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1.
Pith callus tissues were grown under continuous blue (450 mµ),green (545 mµ), red (650 mµ), and white(full-spectrum) light, and in the dark for 22 days at 27±2°C at energy levels of 15,000 ergs cm2 sec1. Mean increases in fresh weight of tissues grown under whiteand blue light were significantly greater than those of tissuesgrown in green and red light and in the dark. Tissues grownin the dark yielded mean fresh weight increases significantlylower than tissues grown under blue, red, and whitelight. No significant differences were shown between blue andwhite, red and green, and green and dark treatmentsrespectively. Cell differentiation occurred in all treatmentsonly to the extent of vessel element formation. There were nodifferences in degree of differentiation between treatments. It was proposed that the high-energy reaction of photomorphogenesiswas in operation in the Pelargonium callus tissue. The resultsindicated the presence in the tissue of high-energy photoreceptor(s).The use of high-intensity, incandescent illumination for experimentalprocedures approximating natural conditions of irradiation wasindicated as desirable for pith callus tissues of Pelargoniumzonale var. Enchantress Fiat. 相似文献
2.
KANAMORI-FUKUDA IKUKO; ASHIHARA HIROSHI; KOMAMINE ATSUSHI 《Journal of experimental botany》1981,32(1):69-78
Marked changes in the activity of the de novoand salvage pathways of pyrimidine biosynthesisduring growth of Vinca rosea cells in a batch suspension culturewere observed. The activity of these pathways was investigated by determiningthe contribution of 14C of [2-14Cluracil, 12-14Cluridine. and[6-14Clorotate to the cell constituents and by measuring theactivity of the several enzymes of these pathways. During the lag phase of the culture, uracil- anduridine-salvage pathways made the predominantcontribution to nucleotide biosynthesis, but, following theinitiation of cell division, the de novo pathwayfor nucleotide biosynthesis operated appreciably. These results suggest that nucleotide synthesis during cellgrowth in a suspension culture can be divided into two stages:a turnover stage, during the lag phase of cellgrowth, and a true biosynthetic stage, which isinitiated in the cell division phase. 相似文献
3.
The relationship between the induction of tracheary elementdifferentiation and exogenous L-methionine was examined in agar-growncultures of soya bean callus initiated from Glycine max L. Wayneand Clark 63. Although Wayne is a normal cultivarsoya bean, seedlings of Clark 63 exhibit abnormal growth at25 °C due to exessive ethylene biosynthesis at this temperature.Wayne callus showed increased xylogenesis in the presence ofexogenous L-methionine (3.7 µg 11) in comparisonto IAAKN controls at both 20 and 25 °C. Clark 63callus produced greater numbers of tracheary elements in responseto exogenous L-methionine only at 25 °C. The induction ofxylem differentiation was independent of the maintenance temperatureof the stock cultures of both cultivars. Xylogenesis initiatedbyan IAAKN medium was inhibited by the addition of AgNO3(20 mg 11) to the extent of 76.5 per cent in cv. Wayneand 6 per cent in cv. Clark 63. The inhibitory effect was partiallyreversed by the addition of L-methionine (3.7 µg 11)to the IAAKNAgNO2 medium. These data support thehypothesis that xylogenesis in vitro involves auxin, cytokininand ethylene. differentiation, xylogenesis, L-methionine, ethylene, Glycine max L., soya bean, callus culture, auxin, kinetin 相似文献
4.
