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1.
An 18-h treatment of synchronously-grown Chlorella pyrenoidosawith 2,4-D did not significantly alter the size, dry weight,degree of synchrony, or pigment content of the cells, nor weredetectable quantities of ethylene produced. When Chlorella pyrenoidosawas treated with 5?104 M 2,4-D, there was a statisticallysignificant stimulation of both net oxygen uptake and productionwhile 5?10 M 2,4-D inhibited both processes. When Chlorellapyrenoidosa was treated with 5?104 M and 5?103M 2,4-D, significantly greater amounts of glycollate were presentin the culture medium, even though an assay for glycollate dehydrogenaseshowed that the activity of this enzyme from 2,4-D-treated Chlorellapyrenoidosa was three times greater than in control cells. Looselybound 2,4-D was partitioned from a nonaqueously isolated chloroplastfraction, while other cell fractions failed to show detectablequantities of 2,4-D. It is postulated that in Chlorella pyrenoidosathe chloroplast is a target for 2,4-D action and that interferencein photorespiratory processes may underlie the observed responses. 相似文献
2.
Cellus induction was observed from Jerusalem artichoke tubertissue on a synthetic medium containing 2,4-D at 106,105 (optimum conc.) and 104 M. The first DNA synthesis(thymidine incorporation) was observed only at 2,4-D concentrationsof 105 to 104M. In 105 M 2,4-D treatedtissue, DNA synthesis increased after a 20 hr lag and reacheda maximum at 36 hr, after which it decreased. Actinomycin Dand 8-aza-guanine; inhibitors of RNA synthesis, inhibited DNAsynthesis completely. 2,4-D caused the characteristic changesin RNA and protein syntheses. In comparison with the control,RNA and protein syntheses were first repressed then inducedbefore the peak of DNA synthesis. Treatment with cycloheximide(104M) for one hour before inoculation inhibited proteinsynthesis completely for 12 hr; consequently DNA synthesis wasalso delayed. The results suggest that RNA and protein synthesesneeded for callus induction are regulated by 2,4-D in the firstDNA synthesis. (Received July 19, 1973; ) 相似文献
3.
Suspension cultures of Oryza sativa L. var IR 20 grew in Murashigeand Skoog medium (MS) supplemented with 2,4-D and kinetin ina density-dependant manner with a critical minimum inoculation-densityof 10,000 cells ml1. Conditioned medium obtained fromthese cultures and added to MS+2,4-D+kinetin induced the growthof cultures at 1,000 cells ml1. Growth stimulation byconditioned medium was mimicked by spermidine but not by otherpolyamines viz. putrescine and spermine. This is the first reportof a polyamine substituting for conditioned medium in cultures.
2 Present address: Vice-Chancellor, Pondicherry University,Pondicherry 605 014, India. 相似文献
4.
Excised embryonic axes of Phaseolus vulgaris L. (var. WhiteMarrowfat) begin cell elongation after approximately 4 hr ofincubation at 26°C. The incorporation of 32P into nucleicacids and phenylalanine-l-14C into protein markedly increasesduring the 4th hr of incubation, prior to initiation of cellelongation. CH, which inhibits incorporation of phenylalanine-l-14C intoprotein by 93% during the 2nd hr after its addition, completelyprevents the initiation of axis elongation if added up to 2hr after the beginning of imbibition. Actinomycin D reducesthe fresh weight increase of the axes, and inhibits both 32Pincorporation into nucleic acids and phenylalanine-l-14C incorporationinto protein. 5-FU inhibits 32P incorporation into nucleic acidsbut not phenylalanine-l-14C incorporation into protein or thefresh weight increase of the axes. MAK column chromatography indicates that actinomycin D inhibitsthe synthesis of all types of nucleic acids to about the sameextent, while 5-FU almost completely inhibits the accumulationof 32P in ribosomal RNA with lesser but significant inhibitoryeffects on accumulation of 32P in tRNA. The results suggest an absolute requirement for protein synthesisprior to initiation of cell elongation and at least a partialrequirement for synthesis of nucleic acid species other thanribosomal RNA, tRNA and DNA. The kinetic data suggest that theaxes develop a greatly increased capacity for nucleic acid andprotein synthesis prior to initiation of axis elongation.
