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1.
Recalling Taste Intensities in Sweetened and Salted Liquids 总被引:2,自引:1,他引:1
The effect of training on recalling taste intensities over 6weeks was studied using an ad libitum mixing procedure. Subjectstasted sweet and salty standards labeled as weakand strong (3 and 8% sucrose in redcurrant juice;0.4 and 1.2% NaCl in beef broth). They subsequently mixed unsweetenedand sweetened juice, and unsalted and salted broth, to producetaste intensities that corresponded to the standards. A minimumtraining (MT) group (n = 13) produced comparison stimuli bytasting and directly comparing with standards in one sessiononly; an extensive training (ET) group (n = 13) did this insix sessions before producing comparison stimuli based on memoryonly at 1 h, 1 day, 1 week and 6 weeks. An upward bias (chemicallydetermined concentrations of comparison stimuli exceeding thoseof standards) occurred at 1 day or 1 week in MT subjects forweak and strong sweetness, and forstrong saltiness, and sustained thereafter. Theupward tendency was also observed in ET subjects but was significantonly for strong sweetness. It is important torecognize memory effects such as the one described, as theyaffect food perceptions and can be a major source of bias insensory food research. Chem. Senses 21: 2934, 1996.
3Current address: Psychonomics Department, Utrecht University,Heidelberglaan 2, 3584 CS Utrecht, The Netherlands 相似文献
2.
Feeding behavior of the brittle star Ophiura ophiura includesorienting posture, orienting movements, arm walking,changing the direction of walking arm coilingand ingestion. All sequential behavior patterns were releasedor enhanced by single low-molecular-weight compounds. Stimuliwhich released walking behavior at high concentrations(104 M) in all the test animals are listed in decreasingorder of sensitivity: sarcosine, glycine, urea, L-valine, L-leucine,L-methionine, L-homocysteine, L-norvaline, L-norleucine, L-threonine,L-serine, S-methyl-L-cysteine, L-proline. Threshold values forsingle amino acids were as much as 100 times different in differentindividuals and ranged from 3 x 109 to 3 x 107M for the most effective stimulus, sarcosine, and from 106to 104 M for proline. Above 105 M, only L-prolineregularly released a second behavior pattern, the arm coilingresponse, which temporarily inhibited the walkingbehavior. Behavioral thresholds for the walkingbehavior for L(+)-lactate and L-alanine were higher than thosefor the orienting movements. Thyoglycolic acid and ß-alaninereleased tube feet walking, which is not part of the feedingbehavior. Structureactivity comparisons were studied at estimated105 M concentrations. Gycline, sarcosine, L-valine, L-norvaline,L-leucine, L-isoleucine, DL-norleucine and DL-homocysteine releasedarm walking behavior in more than 75% of all thetests. With the exceptions of S-methyl-and S-ethyl-cysteine,and glycine methylester, derivatives of amino acids were noteffective behavioral stimuli in Ophiura ophiura. L-Isomers ofvaline and leucine regularly stimulated the walkingbehavior while their D-isomers were effective in some testsand ineffective in others. Acetylcholine iodide, acetyl-ß-methylcholine chloride and choline phosphate chloride regularly releasedwalking behavior at concentrations above 105M. 相似文献
3.
《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
4.
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
5.