Measurements of cavitation occurring in xylem conduits of differentstem parts in whole Chorisia insignis H.B. et. K. plants subjectedto water stress are reported. Pre-stressed plants were shownto undergo cavitation over 10 times greater than watered ones.The most vulnerable parts of plants were one-year-old twigswhere cavitation reached a peak of over 50 acoustic emissions(AE) min1 while in two-year-old twigs AE min1were about one half this value. Stem zones were found wherecavitation was typically very low even during water stress:these were one-year-old nodes and junctions where branches meet.Measurements of the inside diameters of xylem conduits and distributionof conduit ends in stem parts where AE were detected, showedthat nodes have a significantly larger percentage of narrowxylem conduits than internodes. Similar constricted zoneswere found injunctions with respect to two-year-old twigs. Hereabout 50 per cent of the xylem conduits were as narrow as 20to 50 µm in diameter. The distribution of xylem conduitends show about 3 per cent of them ending in the nodes and 1per cent in the internodes of one-year-old twigs. About 11.6per cent of xylem conduits end in the junctions and about ahalf in two-year-old internodes. Our data would give furtherexperimental evidence to the functional concept of plantsegmentation into zones (internodes) more efficient inwater conduction, i.e. with wider xylem conduits but more vulnerableto cavitation and others (nodes and junctions) with oppositecharacteristics. Chorisia insignis, acoustic emissions, water stress, nodes, internodes, xylem conduit size, vessel ends 相似文献
5.
The theory and practice of applying the thermodynamics of irreversibleprocesses to mass-flow theories is presented. Onsager coefficientswere measured on cut and uncut phloem and cut xylem strandsof Heracleum muntegazzimum. In 0.3 N sucrose + 1 mN KC1 theyare as follows. In phloem, LEE = 5 ? 104 mho cm1,LpE = 9 ? 106 cm3 s1 cm2 volt1 cm,and LPP = 0.16 cm3 s1 cm2 (J cm3)1cm. In uncut phloem strands LEE is about 1 ? 103 mhocm1. In xylem in 2 x 103 N KCI, Lpp = 50 to 225,LPE = 2 ? 104, and LEE = 4 ? 103. The measurementsare tentative since the blockage of the sieve plates is an interferingfactor, but if they are valid they lead to the conclusion thatneither a pressure-flow nor an electro-kinetic mechanism envisaginga long distance current pathway can be the majormotive force for transport in mature phloem. Measurementsof biopotentials along conducting but laterally detached phloembundles of Heracleum suggest, nevertheless, that there may bea small electro-osmotic component of at least 0.1 mV cm1endogenous in the phloem. 相似文献
6.
A Cytochrome P450 Mediated Naringenin 3'-Hydroxylase from Sweet Orange Cell Cultures 总被引:1,自引:0,他引:1
Doostdar Hamed; Shapiro Jeffrey P.; Niedz Randall; Burke M.D.; McCollum T. Gregory; McDonald Roy E.; Mayer Richard T. 《Plant & cell physiology》1995,36(1):69-77
A microsomal flavonoid 3'-hydroxylase (F3'H) catalyzing themetabolism of naringenin to eriodictyol in Citrus sinensis (L.)Osbeck cv. Hamlin cell suspension cultures wasshown to be a cytochrome P450 enzyme. This reaction requiredO2 and NADPH and was inhibited by CO, with partial reversalof CO-inhibition by light at 450 nm. Cytochrome P450 contentranged from 1020 pmol (mg microsomal protein)1.The F3'H reaction was shown to be linear in regard to proteinconcentration between 2.5 and 25 µg of microsomal protein.The optimum pH for the reaction was 7.47.6 and the temperatureoptimum was between 30 and 37°C. The apparent Km and Vmaxfor naringenin were 24 µM±3.2 and 81.4±7.9pmol eriodictyol min1 (mg protein)1, respectively.The microsomal F3'H was also capable of forming dihydroquercetinfrom dihydrokaempferol (40 pmol min1 (mg protein)1)and of quercetin from kaempferol (3.25 pmol min1 (mgprotein1). Cytochrome c and ketoconazole were the bestinhibitors of WH activity followed by piperonyl butoxide anda-naphthoflavone. Light was shown to be an inducer of the F3'Halmost doubling the specific activity and increasing the microsomalcytochrome P450 content by 30% over that of dark grown cells.F3'H activity was also confirmed in microsomal preparationsof young (new flush) leaves from Hamlin treesand flavedo of Hamlin oranges, Marshgrapefruit, and Lisbon lemon. No activity wasobserved in older, hardened leaves and albedo of all the fruittested. Initiation of embryogenesis in the Hamlincell suspension cultures by switching from a sucrose mediumto a glycerol-based medium resulted in the down-regulation ofF3'H.