1This research was supported by NSF grant GB 4145 and a grantfrom the U. S. Forest Service. (Received December 16, 1968; ) 相似文献
5.
Mycclia of Neurospora crassa wild type (FE SC no. 853), harvestedduring the exponential phase of growth on defined minimal mediaincorporated glycine-2-14C, serine-3-14C and formate-14C intoproteins, DNA and RNA. Supplementing the growth medium with1 mM glycine increased the flow of glycine and formate carboninto these products. In contrast, this supplement decreasedthe incorporation of serine-14C. When such cultures were preincubatedfor 30 min with adenine, formaldehyde, formate or L-methionine,labelling of the nucleic acids and protein fractions by glycine-2-14Cwas altered. It is concluded that glycine increases the turnoverof C1 units in Neurospora, resulting in greater contributionsof the C-2 in nucleic acid and protein synthesis. (Received May 14, 1977; ) 相似文献
6.
Embryogenic callus cultures were initiated from mature embryosof Lasiurus scindicus on Murashige and Skoog's medium supplementedwith 6 mg l1 2,4-Dichlorophenoxyacetic acid (2,4-D).These cultures were maintained on 2 mg l1 2,4-D. Plantletswere regenerated via somatic embryogenesis when the calli weretransferred onto hormone-free MS basal medium. Young plantswere successfully transplanted to pots and grown to maturityin a greenhouse. Grass, Lasiurus scindicus, Thar Desert, drought tolerant, somatic embryogenesis, plant regeneration 相似文献
7.
The Regulation of Synthesis of Phenolics in Stationary Phase Cell Cultures of Acer pseudoplatanus L.
The addition of 2/ (w/v) sucrose to stationary phase suspensioncultures of sycamore (Acer pesudoplatanus) in medium depletedof nitrogen and phosphorus leads to the accumulation of highlevels of phenolics after a 5 d lag period. Urea and 2,4-D inhibitthis accumulation of phenolics. Urea results in a stimulationin cell protein content coincident with phenolics in hibition,and leads to a substantial diversion of the common precursorphenylalanine from phenolics synthesis into protein synthesis.2,4-Dichlorophenoxyacetic acid (2,4-D) does not lead to proteinaccumulation since the cultures are nitrogen-limited, but stimulatesan increase in protein turnover coincident with phenolics inhibition.The role of protein synthesis in the regulation of phenolicsmetabolism through competition for common precursors is discussed. 相似文献
8.
Embryogenic callus was induced from immature inflorescence segmentsof Java citronella (Cymbopogon winterianus) and maintained for2 years on Murashige and Skoog's medium supplemented with 2,4-D(l mg l1). The callus cells retained the original chromosomenumber of 2n = 20. The somatic embryos germinated into plantletson MS basal medium or medium with IAA, NAA, BAP or KN individually(l mg l1). The regenerated plantlets developed a goodroot system on full strength solid MS inorganics medium withIAA (1 mg l1). The regenerated plants were similar tothe donor plant in morphology and had the same chromosome number,but showed some variation in the essential oil content. Java citronella, Cymbopogon winterianus, somatic embryogenesis, regeneration, inflorescence culture 相似文献
9.
Somatic Embryogenesis and Plant Regeneration from Cultured Leaf Explants of Zea mays 总被引:4,自引:0,他引:4
Young leaf segments of Zea mays L. seedlings were cultured onMurashige and Skoog's basal nutrient medium supplemented with2 mg l1 2, 4-D and sub-cultured on medium containing8 mg l1 2,4-D. Two types of callus tissues appearedembryogenicand non-embryogenic. The embryogenic callus tissue producednumerous somatic embryos which on transfer to media containinglow amounts of 2,4-D or ABA produced plantlets. Callus tissuesexhibited embryogenic potential for more than 1 year. Zea mays L. cv. Ageti-76, Zea mays L. cv. N-L-D-Comp., maize, leaf, callus, somatic embryogenesis, regeneration 相似文献
10.
