首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
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 1.4–2.4 mm3 h–1 per plantwith a K+ concentration of 10–20 mM; for exuding plantsthe flow was 4.2–7.6 mm3 h–1 per plant and K+ concentration35–55 mM. Abscisic acid (ABA) at 10–6 to 10–4 M 0–2h 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 10–8 to 10–5 M)and kinetin (5 x 10–6 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   

2.
3.
Epidermal strips and leaf fragments of Commelina and leaf fragmentsof maize were incubated on solutions containing naturally-occurringor synthetic cytokinins and/or ABA. The effects of these treatmentson stomatal behaviour were assessed. Cytokinins alone did notpromote stomatal opening in either species but concentrationsof both zeatin and kinetin from 10–3 to 10–1 molm–3 caused some reversal of ABA-stimulated closure ofmaize stomata. The reversal of the ABA effect increased withincreasing cytokinin concentration. Cytokinins had no effecton ABA-stimulated closure of Commelina stomata. When appliedalone, at high concentration (10–1 mol m–3), toCommelina epidermis or leaf pieces both zeatin and kinetin restrictedstomatal opening. Key words: ABA, Cytokinins, Stomata, Maize, Commelina  相似文献   

4.
Potato plants (Solanum tuberosum L.) were grown in water culture.About 14 d after tuber initiation no significant differenceswere found between apical and basal tuber parts in 14C-uptakeand partitioning into various fractions from 14C-labelled photosynthate.Thus, the fresh weight of these tubers could be used as a parameterfor the sink size. The 14C-content per tuber (sink strength)20 h after 14CO2-supply to the foliage was significantly correlatedwith the tuber fresh weight. No correlation was found betweenthe 14C-concentration of the tuber (sink activity; ct. ming fr. wt.) and tuber fresh weight. Consequently, tuberfresh weight (sink size) per se must have been a factor whichinfluenced sink strength. Stolon parameters characterizing theirgrowth prior to tuber initiation (e.g. stolon volume) and theircapacity for photosynthate transport (diameter, length) weremeasured at the time of tuber initiation. Significant correlationswere found between these stolon parameters and subsequent growthof individual tubers. Anatomical studies on the proportion ofvarious tissues in the cross sectional area of stolons supportthe idea of a negative relation between growth of individualtubers and transport resistance in the phloem of the stolons.It is concluded that in the initial phase of tuber growth, mainlyfactors outside of the tuber determine its growth rate. In laterstages of tuber growth, when the sink strength increases, thecompeting strength of individual tubers for photosynthate isdominated mainly by factors within the tuber itself, such astheir sink size and sink activity. Key words: Potato tuber, sink size, tuber initiation, transport resistance  相似文献   

5.
Incorporation of polyamine-spermidine into the nutrient mediumat 10–6 and 10–5 M concentrations stimulates pollen-tubegrowth in vitro in Catharanthus roseus L. G. Don. MGBG, an inhibitorof spermidine biosynthesis, at 0.5 x 10–3 and 1 x 10–3M concentrations reduced the percentage of germination as wellas tube growth and at a concentration of 1.5 x 10–3 Mgermination was totally inhibited. Pollen grains incubated inthe medium containing 1.5 x 10–3 M MGBG, when transferredto a fresh medium with 10–5 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   

6.
Protoplasts were successfully isolated from internodal callustissues of both Oxalis glaucifolia and O. rhombeo-ovata whenthey were digested in a solution containing 0.1% (w/v) MacerozymeR-10, 0.5% (w/v) cellulase Onozuka R-10 and 0.3 mmol m–3sucrose. Protoplasts proliferated to give cell colonies on Gamborget al.'s B5 medium supplemented with 0.3 mmol m–3 mannitol,0.5 mg dm–32, 4-D, and 2.0 mg dm–3 kinetin. Calluswas produced upon transfer of cell colonies to Murashige andSkoog medium containing 2.0 mg dm–3 l-naphthaleneaceticacid (NAA) and 0.1 mg dm–3 kinetin for O. glaucifolia,or with 5.0 mg dm–3 NAA and 0.5 mg dm–3 6-benzylaminopurine,for O. rhombeo-ovata. Plants were regenerated from O. glaucifoliaprotoplasts on a medium containing 0.1 mg dm–3 NAA, 1.0mg dm–3 kinetin and 1.0 mg dm–3 gibberellic acid,but only vascular nodules were differentiated by O. rhombeo-ovataprotoplast-derived calli. Key words: Tissue culture, protoplasts, plant regeneration, Oxalis spp  相似文献   

