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1.
2.
Initiation of somatic embryogenesis in Pinus banksiana,
P. strobus, P. pinaster, and P. sylvestris at three laboratories
in Canada and France 总被引:1,自引:0,他引:1
Y. S. Park M. A. Lelu-Walter L. Harvengt J. F. Trontin I. MacEacheron K. Klimaszewska J. M. Bonga 《Plant Cell, Tissue and Organ Culture》2006,86(1):87-101
During 2002–2004, three laboratories in Canada and France collaborated to improve initiation of somatic embryogenesis (SE) in jack pine (Pinus banksiana Lamb.), eastern white pine (P. strobus L.), maritime pine (P. pinaster Ait.), and Scots pine (P.␣sylvestris L.), giving particular attention to the effects of (1) N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU) versus various concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and benzyladenine (BA), (2) differences in basal nutrient media, i.e., macro- and microelements, and (3) gelling agent concentration. The work was carried out separately at␣each laboratory, but the details of media compositions were shared and tested on their respective species. Results indicate that the developmental stage of the zygotic embryo (ZE) and genotype effects had a large influence on SE initiation, and that genetic effects were consistent over time. Different species responded differently to PGR types and concentration, basal nutrient media, trace elements, and their combinations. Currently, our best initiation rates based on a selected group of genotypes, optimal development stage of ZE, and medium are 3.9% for jack pine, 54.6% for eastern white pine, 76.2% for maritime pine, and 19.7% for Scots pine. 相似文献
3.
Use of Acadian marine plant extract powder from Ascophyllum nodosum in tissue culture of Kappaphycus varieties 总被引:1,自引:0,他引:1
Anicia Q. Hurtado Dianne Aster Yunque Keneth Tibubos Alan T. Critchley 《Journal of applied phycology》2009,21(6):633-639
Three varieties of Kappaphycus alvarezii (Kapilaran, KAP), Tambalang purple (PUR), Adik-adik (AA), and one variety of Kappaphycus striatum var. sacol (green sacol (GS) were used to determine the efficiency of Acadian marine plant extract powder (AMPEP) as a culture medium
at different concentrations, for the regeneration of young plants of Kappaphycus varieties, using tissue culture techniques for the production of seed stock for nursery and outplanting purposes for the
commercial cultivation of carrageenophytes. A shorter duration for shoot formation was observed when the explant was treated
with AMPEP + Plant Growth Regulator (PGR = PAA + zeatin at 1 mg L−1) compared to AMPEP when used singly. However, four explants responded differently to the number of days required for shoot
formation. The KAP variety took 46 days to form shoots at 3–4 mg L−1 AMPEP + PGR; while PUR required 21 days at 3–5 mg L−1 AMPEP and 3–4 mg L−1 AMPEP + PGR. AA required 17 days at 3–5 mg L−1 AMPEP and AMPEP + PGR; and GS 25 days at 1 mg L−1 AMPEP + PGR. It was observed that among the four explants used, PUR and AA initiated shoot formation with the use of AMPEP
only at higher concentrations (3–5 mg L−1) after a shorter period. Only PUR responded positively to ESS/2 for shoot initiation. The use of AMPEP alone and/or in combination
with PGR as a culture medium in the propagation of microplantlets using tissue culture technique is highly encouraging. 相似文献
4.
E.I. Hamadina P.Q. Craufurd N.H. Battey R. Asiedu 《The Annals of applied biology》2010,157(2):203-212
Dormancy is a mechanism that regulates the timing of sprouting (germination) of affected plant parts as well as ensures that the food quality of edible parts is maintained in storage until the following growing season. In yam, however, little is known about the control of tuber initiation or tuber dormancy. The objective of this study was to determine the effects of selected plant growth regulators (PGRs) on tuber initiation and dormancy, using an in vitro system. In two replicated experiments, 2-chloroethylphosphonic acid (ethephon, an ethylene source), abscisic acid (ABA) and gibberellin (GA3) – and their inhibitors silver nitrate, fluridone and 2-chloroethyl-trimethylammonium chloride, respectively – were added at two concentrations to the culture medium prior to explant culture. Dates of micro-tuber initiation and sprouting (end of dormancy) and tuber number were recorded. In the control (no PGR) in Experiment 1, micro-tubers were initiated at the base of the stem after 176 days and sprouted 235 days later, that is 411 days after culturing. Most PGR treatments had only small effects (±30 days) on the duration of dormancy and the time of micro-tuber initiation. However, in GA3 micro-tuber initiation occurred after 76 days, about 100 days earlier than in the control, whereas fluridone affected the position of micro-tubers and duration of dormancy. With fluridone treatments, tubers were found at the base of the stem (normal position) and on lower and upper nodes. Lower node tubers sprouted within 225 days of culturing compared with about 420 days after culturing at other nodal positions and in other PGR treatments. These data suggest an important role for ABA and gibberellic acid in yam micro-tuber initiation and the induction of dormancy. 相似文献
5.
