共查询到20条相似文献,搜索用时 46 毫秒
1.
The structure of ice nucleation (IN) genes was compared among 20 strains of Erwinia herbicola-group bacterium of plant- and insect-origin including E. herbicola M1 (IceE) and E. ananas IN10 (inaA) that had been previously reported. When the DNAs of N-domain or C-domain were amplified, PCR products with similar size
were obtained in all strains, while the size of the PCR products from the whole genes containing the R domain varied remarkably
within a range of 3.8 kb to 4.4 kb. RFLP analysis of the IN genes revealed that the size of the R-domains were varied within
the region from the PvuII site to DraI site, and 20 IN genes were classified into 12 groups. Furthermore, all the strains identified as E. ananas based on six bacteriological properties were different from those of E. herbicola. These results suggest that the IN genes may be distributed only in E. ananas strains among “herbicola group bacteria.”
Received: 18 March 1998 / Accepted: 28 April 1998 相似文献
2.
Wheat straw smoke aerosols and liquid smoke condensates reduced significantly both the viability and the ice-nucleating activity of Pseudomonas syringae pv. syringae and Erwinia herbicola in vitro and on leaf surfaces in vivo. Highly significant reductions in numbers of bacterial ice nuclei on the surface of both corn and almond were observed after exposure to smoke aerosols. At −5°C, frost injury to corn seedlings colonized by ice nucleation-active bacteria was reduced after exposure to smoke aerosols. Effects on −9°C ice nuclei, although significant, were less than on ice nuclei active at −5°C. These results suggest that smoke from wildfires or smudge pots may reduce plant frost susceptibility and sources of ice nuclei important in other natural processes under some conditions. 相似文献
3.
Dependency of Antarctic zooplankton species on ice algae‐produced carbon suggests a sea ice‐driven pelagic ecosystem during winter
下载免费PDF全文
![点击此处可从《Global Change Biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Doreen Kohlbach Martin Graeve Benjamin A. Lange Carmen David Fokje L. Schaafsma Jan Andries van Franeker Martina Vortkamp Angelika Brandt Hauke Flores 《Global Change Biology》2018,24(10):4667-4681
How the abundant pelagic life of the Southern Ocean survives winter darkness, when the sea is covered by pack ice and phytoplankton production is nearly zero, is poorly understood. Ice‐associated (“sympagic”) microalgae could serve as a high‐quality carbon source during winter, but their significance in the food web is so far unquantified. To better understand the importance of ice algae‐produced carbon for the overwintering of Antarctic organisms, we investigated fatty acid (FA) and stable isotope compositions of 10 zooplankton species, and their potential sympagic and pelagic carbon sources. FA‐specific carbon stable isotope compositions were used in stable isotope mixing models to quantify the contribution of ice algae‐produced carbon (αIce) to the body carbon of each species. Mean αIce estimates ranged from 4% to 67%, with large variations between species and depending on the FA used for the modelling. Integrating the αIce estimates from all models, the sympagic amphipod Eusirus laticarpus was the most dependent on ice algal carbon (αIce: 54%–67%), and the salp Salpa thompsoni showed the least dependency on ice algal carbon (αIce: 8%–40%). Differences in αIce estimates between FAs associated with short‐term vs. long‐term lipid pools suggested an increasing importance of ice algal carbon for many species as the winter season progressed. In the abundant winter‐active copepod Calanus propinquus, mean αIce reached more than 50% in late winter. The trophic carbon flux from ice algae into this copepod was between 3 and 5 mg C m?2 day?1. This indicates that copepods and other ice‐dependent zooplankton species transfer significant amounts of carbon from ice algae into the pelagic system, where it fuels the food web, the biological carbon pump and elemental cycling. Understanding the role of ice algae‐produced carbon in these processes will be the key to predictions of the impact of future sea ice decline on Antarctic ecosystem functioning. 相似文献
4.