1Mention of a trademark, warranty, proprietary product, or vendordoes not constitute a guarantee by the U.S. Department of Agricultureand does not imply its approval to the exclusion of other productsor vendors that may also be suitable. 相似文献
7.
This study was conducted with Lolium temulentum, Festuca pratensis,and the two hybrids L. multiflorum x F. pratensis Elmetand L. perenne x F. pratensis Prior. In a comparisonof various durations (742 d) of pretreatment at 4 or7 °C the highest yield of microspore-derived callus of L.temulentum was obtained after pretreatment of spikes at 7 °Cfor 28 d, conditions which also proved optimal for panicle pretreatmentwith F. pratensis. For Elmet, durations of 2142d were optimal, and for Prior the responses tendedto decline with increasing duration. In L. temulentum addition of charcoal (12 g l1)to medium containing 2, 4-D and KN wa 相似文献
8.
Whipple Stuart J.; Patten Bernard C.; Verity Peter G. 《Journal of plankton research》2005,27(5):495-501
Using well plates of Phaeocystis pouchetii colonies isolatedfrom experimental mesocosms in western Norway, increases incolony size and division were documented. Median longest lineardimensions increased 07 µm h1; literaturePhaeocystis globosa values are 0.94.7 µm h1.Ten to twelve percent of colonies divided at rates of 0.210.28divisions day1. Daughter colonies were 100 µm smallerthan mother colonies. Colonies delayed 3.54.9 days tofirst division, compared with literature values of 45days for P. globosa. This study provides the first experimentalevidence for colony division of wild P. pouchetii. 相似文献
9.
Nodulated 1-1.5-year-old plants of Acacia littorea grown inminus nitrogen culture were each partnered with a single seedlingof the root hemiparasite Olax phyllanthi. Partitioning of fixedN between plant organs of the host and parasite was studiedfor the period 48 months after introducing the parasite.N fluxes through nodules of Acacia and xylem-tapping haustoriaof Olax were compared using measured xylem flows of fixed Nand anatomical information for the two organs. N2 fixation duringthe study interval (635 µg N g FW nodules1 d1)corresponded to a xylem loading flux of 0.20 µg N mm2d1 across the secretory membranes of the pencycle parenchymaof the nodule vascular strands. A much higher flux of N (4891µg mm2 d1) exited through xylem at the junctionof nodule and root. The corresponding flux of N from host xylemacross absorptive membranes of the endophyte parenchyma of Olaxhaustorium was 1.15 µg N mm1 d1, six timesthe loading flux in nodules. The exit flux from haustorium toparasite rootlet was 20.0 pg N mm1 d1, 200-foldless than that passing through xylem elements of the nodule.Fluxes of individual amino compounds in xylem of nodule andhaustorium were assessed on a molar and N basis. N flux valuesare related to data for transpiration and partitioning of Cand N of the association recorded in a companion paper. Key words: Olax phyllanthi, host-parasite relationships, N flux, Acacia, N2 fixation 相似文献
10.
The layer of daytime concentration of Calanus ponticus (VC andVI C) performing daily vertical migrations and the layer ofwinter stock aggregation are confined to the depthof maximal gradient of the main pycnocline under an unusuallysharp oxycline. The concentration layer thickness ranges from2 to 2030 m and the Calanus concentration in it is >250ind. m3, sometimes being 3500 ind. m3 and evenmore. The population in the concentration layer is divided intotwo ecological groups: I, feeding and migrating specimens ofcopepodite stages V and VI, their body lipid contents being2560 µg min.1; and II, non-feeding and non-migratingspecimens of copepodite stage V, their body lipid contents being100150 µg ind.1. The relationship with oxygenconcentration was studied in both ecogroups. The experimentsshow that specimens of ecogroup II can exit at an oxygen concentrationof 0.06 ml 11, but at such concentration falling intoanabiosis. They die at 0.04 ml O2 11. Estimates of respirationof the group II specimens (winter stock) showthat lipids they store are sufficient for 7 months' survival.Depth of Calanus concentration is determined by water densityrather than concentration of oxygen. 相似文献
11.