7.
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 10–3 M, 1.3 x 10–4M, 4.3 x 10–5 M; the maximum velocity values were 3.3x 10–8, 4.5 x 10–9, 1.8 x 10–9 mol/10 min/4x 106 cells. (Received April 18, 1981; Accepted August 25, 1981)  相似文献   

8.
DALESSANDRO  G. 《Annals of botany》1973,37(2):375-382
The time course of xylem differentiation was determined in explantsof lettuce pith parenchyma (Lactuca sativa L. cv. Romana) culturedon Murashige and Skoog (1962) medium using different concentrationsof auxin (IAA) and one cytokinin (zeatin or kinetin). Increasinglevels of auxin from I mg 1–1 to 15 mg 1–1 in thepresence of a constant level of a cytokinin (zeatin or kinetin)yielded up to 10 mg 1–1 IAA, an increase in the numberof tracheary element formations. Cytokinin concentrations aboveand below o.1 mg 1–1 interacting with an optimal xylogenicamount of auxin inhibited xylogenesis. The IAA (10 mg 1–1)-zeatin(0.1 mg 1–1) treatment produced the greatest number oftracheids, while kinetin compared to zeatin did not producesuch an effect. The different effectiveness of zeatin and kinetinin inducing tracheary element formations was not due to a differentcapacity of the two cytokinins to stimulate cell division butit seems likely that zeatin, because of interaction with IAA,is more active than kinetin in the determination of the dividingcells in a specific type of cytodifferentiation. The IAA (10mg 1–1)-zeatin (0.1 mg 1–1) treatment produced about6.9 per cent tracheids with respect to cell division while IAA(10 mg 1–1)-kinetin (0.1 mg 1–1) produced 4.2 percent. These results are discussed with reference to the problemsof hormonal control of xylem differentiation.  相似文献   

9.
The rate of indole-3-butyric acid (IBA) synthesis in maize seedlingsis dependent on the culture conditions of the plants. When theseedlings were grown on filter paper soaked with different amountsof water, the activity of IBA synthetase differed strongly.High amounts of water (150 and 200 ml per bowl) inhibited IBAsynthesis completely in vitro, whereas 30 and 50 ml water perbowl increased the activity dramatically. Under conditions whereIBA synthetase was inhibited (150 ml H2O), an increase of enzymeactivity was observed when abscisic acid (ABA) was exogenouslyadded in concentrations between 510–4 to 510–7M. Under ‘drought’ conditions (50 ml H2O per bowl)the same ABA concentrations were inhibitory. Jasmonic acid andsalicylic acid also enhanced IBA synthetase activity to someextent, whereas indole-3-acetic acid (IAA) and kinetin had noeffect. Activity could also be enhanced by osmotic stress (NaCIand sorbitol), but not under temperature stress. In accompanyinginvestigations the endogenous contents of IAA, IBA, and ABAunder the different culture conditions have been determinedas well as the energy charge of the seedlings. Similar observationshave been made with Amaranthus, wheat and pea seedlings Key words: Abscisic acid, Amaranthus paniculatus, drought stress, inole-3-butyric acid biosynthesis, Pisum sativum, Triticum aestivum, Zea mays  相似文献   

10.
Neill, S. J., McGaw, B. A. and Horgan, R. 1986. Ethylene and1-aminocyclopropane-l-carboxylic acid production in flacca,a wilty mutant of tomato, subjected to water deficiency andpretreatment with abscisic acid —J. exp. Bot. 37: 535–541. Plants of Lycoperstcon esculentum Mill. cv. Ailsa Craig wildtype and flacca (flc) were sprayed daily with H2O or 2?10–2mol m–3 abscisic acid (ABA). ABA treatment effected apartial phenotypic reversion of flc shoots; leaf areas wereincreased and transpiration rates decreased. Leaf expansionof wild type shoots was inhibited by ABA. Indoleacetic acid (IAA), ABA and l-aminocyclopropane-l-carboxylicacid (ACC) concentrations were determined by combined gas chromatography-massspectrometry using deuterium-labelled internal standards ABAtreatment for 30 d resulted in greatly elevated internal ABAlevels, increasing from 1?0 to 4?3 and from 0?45 to 4?9 nmolg–1 fr. wt. in wild type and flc leaves respectively.Endogenous IAA and ACC concentrations were much lower than thoseof ABA. IAA content ranged from 0?05 to 0?1 nmol g–1 andACC content from 0?07 to 0?24 nmol g–1 Ethylene emanationrates were similar for wild type and flc shoots. Wilting of detached leaves induced a substantial increase inethylene and ACC accumulation in all plants, regardless of treatmentor type. Ethylene and ACC levels were no greater in flc leavescompared to the wild type. ABA pretreatment did not preventthe wilting-induced increase in ACC and ethylene synthesis. Key words: ABA, ACC, ethylene, wilting, wilty mutants  相似文献   

