共查询到20条相似文献,搜索用时 140 毫秒
1.
The response of isolated stolons cultured in vitro, to abscisicacid (ABA) has been studied in the presence and absence of kinetin(6-furfurylaminopurine). ABA alone in concentrations from 7.5x 104 mM to 7.5 x 102 mM, inhibited stolon elongationbut failed to promote tuber initiation. In the presence of kinetin,ABA at concentrations of 3.0 x 102 and 7.5 x 102mM markedly inhibited kinetin-induced tuber initiation and stolonelongation, but at 7.5 x 104 and 7.5 x 103 mMABA did not prevent tuber initiation. When stolons were incubated on a medium containing kinetin andlater transferred to one containing ABA with or without kinetin,the inhibitory effect of ABA decreased appreciably as the timeof incubation on kinetin is increased. The results are discussed in relation to the role of ABA inthe inhibition of nucleic acid and protein synthesis and theinteraction with cytokinins and the possible effect of ABA onkinetin uptake, transport and accumulation at the locus of action. (Received February 26, 1969; ) 相似文献
2.
K+ efflux from tobacco (Nicotiana tabacum L, cv. Samsun NN)leaf discs into the external medium was increased and the membranepotential (Em) changed in the positive direction with a changein pH from 8.0 to 4.0. Em was affected by the external concentrationof KCl, greatly decreasing with a change in concentration from1 mM to 100 mM. The equilibrium potential of the membrane forK+ (Ek) was decreased in a Nernst fashion with increasing externalconcentrations of KCl. Ek is more positive than Em above ca.50 µM KCl. Most of the experiments were carried out underconditions in which the difference between the electrochemicalpotential for K+ on the inside to the outside of the cell (µkis positive. Thus, K+ may passively flow to the outside of thecells accompanied by the depolarization of the membrane. Abscisic acid (ABA) increased the K+ efflux under conditionsof passive transport. K+ efflux was accelerated with an increasingconcentration of ABA, being maximal at 104 M103M. This acceleration was due to the enhancement of the potassiummotive force (µk/F) which is the force causing the netpassive transport of K+. The membrane potential was decreasedfrom 205 mV to 170 mV by 2 x 104 M ABAwithin 10 min. The depolarization was not transient, being lostfor at least 3 hr. These results show that ABA accelerated passive K+ efflux, whichaccompanied depolarization of the membrane. (Received June 22, 1981; Accepted August 24, 1981) 相似文献
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 103 to 101 molm3 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 (101 mol m3), toCommelina epidermis or leaf pieces both zeatin and kinetin restrictedstomatal opening. Key words: ABA, Cytokinins, Stomata, Maize, Commelina 相似文献
4.
Two hydroponic experiments were conducted to determine the effectsof brief and prolonged AI3+ exposures on the hydraulic conductivity(Lp) of northern red oak (Quercus rubra L.) root systems. RootLp was determined using the pressure chamber method of Fiscus(1977). In the first experiment, 28- to 40-d-old seedlings weretreated for 4 d with complete nutrient solutions containingone of three Al concentrations (0.04, 1.85 or 3.71 mol m3)and either 0 or 50 mmol m3 P. Neither Lp nor daily transpirationwas affected by treatment. In Experiment II, seedlings were grown for 4863 d incomplete solutions containing one of three Al concentrations(0, 0.75 or 2.00 mol m3) and either 10 or 250 mmol m3Ca. Lp and leaf area to root length ratio (LA/RL) were reducedwhen (AI3+/ Ca2+), the solution activity ratio, was 2.9 andhigher. Lp and LA/RL were also negatively correlated with Alconcentration and Al/Ca concentration ratio in the roots. Lpwas positively correlated with LA/RL in both experiments. Itis unclear whether Lp in the second experiment was reduced directlyby solution and root chemistry or whether Lp changed in responseto altered leaf/root balance. Key words: Al phytotoxicity, Al x Ca interaction, Quercus rubra, root hydraulic conductivity 相似文献
5.