In Escherichia coli, Vitreoscilla hemoglobin (VHb) protects against oxidative stress, perhaps, in part, by oxidizing OxyR. Here this protection, specifically
VHb-associated effects on superoxide dismutase (SOD) and catalase levels, was examined. Exponential or stationary phase cultures
of SOD+ or SOD−
E. coli strains with or without VHb and oxyR antisense were treated with 2 mM hydrogen peroxide without sublethal peroxide induction, and compared to untreated control
cultures. The hydrogen peroxide treatment was toxic to both SOD+ and SOD− cells, but much more to SOD− cells; expression of VHb in SOD+ strains enhanced this toxicity. In contrast, the presence of VHb was generally associated in the SOD+ background with a modest increase in SOD activity that was not greatly affected by oxyR antisense or peroxide treatment. In both SOD+ and SOD− backgrounds, VHb was associated with higher catalase activity both in the presence and absence of peroxide. Contrary to its
stimulatory effects in stationary phase, in exponential phase oxyR antisense generally decreased VHb levels. 相似文献
5.
Cryoprotective and osmotic responses to cold acclimation and freezing in freeze-tolerant and freeze-intolerant earthworms 总被引:3,自引:3,他引:0
M. Holmstrup J. P. Costanzo R. E. Lee Jr 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1999,169(3):207-214
In this paper we present the results of physiological responses to winter acclimation and tissue freezing in a freeze-tolerant
Siberian earthworm, Eisenia nordenskioeldi, and two freeze-intolerant, temperate earthworm species, Lumbricus rubellus and Aporrectodea caliginosa. By analysing the physiological responses to freezing of both types we sought to identify some key factors promoting freeze
tolerance in earthworms. Winter acclimation was followed by a significant increase in osmolality of body fluids in E. nordenskioeldi, from 197 mosmol kg−1 in 10 °C-acclimated animals to 365 mosmol kg−1 in animals acclimated to 0 °C. Cold acclimation did not cause any change in body fluid osmolality in the two freeze-intolerant
species. As a response to ice formation in the body, the freeze-intolerant species produced copious amounts of slime and expulsion
of coelomic fluids, and thereby lost 10–30% of their total water content. Contrary to this, the freeze-tolerant species did
not lose water upon freezing. At temperatures down to −6.5 °C, the ice content in the freeze-tolerant E. nordenskioeldi was significantly lower than in L. rubellus. At lower temperatures there were no differences in ice content between the two species. Cold acclimated, but unfrozen, specimens
of all three species had low levels of ammonia, urea, lactate, glycerol and glucose. As a response to ice formation, glucose
levels significantly increased within the first 24 h of freezing. This was most pronounced in E. nordenskioeldi where a 153-fold increase of glucose was seen (94 mmol · l−1). In L. rubellus and A. caliginosa a 19-fold and 17-fold increase in glucose was seen. This is the first study on physiological mechanisms promoting freeze
tolerance in E. nordenskioeldi, or any other oligochaete. Our results suggest that the cryoprotective system of this species more closely resembles that
of freeze-tolerant anurans, which synthesize cryoprotectants only after tissues begin to freeze, than that of cold-hardy invertebrates
which exhibit a preparatory accumulation of cryoprotectants during seasonal exposure to low temperature.
Accepted: 10 February 1999 相似文献
6.
M. Arnold A. Reittu A. von Wright P. J. Martikainen M.-L. Suihko 《Applied microbiology and biotechnology》1997,48(6):738-744
A biofiltration process was developed for styrene-containing off-gases using peat as filter material. The average styrene
reduction ratio after 190 days of operation was 70% (max. 98%) and the mean styrene elimination capacity was 12 g m−3 h−1 (max. 30 g m−3 h−1). Efficient styrene degradation required addition of nutrients to the peat, adjustment of the pH to a neutral level and efficient
control of the humidity. Maintenance of the water balance was easier in a down-flow than in an up-flow process, the former
consequently resulting in much better filtration efficiency. The optimum operation temperature was around 23 °C, but the styrene
removal was still satisfactory at 12 °C. Seven different bacterial isolates belonging to the genera Tsukamurella, Pseudomonas, Sphingomonas, Xanthomonas and an unidentified genus in the γ group of the Proteobacteria isolated from the microflora of active peat filter material were capable of styrene degradation. The isolates differed in
their capacity to decompose styrene to carbon dioxide and assimilate it to biomass. No toxic intermediate degradation products
of styrene were detected in the filter outlet gas or in growing cultures of isolated bacteria. The use of these isolates in
industrial biofilters is beneficial at low styrene concentrations and is safe from both the environmental and public health
points of view.
Received: 30 May 1997 / Received revision: 22 August 1997 / Accepted: 25 August 1997 相似文献
7.
