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1.
The Absorption and Distribution of Strontium in Plants: I. PRELIMINARY STUDIES IN WATER CULTURE 总被引:2,自引:1,他引:1
The absorption and distribution of strontium in barley plantshas been studied, in water culture, both in the presence andabsence of calcium. Tracer methods have been employed. When no other bivalent ions were present in the external solutionthe absorption of strontium was proportional to the concentrationover a wide concentration range (106 to 101 m.equiv./l.).In the presence of calcium, however, absorption was reducedand appeared to be dependent on the total concentration of calciumplus strontium rather than on that of 8trontlum alone. The translocationof stron tium from the root to the shoot increased as the externalconcentration of both ions was raised. In plants of low initialcalcium status the rate of translocation of strontium was markedlyreduced, apparently because of its retention at or near theroot surface. Autoradiographs of plants treated with labelled strontium for24 hours at different stages of growth and grown subsequentlyfor varying periods of time in unlabelled nutrient solutionsshowed that very little redistribution of strontium occurredwithin the plant. Leaves which developed after treatment inthe labelled solutions contained little or no strontium evenwhen the concentration in the older leaves was very high. Strontiumwas initially retained in the nodes of the stems, but the greatestaccumulation was later found to be in the leaves which had beengrowing most actively at the time of absorption. 相似文献
2.
- As part of a general investigation into the exchange of gasesbetween the bogbean, Menyanthes trifoliata, and its environment,determinations have been made of the composition of the internalatmosphere of the plant at five different levels, viz. leafyshoot, three successive portions of stem, and roots.
- Procedureis described for the analysis of small gas samplesusing a modificationof the Bonnier and Mangin apparatus.
- In darkness with thelower part of the plant surrounded by anatmosphere of nitrogen,it has not been possible to show thepresence of a regular downwardsgradient of oxygen, such aswould be expected on a basis ofnormal gaseous diffusion.
- Under these Air Top/Nitrogen Bottomconditions the roots areshown to contain between 12?5 and 17?5percent, of oxygen intheir intercellular gas system. The portionof stem immediatelyadjacent to the roots showed an oxygen levelof from 14?0 to18?0 per cent.
- In plants kept under NitrogenTop/Air Bottom conditions in thedark for 48 hours, the concentrationof oxygen in the rootsfell to a level of 3?1 per cent, or belowin three plants andto 6?o per cent, in a fourth. The oxygenconcentration in theadjacent lowermost part of the stem wasas high as 18?0 percent., depending on the degree of aerationof the solution bathingthe stem. It is suggested that thisdistribution of oxygen canbe related to the relative impermeabilityof roots and of stemendodermis to gaseous diffusion from without,and it is thoughtthat the major part of the oxygen supply tothe roots is transportedto them through the stelar air passages.
- Some evidence is presented to show that oxygen passes fromthelower parts of the plant into the medium surrounding it.
3.
ORGANIC ACID SYNTHESIS IN RESPONSE TO EXCESS CATION ABSORPTION IN VACUOLATE AND NON-VACUOLATE SECTIONS OF CORN AND BARLEY ROOTS 总被引:2,自引:0,他引:2
- 14CO2 fixation into organic acids in tips and proximal sectionsof both corn and barley roots was studied as a function of thenature and concentration of the salt in the external solution.
- In comparison with the level of 14CO2 fixation by vacuolateproximal sections in KCI, incorporation was markedly enhancedin K2SO4 and diminished in CaCk. By contrast, non-vacuolateroot tips were indifferent to the type of external salt withrespect to UCO2 incorporation into organic acids.
- The effectof salt type on organic acid formation from 14CO2was most pronouncedat relatively high concentrations.
- The conclusion was reachedthat organic acid synthesis in responsetoexcess cation uptakeis the result of cation movement into thevacuole, and thattransport into the vacuole is mediated bythe low-affinity componentof the dual mechanisms involved inion absorption.
4.
- Effect of light on ion absorption and resting potential of theinternodal cell of Nitella flexilis was investigated under variousconditions.
- On illumination, the resting potential increasedby about 30mVin 104 M KCl and by about 60 mV in 104M NaClsolution. A similar photoelectric response was also observedin 103 M KCl, 102 M CaCl2 and 5 x 102 MCaCl2 solutions, but not at all in 102 M KCl solution.
- Absorption of ions by the cell took place in parallel withthelight-induced change in resting potential.
