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1.
Effects of 1-MCP and exogenous ethylene on fruit ripening and antioxidants in stored mango 总被引:2,自引:0,他引:2
Baogang Wang Jianhui Wang Xiaoyuan Feng Lin Lin Yumei Zhao Weibo Jiang 《Plant Growth Regulation》2009,57(2):185-192
Mango (Mangifera indica L. cv. Tainong) fruits were harvested at the green-mature stage in Hainan and air-freighted to the laboratory at Peking.
The fruits were treated with either 1 μl l−1 1-MCP or 5 μl l−1 ethylene for 24 h and stored at 20°C for up to 16 days. 1-MCP maintained fruit firmness, whereas exogenous ethylene decreased
fruit firmness. Exogenous ethylene accelerated the increase in ethylene and 1-aminocyclopropane-1-carboxylate (ACC) oxidase,
whereas 1-MCP reduced both. Exogenous ethylene stimulated and 1-MCP inhibited the production of H2O2 of mango fruit during storage. Ascorbic acid was maintained at a high concentration in 1-MCP-treated fruit but was low in
ethylene-treated fruit. 1-MCP inhibited activities of antioxidant enzymes including catalase, superoxide dismutase and ascorbate
peroxidase. These results suggest that 1-MCP could play a positive role in regulating the activated oxygen metabolism balance.
Baogang Wang and Jianhui Wang contributed equally to this work. 相似文献
2.
T. Chakbavarty J. G. Norcini J. H. Aldrich R. S. Kalmbacher 《In vitro cellular & developmental biology. Plant》2001,37(5):550-554
Summary Creeping bluestem (Schizachyrium scoparium (Michx.) Nash var. stoloniferum (Nash) J. Wipff) embryogenic callus growing on solid medium was used to establish a cell suspension culture in Murashige
and Skoog (MS) basal medium supplemented with 1.5 mg l−1 (6.8 μM) 2,4-dichlorophenoxyacetic acid (2,4-D), 0.2 mg l−1 (0.88 μM) 6-benzylaminopurine (BA), 0.5 mg l−1 (1.4 μM) zeatin, 0.2 mg l−1 (0.58 μM) gibberellic acid (GA3), and 10% (v/v) of coconut water (CW). Pro-embryos from suspension culture matured on semi-solid MS medium in about 18 wk,
and were then cultured on semi-solid MS medium without growth regulators for 2–3 wk. Shoots were regenerated on MS basal medium
supplemented with 3.0 mg L−1 (13.6 μM) 2,4-D, 1.0 mg l−1 (4.4 μM) BA, 1.0 mg l−1 (2.9 μM) GA3, 0.5 mg l−1 (2.7 μM) 1-naphthaleneacetic acid (NAA), 500 mg l−1 easein hydrolysate, and 10% (v/v) CW. Rooted plantlets were successfully accelimatized to greenhouse and outdoor conditions.
Using this protocol, it would be possible to produce at least 1300 fully acclimatized plantlets annually. 相似文献
3.
Boiero L Perrig D Masciarelli O Penna C Cassán F Luna V 《Applied microbiology and biotechnology》2007,74(4):874-880
The aim of this work was to evaluate phytohormone biosynthesis, siderophores production, and phosphate solubilization in three
strains (E109, USDA110, and SEMIA5080) of Bradyrhizobium japonicum, most commonly used for inoculation of soybean and nonlegumes in USA, Canada, and South America. Siderophore production and
phosphate solubilization were evaluated in selective culture conditions, which had negative results. Indole-3-acetic acid
(IAA), gibberellic acid (GA3), and abscisic acid (ABA) production were analyzed by gas chromatography–mass spectrometry (GC-MS). Ethylene and zeatin biosynthesis
were determined by GS–flame ionization detection and high-performance liquid chromatography (HPLC-UV), respectively. IAA,
zeatin, and GA3 were found in all three strains; however, their levels were significantly higher (p < 0.01) in SEMIA5080 (3.8 μg ml−1), USDA110 (2.5 μg ml−1), and E109 (0.87 μg ml−1), respectively. ABA biosynthesis was detected only in USDA110 (0.019 μg ml−1). Ethylene was found in all three strains, with highest production rate (18.1 ng ml−1 h−1) in E109 cultured in yeast extract mannitol medium plus l-methionine. This is the first report of IAA, GA3, zeatin, ethylene, and ABA production by B. japonicum in pure cultures, using quantitative physicochemical methodology. The three strains have differential capability to produce
the five major phytohormones and this fact may have an important technological implication for inoculant formulation. 相似文献
4.