Lake Vida is a large, permanently ice-covered lake in the Victoria Valley of the McMurdo Dry Valleys, Antarctica and is unique
among Dry Valley lakes because it is ice-sealed, with an ice-cover of nearly 19 m. Enrichment cultures of melt-water from
Lake Vida 15.9 m ice yielded five pure cultures of aerobic, heterotrophic bacteria. Of these, one strain grew at −8°C and
the four others at −4°C. All isolates were either halotolerant or halophilic, with two strains capable of growth at 15% NaCl.
Phylogenetic analysis revealed the Lake Vida isolates to be Gammaproteobacteria, related to species of Psychrobacter and Marinobacter. This is the first report of pure cultures of bacteria from Lake Vida, and the isolates displayed a phenotype consistent
with life in a cold hypersaline environment. 相似文献
8.
Phylogenetic and Physiological Diversity of Bacteria Isolated from Puruogangri Ice Core 总被引:2,自引:0,他引:2
The microbial abundance, the percentage of viable bacteria, and the diversity of bacterial isolates from different regions
of a 83.45-m ice core from the Puruogangri glacier on the Tibetan Plateau (China) have been investigated. Small subunit 16S
rRNA sequences and phylogenetic relationships have been studied for 108 bacterial isolates recovered under aerobic growth
conditions from different regions of the ice core. The genomic fingerprints based on ERIC (enterobacterial repetitive intergenic
consensus)-polymerase chain reaction and physiological heterogeneity of the closely evolutionary related bacterial strains
isolated from different ice core depths were analyzed as well. The results showed that the total microbial cell, percentages
of live cells, and the bacterial CFU ranged from 104 to 105 cell ml−1 (Mean, 9.47 × 104; SD, 5.7 × 104, n = 20), 25–81%, and 0–760 cfu ml−1, respectively. The majority of the isolates had 16S rRNA sequences similar to previously determined sequences, ranging from
92 to 99% identical to database sequences. Based on their 16S rRNA sequences, 42.6% of the isolates were high-G + C-content
(HGC) gram-positive bacteria, 35.2% were low-G + C (LGC) gram-positive bacteria, 16.6% were Proteobacteria, and 5.6% were CFB group. There were clear differences in the depth distribution of the bacterial isolates. The isolates
tested exhibited unique phenotypic properties and high genetic heterogeneity, which showed no clear correlation with depths
of bacterial isolation. This layered distribution and high heterogeneity of bacterial isolates presumably reflect the diverse
bacterial sources and the differences in bacteria inhabiting the glacier’s surface under different past climate conditions. 相似文献
9.
Klaus Martin Meiners S. Papadimitriou D. N. Thomas L. Norman G. S. Dieckmann 《Polar Biology》2009,32(7):1055-1065
Physical, biogeochemical and photosynthetic parameters were measured in sea ice brine and ice core bottom samples in the north-western
Weddell Sea during early spring 2006. Sea ice brines collected from sackholes were characterised by cold temperatures (range
−7.4 to −3.8°C), high salinities (range 61.4–118.0), and partly elevated dissolved oxygen concentrations (range 159–413 μmol kg−1) when compared to surface seawater. Nitrate (range 0.5–76.3 μmol kg−1), dissolved inorganic phosphate (range 0.2–7.0 μmol kg−1) and silicic acid (range 74–285 μmol kg−1) concentrations in sea ice brines were depleted when compared to surface seawater. In contrast, NH4
+ (range 0.3–23.0 μmol kg−1) and dissolved organic carbon (range 140–707 μmol kg−1) were enriched in the sea ice brines. Ice core bottom samples exhibited moderate temperatures and brine salinities, but high
algal biomass (4.9–435.5 μg Chl a l−1 brine) and silicic acid depletion. Pulse amplitude modulated fluorometry was used for the determination of the photosynthetic
parameters F
v/F
m, α, rETRmax and E
k. The maximum quantum yield of photosystem II, F
v/F
m, ranged from 0.101 to 0.500 (average 0.284 ± 0.132) and 0.235 to 0.595 (average 0.368 ± 0.127) in the sea ice internal and
bottom communities, respectively. The fluorometric measurements indicated medium ice algal photosynthetic activity both in
the internal and bottom communities of the sea ice. An observed lack of correlation between biogeochemical and photosynthetic
parameters was most likely due to temporally and spatially decoupled physical and biological processes in the sea ice brine
channel system, and was also influenced by the temporal and spatial resolution of applied sampling techniques. 相似文献
10.