Optimized somatic embryogenesis in Pinus strobus L. 总被引:5,自引:0,他引:5
Krystyna Klimaszewska Yill-Sung Park Cathy Overton Ian Maceacheron Jan M. Bonga 《In vitro cellular & developmental biology. Plant》2001,37(3):392-399
Summary Somatic embryogenesis (SE) initiation in Pinus strobus was optimized by the manipulation of plant growth regulator (PGR) concentrations in the culture medium. Modified Litvay medium
(MLV) of Litvay et al. (1985) supplemented with lower than routinely used PGR concentration increased initiation of established
embryogenic cultures from approximately 20 to 53%. The original developmental stage of zygotic embryos had a pronounced effect
on the SE response. The optimum stage was the pre- to shortly post-cleavage stage. A substantial genetic influence on initiation
of SE was indicated by a significant variance component due to families. Genotype X collection date and genotype X media interactions
had large effects on initiation of SE. The PGR levels in the culture medium prior to maturation had a significant effect on
subsequent production of mature somatic embryos. Embryogenic tissue initiated and proliferated on medium with a low level
of PGR consistently produced a high number of somatic embryos, indicating that optimized initiation protocol also enhanced
somatic embryo production. Somatic embryos of 93 embryogenic lines (representing five families) that were initiated on media
with different PGR concentrations were converted to plants at an overall frequency of 76%, and grown in the greenhouse. With
these improved protocols, application of P. strobus SE in commercial clonal forestry is feasible as an alternative to traditional breeding and reforestation. 相似文献
6.
Dianne Aster T. Yunque Keneth R. Tibubos Anicia Q. Hurtado Alan T. Critchley 《Journal of applied phycology》2011,23(3):433-438
To improve the production of Kappaphycus plantlets in tissue culture, optimum media concentrations of an Ascophyllum nodosum extract (Acadian Marine Plant Extract Powder, AMPEP), plant growth regulators (PGR), pH–temperature combinations, and explant
density were determined. Kappaphycus alvarezii var. tambalang purple (PUR), kapilaran brown (KAP), vanguard brown (VAN), adik-adik (AA), tungawan green (TGR), and K. striatum var. sacol green (GS) were used as explants. Based on the shortest period for shoot emergence and the economical use of AMPEP, the optimum
enriched media was 3.0 mg L−1 AMPEP and 0.1 mg L−1 AMPEP + PGR 1 mg L−1 each phenylacetic acid (PAA) and zeatin for PUR, 1.0 mg L−1 AMPEP + PGR for KAP and GS, 0.1 mg L−1 AMPEP + PGR for VAN, and 3.0 mg L−1 AMPEP and 0.001 mg L−1 AMPEP + PGR for AA and TGR. Results showed that the addition of PGR to low concentrations of AMPEP hastened shoot formation.
pH–temperature combinations for the most rapid shoot formation were determined for the brown (KAP) and purple (PUR) color
morphotypes of K. alvarezii var. tambalang and the green morphotype of K. striatum var. sacol (GS) cultured in 1.0 mg L−1 AMPEP + PGR. The brown morphotype produced the most number of shoots at pH 7.7 at 20°C after as little as 20 days. Purple
K. alvarezii showed an increased shoot formation at pH 6.7 at 25°C and the green K. striatum morphotype at pH 8.7 at 25°C. The optimum number of explants added to the culture media was also determined for tungawan
green (TGR), brown (KAP), and tambalang purple (PUR) varieties of K. alvarezii in 1.0 mg L−1 AMPEP + PGR. The number of explants and the volume of the culture media combination were also tested. The highest average
number of shoots formed occurred in two explants:1 mL culture media (2:1) for KAP and PUR (35.00% and 16.67%, respectively)
and 1 explant: 2 mL culture media for the TGR (100.00%) with a range of 0.5–3.0 mm shoot length after 40 days in culture.