Behzad Ahmadi Khoshnood Alizadeh Jaime A. Teixeira da Silva 《Plant Cell, Tissue and Organ Culture》2012,109(3):525-533
The effects of three periods of incubation (10, 20 and 30 min) at different levels of bleomycin (0, 0.1, 0.2, 0.3, 0.4 and
0.5 μg ml−1), as well as three periods of exposure (12, 24 and 48 h) to different levels of the anti-auxin p-chlorophenoxyisobutyric acid (PCIB), including 1, 2, 3, 4 and 5 mg l−1, on microspore embryogenesis of rapeseed cv. ‘Amica’ were investigated. Microspore embryogenesis was significantly enhanced
following 20 min treatment with 0.2 μg ml−1 bleomycin compared with untreated cultures. Highest embryo yield (163 embryos Petri dish−1) was observed with 24 h treatment of 4 mg l−1 PCIB. The highest percentage of secondary embryogenesis was observed on B5 medium containing 0.15 mg l−1 of gibberellic acid (GA3) and 0.2 mg l−1 6-benzyladenine (BA) in 4–6 mm microspore-derived embryos (MDEs). Most callus formed on B5 medium containing 0.15 mg l−1 GA3, 0.1 mg l−1 BA and 0.1 mg l−1 indole-3-acetic acid (IAA) when 4–6 mm embryos were used. Regeneration was highest on B5 medium containing 0.05 mg l−1 GA3 or 0.1 mg l−1 BA and 0.2 mg l−1 IAA with 2–4 mm embryos. Microspore embryogenesis and plant regeneration could be improved by both bleomycin and PCIB when
the appropriate MDE length and phytohormone level were selected. 相似文献
5.
Yassen Mohamed-Yasseen 《In vitro cellular & developmental biology. Plant》2001,37(2):204-205
Summary Agar and activated charcoal (AC) are commonly used in tissue culture. However, their deeper actions and functions are largely
unknown. This experiment investigated the effect of agar and AC, singly and jointly, on gibberellin (GA) uptake by corn shoots.
Corn seeds were germinated on Murashige and Skoog medium (MS). Shoot excised from 1-wk-old seedlings were cultured on liquid
(0.0 g l−1 agar) or solid (8 g l−1 agar) MS containing 3 μM indole-3-acetic acid, 13.3 μM N6-benzyladenine, and 6000 CPM ml−1 [3H]GA4 as tracer. Both liquid and solid media had two treatments, one without AC and one supplemented with 5 g l−1AC. Uptake of [3H]GA4 and morphogenesis of corn shoots were recorded after 2 wk of culture. Corn explants cultured in AC-free media acquired high
levels of [3H]GA4, while explants from AC-containing media showed only traces of [3H]GA4. Explants cultured in AC-free liquid medium contained about twice the amount of [3H]GA4 as those from AC-free solid medium. Addition of agar reduced shoot length, while addition of AC increased both shool and
root length. It is concluded that: (1) agar reduced the uptake of GA4; and (2) GA4 was irreversibly adsorbed by AC, and thus became unavailable to corn explants. 相似文献
6.
Perrig D Boiero ML Masciarelli OA Penna C Ruiz OA Cassán FD Luna MV 《Applied microbiology and biotechnology》2007,75(5):1143-1150
We evaluated phytohormone and polyamine biosynthesis, siderophore production, and phosphate solubilization in two strains
(Cd and Az39) of Azospirillum brasilense used for inoculant formulation in Argentina during the last 20 years. Siderophore production and phosphate solubilization
were evaluated in a chemically defined medium, with negative results. Indole 3-acetic acid (IAA), gibberellic acid (GA3), and abscisic acid (ABA) production were analyzed by gas chromatography-mass spectrometry. Ethylene, polyamine, and zeatin
(Z) biosynthesis were determined by gas chromatography-flame ionization detector and high performance liquid chromatography
(HPLC-fluorescence and -UV), respectively. Phytohormones IAA, Z, GA3, ABA, ethylene, and growth regulators putrescine, spermine, spermidine, and cadaverine (CAD) were found in culture supernatant
of both strains. IAA, Z, and GA3 were found in all two strains; however, their levels were significantly higher (p < 0.01) in Cd (10.8, 2.32, 0.66 μg ml−1). ABA biosynthesis was significantly higher (p < 0.01) in Az39 (0.077 μg ml−1). Ethylene and polyamine CAD were found in all two strains, with highest production in Cd cultured in NFb plus l-methionine (3.94 ng ml−1 h−1) and Az39 cultured in NFb plus l-lysine (36.55 ng ml−1 h−1). This is the first report on the evaluation of important bioactive molecules in strains of A. brasilense as potentially capable of direct plant growth promotion or agronomic yield increase. Az39 and Cd showed differential capability
to produce the five major phytohormones and CAD in chemically defined medium. This fact has important technological implications
for inoculant formulation as different concentrations of growth regulators are produced by different strains or culture conditions. 相似文献
7.