Ion Content of the Halotolerant Alga Dunaliella salina 总被引:3,自引:0,他引:3
The intracellular concentration of the major ions in Dunaliellasalina cells were determined, following the removal of extracellularions by ion-exchange minicolumns. Log phase cells, grown inmedia containing 14 molar NaCl, contained 3050mM chloride and 200350 mM magnesium (5 mM in medium).Phosphorus, which is present intracellularly mostly as polyphosphate,was present in amounts of 60100 fmoles per cell, equivalentto a concentration of 6001,000 mM (0.2 mM in medium).Previous data indicated that such cells contained 2040mM Na+, 150300mM K+, 20mM SO24, and very low concentrationsof Ca2+ and charged nitrogenous compounds. Mg2+ and K+ seemto serve as the major counter ions for the intracellular negativecharge present in the massively accumulated polyphosphates.The former accounts for about 2/3 of the required positive charge.This is supported by the observation that limitation in thephosphate or K+ supply in the medium lead to a parallel decreasein the accumulation of intracellular phosphorus, Mg2+ or K+.
1Present address: Department of Vegetables, The Volcani Center,Bet-Dagan 50250, Israel. (Received June 13, 1988; Accepted August 25, 1988) 相似文献
6.
Mechanisms Controlling Changes in Water Movement Through the Roots of Helianthus annuus L. During Continuous Exposure to Oxygen Deficiency 总被引:2,自引:0,他引:2
The effects of oxygen deficiency on suction-induced water flux(Jv) through detached roots of hydroponically-grown sunflowerwere investigated over a period of up to 6 d. Jv was reducedby the time the oxygen partial pressure in the solution, spargedwith oxygen-free N2, had fallen below 2 kPa (air 20.6kPa). This reduction resulted from a decline in the hydraulicconductivity of the radial pathway for water movement (Lp),although up to 46% of the decline was attributable to changesin the osmotic component of the driving force (). Lp (mm s1MPa1), for aerobic roots was 2.23 ? 105 and foranaerobic roots during the initial 16 h, 1.21 ? 105. At 22 h after the onset of anaerobic treatments, Jv and Lp increased,with Lp values becoming 3 times greater than those measuredbetween 4 h and 16 h of treatment and 1.4 times greater thanin aerated roots. However, Lp increased a further 15-fold whenroots were killed by immersion in boiling water for 2 min. Duringand up to 6 d of anaerobic treatment, some roots retained Lpvalues similar to those at 22 h, while others displayed characteristicstypical of dead roots. At no time was there any indication ofreduced axial conductivity due to xylem vessel blockage. The results are discussed in terms of possible energy sourcesfor the maintenance of root integrity and their importance toplant survival during long periods of severe oxygen shortage. Key words: Anaerobiosis, oxygen deficiency, hydraulic conductivity, osmotic potential, water 相似文献
7.