Asli Giray Kurt Emel Aytan Ufuk Ozer Burhan Ates Hikmet Geckil Professor 《Biotechnology journal》2009,4(7):1077-1088
Given the well-established beneficial effects of Vitreoscilla hemoglobin (VHb) on heterologous organisms, the potential of this protein for the production of L -DOPA and dopamine in two bacteria, Citrobacter freundii and Erwinia herbicola, was investigated. The constructed recombinants bearing the VHb gene (vgb+) had substantially higher levels of cytoplasmic L -DOPA (112 mg/L for C. freundii and 97 mg/L for E. herbicola) than their respective hosts (30.4 and 33.8 mg/L) and the vgb– control strains (35.6 and 35.8 mg/L). Further, the vgb+ recombinants of C. freundii and E. herbicola had 20-fold and about two orders of magnitude higher dopamine levels than their hosts, repectively. The activity of tyrosine phenol-lyase, the enzyme converting L -tyrosine to L -DOPA, was well-correlated to cytoplasmic L -DOPA levels. As cultures aged, higher tyrosine phenol-lyase activity of the vgb+ strains was more apparent. 相似文献
11.
An ice-nucleating bacterium, strain KUIN-1, was isolated from the leaves of field beans (Phaseolus vulgaris L.). Strain KUIN-1 was identified as Pseudomonas fluorescens from its taxonomical characteristics. Ice-nucleating activity was obtained when strain KUIN-1 was cultured aerobically in a medium containing Koser citrate broth (pH 7.0) for 24 hr at 18°C. The ice- nucleating activity did not appear until the bacterial cell concentration reached 107 to 108/ml. Nucleation at — 3.0°C was detected in suspensions (1.8 × 109 cells/ml) of cells that had been grown on the medium containing Koser citrate broth. Strain KUIN-1 produced a lower nucleation frequency (i.e. the number of ice nuclei/cell) than did ice-nucleating Pseudomonas syringae No. 31 suspensions, particularly at temperatures above — 5°C. The nucleation frequency of strain KUIN- 1-suspensions was similar to that obtained for an ice-nucleating Erwinia herbicola No. 26 at — 5°C. 相似文献
12.
Transposon Tn5 mutagenesis was used to generate random mutations in Shewanella baltica MAC1, a polyunsaturated fatty acid (PUFA)-producing bacterium. Three mutants produced 3–5 times more eicosapentaenoic acid (EPA 20:5 n−3) compared to the wild type at 10°C. One of the mutants produced 0.3 mg EPA g−1 when grown at high temperature (30°C). Moreover, 2 mg docosahexaenoic acid (DHA 22:6 n−3) g−1 was produced by S. baltica mutants at 4°C. Sequencing of insertion mutation(s) showed 96% homology to trimethylamine N-oxide (TMAO) reductase gene and 85% homology to rRNA operons of E. coli. Tn5 transposon mutagenesis therefore is a suitable technique to increase PUFA formation in bacteria. 相似文献
13.
Park S Kang K Lee SW Ahn MJ Bae JM Back K 《Applied microbiology and biotechnology》2011,89(5):1387-1394
A plant-specific biogenic amine, serotonin, was produced by heterologous expression of two key biosynthetic genes, tryptophan
decarboxylase (TDC) and tryptamine 5-hydroxylase (T5H), in Escherichia coli. The native T5H, a cytochrome P450 enzyme, was unable to be functionally expressed in E. coli. Through a series of N-terminal deletions or additions of tagging proteins, we generated a functional T5H enzyme construct
(GST∆37T5H) in which glutathione S transferase (GST) was translationally fused with the N-terminal 37 amino acid deleted T5H. Dual expression
of GST∆37T5H and TDC using a pCOLADuet-1 E. coli vector produced serotonin at concentrations of approximately 24 mg l−1 in the culture medium and 4 mg l−1 in the cells. An optimum temperature of approximately 20°C was required to achieve peak serotonin production in E. coli because the low induction temperature gave rise to the highest soluble expression of GST∆37T5H. 相似文献
14.