Jan G. H. M. Rijnders Young-Yell Yang Yuji Kamiya Nobuta Takahashi Gerard W. M. Barendse Cornelis W. P. M. Blom Laurentius A. C. J. Voesenek 《Planta》1997,203(1):20-25
The role of gibberellin (GA) and ethylene in submergence-induced petiole elongation was studied in two species of the genus
Rumex. Analysis of endogenous GAs in the flooding-tolerant Rumex palustris Sm. and the intolerant Rumex acetosa L. by gas chromatography-mass spectrometry showed for both species the presence of GA1, GA4, GA9, GA19, GA20 and GA53. Gas chromatography-mass spectrometry analysis of R. palustris petiole tissue of submerged plants showed an increase in levels of 13-OH GAs, especially GA1, compared with drained plants. This effect could be mimicked by application of 5 μL L−1 ethylene. In R. acetosa, no differences between levels of GAs in drained or submerged plants were found. In R. palustris, both submergence and ethylene treatment sensitized petioles to exogenous gibberellic acid (GA3). In R. acetosa the effect was opposite, i.e. submergence and ethylene de-sensitized petioles to GA3. Our results demonstrate the dual effect of ethylene in the submergence response related to flooding tolerance, i.e. in the
flooding-tolerant R. palustris ethylene causes an increased concentration of and sensitivity to GA with respect to petiole elongation while in the intolerant
R. acetosa ethylene reduces growth independent of GAs.
Received: 5 November 1996 / Accepted: 8 February 1997 相似文献
8.
In vitro propagation of northern red oak (Quercus rubra) shoots was successful from cotyledonary node explants excised from 8-wk-old in vitro grown seedlings. Initially, four shoots per explant were obtained on Murashige and Skoog (MS) medium supplemented with 4.4 μM
6-benzylaminopurine (BA), 0.45 μM thidiazuron (TDZ), and 500 mg l−1 casein hydrolysate (CH) with a regeneration frequency of 64.7% after 3 wk. Subculturing explants (after harvesting shoots)
to fresh treatment medium significantly increased shoot bud regeneration (16.6 buds per explant), but the buds failed to develop
into shoots. A higher percentage (73.3%) of the explants regenerated four shoots per explant on woody plant medium (WPM) supplemented
with 4.4 μM BA, 0.29 μM gibberellic acid (GA3), and 500 mg l−1 CH after 3 wk. Explants subcultured to fresh treatment medium after harvesting shoots significantly increased shoot regeneration
(16 shoots per explant). Shoot elongation was achieved (4 cm) when shoots were excised and cultured on WPM supplemented with
0.44 μM BA and 0.29 μM GA3. In vitro regenerated shoots were rooted on WPM supplemented with 4.9 μM indole-3-butyric acid. A higher percentage regeneration response
and shoot numbers per explant were recorded on WPM supplemented with BA and GA3, than on MS medium containing BA and TDZ. Lower concentrations of BA and GA3 were required for shoot elongation and prevention of shoot tip necrosis. Each cotyledonary node yielded approximately 20
shoots within 12 wk. Rooted plantlets were successfully acclimatized. 相似文献
9.
