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1.
The activities of enzymes involved in general phenylpropanoidmetabolism were followed in a carrot suspension culture duringthe induction and reduction of anthocyanin synthesis regulatedby 2,4-D. When no anthocyanin synthesis occurred in a mediumcontaining 2,4-D (+2,4-D medium), the activities of phenylalanineammonia-lyase (PAL) and 4-coumarate:CoA ligase (4CL) increased1 day after transfer due to the transfer effect, but subsequentlydecreased and remained at a low level. Cinnamate-4-hydroxylase(C4H) activity showed a low level throughout culture. When cellswere transferred to a medium lacking 2,4-D (2,4-D medium),the activities of PAL, C4H and 4CL increased and maximum activitiesof these enzymes were observed 67 days after transfer,when anthocyanin was most rapidly synthesized. When cells were cultured in the 2,4-D medium, the additionof 2,4-D immediately reduced the induced activity of PAL. PALactivity was super-induced by the transfer effect, while anthocyaninsynthesis decreased. The addition of intermediates of generalphenylpropanoid metabolism, with 2,4-D, to the medium 6 daysafter transfer to the 2,4-D medium did not promote anthocyaninsynthesis, whereas dihydroquercetin did promote it. Regulationof anthocyanin synthesis by 2,4-D is discussed in relation tochanges in enzyme activities involved in general phenylpropanoidmetabolism.
1 Present address: Cell Science and Technology Division, FermentationResearch Institute, Agency of Industrial Science and Technology,Yatabe-machi, Ibaraki 305, Japan.
2 Present address: Biological Institute, Faculty of Science,Tohoku University, Sendai 980, Japan. 相似文献
2.
Effects of Growth Regulators on the Induction of Anthocyanin Synthesis in Carrot Suspension Cultures 总被引:5,自引:0,他引:5
The effects of plant growth regulators were investigated onanthocyanin synthesis induced by removing auxin from carrotsuspension cultures. Of the auxins tested, 2,4-D showed thestrongest inhibiting effect on anthocyanin synthesis and hadthe strongest promoting effect on undifferentiated growth. When2,4-D was added to anthocyanin synthesizing cells, in whichcell division had ceased, anthocyanin synthesis was repressedimmediately, accumulated anthocyanin disappeared and cell divisionresumed. All cytokinins examined promoted anthocyanin synthesisin the absence of auxin. Both gibberellic acid (GA3) and abscisicacid inhibited anthocyanin synthesis in media lacking 2,4-D,though GA3 showed no effect on cell division. These effectsof growth regulators on anthocyanin synthesis are similar tothose reported for their effects on embryogenesis [Fujimuraand Komamine (1975) Plant Sci. Lett. 5: 359, (1979) Z. Pflanzenphysiol.95: 13, (1980) Z. PJlanzenphysiol. 99: 1]. The relationshipbetween the induction of anthocyanin synthesis, metabolic differentiation,and embryogenesis are discussed.
1 Present address: Department of Biology, College of Arts andSciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo153, Japan.
2 Present address: Biological Institute, Faculty of Science,Tohoku University, Sendai, Miyagi 980, Japan. (Received November 28, 1985; Accepted July 23, 1986) 相似文献
3.
The changes in the activities of active oxygen scavenging enzymesand lipid peroxidation during callus formation from germinatingmature rice embryo was investigated. Superoxide dismutase (SOD)and catalase (CAT) activities were much lower during callusformation than during seedling growth indicating the decliningcapacity of the callus tissue to scavenge O.-2 and H2O2 respectively.Other H2O2-utilizing enzymes such as guaiacol peroxidase (GPOX)and ascorbate peroxidase (APOX) had also much lower activitiesduring the initial period of callus formation than during normalgermination but soon these enzyme activities were rapidly enhancedduring callus growth but declined during seedling growth. SinceH2O2 level was quite high in the callus tissue, it is probablethat GPOX and APOX are not efficient in decomposing H2O2 inthis tissue. Water soluble non-protein -SH compounds of whichGSH is the major component increased more rapidly during seedlinggrowth than during callus formation. This was reflected by thehigher activity of glutathione reductase (GR) in the seedlingtissue than in the callus tissue. Although peroxide and malondialdehydedid not accumulate during the callus initiation period, thefast decrease in the SOD and CAT activities indicates that duringthis transition period the tissue has increasing tendency towardsan oxidative state because of the weakening of the scavengingmechanism. The cellular environment, thereafter, becomes moreoxidizing during callus growth when compared with the normalseedling development in the absence of 2,4-D. (Received September 8, 1994; Accepted February 16, 1995) 相似文献
4.