Hydraulic and osmotic properties of spruce roots 总被引:9,自引:6,他引:3
Rdinger Marcus; Hallgren Stephen W.; Steudle Ernst; Schulze Ernst-Detlef 《Journal of experimental botany》1994,45(10):1413-1425
Hydraulic and osmotic properties of roots of 2-year-old Norwayspruce seedlings (Plcea abiea (L.) Karst) were investigatedusing different techniques (steady flow, pressure probe, andstop flow technique). Root pressures were measured using theroot pressure probe. Compared to roots of herbaceous plantsor deciduous trees, excised root systems of spruce did not developappreciable root pressure (-0.001 to 0.004 MPa or -10 to 40cm of water column). When hydrostatic pressure gradients wereused to drive water flows across the roots, hydraulic conductivities(Lpr) were determined in two types of experiments: (i) rootpressure relaxations (using the root pressure probe) and (ii)steady flow experiments (pneumatic pressures applied to theroot system or xylem or partial vacuum applied to the xylem).Root Lpr ranged between 0.2 and 8108m s1 MPa1(on average) depending on the conditions. In steady flow experiments,Lpr depended on the pressure applied (or on the flow acrossthe roots) and equalled (0.190.12) to (1.21.7)108m s1 MPa1 at pressures between 0.2 and 0.4 MPaand (1.51.3)108 m s1 MPa1 at appliedpressures between 0.8 and 1.0 MPa. When pressures or vacuumwere applied to the xylem, Lpr values were similar. The hydraulicconductivity measured during pressure relaxations (transientwater flows) was similar to that obtained at high pressures(and water flows). Although there was a considerable scatterin the data, there was a tendency of the hydraulic conductivityof the roots to decrease with increasing size of the root system.When osmotic gradients were used to drive water flows, Lpr valuesobtained with the root pressure probe were much smaller thanthose measured in the presence of hydrostatic gradients. Onaverage, a root Lpr=0.017108 was found for osmotic andLpr=6.4108 m s1 MPa1 in correspondinghydrostatic experiments, i.e. the two values differed by a factorwhich was as large as 380. The same hydraulic conductivity asthat obtained in osmotic experiments using the pressure probewas obtained by the 'stop flow techniquel. In this technique,the suction created by an osmoticum applied to the root wasbalanced by a vacuum applied to the xylem. Lpr values of rootsystems did not change significantly when measured for up to5 d. In osmotic experiments with different solutes (Na2S04,K2S04, Ca(NO3)2, mannitol), no passive uptake of solutes couldbe detected, i.e. the solute permeability was very low whichwas different from earlier findings on roots of herbs. Reflectioncoefficients of spruce roots (O were low for solutes for whichplant cell membranes exhibit values of virtually unity ( 相似文献
8.
Low salt roots of Cucumis sativus L. cv. Burpeeana Hybrid weresubjected to iso-ionic treatments in which the external solutionconcentration of K+ was maintained at 14 mM. Solution concentrationof varied from 0 to 14 mM, other anions compensating. When Cl was the compensating ion, its concentrationin the exudate increased during the first 4 h and thereafterwas nearly the same as that of the external solution in alltreatments containing I mM or more. After 8 h of equilibration the concentration in the exudate increased almost exactly as its concentrationin the external solution. Rates of exudation and K+ transportwere almost constant between I and 14 mM KNO2. More Clwas transported from solutions of similar Cl concentrationwhen was also present. When water transport was inhibited with mannitol in treatments containing both KNO3and KCI, exudate concentrations of K+ and were increased, but exudate concentration of Cl was notsignificantly affected except at the highest Cl 相似文献
9.
A Study of the Exudation of Excised Maize Roots after Removal of the Epidermis and Outer Cortex 总被引:1,自引:1,他引:0
The fluid exudation rates and the ionic composition of the exudatesof isolated maize roots were compared with those of similarroots from which the epidermal and outer cortical cells hadbeen removed. The results indicate that in low ionic strengthmedia the salt fluxes into the exudation stream are severaltimes larger in the control than in the treated roots. As theionic strength of the bathing medium increases to 10 mM KClor greater, the salt fluxes become equal. A mechanism to accountfor this behaviour is discussed. The values of Lp, the hydraulic conductivity of the roots toradial water flow, are 0.26 x 106 cm sec1 atm1for treated and 0.14 x 106 cm sec1 atm1for control roots, but a statistical technicality precludeda significance test on this apparent difference. The kinetics of tritiated water exchange from external mediumto the exudation fluid in both control and treated roots werenot significantly different. The entry of labelled water seemsto be achieved by the fluid exudation rate in both cases; thusthe barrier to water movement to the exudate compartment remainsintact after removal of the epidermis. 相似文献
10.