The earliest shoot formation was observed after 21 days for the brown and 9 days for both the green and purple color morphotypes
of Kappaphycus, in all densities investigated. This indicated that within the range tested, the density of explants did not have a significant
effect on the rate of shoot formation but did influence the average number generated from the culture. The rate of production
of new and improved Kappaphycus explants for a commercial nursery stock was improved through the use of AMPEP with optimized culture media pH, temperature,
and density conditions. 相似文献
7.
Youshi Tazoe Noriko Ishikawa Toshiharu Shikanai Keiki Ishiyama Daisuke Takagi Amane Makino Fumihiko Sato Tsuyoshi Endo 《The Plant journal : for cell and molecular biology》2020,103(2):814-823
C4 plants can fix CO2 efficiently using CO2‐concentrating mechanisms (CCMs), but they require additional ATP. To supply the additional ATP, C4 plants operate at higher rates of cyclic electron transport around photosystem I (PSI), in which electrons are transferred from ferredoxin to plastoquinone. Recently, it has been reported that the NAD(P)H dehydrogenase‐like complex (NDH) accumulated in the thylakoid membrane in leaves of C4 plants, making it a candidate for the additional synthesis of ATP used in the CCM. In addition, C4 plants have higher levels of PROTON GRADIENT REGULATION 5 (PGR5) expression, but it has been unknown how PGR5 functions in C4 photosynthesis. In this study, PGR5 was overexpressed in a C4 dicot, Flaveria bidentis. In PGR5‐overproducing (OP) lines, PGR5 levels were 2.3‐ to 3.0‐fold greater compared with wild‐type plants. PGR5‐like PHOTOSYNTHETIC PHENOTYPE 1 (PGRL1), which cooperates with PGR5, increased with PGR5. A spectroscopic analysis indicated that in the PGR5‐OP lines, the acceptor side limitation of PSI was reduced in response to a rapid increase in photon flux density. Although it did not affect CO2 assimilation, the overproduction of PGR5 contributed to an enhanced electron sink downstream of PSI. 相似文献
8.
David H. Levenson Paul J. Ponganis Michael A. Crognale Jess F. Deegan II Andy Dizon Gerald H. Jacobs 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2006,192(8):833-843
Rod and cone visual pigments of 11 marine carnivores were evaluated. Rod, middle/long-wavelength sensitive (M/L) cone, and short-wavelength sensitive (S) cone opsin (if present) sequences were obtained from retinal mRNA. Spectral sensitivity was inferred through evaluation of known spectral tuning residues. The rod pigments of all but one of the pinnipeds were similar to those of the sea otter, polar bear, and most other terrestrial carnivores with spectral peak sensitivities (λmax) of 499 or 501 nm. Similarly, the M/L cone pigments of the pinnipeds, polar bear, and otter had inferred λmax of 545 to 560 nm. Only the rod opsin sequence of the elephant seal had sensitivity characteristic of adaptation for vision in the marine environment, with an inferred λmax of 487 nm. No evidence of S cones was found for any of the pinnipeds. The polar bear and otter had S cones with inferred λmax of ∼440 nm. Flicker-photometric ERG was additionally used to examine the in situ sensitivities of three species of pinniped. Despite the use of conditions previously shown to evoke cone responses in other mammals, no cone responses could be elicited from any of these pinnipeds. Rod photoreceptor responses for all three species were as predicted by the genetic data.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
9.
N. S. Hart J. C. Partridge I. C. Cuthill A. T. D. Bennett 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2000,186(4):375-387
The spectral absorption characteristics of the retinal photoreceptors of the blue tit (Parus caeruleus) and blackbird (Turdus merula) were investigated using microspectrophotometry. The retinae of both species contained rods, double cones and four spectrally
distinct types of single cone. Whilst the visual pigments and cone oil droplets in the other receptor types are very similar
in both species, the wavelength of maximum sensitivity (λmax) of long-wavelength-sensitive single and double cone visual pigment occurs at a shorter wavelength (557 nm) in the blackbird
than in the blue tit (563 nm). Oil droplets located in the long-wavelength-sensitivesingle cones of both species cut off wavelengths
below 570–573 nm, theoretically shifting cone peak spectral sensitivity some 40 nm towards the long-wavelength end of the
spectrum. This raises the possibility that the precise λmax of the long-wavelength-sensitive visual pigment is optimised for the visual function of the double cones. The distribution
of cone photoreceptors across the retina, determined using conventional light and fluorescence microscopy, also varies between
the two species and may reflect differences in their visual ecology.
