growing areas. Exposure of explants to ethyl
alcohol (70%, v/v) for 30 s, then mercuric chloride (0.1%, w/v) for 30 s, followed by three independent rinses of 5 min each in autoclaved, double-distilled water satisfactorily reduced
the contamination. Male floral bud explants were cultured on Murashige and Skoog (MS) basal medium supplemented with different
combinations of 6-benzylaminopurine (BAP), coconut water, naphthaleneacetic acid, gibberellic acid, and additional supplements.
MS medium supplemented with 5 mg l−1 BAP and coconut water (15%) was the most efficient media for shoot initiation and multiple shoot formation (15 shoots from
a single part of a floral bud). The best response for shoot elongation was obtained using the combination of basal MS, 5 mg l−1 BAP, 1 mg l−1 naphthaleneacetic acid and 1.5 mg l−1 gibberellic acid. Regenerated shoots were rooted in basal MS medium within 15–20 d. The rooted plantlets were transferred
to a soil mixture and maintained at a temperature of 25 ± 2°C for 10 d and then at room temperature (30–32°C) for 2 wk, before
transferring to a greenhouse. The regenerated plantlets showed 100% survival. 相似文献
13.
Han Gil Choi Ki Hoon Lee Hyun Il Yoo Pil Jun Kang Young Sik Kim Ki Wan Nam 《Journal of applied phycology》2008,20(5):729-735
The effects of temperature, irradiance, and daylength on Sargassum horneri growth were examined at the germling and adult stages to discern their physiological differences. Temperature–irradiance
(10, 15, 20, 25, 30°C × 20, 40, 80 μmol photons m−2s−1) and daylength (8, 12, 16, 24 h) experiments were carried out. The germlings and blades of S. horneri grew over a wide range of temperatures (10–25°C), irradiances (20–80 μmol photons m−2s−1), and daylengths (8–24 h). At the optimal growth conditions, the relative growth rates (RGR) of the germlings were 21% day−1 (25°C, 20 μmol photons m−2s−1) and 13% day−1 (8 h daylength). In contrast, the RGRs of the blade weights were 4% day−1 (15°C, 20 μmol photons m−2s−1) and 5% day−1 (12 h daylength). Negative growth rates were found at 20 μmol photons m−2s−1 of 20°C and 25°C treatments after 12 days. This phenomenon coincides with the necrosis of S. horneri blades in field populations. In conclusion, we found physiological differences between S. horneri germlings and adults with respect to daylength and temperature optima. The growth of S. horneri germlings could be enhanced at 25°C, 20 μmol photons m−2s−1, and 8 h daylength for construction of Sargassum beds and restoration of barren areas. 相似文献
14.
Elmira Jafarieh Yazdi Kevin C. Falk Ginette Séguin-Swartz 《In vitro cellular & developmental biology. Plant》2013,49(6):682-689
Factors affecting microspore embryogenesis of Ethiopian mustard (Brassica carinata A. Braun) were evaluated, including flower bud length, pollen developmental stage, and microspore density. An embryogenic frequency of 300 embryos per Petri plate was observed with NLN (Nitsch-Lichter-Nitsch) medium supplemented with 13% sucrose, 3.0–3.4-mm-long buds, and a plating density of 65,000 microspores/ml. About 65% of the microspores from buds 3.0–3.4-mm long were at the late uninucleate stage. Microspore-derived embryos were successfully transferred to solid medium for germination. After 4 wk, the resulting plantlets were transplanted to a soilless potting mixture and grew well under greenhouse conditions. 相似文献
15.
