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1.
The rooting responses of isolated leaves of the dwarf Frenchbean and the ivy were studied by applying solutions of growthsubstances to the petiole: ß-indolyl-butyric acid(I.B.A.) for the former and -naphthyl-acetic acid (N.A.A.) forthe latter. The following factors were investigated:
- The variation in response of successive leaves from the apextowards the base of the plant.
- The optimal concentrationsof the growth substances and therelation between duration ofapplication and concentration.
- The relation of age of theleaf and optimal concentration(ivy).
- The nutritive factorsconcerned in the response were studied,(a) by varying periodsof contact between lamina and petiole,(b) by varying durationof light, (c) by varying the amountof light, and (d) by feedingwith sucrose and asparagine.
2.
- The capacity of green leaves for absorbing and converting substancesrelated to L-ascorbic acid was investigated, using detachedleaves of various plants, including soybean, pea, barley andspinach.
- The greater portion of the absorbed dehydroascorbicacid wasrecovered in the leaves as ascorbic acid, minor portionsbeingdiscovered as dehydroascorbic acid and 2,3-diketogulonicacid. The recovery was about 60% of the absorbed dehydro ascorbicacid, in the cases of detached soybean and barley leaves, forinstance, thus suggesting the instability of the substance invivo.
- The absorption and conversion of ascorbic acid and 2,3-di-ketogulonic acid in detached green leaves were also investigated.Most of the absorbed ascorbic acid reappeared in the leaves.On the other hand, no evidence for the conversion of 2,3-diketogulonicacid into ascorbic and dehydroascorbic acids was observed. Thegreater portion of the absorbed 2, 3-diketogulonic acid seemsto be decomposed in the leaves, under the condition of the presentstudy.
3.
- The organic acids present are citric, isocitric, and l-malic,with a small residue of unidentified acids.
- The diurnal variationin acidity is due chiefly to changes,in malic acid, with aparallel fluctuation shown by citric acid.Under these conditionsisocitric acid shows little change.
- The importance of carbondioxide during acidification is confirmed,and it is shown thatat room temperatures or higher the CO2produced in respirationis sufficient to produce maximum acidification.At lower temperaturesthe supply of CO2 limits acid production.
- In the absence ofoxygen no acidification occurs, but even smallquantities (approx.1 per cent.) are sufficient to cause someacid production.
- Completebalance-sheets are presented for acids, carbohydrates,CO2 andoxygen for leaves maintained in the dark at high andlow temperatures.As acids are produced there is a correspondingloss of carbohydrate(chiefly starch). A scheme of reactionsis suggested to explainthe experimental results.
4.
- Addition of exogenous acetate or ethanol to autotrophic culturesof Euglena gracilis strain Z induces formation of the glyoxylateby-pass.
- Visible light decreases the activity of malate synthasein greenEuglena by about 50%. No such effect was found in apermanentlybleached mutant.
- Aconitase activity parallelsthat of malate synthase, but isocitricdehydrogenase activityis constant under all conditions examined.
- Oxygen consumptionis proportional to the activities of malatesynthase and aconitase,but not to that of isocitric dehydrogenase.
- The results ofsimilar studies with other growth substrates(pyruvate, malate,succinate) suggest that some of the oxygenconsumed by C2-grownEuglena may not be associated with energyproduction.
5.
The inequality shown by anisophyllous leaves in plants withdecussate phyllotaxis can be measured as the difference in sizebetween the two leaves at a node, expressed as a percentageof their mean size. This is referred to as the degree of anisophylly. In Acer anisophylly of two types with different causation occurs.
- 1. Primary anisophylly which is shown only by first year shootsdeveloped from axillary buds and which is due to the inequalityof the leaf primordia. Primary anisophylly is thus determinedby events occurring during the formation of the bud and is irreversible.
- 2. Secondary amsophylly which is shown chiefly by the second(and subsequent) year's extension growth of lateral shoots frombuds which are isophyllous and which is due to the positionin which the shoot develops. This type of anisophylly is reversibleif the position of the developing shoot be changed.
6.
- Daily and seasonal variations occur in the water content ofHelix aspersa Müller.