Somatic Embryogenesis from Clonal Leaf Tissues of Cassava 总被引:3,自引:0,他引:3
Leaf lobes were isolated from palmate leaves of clonal cassava(Manihot esculenta Crantz) material growing in vitro or in glasshouseconditions and subjected to a two-stage culture procedure involvingincubation on Murashige and Skoog (MS2) basal medium supplementedwith 212 mg l1 2,4-D for 20 d (Stage I) beforetransfer to MS2 basal medium supplemented with 0.01 mg l12,4-D and 0.1 mg l1 6-benzylamino purine (BAP) (StageII medium). Embryogenetic tissues, foliose structures and somatic embryosdeveloped from leaf lobes at all Stage I 2,4-D concentrations,except on those explants isolated from shoot-tip cultures incubatedon MS2 basal medium supplemented with 0.1 mg l1 NAA and1.0 mg l1 BAP. Leaf lobes isolated directly from glasshouse plants showed optimalembryogenetic competence when subjected to a Stage I cultureperiod of 17 d, although foliose structure initiation was optimalwith shorter Stage I durations. Leaf lobes of 24 mm lengthand those isolated from phyllotaxic leaf numbers 4 and 5 showedthe greatest embryogenetic competence. Manihot esculenta, cassava, somatic embryogenesis, tissue culture, morphogenetic competence 相似文献
11.
Auxin and heat shock activation of a novel member of the calmodulin like domain protein kinase gene family in cultured alfalfa cells 总被引:14,自引:3,他引:11
Davletova S Mészáros T Miskolczi P Oberschall A Török K Magyar Z Dudits D Deák M 《Journal of experimental botany》2001,52(355):215-221
A calmodulin like domain protein kinase (CPK) homologue wasidentified in alfalfa and termed MsCPK3. The full-length sequenceof cDNA encoded a 535 amino acid polypeptide with a molecularweight of 60.2 kDa. The deduced amino acid sequence showed allthe conserved motifs that define other members of this kinasefamily, such as serine-threonine kinase domain, a junction regionand four potential Ca2+-binding EF sites. The recombinant MsCPK3protein purified from E. coli was activated by Ca2+and inhibitedby calmodulin antagonist (W-7) in in vitro phosphorylation assays.The expression of MsCPK3 gene increased in the early phase ofthe 2,4-D induced alfalfa somatic embryogenesis. Heat shockalso activated this gene while kinetin, ABA and NaCl treatmentdid not result in MsCPK3 mRNA accumulation. The data presentedsuggest that the new alfalfa CPK differs in stress responsesfrom the previously described homologues and in its potentialinvolvement in hormone and stress-activated reprogramming ofdevelopmental pathways during somatic embryogenesis. Key words: Medicago sativa, CPK, stress, 2,4-D, phosphorylation, somatic embryogenesis. 相似文献
12.
Omission of 2,4-dichlorophenoxyacetic acid (2,4-D) from batchcultures of sycamore produced an immediate reduction in ratesof cell division and eventually in rates of biomass accumulation.The sequential responses of a chemostat and of turbidostat culturessubjected to gradual withdrawal of 2,4-P were: (i) a transientincrease in biomass accumulation, (ii) increased accumulationof p-coumaric acid, flavonoids, and lignin, (iii) increasedcell aggregation, (iv) reduced rates of cell division, and (v)death. During stepwise reduction of 2,4-D supplied to turbidostatcultures, rates of 2,4-D uptake were reduced when the spentmedium concentration fell to 3?51?0 ? 107 M. Underthese conditions the 2,4-D concentration in soluble and insolublecell fractions declined. The growth responses were correlatedwith the spent-medium 2,4-D concentration but not with its concentrationin the intracellular fractions. 相似文献
13.
Ethylene and Ethane Production in 2,4-D Treated and Salt Treated Tobacco Tissue Cultures 总被引:1,自引:0,他引:1
Gas chromatography was used to measure ethylene (ethene) andethane production by tobacco (Nicotiana tabacum cv. Wisconsinno. 38) callus tissues grown on media containing inorganic saltsaccording to Murashige and Skoog (1962), sucrose, myo-inositol,thiamine-HCl kinetic according to Linsmaier and Skoog (1965),and either 2,4-dichiorophenoxyacetic acid (2,4-D) in the range0100 mgl1 or 2 mgl1 indoi-3-ylacetic acidplus NaCl in the range 0200 Meq l1. Ethylene productionrates were high (> 500 nl h1 g1 fresh weight)initially in all treatments. Subsequently, ethylene productiondeclined in rapidly growing cultures but remained high in moderatelyand severely 2,4-D (> 0·5 mgl1) stressed andin severely NaCl (150 Meql1) stressed cultures. Highinitial rates of ethane production (> 200 nl h1 g1fresh weight) were obtained under conditions of severe stresscaused by 2,4-D or NaCl but not in control or moderately inhibitedcultures. With further incubation ethane production declinedin the severely stressed cultures. It is concluded that ethyleneproduction can be used as an index of moderate 2,4-D stressand severe NaCl stress by virtue of the high persisting ratesof ethylene production in stressed cultures. Ethane productioncan be used as an early index of severe stress caused by either2,4-D or NaCl in vitro. Nicotiana tabacum L., tobacco, ethylene, ethenen, ethane, 2,4-dichlorophenoxyacetic acid, auxin, stress, callus tissue 相似文献
14.