Kreuzwieser Jrgen; Herschbach Cornelia; Stulen Ineke; Wiersema Peter; Vaalburg Willem; Rennenberg Heinz 《Journal of experimental botany》1997,48(7):1431-1438
The processes of NO3 uptake and transport and the effectsof NH4+ or L-glutamate on these processes were investigatedwith excised non-mycorrhizal beech (Fagus sylvatica L.) roots.NO3 net uptake followed uniphasic Michaelis-Menten kineticsin a concentration range of 10µM to 1 mM with an apparentKm of 9.2 µM and a Vmax of 366 nmol g1 FW h1.NH4+, when present in excess to NO3, or 10 mM L-glutamateinhibited the net uptake of NO3 Apparently, part of NO3taken up was loaded into the xylem. Relative xylem loading ofNO3 ranged from 3.21.6 to 6.45.1% of NO3 netuptake. It was not affected by treatment with NH4+ or L-glutamate.16N/13N double labelling experiments showed that NO3efflux from roots increased with increasing influx of NO3and, therefore, declined if influx was reduced by NH4+ or L-glutamateexposure. From these results it is concluded that NO3net uptake by non-mycorrhizal beech roots is reduced by NH4+or L-glutamate at the level of influx and not at the level ofefflux. Key words: Nitrate transport, net uptake, influx, efflux, ammonium, Fagus, Fagaceae 相似文献
11.
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 106).Callus obtained from the seeds, cotyledons, and hypocotyl segmentscultured on a medium fortified with 2,4-D (1 part 106),kinetin (0.1 part 106), and coconut milk (10%, v/v) hasbeen repeatedly subcultured. The callus is slow growing, andon transference to a kinetin (2 parts 106) and IAA (2parts 106) 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
12.
Fusicoccin (FC) inhibited net excretion of Cl by theglands of the pitchers of the carnivorous plant Nepenthes hookeriana;of Na+ and Cl by the salt glands of the halophytes Limoniumvulgare and L. pectinatum and of K+ in the nectar of Acer platanoidesflowers. It had no effect on K+ elimination with nectar of Impatienswalleriana (extrafloral nectaries) and Abutilon striatum. Abscisicacid (ABA) stimulated net excretion of K+ and Cl in Nepenthesand of Na+ and Cl in Limonium but had no effects on K+in nectar. Thus, FC and ABA had opposing effects on ion excretionby the salt eliminating glands of Limonium and Nepenthes. Bothcompounds, however, had similar effects on sugar secretion ofnectary glands which was either inhibited or unaffected by FCand ABA. It is suggested that the effects of FC and ABA on ion excretionby gland cells could be reconciled with literature showing FC-stimulationand possible ABA-inhibition of proton pumps at the plasmalemmaof plant cells. Nepenthes hookeriana, Limonium vulgare, Limonium pectinatum, Acer platanoides, salt-glands, nectaries, excretion, fusicoccin, abscisic acid, proton pump 相似文献
13.
Sodium Exclusion from the Shoots by Roots of Zea mays (cv. LG 11) and its Breakdown with Oxygen Deficiency 总被引:1,自引:0,他引:1
The effects of sodium chloride salinity and root oxygen deficiency(anoxia) were studied in 11-12d old maize plants (Zea mays L.cv. LG 11) in nutrient solution culture. Transport of 22Na bythe roots to the shoot in 24 h was markedly increased by anoxiawhen the external concentration of NaCl was in the range 0·1-10·9mol m3. Anoxia severely inhibited uptake of 42K by rootsand its transport to the shoot, so that the ratio of Na+/K+moving into the shoot was increased by a factor of approximately10. When the external concentration of NaCl was increased to2.4 mol m3, the roots showed much less ability to excludeNa+ under aerobic conditions, and anoxia caused no further increasein the movement of Na+ to the shoot. It is concluded that atthe higher concentration the ability of the roots to excludeNa+, presumably through an active mechanism in the xylem parenchymacells or in the root cortex and transporting Na+ to the outersolution, is saturated by excessive inward diffusion of Na+.The ratio of Na+/K+ transported to the shoot increased by afactor of 600 when the concentration of NaCl was increased from2·4 mol m3 to 40 mol m3 and roots weremade anoxic. Such imbalances in the supply of cations to theshoot, particularly when roots are oxygen-deficient, may contributeto salinity damage. Key words: Anaerobic, Anoxic, Oxygen deficiency, Roots, Salinity, Salt stress, Sodium chloride, Zea mays 相似文献
14.