Accepted: 8 January 2000 相似文献
10.
Conserved role of PROTON GRADIENT REGULATION 5 in the regulation of PSI cyclic electron transport 总被引:2,自引:0,他引:2
There are at least two photosynthetic cyclic electron transport (CET) pathways in most C3 plants: the NAD(P)H dehydrogenase (NDH)-dependent pathway and a pathway dependent upon putative ferredoxin:plastoquinone
oxidoreductase (FQR) activity. While the NDH complex has been identified, and shown to play a role in photosynthesis, especially
under stress conditions, less is known about the machinery of FQR-dependent CET. Recent studies indicate that FQR-dependent
CET is dependent upon PGR5, a small protein of unknown function. In a previous study we found that overexpression of PGR5 causes alterations in growth and development associated with decreased chloroplast development and a transient increase in
nonphotochemical quenching (NPQ) after the shift from dark to light. In the current study we examine the spatiotemporal expression
pattern of PGR5, and the effects of overexpression of PGR5 in Arabidopsis under a host of light and stress conditions. To investigate the conserved function of PGR5, we cloned PGR5 from a species which apparently lacks NDH, loblolly pine, and overexpressed it in Arabidopsis. Although greening of cotyledons
was severely delayed in overexpressing lines under low light, mature plants survived exposure to high light and drought stress
better than wild-type. In addition, PSI was more resistant to high light in the PGR5 overexpressors than in wild-type plants, while PSII was more sensitive to this stress. These complex responses corresponded
to alterations in linear and cyclic electron transfer, suggesting that over-accumulation of PGR5 induces pleiotropic effects,
probably via elevated CET. We conclude that PGR5 has a developmentally-regulated, conserved role in mediating CET. 相似文献
11.
A. J. Sillman C. J. O'Leary C. D. Tarantino E. R. Loew 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1999,184(1):37-47
Scanning electron microscopy, microspectrophotometry, and spectrophotometry of digitonin extracts were employed to characterize
the photoreceptors and visual pigments of two freshwater Acipenseriformes. The retinas of the shovelnose sturgeon, Scaphirhynchus platorynchus (Acipenseridae), and the paddlefish, Polyodon spathula (Polyodontidae) are dominated by large rods with long, broad outer segments. A second rod, rare and much narrower than the
dominant rod, is present in Scaphirhynchus but not seen in Polyodon. The absorbance maximum of the visual pigment in the rods of Polyodon is near 540 nm; that of Scaphirhynchus near 534 nm. The retinas of both species contain substantial numbers of large, single cones, about 33% of the photoreceptors
in Scaphirhynchus; 37% in Polyodon. Scaphirhynchus cone pigments have absorbance maxima near 610 nm, 521 nm and 470 nm, respectively. Polyodon cone pigments absorb maximally near 607 nm and 535 nm, respectively. All visual pigments are based on vitamin A2. The data are compared to those from other Acipenseriformes and are discussed in terms of lifestyle and behavior.
Accepted: 7 October 1998 相似文献
12.