Effect of Abscisic Acid on Banana Fruit Ripening in Relation to the Role of Ethylene 总被引:7,自引:0,他引:7
Abstract
The role of abscisic acid (ABA) in banana fruit ripening was examined with the ethylene binding inhibitor, 1-methylcyclopropene
(1-MCP). ABA (0, 10−5, 10−4, or 10−3 mol/L) was applied by vacuum infiltration into fruit. 1-MCP (1 μL/L) was applied by injecting a measured volume of stock
gas into sealed glass jars containing fruit. Fruit ripening, as judged by ethylene evolution and respiration associated with
color change and softening, was accelerated by 10−4 or 10−3 mol/L ABA. ABA at 10−5 mol/L had no effect. The acceleration of ripening by ABA was greater at 10−3 mol/L than at 10−4 mol/L. ABA-induced acceleration of banana fruit ripening was not observed in 1-MCP treated fruit, especially when ABA was
applied after exposure to 1-MCP. Thus, ABA's promotion of ripening in intact banana fruit is at least partially mediated by
ethylene. Exposure of ABA-treated fruit to 0.1 μL/L ethylene for 24 h resulted in increased ethylene production and respiration,
and associated skin color change and fruit softening. Control fruit (no ABA) was unresponsive to similar ethylene treatments.
The data suggest that ABA facilitates initiation and progress in the sequence of ethylene-mediated ripening events, possibly
by enhancing the sensitivity to ethylene.
Received 29 January 1999; accepted 16 January 2000 相似文献
10.
Effects of post-harvest application of two plant growth regulators viz., gibberellic acid (GA3) and benzyl adenine (BA) with sucrose in the vase solution on cell membrane stability and vase life of gladiolus were investigated.
The vase solution treatment combinations of GA3 and BA with sucrose significantly increased the membrane stability index and enhanced the vase life as compared to the sucrose
alone treatments or the controls. Vase solution treatment of GA3 (50 mg l−1), followed by BA (50 mg l−1) with sucrose (50 g l−1) significantly increased solution uptake, fresh weight and dry weight of cut spikes. The same treatments also enhanced the
concentration of reducing and non-reducing sugars in gladioli petals 4 days after treatment (DAT). Cut spikes in vase solution
enriched with 50 mg l−1 GA3 + 50 g l−1 sucrose showed higher antioxidative enzyme activities of superoxide dismutase (SOD) and glutathione reductase (GR), lower
lipoxygenase (LOX) activity and lipid peroxidation (measured as TBARS). Petal membrane stability index was also highest in
cut spikes 6 DAT with 50 mg l−1 GA3 + 50 g l−1 sucrose vase solution. Treatment of gladiolus cut spikes with 50 mg l−1 GA3 + 50 g l−1 sucrose vase solution showed two fold increase in vase life and improved flower quality with a higher number of open flower
per spike at any one time. These results suggest that post-harvest application of GA3 (50 mg l−1) with sucrose (50 g l−1) maintains higher spike fresh and dry weight, improves anti-oxidative defence, stabilizes membrane integrity leading to a
delay in petal cell death. 相似文献
11.
The role of gibberellins (GAs) in the regulation of shoot elongation is well established but the phytohormonal control of
dry-matter production is poorly understood. In the present study, shoot elongation and dry-matter production were resolved
by growing Brassica napus L. seedlings under five light intensities (photon flux densities) ranging from 25 to 500 μmol m−2 s−1. Under low light, plants were tall but produced little dry weight; as light intensity was increased, plants were progressively
shorter but had increasing dry weights. Endogenous GAs in stems of 16- and 17-d-old plants were analyzed by gas chromatography-selected
ion monitoring with [2H2] internal standards. The contents of GAs increased dramatically with decreasing light intensity: GA1, GA3, GA8 and GA20 were 62, 15, 16 and 32 times higher, respectively, under the lowest versus highest light intensities. Gibberellin A19 was not measured at 25 μmol m−2 s−1 but was 9␣times greater in the 75 compared to 500 μmol m−2 s−1 treatment. Shoot and hypocotyl lengths were closely positively correlated with (log) GA concentration (for example: r
2 = 0.93 for GA1 and hypocotyl length) but shoot dry matter was negatively correlated with GA concentration. The application of gibberellic
acid (GA3) produced elongation of plants grown under high light, indication that their low level of endogenous GA was limiting shoot
elongation. Although endogenous GA20 showed the greatest influence of light treatment, metabolism of [3H]GA20 and of [3H]GA1 was only slightly influenced by light intensity, suggesting that neither 2β- nor 3β-hydroxylation were points of metabolic
regulation. The results of this study indicate that GAs control shoot elongation but are not directly involved in the regulation
of shoot dry weight in Brassica. The study also suggests a role of GAs in photomorphogenesis, serving as an intermediate between light condition and shoot
elongation response.