Changes in respiratory metabolism accompanied by callus formationin cultured explants of carrot root were followed and the followingresults were obtained. 1) When the explant was cultured on amedium containing kinetin and 2,4-D, active cell division occurredand resulted in callus formation by the 9th12th days.2) Fresh weight remarkably increased after a lag-time of about5 days. Changes in protein content on fresh weight basis weresimilar to changes in fresh weight. 3) Respiration rate increasedduring the first few days, when growth could not be distinctlymeasured. Accompanying the rise in respiration, the C6/C1 ratioalso increased. As callus developed, the respiratory rate andC6/C1 ratio gradually decreased and RQ, became higher than unity.4) Alcohol dehydrogenase activity increased between the 4thand 9th days after culture. 5) When sub-cultured callus tissuewas fed with G-U-14C, some radioactivity was detected in thealcohol of the tissues. 6) These results suggest that duringthe first 46 days after culture the activity of the EMBDEN-MEYERHOF-PARNAS-TCApathway was remarkably increased and, as callus developed, therelative participation of the pentose phosphate pathway graduallyincreased and simultaneously alcohol fermentation occurred. (Received December 13, 1968; ) 相似文献
5.
6.
2,4-D-Sustained Photomixotrophic Growth of a Chlorophyllous Cell Suspension Culture of Nicotiana tabacum 总被引:1,自引:0,他引:1
Nagai Tomoo; Nakamura Chiharu; Nagayoshi Teruto; Ono Hajime 《Plant & cell physiology》1989,30(1):17-23
A chlorophyllous, photomixotrophic cell suspension culture oftobacco (Nicotiana tabacum L.) was established using mediumcontaining 30 g/liter of sucrose and 1.5 µM 2,4-D. The2,4-D-sustained photomixotrophic line was able to show rapidregreening in the light after bleaching in the dark and characterizedwith a much slower and longer growth cycle than a heterotrophicline derived from the same original callus (cell doubling timeof 100 h vs. 40 h and duration of logarithmic phase of 17 daysvs. 7 days). The photomixotrophic line took up sucrose morerapidly than the heterotrophic line and accumulated starch duringthe early logarithmic phase when it showed a maximum photosyntheticcapacity on a chlorophyll basis (6.3µmol O2/min/mg Chl).Chlorophyll content and photosynthetic capacity on a per cellbasis and on a cell fresh weight basis, on the other hand, decreasedduring this phase and reincreased later to reach maximum levels(310 µg Chl/g fr wt; 1.4 µmol O2/min/g fr wt) whenthe line exhibited the highest activities of dark respiration(1.0 µmol; O2/min/g fr wt) and cell division (mitoticindex of 3.0%). These characteristics of the photomixotrophicline were lost if it was grown in the dark to become non-chlorophyllous.Although net O2 evolution could not be detected in the photomixotrophicline throughout the growth cycle when assayed under suboptimumlight intensity, reaccumulation of starch and a marked increasein cell fresh weight upon addition of minerals, vitamins and2,4-D without sucrose at the late logarithmic phase indicatedthe development of photosynthetic activity under the cultureconditions.
1The investigations reported were included in the thesis submittedto the Graduate School, Faculty of Agriculture, Kobe University,in partial fulfillment of the requirement for M. Agr. degree. (Received May 30, 1988; Accepted October 5, 1988) 相似文献
7.
The effects of different concentrations of L--aminooxy-ß-phenyIpropionicacid (AOPP), an analog of L-phenylalanine, on the activity ofphenylalanine ammonia-lyase (PAL, EC 4.3.1.5
[EC]
) and the growthof radicles in 24 h old germinating lettuce (Lactuca salivaL.) seeds were investigated. AOPP causes a significant inhibitionof PAL activity in the seeds (85% inhibition at 104 M). It alsocauses a stimulation of radicle growth at that concentration.The results show that the inhibition of PAL by AOPP may be dueto an irreversible binding of the inhibitor to the enzyme leadingto its inactivation. AOPP also inhibits ethylene biosynthesisin germinating lettuce seeds which could probably explain thestimulation of radicle growth in these seeds. The enzyme shows typical Michaelis-Menten kinetics. The Km forL-phenylalanine is 4.2 x 105 M. The enzyme does not show anytyrosine ammonia-lyase activity. Various substrate analogs suchas D-phenylalanine, p-fluorophenylalanine, ß-phenyllacticacid, tryptophan and the product of the enzyme reaction, trans-cinnamicacid, inhibit the enzyme competitively. A number of intermediatesand endproducts of the phenylpropanpid pathway, except chlorogenicacid, do not show any inhibition.