《Journal of experimental botany》1977,28(6):1247
Effects of coupled solute and water flow in plant roots withspecial reference to Brouwer's experiment. Edwin L. Fiscus. p. 71 Abstract: Line 3 delete interval insertinternal. p. 73 Materials and Methods: line 6: delete diversion insert division line 9 equation should read Jv=Lp PRT(C0C1). 74 Last line of figure legend: 101 should read 1011. 75 Line 11: delete seems insert seem. le 1 column heading106 should read 1011. 77 delete ...membrane in series of... insert membranein series or... Delete final paragraph. 相似文献
12.
In this paper we report for the first time the occurrence ofan inducible weak CAM in leaves of Talinwn triangulare (Jacq.)Willd. This plant is a terrestrial perennial deciduous herbwith woody stems and succulent leaves which grows under fullexposure and in the shade in northern Venezuela. Plants grownin a greenhouse (sun plants) and a growth cabinet(shade plants) with daily irrigation showed CO2uptake only during the daytime (maximum rate, 4?0 µmolm2 s1) and a small acid accumulation during thenight (6?0 µmol H+g1 FW). Twenty-four hours aftercessation of irrigation, no CO2 exchange was observed duringpart of the night. Dark fixation reached a maximum (1?0 µmolCO2 m2 s1, 100 µmol H+ g1 FW) onday 9 of drought. By day 30 almost no gas exchange was observed,while acid accumulation was still 10 µmol H+ g1FW. Rewatering reverted the pattern of CO2 exchange to thatof a C3 plant within 24 h. Daytime and night-time phosphoenolpyruvatecarboxylase activity increased up to 100% (shade) and 62% (sun)of control values after 10 and 15 d of drought, respectively.Light compensation point and saturating irradiance were similarin well-watered sun and shade plants, values being characteristicof sun plants. CAM seems to be important for the tolerance ofplants of this species to moderately prolonged (up to 2 months)periods of drought in conditions of full exposure as well asshade, and also for regaining high photosynthetic rates shortlyafter irrigation. Key words: Talinum triwigulare, inducible CAM, PEP-C activity, recycling 相似文献
13.
Sixty-eight per cent of nuclei in the cells of the upper fourlayers of carrot slices treated with heat-killed conidia ofBotrytis cinerea for 6 h followed by inoculation with live sporesfor 18 h, migrated to the cell face nearest to the treated surface,compared with 46 per cent in cells of control slices showinga wound-healing response only. Nucleolar volumes in the surfacecell layers of control slices increased from a mean of 1.0 µm3to 3.8 µm3 over 24 h, and in induced slicesto 7.28 µm3. Using a 40 min pulse of [53H]uracil,there was an increase within 15 h of slicing in the number oflabelled nuclei in cells from control slices undergoing healing.Within 8 h after treatment of slice surfaces with heat-killedconidia, there was an accelerated incorporation of label intonuclear RNA. Slices from roots cold-stored for12 months failed to show an induction response and nucleolarvolumes did not increase more than in control slices. Theseresults are discussed in relation to active defence mechanismsin plant tissue. Botrytis cinerea, carrot, induced resistance, nuclear migration, nucleolar volume, RNA incorporation 相似文献
14.