Robert Ornduff 《American journal of botany》1996,83(8):1006-1015
A progeny of the native Florida cycad Zamia integrifolia grown from seeds planted in 1986 was monitored until 1995 to record mortality and the nature and time of expression of primary and secondary sex characters. In addition to gender-specific cone morphologies, males and females differed in secondary sex characters such as age at first cone production, frequency of cone production, mean cone numbers in second and later coning episodes, and, in older plants, mean leaf and branch numbers. Gender differences expressed themselves at different stages in the life history: their nature and extent varied during the years following sexual maturation. By 1995, 46% of the plants in the progeny had died, most of them before producing cones. Prior to 1988 the mean leaf number of plants that died did not differ from that of survivors, but the mean leaf number of plants dying between 1988 and 1989 was 0.4 times that of the survivors during that period, suggesting reduced vigor prior to death. Mean age at first cone production was 5.8 yr for males and 6.6 yr for females. Mean dry masses of individual male cones increased between the first and second coning episodes, but not between the second and third coning episodes. Mean dry masses of the entire cone crop of individual males increased through the third coning episode due to an increase in mean cone number per episode, but mean cone number was unchanged between the third and fourth coning episodes. Mean dry mass of unpollinated female cones did not change between the first and second coning episodes; mean cone numbers did not change between the first and third coning episodes. After the first coning episode, males produced higher mean cone numbers than females. By 1995, the mean dry mass of an individual male's cone crop was greater than that of a female. Coning frequency of males was 1.7 times greater than that of unpollinated females, suggesting a gender difference in the genetic control of coning frequency. Coning frequency of females pollinated 1 or 2 yr previously was reduced compared with that of unpollinated females. Cone production did not affect subsequent leaf production by either gender. Mean leaf numbers increased in some years and not in others. Mean leaf numbers of males and females did not differ prior to cone production. After cone production mean leaf numbers of males were greater than of females. Mean age of males producing first branches was 6.3 yr, with a mean of 2.5 first branches per plant. Mean age of females producing first branches was 7.7 yr, with a mean of 2.5 first branches per plant. By 1995 the mean branch number of males was 5.7 per plant and of females was 2.7 per plant. Between 1993 and 1995 the mean branch number of males and females increased incrementally, but mean leaf numbers did not change. In early years of branching, leaf number increased with branch number; higher mean leaf numbers of males of an age class thus reflected their earlier branching. Males produced first cones earlier than females. Since branch production was associated with cone production, higher branch numbers of males in an age class reflected their earlier first cone production. In 1995 the sex ratio of known males and females in the progeny was 1:1, with a few individuals not having produced cones by that year. 相似文献
13.
Chronic herbivory negatively impacts cone and seed production,seed quality and seedling growth of susceptible pinyon pines 总被引:3,自引:0,他引:3
Although herbivory often reduces the reproduction of attacked trees, few studies have examined how naturally occurring insect-resistant
and susceptible trees differ in their reproduction, nor have these effects been experimentally examined through long-term
herbivore removals. In addition, few studies have examined the effects of herbivory on the quality of seeds produced and the
implications of reduced seed quality on seedling establishment. We evaluated the impact of chronic herbivory by the stem-boring
moth, Dioryctria albovittella, on cone and seed production of the pinyon pine (Pinus edulis) during two mast years. Three patterns emerged. First, moth herbivory was associated with reductions in cone production,
viable seed production and seed mass. Specifically, pinyons susceptible to moth attack had 93–95% lower cone production, and
surviving cones produced 31–37% fewer viable seeds, resulting in a 96–97% reduction in whole tree viable seed production.
In addition, surviving seeds from susceptible trees had 18% lower mass than resistant trees. Second, long-term experimental
removal of the herbivore resulted in increased rates of cone and seed production and quality, indicating that moth herbivory
was the driver of these reductions. Third, seed size was positively associated with seed germination and seedling biomass
and height, suggesting that trees suffering chronic herbivory produce poorer quality offspring. Thus, the resistance traits
of pinyons can affect the quality of offspring, which in turn may affect subsequent seedling establishment and population
dynamics. 相似文献
14.
The effects of gibberellic acid (GA3), kinetin (KIN), benzyladenine and ethylene (E) on mitotic activity and chromosomal aberrations in root tips of barley seeds
(Hordeum vulgare L. cv. “Bülbül 89”) germinated under salt stress were investigated. It was determined that all of these plant growth regulators
(PGRs) decreased mitotic index in root tips of barley seeds germinated at 20 °C and in distilled water. Furthermore, some
of the PGRs studied increased significantly the frequency of chromosomal aberrations. The frequency of chromosomal aberrations
in seeds treated with E and KIN was considerably higher than in the seeds germinated under nonstress conditions. The inhibitory
effect of salt stress on mitotic index increased with increasing salt concentration (0.30, 0.35, 0.40 and 0.45 molal, m).
GA3 and KIN pretreatments showed a successful performance in ameliorating the negative effects of increasing salinity on mitotic
activity. The number of chromosomal aberrations also increased with increasing NaCl concentration. However, most of the PGR
pretreatments studied alleviated the detrimental effects of increasing salinity on chromosomal aberrations. KIN pretreatment
at 0.30 and 0.35 m salinity could not rescued the cytogenetic activity of salt stress on this parameter. 相似文献
15.