- Red and bluelights were very effective in increasing the restingpotential,while green light was almost ineffective. These differenteffectsof color lights were in good agreement with their effectsinincreasing the osmotic value of the cell.
- The photoelectricresponse was not affected by phenylurethane,which, on the otherhand, strongly inhibited the light-inducedion absorption.
- Theuptake of ions by the cell from the external medium intothevacuole is assumed to proceed in two different steps: thefirstis the process involving the ion movements across theoutermostplasmalemma, and the second is that involved in thetransportof ions through the cytoplasmic layer and tonoplast.The formerprocess is considered to be influenced by the increasein restingpotential probably caused by the light absorbed bychlorophyll.The process was, however, suggested to be independentof photosynthesis.On the other hand, the latter process issupposed to be relatedto photosynthesis. A discussion was madealong this line.
5.
- An apparatus is described by means of which the absorptionofions from a complete nutrient solution of constant compositionby excised root systems of plants, grown under known nutrientdeficiencies, may be measured in standard conditions of aerationand temperature. Results of some prelimi nary experiments aredescribed.
- It was found that the roots readily absorbed theelement inwhich they were deficient, but tended to lose thoseelementswhich were already present in normal amounts.
- Therewas almost invariably a loss in fresh weight of the rootsafterthe absorption period and also a loss in dry weight. Thislossappears to be complex and is partly attributable to lossofrespiratory material.
- The addition of 2 per cent. sucroseto the solution from whichthe root systems of phosphorus-deficientbarley plants wereabsorbing increased the nitrogen and phosphoruscontents ofthe roots and maintained the potassium content,while in absenceof sucrose only the phosphorus content increased,but this increasewas significantly less than in the presenceof sucrose.
- It was shown that roots excised from plants growingin soilwere capable of absorbing phosphorus or nitrogenelementsin which they were apparently deficient.
- The interpretationof data obtained from excised roots is discussed,and it isconcluded that excised roots from plants grown incomplete nutrientare not likely to behave in the same way,as regards absorption,as corresponding roots of intact plants,but that roots grownunder conditions of deficiency will behaverather similarlywhether excised or intact. This fact providesa potential methodfor diagnosing and evaluating nutrient deficiencies.
- The low-saltcondition of roots postulated by Hoagland and Broyeris notnecessarily the primary requisite for rapid absorptionof aparticular ion. It is rather that the roots should be deficientin that ion. The roots could be high in other salts.
6.
The assimilation and transport of 15N-labelled ammonium nitrogenin rice plants (Oryza sativa L.) was studied. Plants assimilatedlarge amounts of nitrogen from labelled ammonium into theiramides and amino acids, particularly in the roots and stem,at the end of a 4-day 15N feeding and 10 days later in the upperleaves, especially in the blades. Although the incorporationof 15N into all the nitrogen fractions of the newly emergedpanicle was evident, it was particularly pronounced in the amidesand amino acids of the soluble fractions. The upper leaves hada greater 15N incorporation in their organic N-fractions thandid the lower ones. Amides and amino acids are considered tobe the main forms of nitrogen transported to the shoot fromthe ammonium assimilated in the roots. The transport of theorganic forms of nitrogen was possibly greater to the upperleaves than to the lower ones. The nitrite fraction had more 15N than did the nitrate fractionin all parts of the plant, particularly in the upper leaf blades.It appeared that some of the ammonia might have been oxidizedto nitrite, then to nitrate in some parts of the plant; probablyin the upper leaves. The synthesis of protein and nucleic acid occurred rapidly inthe upper leaves, especially in the blades, also in the rootsas evidenced by the considerable incorporation of 15N in theinsoluble fractions of these parts. The variation in 15N-distribution,during the 10 days, in the different plant parts suggests thatthe nitrogen incorporated during protein synthesis in the rootsand tillers was remobilized and transported to the upper partsof the shoot. A concept for the transport of organic nitrogenouscompounds from the roots to shoot through the phloem and xylemof the rice plant stem is discussed. (Received May 11, 1974; ) 相似文献
7.
- Growth retardants, CCC, Amo-1618, Phosfon-D and B-995, appliedduring seed vernalization inhibited the ear development of winterwheat. CCC applied during green plant vernalization inhibitedflowering,but it had no appreciable effect on the final stemlength. Theinhibition by CCC was reversed by foliar applicationof gibberellin.On the other hand, CCC applied after the vernalizationperiodaffected the final stem length but not flowering.