- The water content is not constantthroughout 24 hours but fluctuatesby 2 to 10%. There is noapparent daily rhythm.
- Humidity has an effect on the watercontent. Falls in relativehumidity to 60% or less, triggera decrease of the snails' hydration,over a range of temperatures,as well as a brief pause in activity.
- Only external climaticconditions produce noticeable fluctuationsof water content,and they more particularly affect juvenileswhich undergo greaterevaporo-transpiration.
- A seasonal rhythm in water contentexists in Helix aspersa,with maxima during spring and autumnand minima in June andJanuary.
- The water content of juvenilesis always superior to that ofthe adults.
- The water contentaffects the duration of the snail's activephase.
7.
- A phenolic pigment was extracted from baker's yeast. The pigmentis slowly autooxidizable, and rapidly oxidized with Rhus-laccaseor polyphenol oxidase and reduced by dithionite.
- The pigmentdissolved in ethylether had an absorption peak at258 mµ,shoulders at 289 and 382 mµ and a plateauat 450500mµ. The difference spectrum between oxidizedand reducedforms of the pigment showed a wide plateau around500 mµ.
- The pigment supported the oxygen uptake by reconstructed enzymesystem: L-lactate, L-lactate cytochhrome c reductase and Rhuslaccaseor polyphenol oxidase. In its absence, no oxygen uptake tookplace. The pigment was replaced successfully with p-quinone,catechol and menadione, but not with ubiquinone. The sequenceof hydrogen transport can be represented: L-lactate L-lactatecytochrome c reductase "phenolic pigment" oxidase oxygen.
8.
Metabolism of some sulfur-containing substances was studiedin a copper-resistant strain of yeast (R), its parent strain(P) and respiratory-deficient(RD) mutants from them. The resultsobtained are as follows:
- Using sulfate, sulfite and thiosulfate as sulfur sources, Rproducedmore H2S than P, and both of these had the activityhigher than their RD mutants. All of them produced a large amountof H2S from cysteine, but only little from methionine, cysteinesulfinic acid and S-sulfocysteine.
- From sulfite and thiosulfate,P and R produced more H2S inaerobicthan in anaerobic condition.With sulfate and cysteine, however,H2S production did not differunder those conditions.
- In both P and R, the sulfate-to-sulfiteand sulfite-to-sulfidereactions were remarkably lowered byiron and zinc deficiencies.But the cysteine-to-sulfide reactionwas not affected by themetal-deficiencies.
- H2S productionfrom sulfate was remarkably depressed by highconcentrationsof pantothenate.
- Rates of reaction steps on a plausible pathway from sulfatetosulfide and to organic sulfur compounds areestimated forthe strainsused. R is characterized by its largecapacity ofthe reaction step from sulfate to sulfite, and excessivesulfitethus formed is liberatedas sulfide not by the way ofcysteine.
9.
- The sugars which induced gigantism of Chlorella cells wereglucose,fructose, galactose, mannose, xylose and arabinose.These sugarswere utilized as respiratory substrates by thealgal cells.
- The cellular division of Chlorella was stimulatedby glucoseand galactose, but suppressed by fructose, mannose,xylose andarabinose, while all these sugars evoked gigantism.No correlationwas found between cellular division and gigantism,
- The photosynthetic activity of giant Chlorella varied withthesorts of sugars added. It was decreased by glucose, fructoseand mannose, but was unaffected by other sugars such as galactose,xylose and arabinose.
- The respiratory activity of giant Chlorellacells as much higherthan that of control cells.
- The amountsof protein-N and dry weight per unit volume of giantChlorellawere much less than those of control cells.
10.
- A substance which inhibits indoleacetic acid (IAA)-and naphthaleneaceticacid (NAA)-induced elongation of Avena coleoptile section andIAA-induced Avena coleoptile curvature was found in an ethersoluble neutral fraction of water extract of sunflower leavesand in agar blocks containing the diffusate from young sunflowerleaves.
- This substance also inhibits the growth of isolatedsunflowerepicotyl.
- The Rf value (0.9) of the substance ona paper chromatogramdeveloped with ammoniacal iso-propanolindicates that it isidentical with the inhibitor reported byAUDUS et al. (1956),but not with inhibitor-ß.