Kinetin (4.7 x 105 M) and 6-benzyladenine (2.22 x 105M) were found to increase ca. 2-fold the putrescine contentin cotyledons of lettuce (Lactuca sativa L.) seedlings grownfor 3 days under fluorescent light. On the other hand, severalinorganic ions (K+, Na+, Ga++, Mg++) at a concentration of 3x 102 M reduced the putrescine content. The combinationof kinetin with one of several inorganic ions at the same levelmarkedly increased the spermine content, but the putrescinecontent decreased; calcium and magnesium ions were less effective.The physiological significance of these findings is discussed. (Received July 4, 1982; Accepted November 6, 1982) 相似文献
15.
Ricinus communis L. (castor bean) plants were grown in the absence(control) and in the presence of 100molm3NaCl with areciprocal split-root system, in which K+ was supplied to oneand NO3 to the other part of the root system. In theseplants shoot and, to a lesser extent, total root growth wereinhibited compared to plants with non-split roots. Without andwith NaCl, growth of roots receiving NO3 but noK+ (minusK/plus N-roots) was substantially more vigorous thanunder the reverse conditions (plus K/minus N-roots1).100mol m3 NaCl inhibited growth of minus K/plus N-roots1to the same extent as that of non-split roots, indicating thatexternally supplied K+ was not required for root growth undersaline conditions. In growth media without added K+ the rootdepleted the external low K + levels resulting from chemicalsdown to a minimum value Cmln (1.0 to 1.4 mmol m3); inthe presence of 100 mol m3 NaCl, Cmin, was higher (1018mmol m3) and resulted from an initial net loss of K +.Cmin, was pH-dependent The distribution of K+, Na+ and Mg2+along the root was measured. In meristematic root tissues, K+ concentrations were scarcely affected by external K+ or byNaCl, where Na + concentrations were low, but somewhat elevatedat low external K+ and/or high NaCl. In differentiated, vacuolatedtissues K + concentrations were low and Na+ concentrations high,if K + was not supplied externally and/or NaCl was present.The longitudinal distribution of ions within the root was usedto estimate cytoplasmic and vacuolar ion concentrations. Thesedata showed a narrow homoeostasis of cytoplasmic K+ concentrations(100140 mol m3) independent of external K + supplyeven in the presence of 100 mol m 3 NaCl. CytoplasmicNa + concentrations were maintained at remarkably low levels.Hence, external K+ concentrations above Cmin, were not requiredfor maintaining K/Na selectivity, i.e. for controlling Na+ entry.The results are discussed with regard to mechanisms of K/Naselectivity and to the importance of phloem import of K+ forsalt tolerance of roots and for cytoplasmic K+ homoeostasis. Key words: Ricinus communis, nitrate, potassium, root (split-root), salt tolerance, phloem transport 相似文献
16.
Osmotic and ionic regulation in Nitella 总被引:2,自引:0,他引:2
When the osmotic value of an internodal cell of Nitella flexiliswas modified by the method of transcellular osmosis, the normalosmotic value was chiefly restored by the release or absorptionof K+. The release or uptake of Na+ was observed only when themodification of osmotic value was significant. Both the uptakeand release of K+ were linearly dependent on the degree of modificationof the osmotic value. The effectiveness of alkali metal cationsin restoring the osmotic value in cells of lower osmotic valueswas in the order K+>Rb+>Na+, Cs+>Li+. The absorptionof K+ by cells of lower osmotic values depended strongly ontemperature, while the release of K+ from cells of higher osmoticvalues did not. To clarify whether the Nitella cell regulates the osmotic valueor regulates the concentration of K+ in the vacuole, the cellsap was exchanged for artificial cell saps whose osmotic valuesand ionic concentrations were varied independent of each other.It was shown that in Nitella two regulating mechanisms are operating,one which regulates the osmotic value of the cell sap irrespectiveof the level of vacuolar K+ (0.1140 mM) and another whichregulates the vacuolar K+-level when it is abnormaly high (>160mM). Both mechanisms are assumed to operate in order to keepthe concentration of K+ in the cytoplasm at a constant level.The presence of Na+ (0100 mM) and Ca2+ (540 mM)did not affect the movement of K+ during osmoregulation.