- Theamount of endogenous gibberellin-like substance(s) was greaterin the vernalized plant than in the non-vernalized plant. Nogibberellin-like substance was detected in the CCC-treated plant.
- Endogenous gibberellin-like substance(s), whose biosynthesisis inhibited by some growth retardants, may play a part in thevernalization process in winter wheat.
8.
The investigation of phosphorus absorption by intact plants during a short period has above all confirmed the validity of the results obtained in the foregoing study of the kinetics of absorption by excised roots. Further, the results show the unquestionably important role of mass flow in transporting ions to plant roots, mainly at lower and medium concentrations, that is, from about 0.1 to 10 mM. Under conditions of growth close to the optimum, the supply by means of mass flow can be sufficient even at lower concentrations of phosphorus, such as 1.47 mM KH2PO4, or the absorption of phosphorus by plants can be higher than in the case of ions being transported to roots by diffusion. With a higher absorption the phosphorus distribution somewhat changes as well, relatively more of it being accumulated in the roots. 2.4-DNP applied to the nutrient solution at a concentration of 10-5 M reduces the phosphorus absorption. 相似文献
9.
- Formyltetrahydrofolate synthetase (E. C. 6. 3. 4. 3) was foundto be widely distributed in higher plants and the high enzymeactivity was observed in green leaves of Brassica and Alliumspecies, spinach, and in pea seedlings. In pea seedlings, theenzyme activity changed during the course of germination, andmost of the enzyme activity was located in a soluble fractionof the cytoplasm.
- The enzyme was labile and lost the activityrapidly, even whenstored at 5 in the presence of 0.1 M mercaptoethanol.It was,however, found that ammonium sulfate was very effectivein stabilizingthe enzyme activity.
- The enzyme has been purifiedapproximately 500-fold from extractsof pea seedlings by treatmentswith ammonium sulfate, protaminesulfate, hydroxylapatite, calciumphosphate gel, and DEAE-cellulosecolumn chromatography.
- Thepurified enzyme was specific for formate, ATP and FAH4,andthe Michaelis constants for these reactants were 2.1 102M, 5.1 104 M, and 5.6 103 M, respectively.
- The optimum pH was found to be 8.0, and the optimal temperaturewas observed at 37. Both NH4$ and a divalent cation (MgSS orMnSS) were required for the optimal activity.
10.
The effects of EDTA·Mg or GEDTA·Mg on the uptakeof nutrient ions, the release of Ca++ and nucleotides into themedium and the nucleic acid contents in rice and red bean rootswere investigated.
- Both EDTA and EDTA·Mg induced similarly the release ofCa from roots.
- EDTA·Mg as well as EDTA brought abouta significant repressionin K uptake, but had an insignificantor no effect on P, NH4and NO3 uptakes. EDTA·Ca did notrepress K, P, NH4 andNO3 uptakes.
- EDTA or GEDTA acceleratedthe degradation of nucleic acid andthe release of nucleotides,while EDTA·Mg or GEDTA·Mghad no such effect.
11.
- 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.
12.
- The protonema of the moss, Funaria hygrometrica, grows continuouslyin calcium-free liquid media.
- The growth was promoted by additionof oxalate, although themorphogenesis resulting in formationof gametophytic buds onthe protonema was suppressed by theaddition.
- Calcium oxalate promoted the growth of protonema,while at ahigh concentration (102 M) it caused the formationofclumped protonema (falsebuds).
- Addition of plant growthhormones, such as IAA, NAA, 2,4-D andgibberellin retarded thegrowth of protonema, while 2,4-D ata low concentration stimulatedthe growth of protonema.
- Kinetin greatly stimulated the formationof gametophytic budsin the protonema, but these buds were foundto be morphologicallyand physiologically abnormal.
13.
- Details of aseptic culture of virus-free tomato seedlings usedin comparative in vivo and in vitro studies on protein synthesisare described.
- Developmental changes in the levels of DNA,RNA, protein andchlorophyll content of seedling cotyledonsand leaves were recorded,and are related to protein synthesis.
- Incorporation of isotopically labeled carbon into proteinwasfollowed both by photosynthetic uptake of 14CO2 and by theuptakeof 14C-amino acids through the roots.
- A marked stimulationby light of 14C uptake was observed, andthe higher rate of14C incorporation from 14CO2 than from 14C-aminoacids intothe protein fraction is discussed in relation tothe pathwaysof protein synthesis in tomato leaves, and alsowith regardto protein turnover.