The effect of the leafless mutation (in whichtendrils replace leaflets and the stipules are reduced to avestigial form) upon foliage area, photosynthetic net CO2 uptakepotential, dry matter production and seed yield in Pisum sativumwas studied by comparing two near-isogenic lines of genotypeafafstst and ++++. The mutation is of potential agronomic valuein that it offers improved lodging resistance, crop drying andharvester throughput. In the conventional phenotype the total foliage area of themain axis attained a plateau (456 cm2) at day 56 from seedlingemergence, whereas corresponding values for the leaflessmutant showed a total area of 208 cm2 at day 68 with no indicationof a plateau. The agronomic consequence of this is discussed.During the vegetative phase of the plant the maximum CO2 uptakepotential in the fully expanded conventional leaf was 8·5mg CO2 leaf1 h1 and in the leaflessmutant this value was 7·0 mg CO2 leaf1 h1.For most leaves of the latter phenotype this valuewas between 30 and 60 per cent less than for their conventionalcounterpart. There was a consistently higher photosyntheticpotential per unit area in tendrils of the leaflessmutant than in leaflets of the conventional phenotype. The respectivemean specific values for the two phenotypes were 53 and 37 mgCO2 dm2 h1. The problem of obtaining a meaningfulsurface area value for tendrils is discussed and the cylindricalnature of tendrils is taken into account. The leafless mutant consistently accumulated 50per cent less dry matter than did conventional plants in theperiod from seedling emergence to anthesis and yield of maturedry seed per plant showed a reduction of 50 per cent both inseed number and total seed weight. The implications for future breeding and selection programmesaimed at haulm reduction are discussed in relation to evaluatingthe ability of the background genotype to produce adequate tendrilsin the presence of afafstst. Triticum aestivum, wheat, callus culture, organogenesis 相似文献
15.
We report that growth of Dunaliella salina at either 13°C/150µmol m2s1 or 30°C/2,500 µmol m2s1 results in the accumulation of comparable levels ofcarotenoids and the zeaxanthin-binding protein, Cbr. We concludethat carotenoid and Cbr abundance in this green alga respondto changes in PSII excitation pressure ratherthan to high light per se. (Received September 19, 1996; Accepted November 20, 1996) 相似文献
16.
SINGH N; SINGH S N; SRIVASTAVA K; YUNUS M; AHMAD K. J; SHARMA S C.; SHARGA A N 《Annals of botany》1990,65(1):41-44
Five Gladiolus cultivars, namely Aldebaran, BrightEye, Illusion, Manisha andManmohan, were exposed to 1 and 2 µg l1sulphur dioxide to test their relative-sensitivity toleranceto the pollutant Plants were fumigated experimentally for 2h daily Foliar injury symptoms were observed first in Manishafollowed by Aldebaran and Illusionat the higher dose Photosynthetic pigments and leaf extractpH were significantly decreased, particularly in Manishaand Illusion Overall disturbances in the plantmetabolism due to SO2 treatment led to retarded growth of plants,as evident from decreased shoot length and phytomass valuesThe order of sensitivity of the five Gladiolus cultivars toSO2 was as follows, with the greatest first Manisha, Illusion,Aldebaran, Bright Eye, Manmohan Cultivars, Gladiolus, sensitivity, sulphur dioxide, tolerance 相似文献
17.
Koike Kazuhiko; Horie Yoshifumi; Suzuki Toshiyuki; Kobiyama Atsushi; Kurihara Kenji; Takagi Kenji; Kaga Shin-Nosuke; Oshima Yasukatsu 《Journal of plankton research》2006,28(1):103-112
In 2003, an occurrence of the yessotoxin (YTX)-producing dinoflagellate,Protoceratium reticulatum, and resultant toxin concentrationin scallops was monitored in Okkirai Bay, northern Japan. Theoccurrence peaked after 1 July and reached a maximum density(400 cells L1) on 16 July. It occurred over a wide rangeof water temperature and inorganic nutrient concentrations andwas tolerant of a broad range of environmental conditions. Hydrologicalparameters were monitored, and it was obvious that P. reticulatumflourished under low salinity (30.5932.60) and occurredat highest density in the surface layer (05 m depth)where effects from rainfall were greatest. In addition, dinoflagellatedensity increase and decrease was well correlated with inflowsof oceanic water into the bay. Thus, it can be assumed thatthe oceanic inflows may cause initial population increases (e.g.excystment or input of a seed population), withresultant growth in rain-affected waters and subsequent spreadthroughout the entire bay via water movement. YTX and 45-OHYTXconcentrations in scallops reached maximum levels (0.79 µgg1 and 0.44 µg g1 of digestive gland, respectively)2 weeks after the maximum cell density of P. reticulatum, andhigh levels of the toxin continued for a month. Low levels ofthe toxin were detected even during periods when cells werenot observed. 相似文献
18.