1Present address: Sanki Engineering Limited, Nagaokakyo, Kyoto,Japan. (Received December 19, 1973; ) 相似文献
17.
Efficiency of Potassium Utilization by Barley Varieties: The Role of Subcellular Compartmentation 总被引:6,自引:3,他引:3
RAZAQUE MEMON ABDUL; SACCOMANI MASSIMO; GLASS ANTHONY D. M. 《Journal of experimental botany》1985,36(12):1860-1876
Memon, A. R., Saccomani, M. and Glass, A. D. M. 1985. Efficiencyof potassium utilization by barley varieties: The role of subcellularcompartmentation.?J. exp. Bot. 36: 18601876. The subcellulardistributions of K+ in roots of three barley (Hordeum vulgareL.) varieties, grown at 10 and 100 mmol m3 external K+([K+]o) were estimated by compartmental analyses. In general,increased [K+]o caused a 23 fold increase in vacuolar[K+], but cytoplasmic [K+] increased only slightly. Nevertheless,the three varieties, which had been selected for study on thebasis of their different rates of K+ utilization, showed distinctdifferences in the allocation of K+ between cytoplasm and vacuole.At 10 mmol m3 [K+]o var. Betzes exhibited typical K+deficiency symptoms while var. Fergus and var. Compana did not,even though Betzes had higher [K+] in shoots and roots. Theinefficient utilization of K+ in this variety appears to beassociated with a failure to mobilize vacuolar K+ into the cytoplasmiccompartment (the ratio of vacuolar: cytoplasmic K+ contentsfor Betzes was 4.1 compared to 2.7 and 2.5, respectively, forFergus and Compana). Fergus and Betzes, which demonstrate pronouncedgrowth responses to increased [K+]0 between 10 and 100 mmolm3, showed significant increases of cytoplasmic [K+]in this range of [K+]o. By contrast, cytoplasmic [K+] in Compana,a variety whose growth is not stimulated by increased [K+]0(from 10 to 100 mmol m3) showed virtually no increase.It is suggested that the efficiency of K+ utilization and thegrowth response to [K+]0 in these varieties are functions ofthe subcellular distribution of this ion between cytoplasm andvacuole. Key words: Barley varieties, K+ subcellular compartmentation, utilization efficiency 相似文献
18.
Diurnal K+ and Anion Transport in Phaseolus Pulvinus 总被引:1,自引:0,他引:1
Diurnal movement of Phaseolus leaf is caused by deformationof the laminar pulvinus located at the joint of the leaf bladeand the petiole. The plants were cultured in solutions withvarious ion compositions, and changes of K+, Na+, Ca2+, Mg2+,Cl, NO3 and P1 concentrations both in the upperand lower parts of the laminar pulvinus were measured. Culturein 10 mM KCl solution caused an increase in K+ and Clconcentrations both in the upper and lower parts without anysignificant change in the concentration of NO3; culturein 10 mM KNO3 solution caused an increase in K+ and NO3concentration without any significant change in the concentrationof Cl; and culture in 10 mM KH2PO4 solution caused anincrease in K+ and P1 concentrations without any significantchange in the concentrations of NO3- and Cl. K+ moved from the upper to lower parts or from the lower toupper parts diurnally in all plants cultured in any solutionmentioned above. The main inorganic anion that accompanied thisK+ movement was Cl in KCl solution, and NO3 inKNO3 solution. When the seedlings were cultured in distilledwater or in KH2PO4 solution, neither Cl NO3 norP1 accompanied this K+ movement. In these cases, mainly H+ and/ororganic anions are supposed to move in exchange for and/or incombination with K+ movement. (Received November 8, 1982; Accepted June 13, 1983) 相似文献
19.
