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1.
Wheat, red clover and ryegrass were grown in flowing solutionculture with sufficient (+ Cu) and deficient (Cu) suppliesof copper. The rates of Cu absorption (µg g1 dryroot day1) did not differ greatly between species ineither treatment. Wheat plants, when transferred from the Cu to the +Cu treatment, absorbed Cu at a much slower rate thanthose which had remained throughout in the + Cu treatment. Inall plants considerable proportions of the absorbed Cu wereretained in the roots, even when the plants were Cu-deficient,and the concentration in roots usually exceeded that in anypart of the shoots in both treatments. Transferring wheat plantsfrom the +Cu to the Cu treatment decreased the concentrationin all plant parts except old leaves; similarly, transferringfrom the Cu to +Cu treatment increased the concentrationin all parts of the shoots, execept old leaves, and in the roots. Lolium perenne, Trifolium pratense, Triticum aestivum, ryegrass, red clover, wheat, absorption, copper, flowing solution culture 相似文献
2.
Lemna paucicostata, normally a short-day plant, can be inducedto flower under long-day conditions by providing a cytokininin a medium containing a high level of ferric citrate (5 x 104M).Interestingly, when a cytokinin and EDDHA are present togetherin the medium, flowering is induced even at low levels of iron(105 and 5 x 105M ferric citrate). However, inthe absence of a cytokinin, flowering takes place only undershort days. (Received September 30, 1968; ) 相似文献
3.
L-Leucine Transport in Isolated Protoplasts of Vinca Suspension Culture: Characterization of Uptake 总被引:1,自引:0,他引:1
The uptake of L-leucine into Vinca protoplasts was studied undervarious conditions. The uptake was highly pH-dependent, withthe optimal pH between 3.0 and 4.0. The uptake was also energydependent, since azide, 2,4-dinitrophenol (DNP), carbonyl cyanidem-chlorophenyl hydrazone (CCCP), and iodoacetate inhibited theuptake. Oligomycin, N,N'-dicycIohexyI carbodiimide (DCCD) andvanadate, but not ouabain, inhibited the uptake, suggestingthat ATPase for H+ electrogenic extrusion was necessary to theuptake of L-leucine. The uptake showed stereospecificity, butwas partially inhibited by other L-amino acids. A kinetic studyof the uptake showed that the uptake was multiphasic with threesaturable phases and one unsaturable phase which occurred atconcentrations of L-leucine over 1 mM. The Km values of thethree affinity sites were 1.4 x 103 M, 1.3 x 104M, 4.3 x 105 M; the maximum velocity values were 3.3x 108, 4.5 x 109, 1.8 x 109 mol/10 min/4x 106 cells. (Received April 18, 1981; Accepted August 25, 1981) 相似文献
4.
5 x 105 M L-phenylalanine overcame the inhibitory effectof white light on cell division in artichoke callus culturesand increased extractable phenylalanine ammonia-lyase (PAL)activity compared to cultures grown in the presence of 5 x 104M phenylalanine The lower concentration of the amino acid alsoenhanced rates of uptake and incorporation of 14C labelled phenylalaninethroughout G1 and S. Differences between the two concentrationswere greatest during S with a 4-fold increase in uptake anda 3-fold increase in incorporation It is suggested thereforethat the capacity of 5 x105 M phenylalanine to offsetthe light effect is due to an indirect stimulatory effect onamino acid and protein metabolism Increased levels of extractablePAL activity would then be reflected by this general stimulationof protein synthesis. Helianthus tuberosus L, Jerusalem artichoke, callus culture, cell division, phenylalanine ammonia-lyase 相似文献
5.