- Theinhibitor can be transported from leaf to stem, and thetransportseems to be accelerated by illuminating the leaf.
- The auxindiffused from sunflower leaf into agar block may beidenticalwith IAA.
- A substance, which has the same properties as theinhibitorfrom sunflower leaf, was obtained in crystalline formfrom theleaf of Jerusalem artichoke.
- The mechanism of growthinhibition caused by this crystallinesubstance seems to involveinactivation of a sulfhydryl group.
- The reason why the stemgrowth of sunflower seedlings is reducedby strong light isdiscussed: the amount of the inhibitor transportedfrom leafto stem is increased under strong light, and in thestem, growthinhibition is caused by a direct effect of thisinhibitor ongrowth and by its inhibiting effect on the transportof IAAfrom leaf to stem.
11.
- Lactate oxidation system was investigated in Acetobacter suboxydans,which was found to have cytochromes a and b, but no cytochromec. Haemoprotein 558 was also found to exist.
- Carbon monoxideinhibited the lactate oxidation in the darkbut not in the light.WARBURG'S partition constant was estimatedto be 7.
- Additionof haemoprotein 558 noticeably enhanced the oxygenuptake bythe LDH preparation, which was obtained from bacterialcellsand partially purified.
- Haemoprotein 558 has protohaem asits prosthetic group. Notonly its absorption spectrum is reminiscentof that of peroxidase,but it also shows peroxidase-like reactivitywith some ligandswith a few exceptions.
- Ferrohaemoprotein558 reacts with oxygen, forming, at first,a complex, whichhas its SORET absorption peak at 423 mµ.The absorptionmaximum then shifts to 417 mµ, indicatinga transformationto another compound. One of these two productsis likely tobe the oxygenated ferro-haemoprotein 558.
- The mutual transformationbetween cytochrome B and haemoprotein558 is discussed.
12.
- From a strain of Acetobacter suboxydans, a glucose and a lacticenzyme were obtained in cell-free states. The lactic enzymeshows as strong activity as the glucose enzyme but is more stablethan the latter toward various purification procedures: bothare sensitive to high temperature treatment. Activities of thetwo enzymes and the MICHAELIS constants of the glucose enzymewere determined under both aerobic and anaerobic conditions.
- Carbon monoxide inhibits the oxygen-uptake in both glucoseandlactate oxidation. WARBURG's distribution constant for lactateoxidation is 6.7. These results suggest the participation ofan heme enzyme in the oxidation system.
- Effects of copperreagents, narcotics and PCMB were also examined.
- The dehydrogenaseactivities (reduction of dye) of the enzymesare more sensitiveto high temperature than the correspondingactivities in oxygen-uptake.
- By combining a dehydrogenase preparation which has lost itsoxygen-absorbing activity through acetone treatment, with aheated extract, a partial recovery of oxygen-uptake can be realizedin lactate oxidation.
- L-Cysteine is utilized as hydrogen donorby the bacterium. Thisoxidative reaction, unlike the oxidationof lactate, is notinhibited by surface active reagents.
13.
- Using intact cells of Chlorella ellipsoidea, investigationswere made on the effects of some SH-reagents (IAA, CMB and arsenite)upon various reactions pertaining to the primary photogenicagent (designated by R) formed in the mechanism of photosynthesis.
- The pre-illumination experiments using 14CO2 as a tracer haveled us to the inference that (i) the process of photochemicalformation of R is inhibited by IAA, that (ii) the spontaneousdecay of R in the dark is markedly accelerated by CMB and arsenite,but not at all affected by IAA, and that (iii) the participationof R in the cyclic path of carbon leading to the fixation ofCO2 is not affected by IAA and CMB.
- Based on the assumptionthat R is a reducing agent, it was discussedthat the fact mentionedunder (iii) is incompatible with theidea that the reductionof PGA to triose phosphate be the soleor rate-determining reductivestep in the cyclic path of carbonin photosynthesis.
- The possibilitythat R may have a functional SH-group (s) wasinvoked to accountfor the observation that the decay of R inthe dark was markedlyaccelerated by CMB and arsenite.