MURALITHARAN MORLEY S.; CHANDLER STEPHEN F.; VAN STEVENINCK REINHARD F. M. 《Annals of botany》1992,69(5):459-465
Non-selected and Na2SO-, K2SO4- or KCl-selected callus culturesof Vaccinium corymbosum L. cv. Blue Crop were grown on mediasupplemented with 0, 25 and 50 mM Na2SO4 (non-selected and Na2SO(-selectedonly), 0, 25 and 50mMK2SO4 (non-selected and K2SO4-selectedonly) or 0, 50 and 100 mM KCl (non-selected and KCl-selectedonly). On all media, growth of selected callus (on a fresh-weightor dry-weight basis) was greater than that of non-selected callus,and selected callus grew optimally on the level and type ofsalt on which it was selected. Selected callus was friable andmaintained a higher f. wt:d. wt ratio. Tissue water potentialin selected callus was more negative than in non-selected callus. Flame photometry and chloridometry showed Na+, K+ and Claccumulated in callus to concentrations equal to or greaterthan the initial concentration in the medium. Turbidometry showedthat tissue SO42- concentration was lower than the concentrationin the medium. In most cases selected callus accumulated moreNa+, Ksup, SO42 or Cl than non-selected callus.Vacuolar ion concentration was measured by electronprobe X-raymicroanalysis, and on most media selected callus had highervacuolar ion concentrations than non-selected callus. SO42and Cl were accumulated in the vacuoles at concentrationshigher than the external medium, but vacuolar Na+ concentrationdid not reach external concentration on Na2SO4 and on potassiumsalts was maintained between 12 and 17 mM. Vacuolar K+ concentration(approx. 142191 mM on no salt) decreased on Na2SO4 andincreased on K2SO4 and KCl. There was no precise correlation between total or specific ionaccumulation (Na+, K+, SO42 and Cl and fresh-weightyield. Results suggest that selection results in adaptationin response to decreased water potential of the medium. Vaccinium corymbosum, blueberry, electronprobe X-ray microanalysis, callus, in vitro selection, salt tolerance, KCl, K2SO4, Na2SO4 相似文献
20.
Yazaki Yoshiaki; Maki Kazutoshi; Sato Tetsuya; Ohta Eiji; Sakata Makoto 《Plant & cell physiology》1988,29(8):1417-1422
The intracellular K+ concentration and its change in mung bean[Vigna mungo (L.) Hepper] root tips were investigated non-invasivelywith 39K nuclear magnetic resonance spectroscopy using a membraneimpermeable shift reagent, dysprosium (III) tripolyphosphate[Dy(PPPi)72]. The K+ resonance was shifted to highermagnetic field in proportion to the concentration of the shiftreagent. In addition to a reference capillary peak for measuringthe K+ concentration, two well-resolved peaks (intra- and extracellularK+ resonances) were observed in the 39K NMR spectra of mungbean root tips. The intracellular K+ concentration was determinedto be 41 mM, which was similar to the value obtained by flamephotometry. When 20 mM KCl was added to the external medium,the intensity of the intracellular K+ resonance gradually increasedand the net K+ uptake rate was calculated to be 4.1 micromolesper gram fresh weight per hour. After removal of KCl from theperfusion medium, the intracellular K+ concentration considerablydecreased. With 31P NMR method, 2.5 mM Dy(PPPj)712 and20 mM KCl had little effect on the ATP level in the cells. Wehave indicated that the 39K NMR method can be used to determinethe K+ levels and net fluxes of the K+ transport in perfusedroot tips successively. (Received April 6, 1988; Accepted September 29, 1988) 相似文献