Received: 18 June 1998 / Accepted: 29 July 1998 相似文献
12.
Irene ávila-Díaz Ken Oyama Carlos Gómez-Alonso Rafael Salgado-Garciglia 《Plant Cell, Tissue and Organ Culture》2009,99(3):335-343
Laelia speciosa is an endangered epiphytic orchid. The effects of various media components on germination of L. speciosa were evaluated. Pods were collected at 4, 7, and 9 months following hand-pollination, and seeds were germinated on Murashige and Skoog (MS)
media with 30 g l−1 sucrose and five concentrations (0.0, 0.04, 0.22, 0.44, and 2.22 μM) of benzyladenine (BA) under light and dark conditions.
Gibberellic acid (GA3; 0.0, 0.29, 1.44, 2.89, 14. 43 and 28.87 μM) with naphthaleneacetic acid (NAA; 0.0, 0.54, 1.34, 2.69, and 5.37 μM) were evaluated
for in vitro subcultivation. MS medium with 30 g l−1 sucrose was effective for germination. The effects of BA and light on germination of L. speciosa seeds differed with pod maturity. All mature seeds germinated using 0.44 μM BA and light. The highest frequency of germinated
seedlings (60%) was obtained using mature seeds grown on MS medium without BA and under light conditions. For subculture,
MS with 30 g l−1 sucrose, 2.69 μM NAA, and 0.29 μM GA3 was effective. Plantlets of 5 cm in length were transplanted to the greenhouse, and a 77.5% of survival rate was obtained.
A successful protocol for micropropagation by seed germination will contribute to the development of a sustainable management
program for L. speciosa. 相似文献
13.
The biokinetics of glucose metabolism were evaluated in Aeromonas hydrophila during growth in an anaerobic biosystem. After approx 34 h growth, A. hydrophila metabolized 5,000 mg glucose l−1 into the end-products ethanol, acetate, succinate and formate. The maximum growth rate, μ
m, half saturation coefficients, K
s, microbial yield coefficient, Y, cell mass decay rate coefficient, k
d, and substrate inhibition coefficient, K
si were 0.25 ± 0.03 h−1, 118 ± 31 mg glucose l−1, 0.12 μg DNA mg glucose−1, 0.01 h−1, and 3,108 ± 1,152 mg glucose l−1, respectively. These data were used to predict the performance of a continuous growth system with an influent glucose concentration
of 5,000 mg l−1. Results of the analysis suggest that A. hydrophila will metabolize glucose at greater than 95% efficiency when hydraulic retention times (HRTs) exceed 7 h, whereas the culture
is at risk of washing out at an HRT of 6.7 h. 相似文献
14.
Molecular characterization of phenylalanine ammonia lyase gene from <Emphasis Type="Italic">Cistanche deserticola</Emphasis> 总被引:1,自引:0,他引:1
Hu GS Jia JM Hur YJ Chung YS Lee JH Yun DJ Chung WS Yi GH Kim TH Kim DH 《Molecular biology reports》2011,38(6):3741-3750
We cloned the gene, CdPAL1, from Cistanche deserticola callus using RACE PCR with degenerate primers that were designed based on a multiple sequence alignment of known PAL genes
from other plant species. The gene shows high homology to other known PAL genes registered in GenBank. The recombinant protein
exhibited Michaelis–Menten kinetics with a K
m of 0.1013 mM, V
max of 4.858 μmol min−1, K
cat of 3.36 S−1, and K
cat/K
m is 33,168 M−1 S−1. The enzyme had an optimal pH of 8.5 and an activation energy of 38.92 kJ mol−1 when l-Phenylalanine was used as a substrate; l-tyrosine cannot be used as substrate for this protein. The optimal temperature was 55°C, and the thermal stability results
showed that, after a treatment at 70°C for 20 min, the protein retained 87% activity, while a treatment at 75°C for 20 min
resulted in a loss of over 85% of the enzyme activity. Treatment with heavy metal ions (Hg2+, Pb2+, and Zn2+) showed remarkable inhibitory effects. Among the intermediates from the lignin (cinnamyl alcohol, cinnamyl aldehyde, coniferyl
aldehyde, coniferyl alcohol), phenylpropanoid (cinnamic acid, coumaric acid, caffeic acid, and chlorogenic acid) and phenylethanoid
(tyrosol and salidroside) biosynthetic pathways, only cinnamic acid showed strong inhibitory effects against CdPAL1 activity with a K
i of 8 μM. Competitive inhibitor AIP exhibited potent inhibition with K
i = 0.056 μM. 相似文献
15.