1Scientific contribution number 1423 from the New HampshireAgricultural Experiment Station. (Received May 9, 1986; Accepted September 8, 1986) 相似文献
8.
R. J. Westcott 《Planta》1976,131(3):209-210
Summary 2-(Chloroethyl)phosphonic acid (CEPA) inhibited the rise in tannin production and phenylalanine ammonia-lyase EC 4.1.1.5 (PAL) activity shown by Acer cells in media containing 9.0×10–7 M 2,4-D for a period of 2–3 days after its addtion.Abbreviation 2,4-D
2,4-dichlorophenoxyacetic acid 相似文献
9.
Abstract The effects of light and gibberellic acid (GA3) on growth and phenylalanine ammonia-lyase (PAL) activity were studied in seedlings of lettuce (Lactuca sativa L.). Using an in vivo assay for PAL it was shown that wounding caused by excising hypocotyls results in an increase in PAL activity with time that can mask the effect of light on the activity of this enzyme. When hypocotyl sections were excised from light-treated seedlings immediately prior to the in vivo assay of PAL, light was shown to cause a marked increase in PAL activity. Experiments with an inhibitor of PAL activity, α-aminooxy-β-phenylpropionic acid (AOPP), confirmed that the volatile radioactive products measured in the in vivo assay resulted from the activity of PAL. Gibberellic acid suppresses the light-induced increase in PAL activity and there is an inverse relationship between GA3-induced growth and the activity of PAL. Over a wide range of GA3 concentrations, the activity of PAL is also inversely correlated with growth rate along the length of the hypocotyl section; the upper halves of sections elongate more rapidly and have lower levels of PAL than the lower halves. Despite the strong correlation between growth and PAL activity, experiments with AOPP and t-cinnamic acid show that it is unlikely that elongation is regulated directly by products of PAL activity. 相似文献
10.
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
11.
Omission of 2,4-dichlorophenoxyacetic acid (2,4-D) from batchcultures of sycamore produced an immediate reduction in ratesof cell division and eventually in rates of biomass accumulation.The sequential responses of a chemostat and of turbidostat culturessubjected to gradual withdrawal of 2,4-P were: (i) a transientincrease in biomass accumulation, (ii) increased accumulationof p-coumaric acid, flavonoids, and lignin, (iii) increasedcell aggregation, (iv) reduced rates of cell division, and (v)death. During stepwise reduction of 2,4-D supplied to turbidostatcultures, rates of 2,4-D uptake were reduced when the spentmedium concentration fell to 3?51?0 ? 107 M. Underthese conditions the 2,4-D concentration in soluble and insolublecell fractions declined. The growth responses were correlatedwith the spent-medium 2,4-D concentration but not with its concentrationin the intracellular fractions. 相似文献
12.
Summary Phenolic metabolism is influenced by the levels of sucrose, nitrogen and 2,4 dichlorophenoxyacetic acid (2,4-D) in the growth medium. Chromatographic evidence suggests that the principle products are polymers of leucocyanin, (-) epicatechin and (+) catechin, constituting condensed tannins. Comparison of ethanolic cell extracts with extracts from plant organs shows that although these compounds are present in parts of the plant they are not the major phenolics.Cells maintained in a modified Heller's medium containing 9.0×10–7 M 2,4-D produce increased levels of tannins from mid passage (day 12) onwards. The presence of 2,4-D at 9.0×10–6 M supresses this response and increased initial sucrose levels cause the amount of tannins to be greater. At the period when tannin levels increase the standard medium is exhaused of its nitrogen sources, urea and nitrate. Increased initial nitrogen levels delay the beginning of increased tannin production and the addition of urea or 2,4-D to cultures already containing high levels of tannins causes the tannin content per gram fresh weight and per culture to decline. These results indicate an antagonism between tannin synthesis and nitrogen metabolism. The activity of phenylalanine ammonia-lyase EC 4.1.1.5. (PAL) estimated by a spectrophotometric method in acetone powders derived from Acer cells increases three to four fold at the onset of increased tannin synthesis and then declines sharply. The phase of high PAL activity correlates with the exhausion of the medium nitrogen sources.Abbreviation 2,4-D
2,4-dichlorophenoxyacetic acid
One of the authors (R.J.W.) was supported by a Science Research Council Studentship during the course of this work. 相似文献
13.