Characterization of Intravacuolar Pigmented Structures in Anthocyanin-Containing Cells of Sweet Potato Suspension Cultures 总被引:2,自引:0,他引:2
Nozue Masayuki; Kubo Hiroyoshi; Nishimura Mikio; Katou Akira; Hattori Chiho; Usuda Nobuteru; Nagata Tetsuji; Yasuda Hitosi 《Plant & cell physiology》1993,34(6):803-808
Intravacuolar pigmented structures occurred in anthocyanin-producingcultured cells of sweet potato (Ipomoea batatas) were characterized.Formation of the pigmented structures in sweet potato cellswas induced by transfer of callus cultured in 2,4-D containingagar medium into 2,4-D free liquid medium under continuous illumination.These structures were found in the vacuoles. The pigmented structureswere isolated from the protoplasts by precipitation in 60% (w/w)sucrose after centrifugation. Electron microscopic observationsof the anthocyanin-containing cultured cells showed these structureshad neither membrane boundary nor internal structures, and werefound as strongly osmiophilic globules in vacuoles. Numeroussmall osmiophilic globules were observed in central vacuolesat the early stage of anthocyanin accumulation, but not foundin cytoplasm. Similar pigmented structures in vacuoles werealso formed by treatment with neutral red. These observationsindicate that these pigmented structure is the high densityand insoluble globules highly concentrated with anthocyanin,which was synthesized in cytoplasm and transported to the centralvacuoles.
4Present address: Department of Cell Biology, National Institutefor Basic Biology Myodaijicho, Okazaki, 444 Japan 相似文献
15.
Embryogenic cell suspension cultures were established from calliderived from young leaves of sugarcane (Saccharum officinarumL.) by placing them in liquid medium containing 5 per cent coconutwater (CW), 23 mg 11 2, 4-D and 500 mg 11casein hydrolysate (CH). The cultures were maintained by transferring2.55.0 ml of the suspension to 35 ml of fresh mediumevery 45 days. Organized structures resembling the earlystages of embryogeny were formed when 2, 4-D in the medium waslowered (0.11.0 mg 11) but these did not developbeyond the globular or early scutellar stages. High levels ofsucrose (610 per cent) promoted the formation of proembryoids.Plating of the suspension on MS agar medium supplemented with0.252.0 mg 11 2, 4-D, 5 per cent CW, 500 mg 11CH, with or without activated charcoal, resulted in the formationof embryogenic calli. A large number of embryoids were formedin media containing lower 2, 4-D concentrations. Transfer ofembryoids to half-strength MS medium with 6 per cent sucroseestablished plantlets which were successfully transferred tosoil. Saccharum officinarumL, sugarcane, suspension culture, embryogenesis, regeneration 相似文献
16.
An auxin-binding protein (ABP-II) was purified from the extractof etiolated mung bean seedlings by affinity chromatographyon 2,4-D-linked Sepharose 4B and by gel filtration on Sepharose4B and Sephacryl S-200. The molecular weight was estimated tobe about 190,000 by gel filtration on Sephacryl S-200. ABP-IIgave a single band corresponding to a molecular weight of about48,000 on SDS-polyacrylamide gel electrophoresis. The dissociationconstants of ABP-II for 2,4-D determined by amrnonium sulfateprecipitation and equilibrium dialysis were 9.5?106 Mand 1.1?105 M, respectively. 14C-2,4-D-binding to ABP-IIwas reversible and inhibited by addition of IAA, naphthalene-1-aceticacid, 2,4,5-trichlorophenoxyacetic acid or p-chlorophenoxyisobutylicacid to the assay mixture. (Received September 5, 1984; Accepted November 5, 1984) 相似文献
17.