Nannochloropsis sp. was grown with different levels of nitrate, phosphate, salinity and temperature with CO2 at 2,800 μl l−1. Increased levels of NaNO3 and KH2PO4 raised protein and polyunsaturated fatty acids (PUFAs) contents but decreased carbohydrate, total lipid and total fatty acids (TFA) contents. Nannochloropsis sp. grew well at salinities from 22 to 49 g l−1, and lowering salinity enhanced TFA and PUFAs contents. TFA contents increased with the increasing temperature but PUFAs contents decreased. The highest eicosapentaenoic acid (EPA, 20:5ω3) content based on the dry mass was above 3% under low N (150 μM NaNO3) or high N (3000 μM NaNO3) condition. Excessive nitrate, low salinity and temperature are thus favorable factors for improving EPA yields in Nannochloropsis sp. 相似文献
16.
Plum is a highly perishable fruit and postharvest fruit softening limits its shelf life. The aim of this work was to study
the specific effects of 1-methylcyclopropene (1-MCP) treatment on physiological changes in ‘Zaohong’ plums. Plums were treated
with 500 nL L−1 1-MCP at 20°C for 18 h followed by 20°C storage. The results showed that 1-MCP treatment significantly reduced endogenous
ethylene production and the activities of ethylene biosynthetic enzymes’ (1-aminocyclopropane-1-carboxylic acid synthase,
ACS and 1-aminocyclopropane-1-carboxylic acid oxidase, ACO) in plum fruit during storage when compared with untreated fruit.
Although 1-MCP treatment inhibited ethylene production and 1-aminocyclopropane-1-carboxylic acid (ACC) accumulation, it did
not inhibit the accumulation of N-malonyl-ACC (MACC). Higher firmness was also found in 1-MCP-treated plums than in controls. During storage, superoxide anion
(O2−·) and hydrogen peroxide (H2O2) levels decreased in 1-MCP-treated fruit. 1-MCP treatment also regulated superoxide dismutase (SOD) and catalase (CAT) activities
during storage. Xylanase activity was upregulated while activities of polygalacturonase (PG), pectin methyl esterase (PME)
and cellulase enzymes in the fruit were downregulated by 1-MCP treatment. In conclusion, 1-MCP might be a potent compound
for extending both storage period and shelf life of ‘Zaohong’ plums by suppressing ethylene biosynthesis, regulating cell
wall degradation enzymes and reducing fruit softening. 相似文献
17.
P. Glocke K. Delaporte G. Collins M. Sedgley 《In vitro cellular & developmental biology. Plant》2006,42(2):139-143
Summary Micropropagation via enhanced axillary shoot proliferation was investigated in the ornamental Eucalyptus cv. ‘Urrbrae Gem’ using in vitro germinated seedlings and was successfully achieved using woody plant medium (WPM) supplemented with 2.2 μM benzylaminopurine, 1.0 μM α-naphthaleneacetic acid, and 1.5 μM gibberellic acid (GA3), gelled with 5 g l−1 Phytagel?. Shoot proliferation was greater on WPM and QL media with GA3 compared to B5, AP, and TK media with or without GA3. GA3 was required for shoot elongation as the internodes were otherwise very short and unsuitable for multiplication or root initiation.
Root initiation was improved using (1/2) WPM supplemented with 20 μM indole-3-butyric acid (IBA) over a 7 d pulse, followed by subculture to IBA-free medium, compared to placing shoots on low
levels of IBA for 4–6 wk. Plantlets were successfully hardened off to the natural environment via a fogger at 67% relative,
humidity at 21°C for 3 d and continued to thrive as potted plants. This is the first report of successful, micropropagation
in an ornamental eucalypt (subgenus Symphyomyrtus) from seedling explants. 相似文献
18.