14.
Chemical and physicochemical properties of peroxidases producedback rotted sweet potato roots were investigated in comparisonwith those produced in cut one. Peroxidases in either diseased or cut tissue were composed offour major (D-A, D-B, D-C and D-D in diseased tissue and C-A,C-B, C-C and C-D in cut tissue) and several minor components.These peroxidases were separated from each other by DEAE-cellulosecolumn chromatography and other procedures. Several propertiesof the peroxidases were investigated.
- Optimum pH's of peroxidase were in the range of 5.5 to 6.0.
- The activity of each peroxidase was inhibited by acid, alkaliand some inhibitors such as cyanide, fluoride and azide. Azideinhibited more strongly D-A and C-A than D-B and C-B. On theother hand, cyanide and fluoride inhibited more strongly D-Band C-B than D-A and C-A.
- Substrate specificity as determimedby using pyrogallol, guaiacol,chlorogenic acid, caffeic acidand umbelliferone differed betweenthe main peroxidases. Thedegree of indoleacetic acid oxidaseactivity of these peroxidaseswas also different from each other.
- Light absorption spectraof the peroxidases showed that theybelonged to a-type peroxidaseexcept C-D. More precise investigationsof the spectra showedthat the spectra of D-A and C-A were differentfrom those ofD-B and C-B.
15.
- Effect of various treatments on the fluorescence yield of chlorophyllo in isolated chloroplasts was studied in relation to the activitiesof the HILL reaction and the ascorbate photooxidation.
- CMUand o-phenanthroline showed no appreciable effect on thefluorescenceyield at the concentration which completely inhibited the HILLreaction.
- 0.01% SDS was sufficient to inactivate the HILLreaction completelyand caused a 40% decrease in the fluorescenceyield, althoughno shift of the absorption and fluorescencebands could be observed.At higher concentrations of SDS, thefluorescence yield increasedby more than three times the originalvalue and the absorptionand fluorescence bands shifted by 5rap toward the shorter wavelengthside.
- Ultraviolet irradiation,incubation at pH 9.2, heating at 40and digestion with trypsinresulted in loss of the HILL activityand decrease of the fluorescenceyield.
- The DPIP-mediated photooxidation of ascorbate was enhancedbyheating broken chloroplasts at 55 for 5 min, and inactivatedat 70. The photooxidation of ascorbate in the absence of thedye was inhibited by 60% on heating at 55. The o-phenanthroline-sensitivephotooxidation of ascorbate was inactivated at 55. The o-phenanthroline-resistantphotooxidation of ascorbate was rather thermostable. The fluorescenceyield was reduced by 4050% at 55.
16.
An investigation was made to study the assimilation and transportof 15N-labelled nitrate nitrogen in rice plant (Oryza sativaL.). Nitrogen from labelled nitrate at the end of plant feedingwas found mainly in nitrate form, and was more prevalent inroots, stem and leaf sheaths. The nitrite fraction had the nextlargest 15N enrichment. The 15NO3 assimilation in the newlyemerged panicle was mainly in amide and amino acid. The 15N-incorporation at day 0 was greatest in amino acid andnitrate of roots and decreased towards the stem and leaves.Incorporation in these fractions considerably decreased fromday 0 to day 10. Probably most of the nitrogen from the nitratesource was transported from the roots to the shoot in nitrateand amino acid forms. A decrease of 15N-incorporation in the soluble N fraction andincrease in the insoluble N fraction from day 0 to day 10 inplant parts, particularly the blades, suggested that proteinsynthesis occurred mostly in young parts of the shoot duringthis period. The marked variation in 15N distribution in differentparts of the plant during the 10 days indicated that the nitrogenin roots and tillers was probably remobilized and transportedto other parts, particularly the upper leaf blades. Ammonium and nitrate nitrogen transport in rice plant are compared. (Received May 11, 1974; ) 相似文献
17.