Jamal MT Morris PC Hansen R Jamieson DJ Burgess JG Austin B 《Marine biotechnology (New York, N.Y.)》2006,8(6):587-592
Of 131 bacterial isolates from seaweed, a culture of Bacillus licheniformis produced a novel protein with antibacterial activity against methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and Listeria monocytogenes. The antibacterial activity was maximal in cultures prepared in Columbia broth containing pieces of synthetic polyurethane
sponge and shaken at 210 to 230 rpm. Antibacterial activity was not found in cultures grown statically or with different speeds
of rotary shaking. Reduced activity was apparent in supernatants prepared from marine 2216E broth and tryptone soya broth
with or without 1% (wt/vol) sodium chloride. The antibacterial compound was sensitive to proteinase K, pronase, and trypsin,
but was not affected by Tween−20, −40, −60, or −80, or α− or β-amylase. Activity was not adversely affected by heating up
to 40°C or treatment at pH 5 to 14. The bioactive compound was determined to be associated with a protein of 30.7 kDa, which
had homology to the YbdN protein of B. licheniformis ATCC 14580. 相似文献
15.
A mutan-degrading bacterium, closely related to Paenibacillus curdlanolyticus, was isolated from soil. It produced 0.4 U mutanase ml−1 in 2 days in shake-flask cultures when bacterial mutan was the sole carbon source. Mutanase activity was optimal at pH 6.2
and 45°C over 1 h and was stable between pH 5.8 and 12 at 4°C for 24 h and up to 40°C for 1 h. Mutan produced by Streptococcus mutans was rapidly hydrolyzed by this enzyme. The hydrolysis of mutan (1 g l−1) resulted in 17% saccharification over 2 h and, at the same time, glucan was entirely solubilized. 相似文献
16.
Evidence for active microbial nitrogen transformations in sea ice (Gulf of Bothnia, Baltic Sea) in midwinter 总被引:5,自引:3,他引:2
Hermanni Kaartokallio 《Polar Biology》2001,24(1):21-28
Nutrient concentrations, chlorophyll-a, bacterial biomass and relative activity of denitrifying organisms were investigated from ice-core, brine and underlying
water samples in February 1998 in the Gulf of Bothnia, Baltic Sea. Examined sea ice was typical for the Baltic Sea; ice bulk
salinity varied from 0.1 to 1.6 psu, and in underlying water salinity was from 4.2 to 4.7 psu. In 2- to 3-months-old sea ice
(thickness 0.4–0.6 m), sea-ice communities were at the winter stage; chl-a concentrations were generally below 1 mg m−3 and heterotrophic organisms composed 7–20% of organism assemblage. In 1-month-old ice (thickness 0.2–0.25 m), an ice spring
bloom was already developing and chl-a concentrations were up to 5.6 mg m−3. In relation to low salinity, high concentrations of NH+
4, NO−
2, PO3+
4 and SiOH4 were found in the ice column. The results suggest that the upper part of ice accumulates atmospheric nutrient load during
the ice season, and nutrients in the upper 10–20 cm of ice are mainly of atmospheric origin. The most important biological
processes controlling the sea-ice nutrient status are nutrient regeneration, nutrient uptake and nitrogen transformations.
Nutrient regeneration is specially active in the middle parts of the 50- to 60-cm-thick ice and subsequent accumulation of
nutrients probably enhances the ice spring bloom. Nitrite accumulation and denitrifying activity were located in the same
ice layers with nutrient regeneration, which together with the observed significant correlation between the concentrations
of nitrogenous nutrients points to active nitrogen transformations occurring in the interior layers of sea ice in the Baltic
Sea.
Accepted: 12 June 2000 相似文献
17.
Determination of the kinetics of permeation of dimethyl sulfoxide in isolated corneas 总被引:2,自引:0,他引:2
Corneal cryopreservation requires that endothelial cells remain viable and intercellular structure be preserved. High viability
levels for cryopreserved endothelial cells have been achieved, but preserving intercellular structure, especially endothelial
attachment to Descemet's membrane, has proved difficult. Cell detachment apparently is not caused by ice, suggesting osmotic
or chemical mechanisms. Knowledge of the permeation kinetics of cryoprotectants (CPAs) into endothelial cells and stroma is
essential for controlling osmotic and chemical activity and achieving adequate tissue permeation prior to cooling. Proton
nuclear magnetic resonance (NMR) spectroscopy was used to assess the permeation of dimethyl sulfoxide (DMSO) into isolated
rabbit corneas. Corneas with intact epithelia were exposed to isotonic medium or 2.0 mol/L DMSO for 60 min and subsequently
transferred to 2.0 or 4.0 mol/L DMSO, respectively, at 22, 0, or −10°C. DMSO concentration in the cornea was measured vs time.