The Growth and Carbon Allocation Patterns of White Clover (Trifolium repens L.) Plants of Contrasting Branching Structure 总被引:1,自引:0,他引:1
The growth, morphology and carbon allocation patterns of F1progeny white clover (Trifolium repens L.) plants selected foreither low (LBF) or high (HBF) frequencyof stolon branching were compared in two controlled-environmentexperiments. Selections from within both a small-leaved (GrasslandsTahora) and a large-leaved (Grasslands Kopu)clover cultivar were compared, and plants were grown under arelatively lenient defoliation treatment (expt 1) or under threelevels of defoliation seventy (expt 2). Carbon allocation patternswere measured by 14CO2 pulse-chase labelling using fully unfoldedleaves on the main (parent) stolon. LBF and HBF displayed consistent differences in the selectedcharacter though, within cultivars, the difference between selectionswas most pronounced for Kopu. The selections developed fundamentallydifferent branching structures resulting from differences inbranching frequency, with total branch weight per plant averaging122 mg for LBF and 399 mg for HBF (mean of both experiments).More C moved from parent stolon leaves to branches in HBF thanin LBF (mean 22.6% vs. 15.1% respectively of the 14C exportedfrom source leaves). More C also moved to stolon tissue in HBF,but, counterbalancing this and the difference in allocationto branches, less moved to developing leaves and roots on theparent stolon itself compared to LBF. However, the total weightof developing leaves and roots per parent stolon was generallygreater in HBF than in LBF, probably reflecting greater C importby these sinks from the higher number of branches present perplant in the former selection. HBF plants were consistentlylarger at harvest than LBF plants. There were no defoliationtreatment x selection interactions in C allocation patternsin expt 2. The implications of the results for plant performancein grazed pastures are discussed. Branching, carbon translocation, defoliation, growth, morphology, Trifolium repens, white clover 相似文献
6.
Pattern of Respiration of a Perennial Ryegrass Crop in the Field 总被引:3,自引:0,他引:3
Dark respiratory losses of CO2 were measured ona one year old sward of S24 perennial ryegrass (Lolium perenneL.) at intervals during a 74 day reproductive growth period,between April and June, and a 21 day vegetative growth period,in July and August. Part of the sward was shaded for one weekbefore measure ments commenced. Measurements of darkrespiration continued for 46 hand it was possible to distinguishtwo components which are designated maintenanceand synthetic Maintenance respiration was taken to be the meanrate of CO2 efflux after 4046 h darkness. When calculatedon a plant d. wt basis at 15°C it ranged between 6 to 32mgCO2 g-1 day-1 during reproductive growth and 1014 mgCO2 g-1 day-1 during vegetative growth. During reproductivegrowth, sward protein content ranged between 723 percent and when maintenance respiration was recalculated on thebasis of protein content it changed relatively little throughoutthe growth period (90140 mg CO2 g pro tein-1 day-1);the value for vegetative growth ranged between 70100mgCO2 g protein-day-1. Total synthetic CO2 flux was determined duringreproductive growth and a rate of synthetic CO2flux was determined during both reproductive and vegetativegrowth. Between 15 and 35 per cent of the CO2 fixed in the previousphotoperiod was lost in synthetic respirationof above-ground material in reproductive swards. Previous shadingincreased the proportion of synthetic CO2 lossfrom above ground. The rate of synthetic CO2 outputduring the first hours of darkness increased with amount ofCO2 fixed in the previous photoperiod, although it was not proportionalto it. There is some evidence that assimilate is carried-overfrom one photoperiod to the next. 相似文献
7.
DRAKEFORD DAVID R.; MUKHERJEE ILABANTA; REID DAVID M. 《Journal of experimental botany》1985,36(11):1705-1715
Drakeford, D. R., Mukherjee, I. and Reid, D. M. 1985. Some earlyresponses of Helianthus annuus L. to flooding. I. The effectsof flooding on the uptake and leakage of non-electrolytesby roots.J. exp. Bot. 36: 17051715. The object of this work was to examine some of the early effectsof flooding on roots. A hydroponic system was developed thatgave good control over watering, degree of oxygenation of thebathing medium and allowed measurement of short term changesin the composition of the bathing medium. Excised roots, floodedfor 24 h, were shown to take up less [3H) ß-alaninethan non-flooded roots and also leaked more [3H] ß-alanineinto a distilled water bathing medium. Further, flooded excisedroots lost more protein to the bathing medium, with young(57 d) roots showing greater losses than old(1114 d) roots. However, young roots had more proteinin the tissue even after greater loss. Young roots remainedhealthier and lost less fresh weight than old roots. Abscisicacid was shown to have a small role in protecting youngroots from the effects of flooding. Key words: ABA, abscisic acid, anaerobic, flooding, leakage, roots, uptake, waterlogging 相似文献
8.
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
9.