The effect of changes in nitrate-nitrogen supply on the absorptionand distribution of copper was examined in grasses grown inflowing solution culture with a maintained concentration ofcopper. Absorption by roots (µg Cu g1 dry root)decreased markedly when nitrogen had been depleted or was maintainedat 0.1 mg l1 N, but there was an immediate increase whennitrogen was maintained at 1.0 or 10.0 mg l1. There werealso large increases in the concentration of copper in the shootsof plants grown with 1.0 and 10.0 mg 11 N. The rootsof plants grown with 0.1 or 1.0 mg 11 N retained similarproportions of uptake, but a lower proportion was retained whenthe plants were grown with 10.0 mg 11. Although a lowerproportion of the copper was associated with cell walls in theplants grown at 10.0 mg 11 N this was the result of alower content of cell walls rather than an effect on copperitself. In a longer-term experiment in conventional solutionculture with a range of nitrogen concentration, the concentrationof copper in shoots was largely determined by shoot growth. Dactylis glomerata, Festuca arundinacea, Lolium perenne, cell walls, copper absorption, copper distribution, flowing solution culture, nitrate-nitrogen 相似文献
6.
LAURIE STUART H.; TANCOCK NIGEL P.; MCGRATH STEPHEN P.; SANDERS J. ROGER 《Journal of experimental botany》1991,42(4):509-513
After growing barley (Hordeum vulgare L.) in nutrient solutionscontaining EDTA, uptake of the nutrient metals was determinedat three harvests and concentrations of the various chemicalspecies of each metal in the growth solutions was modelled bycomputer simulation. Complexation with EDTA had different effectson the uptake of the ions Fe3+, Mn2+, Cu2+, and Zn2+. At thehighest EDTA level (EDTA/Fe=2/l) the plants were chlorotic andgrowth was inhibited. This is attributed to a deficiency inZn rather than in Fe. The critical level of free Zn2+ requiredin nutrient solutions for healthy growth was found to be approximately10101010 mol dm3, which is consistent withthat found by earlier workers for other plant species. Barleytolerated much lower levels of the free ions of copper and ironwithout exhibiting any obvious adverse effects. Key words: EDTA, micronutrients, trace metals, computer simulation, deficiencies, absorption, iron, manganese, copper, zinc 相似文献
7.
Induction of CN-insensitive respiration with low concentrationsof respiratory inhibitors was studied. If roots were treatedwith 103 M CN for 96 hr, the plants died, whilethose treated with 104 M CN showed healthy growth. O2 uptake in untreated rice and wheat roots showed a negativeresponse to 102 M CN to a considerable extent.On the other hand, pretreatment with 104 M CNfor more than 6 hr did not greatly affect respiratory rate,but made respiration insensitive to 102 M CN.A similar induction of CN-insensitivity was also broughtabout with 104 and 103 M H2S and 104 MNaN3. (Received July 6, 1971; ) 相似文献
8.
AGARWALA S. C.; CHATTERJEE C.; SHARMA C. P.; NAUTIYAL N. 《Journal of experimental botany》1985,36(6):881-888
Sugarbeet (Beta vulgaris L.) plants were grown in refined sandat graded levels of copper ranging from acute deficiency (0.000325µg Cu cm3) to excess (65 µg Cu cm3).Visible effects of copper deficiency appeared up to 0-00065µg Cu cm3and depression in growth up to 00065µCucm3. Copper deficiency decreased the concentrations ofDNA and RNA and the activities of polyphenol oxidase, cytochrome-coxidase, catalase and aldolase; and it increased the activitiesof peroxidase, ribonuclease and acid phosphatase in leaves.The maximum sucrose concentration in roots was obtained at 0-65µCucm3 Twenty four h after infiltration of a solution of 65µCucm3into copper deficient leaves, the activities of cytochrome-coxidase and peroxidase had increased even in the presence ofcycloheximide but that of polyphenol oxidase increased onlyin the absence of this inhibitor. Key words: Beta vulgaris, Cu deficiency: Enzymes 相似文献
9.