14.
- 3-Indolylacetonitrile is more active than 3-indolylacetic acidin the Avena straight-growth test, but less active in the Avenacurvature test at comparable concentrations. Reasons for thisare discussed, and results of previous work on plant extractsusing the curvature test as a means of assay are considered.
- Transport of both the acid and the nitrile is polar, fromapexto base of the coleoptile. The nitrile can reach the growingcells as easily, and possibly more easily, than the acid. Thesignificance of these findings for a theory on the mechanismof action of the nitrile is discussed.
- The nitrile is inactivein the pea curvature test and straight-growthof pea stem sectionsexcept at high concentrations. It is alsoinactive or only slightlyactive in lateral bud inhibition,root initiation, and petioleabscission at the concentrationstested.
- It is less activethan the acid in root inhibition in cress,but approximatelyas active in Avena. It is approximately asactive as the acidin parthenocarpic fruit development, andinitiation of cambialactivity.
- The significance of these results is discussed.
15.
- Heliangine at 104M promoted the adventitious root formationin hypocotyls of cuttings taken from light-grown (1,900 lux)seedlings of Phaseolus mungo. The promotion was almost completelyreduced by simultaneously supplied 3104M cysteine or1.5104M cystine, but not suppressed by 3104Mof reduced glutathione, alanine or serine.
- A 4 hr pretreatmentwith 3104M cysteine made Phaseoluscuttings less sensitiveto heliangine, but cysteine suppliedafter the treatment withheliangine brought about no effecton the action of heliangine.
- Cysteine also removed the inhibiting effect of heliangineonthe indoleacetic acid-induced elongation of etiolated Avenacoleoptile sections.
- In an aqueous solution heliangine formedan addition productwith cysteine, indicating that cysteinecan inactivate helianginewithout any biological processes.
- On Phaseolus adventitious rooting, no effect was observedofp-chloromercuribenzoic acid, N-ethylmaleimide, 1,4-naphthoquinone,coumarin or penicillin. Reactivity toward sulfhydryl groupsalone does not qualify a substance to be a promotor of rootformation.
- Maleic hydrazide at 104M promoted root formation,butits effect was not removed by cysteine.
16.
A Survey of the Rates and Products of Short-term Photosynthesis in Plants of Nine Phyla 总被引:3,自引:0,他引:3
- Short-term photosynthetic experiments using C14O2 and paperchromatography were performed with 27 different plants representingnine phyla: Schizophyta (Schizophyceae), Euglenophyta, Chlorophyta,Charophyta, Chrysophyta, Rhodophyta, Bryophyta, Pteridophyta,and Spermatophyts.
- There is a remarkable uniformity in thetypes of ethanol-solublecompounds which became radioactivein the entire group of plantsused. The amounts of the differentcompounds varied considerablypercentagewise among the variousplants as would be expectedbecause of their inherent metabolicdifferences and the variationsin their physiological statesinduced by experimental conditions.
- Sucrose became radioactivein very different amounts in twomajor groupings of plants:(a) those containing only photosynthetictissue, and (b) thosecontaining non-photosynthetic tissue aswell. The amount ofradioactive sucrose in the former groupwas much lower thanthat in the latter.
- An unidentified compound became radioactivein appreciable amountsin two of the blue-green algae, but wasradioactive in verysmall amounts or not visible at all on thechromatograms ofall other plants.
17.
- The effects of 3-(4'-chlorophenyl)-1, 1-dimethylurea (CMU)onthe fluorescence of photosynthetic pigments in vivo wereinvestigatedin blue-green, red and brown algae and in isolatedspinach chloroplasts.CMU caused an increase in steady statelevel of fluorescenceof chlorophyll a, but did not influencethe fluorescence ofphycobilins. The spectrum of the fluorescenceincrement hada peak at 685 m/µ and a shoulder at 730740mµ.These two bands probably arise from chlorophyll a(Cf684) belongingto pigment system II.
- On excitation of chlorophylla in a red alga, Porphyra yezoensis,a fluorescence band witha peak at 720 mµ was observedbesides a shoulder at 685mµ. The 720 m band is inferredto arise from chlorophylla (probably, Cf-1) in pigment systemI.