11.
Abscisic acid (ABA) at 1 x 10–4 M or 3 x 10–4 Mwas applied to the apical buds of Chenopodium rubrum plantsexposed to different photoperiodic treatments and showing differentpatterns of floral differentiation. Stimulation of growth inwidth of the apical meristem of the shoot and/or inhibitionof growth in length was obtained under all photoperiodic treatments.This change of growth pattern was followed by different effectson flowering. In non-induced plants grown under continuous light ABA stimulatedpericlinal divisions in the peripheral zone and the initiationof leaves as well as the growth in width of bud primordia. Inplants induced by two short days reduced growth of the meristemcoincided with ABA application. Longitudinal growth of the meristemwas inhibited in this case and only a temporary stimulationof inflorescence formation took place. In plants induced ata very early stage, ABA exerted a strong inhibitory effect onflowering. A permanent and reproducible stimulatory effect onflowering was obtained in plants induced by three sub-criticalphotoperiodic cycles if ABA was applied to apices released fromapical dominance. In this case formation of lateral organs andinternodes was promoted by ABA and was followed by stimulatedinflorescence formation. Gibberellic acid (GA2) at 1x 10–4M or 3 x 10–4 M brought about a similar effect on floweringas ABA, although the primary growth effect was different, i.e.GA2 stimulated longitudinal growth. The effects of ABA and GA2 on floral differentiation have beencompared with earlier results obtained from auxin and kinetinapplications. These growth hormones are believed to regulateflowering by changing cellular growth within the shoot apex.Depending on the actual state of the meristem identical growthresponses may result in different patterns of organogenesisand even in opposite effects on flowering. Shoot apex, flowering, photoperiodic induction, abscisic acid, gibberellic acid, Chenopodium rubrum L.  相似文献   

12.
In azuki bean (Azukia angularis = Vignia angularis) epicotylsections, 5 ? 10–4 M coumarin inhibited the incorporationof radioactivity from [U–14C]glucose into the cellulosefraction by 35% in the absence of indole-3-acetic acid (IAA)and by 40% in the presence of 1 ? 10–4 M IAA. There wasno inhibitory effect on the incorporation of radioactivity intothe other fractions. Coumarin at 5 ? 10–4 M reversed thepromoting effect of 1 ? 10–5 M gibberellin A3 (GA) andthe inhibitory effect of 1 ? 10–5 M kinetin on IAA-inducedelongation of sections with no significant effects on IAA-inducedelongation. Neither GA nor kinetin had any appreciable effectson cellulose synthesis. No inhibition of cellulose syntheiswas observed with 1 ? 10–3 M colchichine, which has beenreported to have effects similar to those of coumarin on GA-or kinetin-affected stem elongation. Coumarin at 5 ? 10–4M was ineffectual in breaking up wall microtubules, while adisrupting effect on wall microtubules was clearly demonstratedwith 3 ? 10–4M colchicine. From these results, the possible involvement of cellulose synthesisin cell expansion controlled by GA or kinetin was suggested. (Received August 3, 1973; )  相似文献   

13.
Daucus carota tissues were grown on Murashige-Skoog medium (MS)at different concentrations with abscisic acid (ABA). Sevenbands of chloroplast fractions were obtained on a sucrose gradient.At 10–5M, ABA highly increased chlorophyll and proteinnitrogen content of medium density chloroplasts. With increasingage of the tissues, the most active chloroplasts according totheir 14CO2 fixation were found in smaller numbers. When treatedwith 10–5 M ABA, 34 day-old tissues cultivated in vitroshowed the chloroplast pattern of 110 day-old tissues. The effectof ABA—given to the tissues during a short pretreatmentor continuously present in the culture medium—on the ribulosediphosphate carboxylase activity was analysed. It was foundthat ABA at 10–5 M strongly inhibited 14CO2 fixation. (Received December 20, 1977; )  相似文献   