Regulation of Sulphate Transport in a Tropical Legume, Macroptilium atropurpureum, cv. Siratro 总被引:2,自引:0,他引:2
CLARKSON DAVID T.; SMITH FRANK W.; BERG PETER J. VANDEN 《Journal of experimental botany》1983,34(11):1463-1483
When young plants of Macroptilium atropurpureum, cv. Siratrowere deprived of external sulphate (-S plants) growth of shootsand roots continued at rates comparable to those in plants wellsupplied with sulphate (control) for 3 d and 5 d respectively.Dilution of internal sulphur therefore took place and redistributionof sulphur occurred between inorganic and organic forms andbetween roots and younger leaves. Even when S-deficiency limitedgrowth, plants contained 16% of their total sulphur as sulphate,but most of this was retained in old leaves and redistributedslowly to growing zones. The capacity for sulphate uptake increased in roots of Splants very soon after they were deprived of external sulphate;within 24 h the absorption from 0.25 mol m3 SO42was more than five times that of control roots. Maximum increasedcapacity was reached after 23 d stress when the Vmaxof system 1 was 1948 nmol h1g1root fr. wt. inS plants and 337 nmol h1g1root fr. wt.in controls. The Kmfor system 1 did not change significantlywith S-stress being between 58 µM in both setsof plants. Absorption of L-cysteine was not stimulated by S-stress. There was a close, positive relationship between plant growthrate and the rate at which sulphate uptake capacity was enhancedby withholding sulphate from culture solutions. When S plants were replaced in sulphate-containing solutiontheir capacity for SO42 declined to the control levelwithin 24 h. Very marked repression of capacity was also foundwhen S plants were treated with L-cysteine, but therewas no immediate effect with methionine. Roots of this species appear to have a very active system fordegrading L-cysteine to sulphate, 30% of the label in 35S-cysteineabsorbed by roots was recovered in 35SO42 after 20 minor 2 h incubation. By contrast, roots had a very weak abilityto reduce sulphate. When part of the root system was in solution lacking sulphatethere was enhanced uptake of sulphate by other parts which themselveswere amply supplied with sulphate. This is seen as an exampleof compensatory absorption. The response to S-stress is specific and there were no positiveinteractions between S-stress and the absorption of phosphate,or P-stress and the uptake of sulphate. The results are discussed in relation to the close control ofsulphate uptake by internal sulphate concentration, redistributionof forms of sulphur during stress and mobility of sulphate inthe phloem. Key words: Kinetics, Amino-S, Sulpholipid, Repression;, Deficiency 相似文献
10.
107 M cycloheximide inhibited bean (Phaseolus vulgaris)root elongation by about 20 per cent but it inhibited absorptionof rubidium, sodium, and phosphate ions to a much greater extent(3471 per cent). Tips of intact plant roots grown inthe inhibitor showed more inhibition in ion uptake than adjacentproximal portions of the same roots and this is taken to indicatethat 107 M cycloheximide does not exert its effect onion uptake by any uncoupling action. Sodium uptake from 0.5 or 10 mM NaCl solutions by root tipswas inhibited by 107 M cycloheximide to twice the extentthat it was in the elongating region of the root. Assuming thatthe inhibitor affects the plasmalemma more than the tonoplast,Epstein's model of parallel operation of system 1 and system2 at the plasmalemma is supported. 相似文献
11.
The NADP$-specific isocitrate dehydrogenase was partially purifiedfrom photosynthetically-grown Rhodospirillum rubrum. The pHoptimum is between 7.5 and 9.0 in phosphate buffer. The apparentKm is 3.1x105 M for isocitrate, 5.1x105 M forNADP$, 1.7x105 M for manganese, 1.5x104 M formagnesium, and 3.5x103 M for inorganic orthophosphate.Arsenate exerts a slight inhibition. The Q10 between 17.5°Cand 40°C is 1.62, and the energy of activation at 25°Cis 9.74 Kcal/mole. Glyoxylate and oxalacetate cause concertedinhibition of the enzyme activity. Various nucleotides inhibitthe activity. The kinetics of inhibition by ATP was found tobe mixed type with respect to NADP$ and isocitrate, the Ki valuesbeing 1.17x103 M and 1.10x103 M respectively.The inhibition between ATP and orthophosphate is competitivewith a Ki of 104M. Thiol binding reagents are inhibitory;this inhibition is reversed by cysteine or reduced glutathione. (Received October 1, 1971; ) 相似文献
12.