The Kedem-Katchalsky model was fitted to the data. Hydraulic permeability (m3/N·s) is 7.1×10−13+216%-11% at 22°C, 8.2×10−13+235%−21% at 0°C, and 1.7×10−14+19% −16% at −10°C. The reflection coefficient is 1.0+2%−1% at 22°C and 0°C, and 0.9±5% at −10°C. Solute mobility (cm/s) is
5.9×10−6+6%–11% at 22°C, 3.1×10−6+12%−11% at 0°C, and 5.0×10−8 cm/s+59%−40% at −10°C. 相似文献
18.
S. Becquevort I. Dumont J.-L. Tison D. Lannuzel M.-L. Sauvée L. Chou V. Schoemann 《Polar Biology》2009,32(6):879-895
Pack ice, brines and seawaters were sampled in October 2003 in the East Antarctic sector to investigate the structure of the
microbial communities (algae, bacteria and protozoa) in relation to the associated physico-chemical conditions (ice structure,
temperature, salinity, inorganic nutrients, chlorophyll a and organic matter). Ice cover ranged between 0.3 and 0.8 m, composed of granular and columnar ice. The brine volume fractions
sharply increased above −4°C in the bottom ice, coinciding with an important increase of algal biomass (up to 3.9 mg C l−1), suggesting a control of the algae growth by the space availability at that period of time. Large accumulation of NH4
+ and PO4
3− was observed in the bottom ice. The high pool of organic matter, especially of transparent exopolymeric particles, likely
led to nutrients retention and limitation of the protozoa grazing pressure, inducing therefore an algal accumulation. In contrast,
the heterotrophs dominated in the underlying seawaters. 相似文献
19.
Thomas L. Kieft 《Applied microbiology》1988,54(7):1678-1681
A newly discovered form of biological ice nucleus associated with lichens is described. Ice nucleation spectra of a variety of lichens from the southwestern United States were measured by the drop-freezing method. Several epilithic lichen samples of the genera Rhizoplaca, Xanthoparmelia, and Xanthoria had nuclei active at temperatures as warm as −2.3°C and had densities of 2.3 × 106 to more than 1 × 108 nuclei g−1 at −5°C (2 to 4 orders of magnitude higher than any plants infected with ice nucleation-active bacteria). Most lichens tested had nucleation activity above −8°C. Lichen substrates (rocks, plants, and soil) showed negligible activity above −8°C. Ice nucleation-active bacteria were not isolated from the lichens, and activity was not destroyed by heat (70°C) or sonication, indicating that lichen-associated ice nuclei are nonbacterial in origin and differ chemically from previously described biological ice nuclei. An axenic culture of the lichen fungus Rhizoplaca chrysoleuca showed detectable ice nucleation activity at −1.9°C and an ice nucleation density of 4.5 × 106 nuclei g−1 at −5°C. It is hypothesized that these lichens, which are both frost tolerant and dependent on atmospheric moisture, derive benefit in the form of increased moisture deposition as a result of ice nucleation. 相似文献
20.
The development of a rapid protocol for high-efficiency somatic embryogenesis and plant regeneration from seed-derived embryogenic
callus cultures of California poppy (Eschscholzia californica Cham.) is reported. The optimized procedure required less than 13 weeks from the initiation of seed cultures to the recovery
of plantlets and involved the sequential transfer of cultures onto solid Murashige and Skoog basal medium containing three
different combinations of growth regulators. All steps were performed at 25 °C. Friable primary callus was induced from seeds
of E. californica cultured on medium supplemented with 1.0 mg l−1 2,4-dichlorophenoxyacetic acid. The primary callus was transferred to medium containing 1.0 mg l−1 1-naphthaleneacetic acid and 0.5 mg l−1 6-benzylaminopurine to establish embryogenic callus and promote somatic embryogenesis. Regenerated plantlets were recovered
after the conversion of somatic embryos on medium containing 0.05 mg l−1 6-benzylaminopurine and showed normal development. Embryogenic callus was induced at a frequency of 85%, an average of 45
somatic embryos were produced per callus, 90% of the somatic embryos converted, and about 70% of the plantlets were recovered
in soil. The growth rate of somatic embryo-derived shoots could be increased by gibberellic acid treatment, but the resulting
plantlets were hyperhydritic.
Received: 14 February 1999 / Revision received: 27 April 1999 / Accepted: 14 May 1999 相似文献