In this paper, we would like to show unexpected morphogenic potential of cell suspensions derived from seedling explants of
Gentiana kurroo (Royle). Suspension cultures were established with the use of embryogenic callus derived from seedling explants (root, hypocotyl
and cotyledons). Proembryogenic mass proliferated in liquid MS medium supplemented with 0.5 mg l−1 2,4-D and 1.0 mg l−1 Kin. The highest growth coefficient was achieved for root derived cell suspensions. The microscopic analysis showed differences
in aggregate structure depending on their size. To assess the embryogenic capability of the particular culture, 100 mg of
cell aggregates was implanted on MS agar medium supplemented with Kin (0.0–2.0 mg l−1), GA3 (0.0–2.0 mg l−1) and AS (80.0 mg l−1). The highest number of somatic embryos was obtained for cotyledon-derived cell suspension on GA3-free medium, but the best morphological quality of embryos was observed in the presence of 0.5–1.0 mg l−1 Kin, 0.5 mg l−1 GA3 and 80.0 mg l−1 AS. The morphogenic competence of cultures also depended on the size of the aggregate fraction and was lower when size of
aggregates decreased. Flow cytometry analysis reveled luck of uniformity of regenerants derived from hypocotyl suspension
and 100% of uniformity for cotyledon suspension. 相似文献
19.
Effects of the gibberellins A4+7(GA4+7) and A3(GA3), benzyladenine (BA) and forchlorfenuron (CPPU) on deposition of the cuticular membrane (CM) in developing tomato (Lycopersicon esculentum L.) fruit were investigated. Growth regulators were applied when fruit development within trusses ranged from the flower
to the mature stage. Developmental stage of fruit at the time of application was indexed by fruit diameter. Fruit were harvested
at maturity, the CM isolated enzymatically on an individual fruit basis and mass of CM per unit fruit surface area calculated.
In mature fruit, mass of CM per fruit increased with fruit size, but mass of CM per unit surface area was independent of fruit
size, position within a truss and position of the truss on the plant. GA4+7 and GA3 increased CM mass per unit fruit surface area at concentrations up to 300 mg l−1. Young fruit (5–10 mm diam. at time of application) was most responsive. Responsiveness decreased as fruit development at
application progressed towards maturity. There was no consistent effect of GA4+7 or GA3 on fruit mass. BA (up to 100 mg l−1) or CPPU (up to 3 mg l−1) had no significant effect on CM mass per unit surface area regardless of developmental stage. Higher concentrations of BA
or CPPU decreased CM mass per unit surface area. There was no effect of BA or CPPU on fruit mass. Potential mechanisms and
benefits of a gibberellin induced increase in CM deposition are discussed. 相似文献
20.
H. J. Carlisle T. G. Hales B. A. Schlinger 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1998,182(4):531-538
Songbirds are widely studied to investigate the hormonal control of behavior. However, little is known about the effects
of steroids on neurotransmission in these birds. We used electrophysiological and pharmacological techniques to characterize
γ-aminobutyric acid (GABA) type A receptors (GABAA) of primary cultured telencephalic and hippocampal neurons from developing zebra finches. Additionally, their modulation
by 17β-estradiol(E2), 5α- and 5β-dihydrotestosterone (DHT), 5α- and 5β-pregnan-3α-ol-20-one, and corticosterone was examined. Whole-cell GABA-evoked
currents were inhibited by picrotoxin (10 μmol l−1) and bicuculline methiodide (10 μmol l−1) and potentiated by pentobarbital (100 μmol l−1) and propofol (3 μmol l−1). Loreclezole (10 μmol l−1) potentiated GABA-evoked currents, suggesting the presence of β2, β3 and/or β4 subunits. Diazepam (1 μmol l−1) potentiated currents, while Zn2+ (1 μmol l−1) caused no inhibition, indicating the presence of γ subunits. 5α- and 5β-Pregnan-3α-ol-20-one (100 nmol l−1) potentiated currents, whereas E2 (1 μmol l−1), 5α- and 5β-DHT (1 μmol l−1), and corticosterone (10 μmol l−1) had no detectable effect. We conclude that zebra finch telencephalic and hippocampal GABAA receptors include α, β, and γ subunits and are similar to their mammalian counterparts in both their biophysical and pharmacological
properties. Additionally, GABA-evoked currents are greatly potentiated by 5α- and 5β-pregnan-3α-ol-20-one but show little
or no acute modulation by sex steroids or corticosterone.
Accepted: 12 November 1997 相似文献