14.
MATHUR  JAIDEEP 《Annals of botany》1992,70(5):419-422
Callus cultures of Nardostachys jatamansi DC. maintained onMurashige and Skoog's medium containing 3.0 mg 1–1 of-naphthaleneacetic acid and 0.25 mg 1–1 of kinetin whenshifted to medium containing 0.25–1.0 mg 1–1 ofindole-3-acetic acid or indole-3-butync acid showed profuserhizogenesis. The callus-regenerated roots when transferredto medium containing 2.0–6.0 mg 1–1 of kinetin producedshoot buds. The de novo shoot bud regeneration took place eitherdirectly from cortical cells or from the inner stelar region.In addition, direct, concomitant root-shoot development wasalso observed. Nardostachys jatamansi, organogenesis, root-buds  相似文献   

15.
UDUEBO  AGNES E. 《Annals of botany》1971,35(1):159-163
Bulbil development in cultured nodes of D. bulbifera proceededin the absence of growth substances from the medium. When IAAwas incorporated into the medium at the concentrations of 5mg l–1 and 10 mg l–1 the cultured nodes producedlarger bulbils than in its absences. When the concentrationof IAA was increased to 15 mg l–1, however, the culturednodes produced a callus instead of a properly organized bulbil.The dry weight of bulbils increased when kinetin was added tothe medium at the concentrations of 0.05, 0.5, and 2.5 mg l–1.The greatest increase was with 0.5 mg l–1 kinetin. Onincreasing the concentration of kinetin in the medium to 5.0mg l–1 the tissue produced had smaller dry weight thanthose produced in the absence of growth substances. Additionof different combinations of IAA and kinetin to the basal mediumresulted in the production of normal bulbils, roots, and shootsin some instances (suitable combinations) and in the productionof callus and abnormal shoots in others (non suitable combinations).  相似文献   

16.
Mitotic activity was studied in the root apices of aeroponicallygrown sunflower seedlings (Helianthus annum L. var. RussianGiant) which were draughted or treated with abscisic acid (ABA)over a 7 d period. Labelling index (LI) and mitotic index (MI)were scored from autoradiographs of median longitudinal sectionsof [3H] methyl-thymidine treated root apices. Both drought stressand ABA-treatment (at a concentration of 10–2 mol m–3inhibited DNA synthesis and mitosis within the first 6 h oftreatment. The depression of mitotic activity was first evidentin the proximal regions of the meristem (1000–1500 µmfrom the cap junction). This was followed by a general depressionof mitotic activity throughout the meristem which was, in turn,followed by a partial recovery of mitotic activity in the distalregions of the meristem. The beginning of this partial recoverywas concurrent with the activation of the quiescent centre (QC).Treatment with lower concentrations of ABA (10–3 mol m–3and 10–4 mol m–3) also inhibited mitotic activity.Exogenous supplements of sucrose to the plant did not alleviatethe inhibition of mitotic activity by drought or ABA. Thesefindings support the hypothesis that ABA mediates drought-inducedchanges in the primary development of sunflower roots. Key words: Abscisic acid, drought, mitotic activity  相似文献   

17.
Mangat, B. S. and Janjua, S. 1987. Cyclic nucleotides and invitro plant cultures. I. Induction of organogenesis in tobacco(Nicotiana tabacum) callus cultures.—J. exp. Bot. 38:2059–2067. The possibility that cyclic nucleotides have a mediatory rolesimilar to cytokinins in plant tissue cultures was examined.Calli obtained from tobacco pith tissue were incubated on growthmedia supplemented with either cyclic AMP, cyclic GMP, adenosineor guanosine, in concentrations ranging from (mg dm–3)0 to 2·0 together with 2·0 mg dm–3 of IAA.Results were compared with identical calli grown on media containingcomparable amounts of kinetin and IAA. Increase in callus growthwas observed on all media containing cyclic AMP, cyclic GMP,adenosine, guanosine or kinetin. Adenosine or guanosine didnot promote organogenesis. Low concentrations (0·02 and0·05 mg dm–3) of kinetin stimulated extensive rootdevelopment. Some root formation was also elicited with higheramounts of cyclic AMP (0·1 and 0·2 mg dm–3)or cyclic GMP (0·2 and 0·5 mg dm–3). Bothkinetin and cyclic GMP promoted shoot differentiation. However,in contrast to kinetin, cyclic GMP induced organogenesis atlower concentrations (0·02 and 0·1 mg dm–3).The addition of 2·0 mg dm –3 of cyclic AM P toIAA-free growth media elicited shoot differentiation. This wasalso the case with a similar concentration of kinetin or cyclicGMP. Results suggest cytokinin activity for the two cyclic nucleotides. Key words: Tobacco, Nicotiana tabacum, tissue culture, cyclic nucleotides, cyclic AMP, cyclic GMP organogenesis  相似文献   