Guttation was used as a non-destructive way to study the flowof water and mineral ions from the roots and compared with parallelmeasurements of root exudation. Guttation of the leaves of barley seedlings depends on age andon the culture solution. Best rates of guttation were obtainedwith the primary leaves of 6- to 7-day-old seedlings grown onfull mineral nutrient solution. The growing leaf tissue becomessaturated with K+ below 1.5 mM K+ in the medium, whereas K+concentration in the guttated fluid still increases furtheras K+ concentration in the medium is raised. At 3 mM K+ averagevalues of guttation were 1.42.4 mm3 h1 per plantwith a K+ concentration of 1020 mM; for exuding plantsthe flow was 4.27.6 mm3 h1 per plant and K+ concentration3555 mM. Abscisic acid (ABA) at 106 to 104 M 02h after addition to the root medium increased volume flow ofguttation and exudation and the amount of K+ exported. Threeh after addition of ABA both volume and amount of K+ were reduced.There was an ABA-dependent increase in water permeability (Lp)of exuding roots shortly after ABA addition. Later Lp was decreasedby 35 per cent and salt export by 60 per cent suggesting aneffect of ABA on salt transport to the xylem apart from itseffect on Lp. Benzyladenine (5 x 108 to 105 M)and kinetin (5 x 106 M) progressively reduced volumeflow and K+ export in guttation and exudation and reduced Lp. Guttation showed a qualitatively similar response to phytohormonesas found here and elsewhere using exuding roots. Hordeum vulgare L., barley, guttation, abscisic acid, cytokinins, benzyl adenine, kinetin 相似文献
13.
Role of Copper Binding, Absorption, and Translocation in Copper Tolerance of Agrostis gigantea Roth 总被引:3,自引:0,他引:3
The capacity of roots to accumulate and retain copper was examinedin two clones of Agrostis gigantea which differ in their toleranceto excess copper. Root elongation growth in the non-tolerantclone was completely inhibited by 16 mmol m3 Cu whereas40 mmol m3 was required for inhibition in the tolerantclone. The amount of readily exchangeable copper was greaterin roots of the tolerant clone than in the non-tolerant clone.The higher capacity for binding copper did not prevent the entryof copper into the cells of intact or excised roots of the tolerantclone. Roots of both clones contained similar amounts of copperafter removal of the readily exchangeable fraction. More copperwas translocated to the shoots of the tolerant than the non-tolerantclone. The explanation of copper tolerance in Agrostis giganteamust be sought in areas other than those of differences in grosscopper absorption and retention by roots. 相似文献
14.
Recognition taste thresholds for phenylthiocarbamide (PTC),a specific bitter substance, in Japanese dental students weremeasured with 372 males of 2036 years old and 55 femalesof 2034 years old. The mean PTC threshold in male studentswas 2.7 x 105 M for tasters and 8.9 x 103 M fornon-tasters. The mean threshold in female students was 2.5 x105 M for tasters and 6.5 x 103 M for the non-tasters.The percentage of non-tasters in a total of 427 male and femalestudents was 5.4%. There was no significant difference in non-tasterdistributions between students from the western districts ofJapan and from other districts. 相似文献
15.
Direct somatic embryogenesis can be obtained from epidermaland cortical cells in roots from in vitro Cichorium plantlets.The first embryogenic cells are seen after six days of culturein darkness, at 35 °C, in a liquid medium supplemented withNAA (1 x 107 M), 6-dimethylallyl-amino-purine (2·5x 106 M), sucrose (0.03 M) and glutamine (1·7x 103 M). Embryogenic cells undergo first a linear andthen a globular segmentation, with increasing cytoplasmic density.These cells and young embryoids show aniline blue fluorescence.SEM allows the same microglobular pattern to be seen on thesurface of young embryoids and on young microspores of Cichoriumused as controls. In this root system, callose deposition seemsto be an early marker in somatic embryogenesis. Somatic embryogenesis, callose, Cichorium 相似文献
16.