The Sensitivity of Net Photosynthesis in Several Plant Species to Short-term Fumigation with Sulphur Dioxide 总被引:4,自引:0,他引:4
The effects of exposure of up to 2 h with sulphur dioxide ona range of plant species was observed by measuring changes inthe rate of net photosynthesis under closely controlled environmentalconditions. Ryegrass, Lolium perenne S23 was thespecies most sensitive to SO2; significant inhibition was detectedat 200 nl l1. Fumigations at 300 nl l1 also inhibitedphotosynthesis in field bean (Vicia faba cv. Three FoldWhite and Blaze) and in barley (Hordeumvulgare cv. Sonja). No effect was detected inwheat (Triticum aestivum cv. Virtue) at concentrationsup to 600 nl l1 SO2, or in oil-seed rape (Brassica napuscv. Rafal) except at 800 nl l1 SO2). Recoverycommenced immediately after the fumigation was terminated andwas complete within 2 h when inhibition had not exceeded 20%during the SO2 treatment. Key words: Sulphur dioxide, short-term fumigation, photosynthesis 相似文献
10.
Abstract line 12: for below 2.03, 0.53 and 0.28 mequiv.K+l1 respectively read below 0.28, 0.53and 2.03 mequiv. K+l1 respectively. 相似文献
11.
Diurnal laminar reorientation was followed in solar-trackingleaves of Lavatera cretica L. under simulated conditions. Asimulated sun was moved over the lamina in a 180?arc in the vertical plane of the mid-vein, at an angular velocityof 15? h1 in a regime of 12-h photoperiods. In one groupof plants the petioles of the experimental leaves were arrangedto face sunrise, while in the other they werearranged to face sunset. At sunrise,the laminae in both groups, which were inclined towards theanticipated direction of sunrise, changed theirelevation towards the rising sun, resulting inprogressive reduction in the angle of incidence (AI) of lighton the laminar surface (AI= differential between laminar andsolar elevation). As a result, laminar and solarelevation converged, and laminar reorientation gradually ceased,until the solar elevation had passed the normalto the laminar surface (AI=0?). laminar reorientation was thenresumed, but its direction was reversed to follow the directionof solar reorientation. During most of the remainingday, laminar elevation (LE) trailed that of thesun by an average of 11?-14?. Laminar reorientationthen anticipated sunset by starting to slow down60 to 90min in advance. During the 12-h dark period, the laminareoriented towards the anticipated direction of the subsequentsunrise. The time-course of nocturnal reorientationwas qualitatively different in the two groups of experimentalplants. The time-course of diurnal phototropism under naturaland simulated conditions is analysed and compared and differencesand similarities between them are discussed. Key words: Diurnal phototropism, solar-tracking, vectorial excitation 相似文献
12.
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
13.
Nitrate provision has been found to regulate the capacity forChara corallina cells to take up nitrate. When nitrate was suppliedto N sufficient cells maximum nitrate uptake was reached after8 h. Prolonged treatment of the cells in the absence of N alsoresulted in the apparent ability of these cells to take up nitrate.Chlorate was found to substitute partially for nitrate in theinduction step. The effects on nitrate reductionwere separated from those on nitrate uptake by experiments usingtungstate. Tungstate pretreatment had no effect on NO3uptake induced by N starvation, but inhibitedNO3 uptake associated with NO3 pretreatment. Chloridepretreatment similarly had no effect on NO3 uptake inducedby N deprivation, but inhibited NO3 uptake followingNO3 pretreatment. The data suggest that there are atleast two mechanisms responsible for the inductionof nitrate uptake by Chara cells, one associated with NO3reduction and induced by CIO3 or NO3and one associated with N deprivation. Key words: Nitrate, Chlorate, Chara corallina, Induction 相似文献
14.
Floral buds of the False Horn plantain clonesMusa (AAB) Harton Verde, Harton Negra,and Currare terminate in a large single floralstructure. The apices of these floral buds are here designatedas determinate since they have lost the ability to produce additionalfloral initials or buds. Terminal peduncle segments can be culturedin a modified Murashige and Skoog (1962) medium supplementedwith N6-benzyl-aminopurine (5 mg I1). Under these conditions,this apparent inability to yield buds can be overcome as vegetativeshoot clusters form in the axils of the bracts. Rooted plantletsare obtainable by treating shoots with naphthaleneacetic acid(1 mg I1) and activated charcoal (0.025%). The adventitiousorigin of the shoots has been established. Musa cultivars, plantains, floral bud, adventitious buds, tissue culture 相似文献
15.