18.
By manipulation of various growth regulators and physical conditions,plants have been regenerated from excised roots, stem segments,cotyledons, leaves, and callus cultures of red cabbage (Brassicaoleracea var. capitata) grown under in vitro conditions. Shootbuds were induced on isolated root segments (1 cm long) culturedon Murashige and Skoog's medium and the frequency of bud formationwas greatly enhanced by the addition of kinetin (0.5 part 10–6).Callus obtained from the seeds, cotyledons, and hypocotyl segmentscultured on a medium fortified with 2,4-D (1 part 10–6),kinetin (0.1 part 10–6), and coconut milk (10%, v/v) hasbeen repeatedly subcultured. The callus is slow growing, andon transference to a kinetin (2 parts 10–6) and IAA (2parts 10–6) medium underwent morphogenesis to give riseto plants. The significance of the propagation of red cabbageby in vitro culture is pointed out.  相似文献   

19.
The response of potato stolons, cultured in vitro, to ethylenewas investigated utilizing 2-chloroethyl-phosphonic acid asthe source of ethylene. Concentrations of 0.067, 0.67, 6.7,and 67 µm did not promote tuber formation which occurredin the presence of 16 µm kinetin. In the presence of 2-chloroethyl-phosphonicacid stolon branching was promoted and they maintained a diageotropicgrowth habit in contrast to the negatively geotropic growthhabit of kinetin-treated cultures. The amount of soluble sugars accumulating at the stolon tipwas similar in the presence of kinetin and 2-chloroethylphosphonicacid. However, the level decreased in kinetin-treated stolonsas starch synthesis increased whereas a high specific activitywas maintained in the presence of 2-chloroethylphosphonic acidwhere no starch synthesis occurred. Higher levels of sucroseoccurred in kinetin-treated cultures. Both 2-chloroethylphosphonic acid and kinetin decreased invertaseactivity at the stolon tip. Peroxidase activity increased withtime in response to 2-chloroethylphosphonic acid whereas activityincreased appreciably in kinetin-treated stolons only afterday 5. Generally higher levels of 3'nucleotidase activity existedin 2-chloroethylphosphonic acid-treated stolons. RNase activitydecreased in kinetin treated stolons while activity increasedin the presence of 2-chloroethylphosphonic acid. It is suggestedthat ethylene may influence stolon growth but may not be directlyinvolved in tuber initiation.  相似文献   

20.
Female gametophytes (at the archegonial stage) excised fromyoung ovules of Ephedra foliata Boiss, were cultured on a basalmedium (Murnshige and Skoog's combinations of major and minorsalts, Iron source, vitamins, myo-inositol along with 2 percent sucrose and 10 per cent coconut milk) under aseptic conditions.Growth and morphogenetic responses of the explants to auxinswere compared at different concentrations and a study of theirinteractions with cytokinins has also been made. At 2 mg 1–1,2, 4-D induced profuse callusing which subsequently producedroots. NAA at 4 mg 1–1 was optimal for callus growth androoting. Combinations of 2,4-D and kinetin were more effectivein inducing roots and shoot buds than those of 2,4-D and benzylamino-purine (BAP). Addition of BAP (0.05 mg 1–1) to themedium containing optimal concentrations of NAA resulted information of a large number of roots. Kinetin induced only rootingin the presence of 4 mg 1–1 NAA. A high concentrationof BAP (8 mg 1–1), stimulated shoot bud formation. Forthe further development of shoot buds, neither auxin nor cytokininwas needed. Cytological observations revealed the presence ofhaploid number of chromosomes, i.e. seven. Ephedra foliata, tissue culture, callus, regeneration, 2,4-dichlorophenoxyacetic acid, naphthalene acetic acid, kinetin, benzyl amino-purine  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号