Growth of the Vicia faba seedling is accompanied by a rapid15-day increase in amine oxidase activity of the apical parts.Cotyledons and roots were found to be devoid of activity. Thepartially purified enzyme from leaves readily oxidized putrescine,cadaverine, agmatine and spermidine, while dopamine (3-hydroxytyramine)and L- and D-lysine were oxidized more slowly. The Km valueswere 1.9?103 M for cadaverine, 3.7?105 M for putrescine,7.8?104 M for spermidine, and 5.9?103 M for dopamine.Carbonyl reagents and copper-binding agents were effective inhibitorsof Vicia faba amine oxidase. The diethyldithiocarbamate-treatedenzyme could be reactivated specifically by cupric copper. (Received May 25, 1977; ) 相似文献
17.
The absorption and distribution of Cu in red clover (Trifoliumpratense L.) were measured in plants grown in flowing solutionculture with Cu maintained throughout at 0.5 µg 11and N supplied either as nitrate or through symbiotic fixation.Although there was a decrease in Cu absorption, both with time,and with a depleted nitrate supply, it increased to its formerrate when nitrate was adjusted to 10 mg N 11 after aperiod of depletion. Differences in absorption between plantsdependent upon fixation and those supplied with nitrate wererelated to the slower initial growth of the plants fixing N.Considerable proportions (> 30 per cent) of the absorbedCu were retained by the roots. At the final harvest, and withthe exception of plants grown with nitrate adjusted to 0.1 mgN 11 after a period of depletion, the proportion of theCu retained was related to the concentration of N in the roots.The different N treatments produced differences in Cu concentrationin the shoots, and the effects were greater in the youngestfully expanded leaves than in older leaves. Trifolium pratense L., red clover, absorption, copper, flowing solution culture, nitrogen 相似文献
18.
Incorporation of polyamine-spermidine into the nutrient mediumat 106 and 105 M concentrations stimulates pollen-tubegrowth in vitro in Catharanthus roseus L. G. Don. MGBG, an inhibitorof spermidine biosynthesis, at 0.5 x 103 and 1 x 103M concentrations reduced the percentage of germination as wellas tube growth and at a concentration of 1.5 x 103 Mgermination was totally inhibited. Pollen grains incubated inthe medium containing 1.5 x 103 M MGBG, when transferredto a fresh medium with 105 M spermidine, resulted in80% germination recovery, along with considerable tube growth.Experiments with actinomycin-D indicate that stimulation ofpollen-tube growth by spermidine may involve de novo synthesisof protein. Catharanthus roseus, pollen germination, tube growth, spermidine, MGBG, inhibition, actinomycin-D 相似文献
19.
Luttge Ulrich; Osmond C. Barry; Ball Erika; Brinckmann Enno; Kinze Gabriele 《Plant & cell physiology》1972,13(3):505-514
Bisulfite compounds are shown to be nonspecific inhibitors ofphotosynthetic processes and of ion transport in green tissues.CO2 fixation and light-dependent transient changes in externalpH are inhibited about 50% by 5x104 M glyoxal-Na-bisulfite.Chloride uptake in the light and in the dark is inhibited tothe same extent at this concentration. At 5x103 M theinhibitor reduces ATP levels in the light and in the dark, andeffects on glycolate oxidase and PEP carboxylase are observed.The extent of inhibition is dependent on time of treatment withglyoxal-Na-bisulfite and freshly prepared NaHSO3 is equallyas effective as the addition compound. Possible explanations of the bisulfite effects and the relationshipsto SO2 effects on photosynthesis are discussed. (Received September 1, 1971; ) 相似文献
20.
The generally-accepted characteristics of ion transport in planttissue do not apply completely in the case of zinc uptake. Inthis case, 5x15 M CCP (which completely stops rubidiumuptake in barley roots) shows little inhibitory effect. In thisrespect it is like DNP which also shows little influence onzinc uptake in this concentration.
1 Present Address: Department of Botany and Plant Pathology,University of Minnesota, St. Paul, Minnesota, U.S.A. 相似文献