Effect of Inorganic Phosphate on the Biosynthesis of Purine and Pyrimidine Nucleotides in Suspension-Cultured Cells of Catharanthus roseus 总被引:1,自引:0,他引:1
The levels of purine and pyrimidine nucleotides in suspensioncultures of Catharanthus roseus were determined 24 h after stationary-phasecells were transferred to fresh complete (+Pi)or phosphate-deficient (Pi) Murashige-Skoogmedium. The levels of ATP, GTP, UTP and CTP were from approx.3 to 5-fold greater in the cells grown in +Pimedium than in the cells grown in Pi medium.The levels of almost all other nucleotides were slightly higherin the cells in +Pi medium. The rates of de novoand salvage biosynthesis of purine and pyrimidine nucleotideswere estimated from the rates of incorporation of radioactivityfrom [14C]formate, [214C]glycine, NaH14CO3, [614C]orotate,[814C]adenine, [814C]adenosine, [214C]uraciland [214C]uridine. The results indicated that the activityof both the de novo and the salvage pathway was higher in thecells in +Pi medium than in the cells in Pimedium. The rate of degradation estimated from the rate of releaseof 14CO2 from labelled purines and pyrimidines indicated thatdegradation of uridine was significantly reduced in the cellsin +Pi medium, but no significant difference wasfound in the degradation of adenine, adenosine and uracil. Thepossible role of Pi in the control of the biosynthesis of nucleotidesand in the degradation of uridine is discussed. Catharanthus roseus, Madagascar periwinkle, suspension culture, inorganic phosphate, nucleotides, purines, pyrimidines, biosynthesis, degradation 相似文献
19.
Quantitative determinations of chemical composition and oxygenconsumption rates were made for a deep-living population ofthe lobate ctenophore Bolinopsis infundibulum. Animals werecollected in the Gulf of Maine with the submersible Johnson-Sea-Linkduring September 1989 at depths ranging from 120 to 240 m. Carbonand nitrogen contents were similar to values reported for epipelagicctenophores. Lipid and protein levels were lower than valuestypical of epipelagic ctenophores, but higher than those ofmesopelagic species. Carbohydrate was nearly an order of magnitudehigher than previously recorded for B.infundibulum. Oxygen consumptionrates ranged from 0.004 to 0.235 µl O2 mg1 dryweight h at temperatures ranging from 5 to 7°C. Carbon-specificmetabolic rates ranged from 0.21 to 12.73 µl O2 mg1C h1. Energy expenditures estimated from respirationdata ( 相似文献
20.
Putrescine, spermidine, and spermine content were analysed inzygotic embryos of barley (Hordeum vulgare L.). Changes in polyaminecontent were observed during zygotic embryo growth. In two cultivars,Bomi and Golden Promise, the totalpolyamine content in the embryos was 2.62.9 nmol mg1fresh weight 10 d after anthesis, the highest content observed.It dropped to 1.3 nmol mg1 fresh weight 14 d after anthesis.This drop was caused by decreases in all three polyamine concentrations.From 14 to 35 d after anthesis the putrescine content continuedto decrease while the spermidine and spermine content increased,thus the total polyamine content remained constant until 35d after anthesis. The mutant Ris? 1508 showeda constant polyamine content around 1.3 nmol mg1 freshweight from 14 to 35 d after anthesis. The polyamine patternwas conserved in all three lines throughout the period of investigationshowing a spermidine content higher than putrescine contentwhich was, in turn, higher or equal to the spermine content.The polyamine content measured as nmol µg1 proteindecreased from 14 to 21 d post anthesis in all three lines,because the protein content (µg mg1 fresh weight)increased during the period. In dedifferentiating zygotic embryoscultured in vitro the putrescine content (nmol mg1 freshweight) rose by a factor of nine and the spermidine contentdoubled within the first week of cultivation, whereas sperminecontent did not change. For embryoderived calli a repeated patternof change in polyamine content was observed throughout the subculturingperiod. Key words: Polyamines, Hordeum vulgare L., embryo development 相似文献