Three neighbouring populations of Lymnaea peregra had recruitmentin the summer (June and July), but one population (Sheaf) hada second recruitment in September and October. We hypothesizedthat juveniles of the Sheaf population would be subject to selectionunder both summer and winter conditions,and thus should be more resistant to low-temperature stressthan juveniles of the other populations. The hypothesis wassupported by the findings that Sheaf juveniles survived andgrew better over a wider range of temperatures (2, 10, 15 and20°C )while juveniles of the other two populations wereadapted only to higher temperatures (15 and 20°C). Therewas evidence that some of these traits were genetically fixed.
*Present address: Department of Applied Science, City Polytechnicof Hong Kong, Mongkok, Kowloon, Hong Kong. (Received 15 September 1988; accepted 16 December 1988) 相似文献
16.
Hama Takeo; Matsunaga Katsuji; Handa Nobuhiko; Takahashi Mikio 《Journal of plankton research》1990,12(1):125-131
The production rate of participate nitrogen (PN) in Lake Biwafrom March to June 1986 was calculated by monthly measurementsof the proteinaceous nitrogen production rates. The newproduction rate was estimated from the decrease in nitrate inthe euphotic zone; during this period (91 days) it was estimatedas 93 mg atoms m2, and accounted for 20% of the totalPN production (460 mg atoms m2). This implies that {smalltilde}80% of the PN produced might be recycled in the euphoticzone. The increase in PN in the euphotic zone during this period(27 mg atoms m2) accounted for 5.9% of the totalPN production. This indicates that the remaining 14% of PN producedin the euphotic zone was vertically transported. Sediment trapexperiments at 30 m depth indicate that 8.1% of the PN producedin the euphotic zone was measured as downward flux at 30 m depthduring the stagnation period. Decompositional loss of PN between12.5 (bottom of the euphotic zone) and 30 m depth was estimatedas 17 mg atoms m2. This was calculated on the basis ofaccumulation of ammonium, which accounted for 3.7% of the totalPN production. The flux from the euphotic zone thus accountedfor 12% of the total PN production, suggestingthe validity of the production model. 相似文献
17.
18.
Subjects from Britain and America were tested on their skillat applying the taste adjectives sweet, sour,salty, and bitter to clearly distinguishablesolutions of sucrose, citric acid, NaCl and quinine sulphate,respectively. The main error that occurred was calling citricacid bitter while the tendency to call quininesulphate sour was not so common; this is the wellknown sour-bitter confusion. A sour-salty confusion was alsonoted as well as a tendency to call citric acid sweet.All these confusions were rectified by mere definition usingstandards. Skill at applying taste adjectives was not alwaysfound to be consistent over time. More errors occurred at lowersolution concentrations, even though stimuli were clearly distinguishable;indistinguishability of stimuli may account for some confusionsin other studies.
*Present address: Department of Psychology, University of Bristol,Bristol BS8 1HH, England. 相似文献
19.
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
20.
Assimilate Uptake and Water Loss in Maturing Barley Grains 总被引:1,自引:1,他引:0
When detached ears of barley were supplied with [U-14C] sucrosefor 4 h, 14C was detected in the endosperms of grains from earsharvested 50 days after anthesis, i.e. 1015days after cell wall modifications had taken placein the chalazal region of the caryopsis. In 55-dayears which had been supplied with [U-14C] sucrose for 20 h no14C was detected in the upper part of the rachis or in grainswith a moisture content of less than about 25%. In the rachisof wheat and barley, the walls of the xylem parenchyma and phloemcells stain strongly with ruthenium red, and in immature rachidesthis stainability is lost when sections are incubated with pectinase.Near the apex of 55-day ears the pectinaceouswall material in the vascular bundles is resistant to digestionby pectinase, and pectic substances, which are removed by pectinase,fill the lumina of the xylem elements. These observations arediscussed in relation to the dehydration of the maturing grain. Key words: Barley, 14C-sucrose, Pectic material, Xylem 相似文献