Dimethipin (2,3-Dihydro-5,6-dimethyl-1,4-dithiin 1,1,4,4-tetraoxide) Effects on Soybean Seedling Growth and Metabolism 总被引:1,自引:0,他引:1
Three-day-old dark-grown soybean [Glycine max (L.) Merr.] seedlingswere transferred to 2 mM CaSO4 or 105 M dimethipin in2 nM CaSO4 and root-fed via liquid culture. Plants were placedin continuous darkness or in continuous white light (200 µE.m2?s11,PAR) at 25?C. Dimethipin inhibited root and shoot elongationin dark-grown plants after 24 h and 48 h, respectively. In thelight, root elongation was inhibited also after 24 h, but hypocotylelongation was not significantly affected. Extractable phenylalanineammonia-lyase (PAL) activity per axis in dimethipin-treateddark-grown axes was not generally affected but, in the lightdimethipin caused a significant decrease in PAL activity (24to 96 h). Total soluble hydroxyphenolics in axes were not affectedby dimethipin in light- or dark-grown plants. Anthocyanin andchlorophyll levels were lowered in hypocotyls of dimethipin-treatedplants after 48 to 96 h. Soluble protein in hypocotyls of light-or dark-grown seedlings was not substantially affected by dimethipin.Nitrate reductase (NR) activity (per organ) was generally notaffected by dimethipin in light-grown cotyledons, but in theroots of these seedlings, NR activity was significantly decreased.Proteolytic enzyme activity using three substrates (leucine-p-nitroanilide,LPNA; proline-p-nitroanilide, PPNA; and benzoylarginine-p-nitroanilide,BAPA) indicated little effect on enzyme activities per organin roots and hypocotyls. These data suggest that dimethipinat low concentrations can cause significant growth inhibitionin soybean seedlings grown in either light or darkness and thatfurthermore, extractable activities of some enzymes associatedwith nitrogen metabolism and secondary metabolism are alteredby this chemical. Light also plays a role in the activity ofthis chemical. (Received November 29, 1983; Accepted January 25, 1984) 相似文献
14.
An 18-h treatment of synchronously-grown Chlorella pyrenoidosawith 2,4-D did not significantly alter the size, dry weight,degree of synchrony, or pigment content of the cells, nor weredetectable quantities of ethylene produced. When Chlorella pyrenoidosawas treated with 5?104 M 2,4-D, there was a statisticallysignificant stimulation of both net oxygen uptake and productionwhile 5?10 M 2,4-D inhibited both processes. When Chlorellapyrenoidosa was treated with 5?104 M and 5?103M 2,4-D, significantly greater amounts of glycollate were presentin the culture medium, even though an assay for glycollate dehydrogenaseshowed that the activity of this enzyme from 2,4-D-treated Chlorellapyrenoidosa was three times greater than in control cells. Looselybound 2,4-D was partitioned from a nonaqueously isolated chloroplastfraction, while other cell fractions failed to show detectablequantities of 2,4-D. It is postulated that in Chlorella pyrenoidosathe chloroplast is a target for 2,4-D action and that interferencein photorespiratory processes may underlie the observed responses. 相似文献
15.
O-Benzylhydroxylamine (OBHA) is a potent inhibitor of phenylalanineammonialyase (PAL, EC 4.3.1.5
[EC]
) and phenylpropanoid metabolismas evidenced by its effects on three plant species [soybean(Glycine max (L.) Merr.), buckwheat (Fagopyrum esculentum Moench.),and mung bean (Vigna radiata L.)]. When supplied to roots, OBHA(105 M) did not significantly inhibit light- or dark-growthof soybean seedlings, but reduced (25%) soluble hydroxyphenoliccompound accumulation in light-grown axes. Higher concentrations(5105 M) of OBHA caused reductions (25%) in axis freshweight of light-grown seedlings (72 h), but did not lower axisweight of dark-grown seedlings. Anthocyanin accumulation inhypocotyls of intact mung bean seedlings was reduced by 25%after 3 days light growth after treatment with OBHA (105M) via root feeding. Anthocyanin content of excised, etiolatedbuckwheat hypocotyls floated on solutions of OBHA (105M) and incubated in the light for 24 h was reduced by 40%. L-Phenylalanineand t-cinnamic acid, intermediates of phenylpropanoid metabolism,were able to partially reverse this inhibition in buckwheat.Extractable PAL activity (specific activity basis) in soybeanaxes was substantially reduced (20% in dark, 40% in light) asearly as 24 h after root feeding with OBHA (105 M). Reductionof PAL activity (specific activity or per axis basis) by OBHAcompared to control levels, continued throughout a time courseof 96 h. Kinetic studies on soybean PAL revealed a Km of 1.1mM for L-phenylalanine and an apparent Ki of 3.5 µM forOBHA. (Received May 31, 1985; Accepted August 6, 1985) 相似文献
16.