Plant regeneration through somatic embryogenesis was achieved using immature zygotic embryos (ZE) of Sorbus pohuashanensis as explants. Over 50% of immature ZEs from immature seed collected at 30 days after pollination produced direct somatic embryos
(SEs) on Murashige and Skoog (MS) medium supplemented with 0–0.44 μM 6-benzyladenine (BA) in combination with 5.73 μM naphthaleneacetic
acid (NAA) or with 0.91–2.26 μM 2,4-dichlorophenoxyacetic acid (2,4-D) alone. Fourteen to 23 SEs per explant were regenerated
on MS medium supplemented with BA 0.44 μM in combination with NAA 5.73 μM. SE formation decreased when sucrose concentrations
were higher than 40 g L−1. Repetitive embryogenesis occurred following culture on solid MS medium containing 12 μM abscisic acid, 75 g L−1 polyethylene glycol, and 20 g L−1 sucrose at 25 ± 1°C under a 16-h photoperiod with a light intensity of 40 μmol m−2 s−1. Over 40% of the mature SEs germinated on solid MS medium under light condition described previously. Up to 40% of the regenerated
plantlets were successfully acclimatized under greenhouse conditions. Plantlets derived from SEs grew vigorously with similar
morphology as those germinated from ZEs. Histological studies of explants at various developmental stages of somatic embryogenesis
revealed that SEs passed through globular, heart, torpedo, and mature stages. Similar to ZE suspensors, similar structures
of SE degenerated in later stages of embryo development. ZE and SE are a effective means of regenerating tissue culture plantlets
for S. pohuashanesis. 相似文献
16.
Protocorm-like bodies (PLBs) of Dendrobium candidum Wall. ex Lindl., orchid, were successfully cryopreserved using an encapsulation vitrification method. PLBs were precultured
in liquid Murashige and Skoog (MS) medium containing 0.2 mg l−1 α-naphthalene acetic acid and 0.5 mg l−1 6-benzyladenine enriched with 0.75 M sucrose, and grown under continuous light (36 μmol m−2 s−1) at 25 ± 1°C for 5 days. PLBs were osmoprotected with a mixture of 2 M glycerol and 1 M sucrose for 80 min at 25°C and dripped
in a 0.5 M CaCl2 solution containing 0.5 M sucrose at 25 ± 1°C and left for 15 min to form Ca-alginate beads (about 4 mm in diameter). Then,
these were dehydrated with a plant vitrification solution 2 (PVS2) consisting of 30% (w/v) glycerol, 15% (w/v) ethylene glycol, and 15% (w/v) dimethyl sulfoxide in 0.5 M sucrose, pH 5.8,
for 150 min at 0°C. Encapsulated and dehydrated PLBs were plunged directly into liquid nitrogen for 1 h. Cryopreserved PLBs
were then rapidly re-warmed in a water bath at 40°C for 3 min and then washed with MS medium containing 1.2 M sucrose for
three times at 10 min intervals. Within 60 days, plantlets with the cryopreserved PLBs developed normal shoots and roots,
and without any observed morphological abnormalities, were obtained. The survival rate of encapsulated-vitrified PLBs was
above 85%. Thus, this encapsulation-vitrification method was deemed promising for cryopreservation of PLBs of D. candidum. 相似文献
17.
Hee-Sung Shin Yong-Jae Kim In-Hwa Yoo Heung-Shick Lee Shouguang Jin Un-Hwan Ha 《Biotechnology letters》2011,33(1):97-102
A genetic locus, encoding putative acyltransferase, was induced by autoinducers in Corynebacterium glutamicum. The autoinducers were maximally produced by the bacterium after 24 h culture. Those molecules are resistant to proteinase
K treatment (300 μg ml−1) for 30 min at 37°C or at 121°C for 15 min, and remained stable after extensive storage at 4°C. Autoinducers in the cell-free
culture fluids from Corynebacterium ammoniagenes and Pseudomonas aeruginosa also induced the expression of acyltransferase in C. glutamicum, suggesting possible cross-recognition of the autoinducers by C. glutamicum. C. glutamicum thus possesses an autoinduction system which secretes autoinducers during growth, triggering the expression of downstream
genes, exemplified by the putative acyltransferase gene. 相似文献
18.