Purification and Properties of an Auxin-Binding Protein from the Shoot Apex of Peach Tree 总被引:2,自引:0,他引:2
Ohmiya Akemi; Kikuchi Motoyuki; Sakai Shingo; Hayashi Tateki 《Plant & cell physiology》1993,34(2):177-183
A soluble auxin-binding protein was purified from the shootapices of peach trees by chromatography on columns of CM-Toyopearl,Sephacryl S-200, 2,4-D-linked-Sepharose 4B and ConA-Sepharose.The molecular mass of the purified protein was estimated tobe about 100 kDa. After electrophoresis on a denaturing gel,the protein gave a single band with a molecular mass of 20 kDa.From Scatchard analyses, the dissociation constant for 2,4-Dwas calculated to be 4.1 105 M and the specific bindingof 2,4-D at saturating concentration was 42 nmol (mg protein)1.The binding of [14C]-2,4-D to the protein was reversible andwas inhibited by IAA, 1-naphthylacetic acid and p-chlorophenoxyisobutyricacid. (Received June 25, 1992; Accepted October 20, 1992) 相似文献
18.
Wheat Callus Culture: the Initiation, Growth and Organogenesis of Callus Derived from Various Explant Sources 总被引:2,自引:0,他引:2
Callus was obtained from mature excised embryos of wheat, fromnodal and internodal stem segments and from rachis segmentsusing the medium of Murashige and Skoog(1962)(M medium), containing1-0mg l1 2,4-D, and from immature embryos using the mediumof Green and Phillips (1975) containing 2 mg l1 2,4-D.Callus yield from mature embryos depended upon the cultivarused. No callus could be obtained from leaf segments. Callusderived from mature embryos and nodal stem segments was successfullymaintained by serial sub-culture on the M medium containing2,4-D for up to 3 years although its growth rate declined toa lower level as culture proceeded. Such cultures consistently produced roots when transferred toa medium containing a low level of 2,4-D or no 2,4-D. The presenceof the auxin was essential for continued proliferation of thecallus tissue. Shoot initiation was infrequent, did not occurafter the first few sub-cultures and could not be enhanced byvarious auxin and cytokinin additions to the medium. Callusderived from immature embryos did not have an enhanced potentialfor shoot initiation. Triticum aestivum, wheat, callus culture, organogenesis 相似文献
19.
UV-A* irradiation caused increases in total protein in Fusariumsolani, while its effect on Alternaria alternata was variable,and not as clear-cut as in F. solani. On the other hand, UV-Birradiation stimulated protein production in both fungi. UV-Airradiation showed an inhibitory effect on total DNA in bothfungi, while the effect on RNA was stimulatory in F. solanibut had no effect on A. alternata. Short fluences of UV-B inhibitedDNA production to some extent in both fungi, however longerfluences increased DNA content especially in F. solani. Theeffect of UV-B on RNA production was inhibitory in F. solanibut not in A. alternata. A. alternata is much more resistantto UV-irradiation than is F. solani, and increases in proteinin the former after UV-irradiation suggests that protein mayplay a part in protection against the harmful effect of UV-irradiation. UV-A, UV-B, fluence, protein, nucleic acids, Alternaria alternata, Fusarium solani 相似文献
20.
The growth of Escherichia coli strain B in a liquid medium wasfound to cease at a cell density of 5x109 cells per ml. (Thiscritical concentration is designated as the maximum or M-concentration.)Even cells harvested from the logarithmic growth phase couldnot divide at this or higher cell densities. Investigationson the metabolic activities of such cultures, however, showedthat the synthesis of cellular protein and nucleic acid wastaking place under such circumstances, showing that only someprocess (or processes) particularly related to cell divisionwas suppressed at the critical cell concentration in question. This finding led us to devise a new method of synchronizationof E. coli: cells harvested from a logarithmic phase were preincubatedat the critical concentration of 5x109 cells per ml for 45 minutes,and then diluted 100 times with fresh medium. This led to synchronizationof cell division, as shown by a stepwise multiplication in cellnumber. (Received June 20, 1961; ) 相似文献