A study has been made of the dark metabolism of CO2 by elongatingfibres of Gossypium arboreum L. cv. LD 133 (a short staple type)and Gossypium hirsutum L. cv. LH 372 (a long staple type) atdifferent fibre ages. In both cultivars, phosphoenolpyruvatecarboxylasc, glutamate-oxalacetate transaminase and malate dehydrogenaseshow elevated activities during the period of rapid fibre growthand lowered activity with ageing. Malic enzyme activity increasesas extension growth levels off. Levels of K+ and malate riseduring rapid extension growth and fall as the rate of elongationdecreases. The results indicate that malate may act as an osmoticumand a counterion for K+ accumulation during rapid expansionof the fibres. Amounts of enzymes, K+ and malate are higherin the fibres of the long staple cultivar than the short staple.During the period of active elongation, K+/malate ratio is higherin the short staple cultivar. Key words: Gossypium hirsutum, CO2 metabolism, Fibre extension 相似文献
17.
The rate of excretion of glycolate by the unicellular greenalga Ankistrodesmus braunii changes during its life cycle. Itis high in the main growth phase during the light period witha maximum 6 hr after the start of illumination, and low duringthe period of cell division in the dark. The glycolate excretion is stimulated by DSPD and HPMS, whilethe total 14CO2-fixation is inhibited by DSPD and enhanced byHPMS. Changes in the effects of DSPD and HPMS on glycolate excretionas well as on photosynthetic 14CO2-fixation during the courseof the algal life cycle were followed using the technique ofsynchronous culture. How far the change of glycolate excretion is due to a changeof glycolate oxidase activity during the life cycle and to achange of C2-supply from the carbon reduction cycle is discussed.The effect of DSPD on glycolate excretion suggests a participationof ferredoxin in the glycolate pathway. (Received August 10, 1968; ) 相似文献
18.
A stable freeze-dried powder was prepared of partly purifiedribulose bisphosphate carboxylase from wheat leaves. As withpreparations from other leaves it is necessary to incubate theenzyme with Mg2$ and CO2 to achieve maximum activity. At 25°C this activity was 0.75 IU mg1 protein for a preparationactivated at 50 °C for 10 min; the Km for CO2 was 15 µM. The time for reactivation of enzyme that had been inactivatedthrough the absence of CO2 and Mg2$ was influenced by the lengthof the inactivating treatment. After a short inactivation periodthe enzyme was reactivated within a few minutes, whereas aftera longer period several hours were needed. Enzyme in the latterstate had some properties in common with enzyme inactivatedby lower temperatures but in the presence of CO2 and Mg2$. Theenzyme kinetic characteristics are similarly affected by bothkinds of inactivation; the maximum velocity is decreased butthe affinity for CO2 is not affected. Reactivation following a long inactivating treatment becomesmore dependent on Mg2$ concentration as the temperature is increasedfrom 0 to 20 °C. 相似文献
19.
IAA, 2,4-D and GA3 promoted the elongation of young hyphae inNeurospora crassa at the optimum concentrations of 106,106 and 104 M, respectively. The effects of IAAand GA3 were additive. (Received June 17, 1983; Accepted December 22, 1983) 相似文献
20.
Changes in composition and synthesis of the proteins in plasmamembranes during early periods of induction of callus from tubertissues of Jerusalem artichoke were examined in relation toanalogous changes in H+-ATPase activity. By the 12th h of culture,vanadate-sensitive ATPase activity had increased more than 3.5-fold.The level of a polypeptide with a molecular mass of 97 kDa,which putatively corresponded to a subunit of the plasma membraneH+-ATPase, also showed a similar increase. Increases in ATPaseactivity and in the level of the 97-kDa polypeptide occurredindependently of the presence of 2,4-D in the culture mediumbut the rate of increase in both cases was slightly higher fortissue disks cultured with 2,4-D than for the control disksin medium without 2,4-D for the first 12 h of culture. The increasein the level of the 97-kDa polypeptide may be ascribed predominantlyto synthesis de novo during the early period of culture. Enhancedsynthesis of the 97-kDa polypeptide in the cultured tissuesmay have resulted in the increases in ATPase activity. Sinceauxin itself may stimulate H+-ATPase activity, the activatedH+-ATPase may be further stimulated in tissue disks culturedwith 2,4-D. The H+-ATPase activated in this way may produceconditions that facilitate the induction of callus from tubertissues of Jerusalem artichoke during the early period of culture. (Received July 13, 1992; Accepted October 19, 1992) 相似文献