Ziguo Zhao Fengjuan Zhao Jianting Yao Jingmei Lu Put. O. AngJr. Delin Duan 《Journal of applied phycology》2008,20(5):925-931
Morphology and culture studies on germlings of Sargassum thunbergii (Mertens et Roth) Kuntze were carried out under controlled laboratory conditions. Growth characteristics of these germlings
grown under different temperatures (from 10 to 25°C), irradiances (from 9 to 88 μmol photons m−2 s−1), and under blue and white light conditions are described. The development of embryonic germlings follows the classic “8
nuclei 1 egg” type described for Sargassaceae. Fertilized eggs spent 5–6 h developing into multicellular germlings with abundant
rhizoids after fertilization. Under conditions of 20°C, 44 μmol photons m−2 s−1 and photoperiod of 12 h, young germlings with one or two leaflets reached 2–3 mm in length after 8 weeks. Temperature variations
(10, 15, 20, 25°C) under 88 μmol photons m−2 s−1 significantly influenced the growth rate within the first week, although this effect became less obvious after 8 weeks, especially
at 15 and 20°C. Variation in germling growth was highly significant under different irradiances (9, 18, 44, 88 μmol photons
m−2 s−1) at 25°C. Low temperature (10°C) reduced germling growth. Growth of germlings cultured under blue light was lower than in
white light. Optimal growth of these germlings occurred at 25°C and 44 μmol photons m−2 s−1. 相似文献
19.
Pankaj Bhowmik Joan Dirpaul Patricia Polowick Alison M. R. Ferrie 《Plant Cell, Tissue and Organ Culture》2011,106(2):359-362
Microspore culture for the purpose of developing doubled haploid plants is routine for numerous plant species; however, the
embryo yield is still very low compared with the total available microspore population. The ability to select and isolate
highly embryogenic microspores would be desirable for high embryo yield in microspore culture. To maximize the efficiency
of canola microspore culture, a combination of bud size selection and microspore fractionation using a Percoll gradient was
followed. This approach has consistently given high embryo yields and uniform embryo development. Microspores isolated from
buds 1.5 to 4.4 mm in length of Brassica napus genotypes Topas 4079, DH12075, Westar and 0025 formed embryos at different frequencies. The most embryogenic bud size range
varied with each cultivar: Topas 4079 3.5–3.9 mm, DH12075 2.0–2.4 mm, and Westar and 0025 2.5–2.9 mm. When the microspores
from 2.0 to 2.4 mm buds of DH12075 were carefully layered on top of a discontinuous Percoll gradient of 10, 20 and 40%, and
subsequently spun through the Percoll layers by centrifugation, bands were formed containing populations of microspores of
uniform developmental stage. The middle layer of the gradient contained the late uninucleate and early binucleate microspores
that were the most embryogenic. In addition, the relationship between the bud size, developmental stage of isolated microspores,
Percoll gradient concentration and the embryogenic frequency of each cultivar were studied. Optimization of these factors
is required for each genotype evaluated. 相似文献
20.
Fengjuan Zhao Ziguo Zhao Aihua Wang Jidong Liu Delin Duan 《Journal of applied phycology》2010,22(2):195-202
Morphological and culture studies of germlings derived from carpospores of Chrysymenia wrightii (Harvey) Yamada were carried out under various treatments combining temperature and irradiance. Basal, main, and tip branches
were applied for inducing callus-like tissue. Focus was on how carpospores develop into germlings, how callus-like tissues
are induced from explants, and how temperature and irradiance affect carpospore germination and discoid crust growth. Results
show that carpospore development can be divided into three stages: division stage, discoid crust stage, and erect juvenile
germling stage. Discoid crusts, even more than ten, might coalesce into a big discoid crust, and then developed into germlings.
Filamentous fronds, formed on the rims of discoid crusts, exhibited in self-existence or co-existence form with germlings,
could form spherical tufts if cultured separately. Filamentous callus-like tissues appeared on the tip branches after 13 days.
PES is suitable for filament induction and culture, and filaments have potential use in germplasm preservation and vegetative
propagation. Temperature (10, 15, 20, 25°C) and irradiance (8 and 36 μmol photons m−2 s−1) significantly influenced carpospore germination rate and discoid crust diameter. Carpospores germinated normally under 36 μmol
photons m−2 s−1, 15~25°C, and maximum growth of discoid crusts was at 25°C, 36 μmol photons m−2 s−1; 10°C and 8 μmol photons m−2 s−1 did not favor carpospore germination or discoid crust growth. 相似文献