Effect of activated charcoal and 6-benzyladenine on in vitro nitrogen uptake by Lagerstroemia indica 总被引:1,自引:0,他引:1
A sterile hydroponic culture system suitable for studying nitrogen (N) uptake ofLagerstroemia indica L.in vitro was developed. Four different treatments were assayed: with and without activated charcoal (AC and NAC, respectively), with
and without 50 μM of 6-benzyladenine (+BA and −BA, respectively). Medium pH, electrical conductivity (EC), NO3
− and NH4
+ concentrations were measured weekly. At the end of the culture, propagules were sampled and SPAD indices, and shoot and root
fresh weights were determined. Explants grown in media with activated charcoal were able to take up both NO3
− and NH4
+, although NH4
+ uptake was lower. Subsequently the pH of the media was maintained between 5.5–6.0. In treatments with no addition of activated
charcoal, NH4
+ uptake was preferential and the pH dropped to 3.1. Explants in these conditions were unable to raise the pH by taking up
NO3
−, especially when root morphogenesis was inhibited by addition of BA. Supply of this PGR produced root growth inhibition,
which was almost complete in the treatment without activated charcoal. This component significantly reduced the inhibitory
effect of 50 μM BA on root growth.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
16.
Susan M. Theiss Thomas J. Lisney Shaun P. Collin Nathan S. Hart 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2007,193(1):67-79
Relatively little is known about the physical structure and ecological adaptations of elasmobranch sensory systems. In particular,
elasmobranch vision has been poorly studied compared to the other senses. Virtually nothing is known about whether elasmobranchs
possess multiple cone types, and therefore the potential for colour vision, or how the spectral tuning of their visual pigments
is adapted to their different lifestyles. In this study, we measured the spectral absorption of the rod and cone visual pigments
of the blue-spotted maskray, Dasyatis kuhlii, using microspectrophotometry. D. kuhlii possesses a rod visual pigment with a wavelength of maximum absorbance (λmax) at 497 nm and three spectrally distinct cone types with λmax values at 476, 498 and 552 nm. Measurements of the spectral transmittance of the ocular media reveal that wavelengths below
380 nm do not reach the retina, indicating that D. kuhlii is relatively insensitive to ultraviolet radiation. Topographic analysis of retinal ganglion cell distribution reveals an
area of increased neuronal density in the dorsal retina. Based on peak cell densities and using measurements of lens focal length
made using laser ray tracing and sections of frozen eyes, the estimated spatial resolving power of D. kuhlii is 4.10 cycles per degree. 相似文献
17.
Summary A simple and efficient micropropagation method was established for direct protocorm-like body (PLB) formation and plant regeneration
from flower stalk internodes of a sympodial orchid, Epidendrum radicans. Small transparent tissues formed on surfaces and cut ends of flower stalk internodes on a modified half-strength Murashige
and Skoog basal medium with or without thidiazuron (TDZ) after 1–2 wk of culture. In the light, the transparent tissues enlarged
and turned into organized calluses on most of the explants. However, PLBs formed only on a medium supplemened with 0.45 μM TDZ within 2 mo. of culture. Sucrose, NH4NO3, and KNO3 were used in media to test their effects on PLB proliferation and shooting. The best response on number of PLBs per tube
was 23.6 at 40 gl−1 sucrose, 825 mgl−1 NH4NO3, and 950 mgl−1 KNO3, and the highest number of PLBs with shoots was found at 10 gl−1 sucrose, 825 mgl−1 NH4NO3, and 950 mgl−1 KNO3. Homogenized PLB tissues produced by blending were used to test the effects of four cytokinins [TDZ, N6-benzyladenine (BA), zeatin-riboside, and kinetin] on PLB proliferation and shoot formation. The best responses on number
of PLBs per tube, proliferation rate, and number of PLBs with shoots per tube were obtained at 4.44 μM BA, 0.28 μM zeatin-riboside, and 1.39 μM kinetin, respectively. Normal plantlets converted from PLBs on the same TDZ-containing medium after 1 mo. of culture. The
optimized procedure required about 12–13 wk from the initiation of PLBs to plantlet formation. The regenerated plants grew
well with an almost 100% survival rate when acclimatized in a greenhouse. 相似文献
18.