Uptake of zinc from chelate-buffered nutrient solutions by wheat genotypes differing in zinc efficiency 总被引:3,自引:0,他引:3
Zinc-efficient Triticum aestivum (cv. Warigal) and Zn-inefficientTriticum turgidum conv. durum (cv. Durati) were grown in chelate-buffered,complete nutrient solutions providing either deficient or sufficientZn supply. When transferred to fresh chelatebuffered nutrientsolutions containing a wide range of Zn supplies (01.28µmol m3 Zn2+ activity) for 2448 h, bothgenotypes increased net Zn uptake linearly with an increasein solution Zn2+ activities. Zincefficient Warigal accumulatedZn at a greater rate than Zn-inefficient Durati. The greaterrate of net Zn uptake was observed by plants of both genotypeswhen pretreated at deficient Zn supply. Net loss of Zn to thesolution was higher in plants pretreated with sufficient Znand was inversely related to Zn2+ activity in the external solution.When continuously supplied with 40 nmol m3 Zn2+, netZn uptake by Zn-efficient Warigal was significantly greaterthan that of Zn-inefficient Durati, but the difference diminishedwith plant age. Shoot concentrations of Fe, Mn and Cu were higherwhen plants were grown at deficient than at sufficient Zn supply.The Zn-efficient genotype transported less Zn and Fe to shootsand had higher Fe concentrations in roots than the Zn-inefficientgenotype, supporting the hypothesis that Zn efficiency may beconnected with inefficient transport of Fe from roots to shootsand thus initiation of the Fe-deficiency response resultingin increased release of Zn- and Fe-binding phytosiderophores.It is concluded that differential Zn efficiency of wheat genotypesis at least partly due to a greater ability of efficient genotypesto accumulate Zn. Key words: Chelate-buffering, genotypes, micronutrients, Triticum spp., uptake, zinc efficiency 相似文献
18.
- The growth of the carrot root callus which had been subculturedfor a long period (CCL) was promoted by the addition of 5l08and 5l07 M kinetin, whereas in the callus subculturedfor a short period (CCS) no growth promotion was observed atany concentrations of kinetin tested.
- CCL showed an increasedgrowth in response to the applicationof kinetin, guanine, adenine,hypoxanthine, uracil, thymine,and cytosine in the presenceof fractions A and C of carrotroot extract, whereas no suchresponse was observed in CCS.CCL required fraction C to respondto uracil and probably purineand pyrimidine derivatives ingeneral.
- The growth of CCL was promoted by kinetin, guanine,adenine,or hypoxanthine in the medium containing inositol andaminoacids mixture. In this case the growth-promoting actionof guanine,adenine, or hypoxanthine was nullified by kinetin.
19.
SHIBAOKA HIROH; ANZAI TADASHI; MITSUHASHI MIEKO; SHIMOKORIYAMA MASAMI 《Plant & cell physiology》1967,8(4):647-656
- Heliangine at 1104 M promoted the adventitious rootformation in hypocotyls of cuttings taken from light-grown (1,900lux) Phaseolus mungo seedlings. The promotion was almost completelyreversed by 3104 M uracil, uridine, cytidine, oroticacid or 6104 M carbamoyl DL-aspartic acid, and partlyby 3104 M thymine or thymidine. Neither 3104M cytosine, adenine, adenosine, guanine, guanosine nor a combinationof 3104 M carbamoyl phosphate and 3104 M L-asparticacid reduced the promotion by heliangine.
- Uracil did not reducethe inhibiting effect of heliangine onthe indoleacetic acidinduced elongation of etiolated Avenacoleoptile sections.
- Helianginein an aqueous uracil solution was recovered unchangedafter24-hr incubation at room temperature.
- The root formation ofPhaseolus cuttings was promoted also by2-thiouracil and 5-fluorouracil.The effect was reversed byorotic acid or carbamoyl asparticacid, but not by carbamoylphosphate plus aspartic acid.
- Ribonucleaseat 100 µg/ml increased the number of rootsprotruded fromhypocotyls of cuttings by about 260%.
- A possible interpretationfor the promotion of root formationby heliangine is offered.
20.
- Purified preparation from rice-plant seedling catalyses a stoichiometricreaction between ATP, glutamate, and NH2OH in the presence ofMg++ to form glutamyl hydroxamate, ADP and inorganic phosphate.
- The method of purification and some of the properties of theenzyme are described. Co++ can be substituted for Mg++. Mn++,NaF, and PCMB inhibit the enzyme strongly.
- Inorganic orthophosphateis liberated from ATP by the additionof or cysteine in the presence of glutamate, Mg++ andthis preparation. Glutamine was detectedin the reaction productsby paperchromatography.
- The same preparation catalyses a reactionbetween gluta mineand NH2OH in the presence of Mg++ or Mn++,ADP and inorganicphosphate, to form glutamyl hydroxamate.