- On addition of CMUto the algal cells, the induction of fluorescencewas modifiedto take a simple time course. The induction wasobserved onlywith respect to the fluorescence of chlorophylla, but not inthe fluorescence of phycobilins. The spectrumof the "transient"fluorescence showed two emission bands ofchlorophyll a at 685mµ and 740 mµ, and was quitesimilar in form tothe spectrum of the CMU-caused increase insteady state fluorescence.
- These facts were interpreted in terms of the correlation offluorescence of chlorophyll a and the photochemical reactionsof photosynthesis
18.
Multiple Forms of Aminopeptidase in Euonymus Leaves 总被引:1,自引:0,他引:1
Three different aminopeptidases (LPAase 1, LPAase 2 and APAase)separable by DEAE-cellulose column chromatography were presentin the leaves of Euonymus alatus f. ciliato-dentalus. Theseenzymes also were verified by polyacrylamide gel electrophoresis,and their substrate specificities were tested with aminoacyl-ß-naphthylamides(aminoacyl-NAs) and aminoacyl-p-nitroanilides (aminoacyl-PAs).The enzymes LPAase 1 and LPAase 2 hydrolyzed leucine-PA (LPA)and phenylalanine-NA. APAase hydrolyzed alanine-PA (APA) andarginine-NA. LPAase 1 and LPAase 2 were not affected by 1,10-phenanthroline,whereas APAase was strongly inhibited by it. All three enzymeswere inhibited by p-chloromercuribenzoate (PCMB). In the Euonymus leaves, the total activity of the three enzymes,LPAase 1, LPAase 2 and APAase, increased as leaves senescedduring autumn. The highest activity of the main enzyme, LPAase2, was found in the leaves collected during October. A markedincrease in LPAase activity was found in the red leaves collectedin December. (Received April 16, 1983; Accepted August 3, 1983) 相似文献
19.
- Solubilization of chioroplasts with a mixture of 1 per centDuponol C and 1 per cent Span 80 (3: 1) caused a destructionof activity in the HILL reaction, but the treatment broughtabout an increase by about 60 per cent in the rate of ascorbatephotooxidation in the presence of DPIP. Heating the broken chloroplastscaused a marked decrease in the photooxidation activity. Byadding surface- active agents to the boiled preparation, theactivity was restored up to almost 80 per cent of the originallevel.
- With colloidal suspensions of isolated chiorophylls,ascorbatewas only slightly photooxidized in the presence ofDPIP. Byaddi tion of the surface-active agents, the activitywas greatlyenhanced.
- Dependency of the photooxidation bywhole and solubilized chloroplastsand isolated chlorophylla on the presence of DPIP was examined.DPIP can serve as anintermediate electron carrier in solubilizedchloroplasts aswell as in whole chloroplasts.
- Effect of o-phenanthrolineon ascorbate photooxidation by thesethree preparations wastested. With solubilized chloroplastsand isolated chlorophylls,the addition of the inhibitor hadno influence on their ascorbatephotooxidation either in thepresence or absence of DPIP.
- Treatmentof whole chloroplasts with the surface-active agentsinducedan activity of photooxidation of cytochrome c. The electron-flowpattern for the photooxidation of ascorbate by whole and solubilizedchloroplasts was briefly discussed.
20.
- Pharbitis plants were cultured on a nutrient medium containing5% sucrose or no sucrose. They were subjected to various lightconditions at temperatures of 10? or 20?.
- All the plants culturedon the sucrose-medium at 10? initiatedflower buds independentlyof the light to which the plants wereexposed.
- Plants culturedon the sucrose-free medium at 10? initiatedflower buds undershort photoperiods, but did not under continuousillumination.
- Plants cultured on the sucrose-medium at 20? initiated flowerbuds in total darkness or under short photoperiods regardlessof the intensity and quality of the light, but those subjectedto continuous illumination did not.
- Plants cultured on thesucrose-free medium at 20? initiatedflower buds under shortphotoperiods but did not initiate themunder continuous illumination.