Ivana Dragićević Radomir Konjević Branka Vinterhalter Dragan Vinterhalter Mirjana Nešković 《Plant Growth Regulation》2008,54(3):189-193
Potato (Solanum tuberosum cv. Désirée) shoots grown in vitro in continuous darkness or in long days (LDs), were used to investigate indole-3-acetic
acid (IAA) effects on stolon initiation and tuber formation, combining IAA with increased or decreased gibberellin levels.
An increased gibberellin (GA) level was achieved by the applying 1 μM GA3, while decreased gibberellin level was presumably realized by the adding 3 μM tetcyclacis (Tc). About 15% of potato shoots
developed stolons both in LDs and in darkness. Stolon initiation was stimulated by GA3 in darkness and by Tc in LDs. Tuber formation was strongly inhibited in LDs and by GA3 both in light and darkness, but stimulated in darkness at low GA level. Exceptionally, tuber formation occurred in LDs at
the highest Tc concentrations, in about 25% of explants. Indole-3-acetic acid alone stimulated stolon formation in LDs, both
in the presence or absence of GA3. IAA alone also stimulated tuber formation in dark-grown shoots, but could not overcome the inhibitory effect of LDs. Indications
that, depending on their concentration ratio, IAA may interact with GA3 in different tuberization phases, have been discussed.
Radomir Konjević—Deceased in July 2006. 相似文献
19.
Responses of the photosynthetic system and peroxidase activity to the rooting conditions of oak micropropagation 总被引:1,自引:0,他引:1
Király István Balla Ildikó Jakab Júlia Tamás László Sárvári Éva 《Plant Cell, Tissue and Organ Culture》2001,66(2):155-158
The effects of indole butyric acid (IBA) concentration and the duration of the plant growth regulator (PGR) treatment on the
rooting ability, peroxidase level and photosynthetic activity of young Quercus robur L. plants were studied. Four-week-old oak shoots were transplanted to rooting media supplemented with 10 or 20 μM IBA. After
2, 3, 4, 5 or 7 days the shoots were transplanted again to a fresh, PGR-free medium. On the tenth day after transfer to rooting
medium, the CO2 fixation capacity, pigment content and peroxidase activity were measured. The photosynthetic parameters varied as a function
of the time spent on medium containing PGR, showing maximum values in plants transplanted on the third to fourth day to PGR-free
medium. The rooting percentage of these plants reached its maximum within two weeks. However, peroxidase activity was the
highest in plants transferred later to PGR-free medium. The most pronounced stimulating effect on rooting was achieved with
the higher initial IBA concentration followed by a transfer to PGR-free medium on the third to fourth day. These plants showed
the highest vitality and the best rooting ability.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
20.
Lixia Chen Guoqing Tian Changxia Shao Everardo Cobos Weimin Gao 《Molecular biology reports》2010,37(7):3105-3110
Curcumin, a polyphenolic compound, is the active component of Curcuma longa and has been extensively investigated as an anticancer drug that modulates multiple pathways. Eukaryotic initiation factors
(eIFs) have been known to play important roles in translation initiation, which controls cell growth and proliferation. Little
is known about the effects of curcumin on eIFs in lung cancer. The objective of this study was to exam the curcumin cytotoxic
effect and modulation of two major rate-limiting translation initiation factors, including eIF2α and eIF4E protein expression
levels in lung adenocarcinoma epithelial cell line A549. Cytotoxicity was measured by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium
bromide) assay and protein changes were determined by Western blot. A549 cells were treated with 0–240 μM curcumin for 4–96 h.
The inhibitory effects of curcumin on cytotoxicity were dose- and time-dependent (P < 0.001). The 50% inhibitory curcumin concentrations (IC50s) at 24, 48, 72, and 96 h were 93, 65, 40, and 24 μM, respectively.
Protein expressions of eIF2α, eIF4E, Phospho-4E-BP1 were down-regulated, while Phospho-eIF2α and Phospho-eIF4E were up-regulated
after A549 cells were treated with 20 and 40 μM curcumin for 24 h. In addition, the effects of curcumin on these protein expression
changes followed a significant dose-response (P < 0.05, trend test). These findings suggest that curcumin could reduce cell viability through prohibiting the initiation
of protein synthesis by modulating eIF2α and eIF4E. 相似文献