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1.
Stomatal Functioning of In Vitro and Greenhouse Apple Leaves in Darkness, Mannitol, ABA, and CO2 总被引:1,自引:0,他引:1
Leaves from in vitro and greenhouse cultured plants of Malusdomestica (Borkh.) cv. Mark were subjected to 4 h of darkness;4 h of 1 M mannitol induced water stress; 1 h of 104M to 107 M cis-trans abscisic acid (ABA) treatment; 1h of 0.12% atmospheric CO2. Stomatal closure was determinedby microscopic examination of leaf imprints. In all treatments,less than 5% of the stomata from leaves of in vitro culturedplants were closed. The diameter of open stomata on leaves fromin vitro culture remained at 8 µm. In contrast, an averageof 96% of the stomata on leaves of greenhouse grown plants wereclosed after 4 h in darkness; 56% after 4 h of mannitol inducedwater stress; 90% after 1 h of 104 M ABA treatment; 61%after 1 h in an atmosphere of 0.12% CO2. Stomata of in vitroapple leaves did not seem to have a closure mechanism, but acquiredone during acclimatization to the greenhouse environment. Thelack of stomatal closure in in vitro plants was the main causeof rapid water loss during transfer to low relative humidity. 相似文献
2.
Water loss was studied in regenerated plantlets of Brassicaoleracea var. botrytis cv. Currawong derived through apicalmeristem culture. Hardening of plantlets was eliminated by asingle application of a polyvinyl resin (S600) sprayed immediatelyafter transplanting. Plantlets sprayed with S600 had highercuticular resistances than unsprayed plantlets; this treatmenthad no effect on stomatal resistance. Leaves formed during theculture period showed very little wax formation and using markedleaves it was found that only reduced levels of wax formed onthese leaves even after transplanting. New leaves formed aftertransplanting, showed typical wax formation compared to seedgrown plants. Abscisic acid (ABA) at 104 M applied as a leaf sprayto transplants did not cause a substantial increase in stomatalresistance in leaves which had been initiated during the cultureperiod. Leaves of seed-grown plants as well as leaves of plantletsformed after transplanting did respond to a leaf spray of ABAat 104 M by a large increase in stomatal resistance. Relative concentrations of K, Na, Ca, P, S and Mg in guard cellswere calculated for each leaf type by X-ray micro-probe analysis.K/Na values decreased in the order: seedling > leaves formedafter transplanting > leaves intiated during culture. A highpositive correlation was also found between K/Na and K/P forthe three leaf types. K:Mg and K:Ca ratios for leaves formedduring culture were low in comparison to the values obtainedfor leaves formed after transplanting and seedlings for whichthe values were similar. Brassica oleracea var. botrytis, cauliflower, regenerated plantlets, meristem culture, stomatal resistance, water loss, abscisic acid, X-ray micro-probe analysis 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.
Kinetin and zeatin(100 mmol m3)reversald the ABA-mediated(100mmol m-2)closure of stomata of young maize leaves but did notaffect stomatal apertures of these leaves when applied alone.As leaves aged, kinetin or zeatin alone promoted increased stomatalapertures, while abscisic acid (ABA) applied alone had a reducedeffect on stomata. Even with older leaves, cytokinins reversadthe effect of ABA on stomata. Maize, stomata, abscisic acid, kineusc, zeatin, Zea mays 相似文献
5.
Pugliesi C.; Fambrini M.; Vernieri P.; Baroncelli S. 《Journal of experimental botany》1994,45(5):533-538
The present study was conducted to characterize geneticallyand physiologically a spontaneous mutation in sunflower whichconfers a wilty phenotype. The wilting condition of the mutantis due to abnormal stomatal behaviour. The mutant stomata resistclosure in darkness. This abnormality is associated with lowlevels of endogenous abscisic acid (ABA). By artificially elevatingthe ABA content of the mutant plants by spray treatments with10 and 10 M solutions it proved possible to effecta phenotypic reversion of the mutant. It has, therefore, beenproposed that the primary effect of this spontaneous mutationis to reduce the level of ABA. The genetic analysis has shownthat the willy phenotype is due to recessive nuclear mutationat a single locus. Key words: ABA, Helianthus annuus L, stomatal conductance, wilty mutant 相似文献
6.
Ward, D. A. and Drake, B. G. 1988. Osmotic stress temporarilyreverses the inhibitions of photosynthesis and stomatal conductanceby abscisic acidevidence that abscisic acid induces alocalized closure of stomata in intact, detached leaves.J.exp. Bot 39: 147155. The influence of osmotic stress on whole leaf gas exchange wasmonitored in detached leaves of Glycine max supplied with anexogenous concentration (105 mol dm3) of ±abscisicacid (ABA) sufficient to inhibit net photosynthesis and stomatalconductance by 60% and 70%, respectively, under a saturatingirradiance and normal air. Raising the osmotic (sorbitol) concentrationof the ABA solutions feeding leaves elicited rapid and synchronousreversals of the ABA-dependent inhibitions of net photosynthesisand conductance. These reversals reached a peak simultaneously,after which photosynthesis and conductance declined. The magnitudeof the transient stimulations at peak height was dependent uponthe sorbitol concentration of the ABA feeding solution, althoughthe time-course of the transients (half time, 46 min)was similar for the different osmotic concentrations applied.Irrespective of transient size the relative changes of photosynthesisand conductance were comparable; consequently the calculatedpartial pressure of CO2 in the substomatal space (Ci) remainedrelatively constant during the transient phase. In contrastto the ABA-treated leaves, elevating the osmotic concentrationof the distilled water supply feeding control leaves stimulatedconductance to a much greater relative extent than photosynthesis.The co-stimulations of photosynthesis and conductance inducedin ABA-treated leaves by osmotic shock were not due to a restrictionin the transpirational uptake of ABA and occurred irrespectiveof the source osmoticum applied. These data are consistent with the hypothesis that the ABA-dependentinhibition of photosynthesis at constant Ci is an artifact causedby the spatially heterogeneous closure of stomata in responseto ABA. Alternative explanations for the responses are, however,considered. Key words: Abscisic acid, photosynthesis, osmotic stress, Glycine max, stomatal conductance 相似文献
7.
Inhibition of Light-Stimulated Leaf Expansion by Abscisic Acid 总被引:9,自引:2,他引:7
Abscisic acid (ABA) applied to intact bean (Phaseolus vulgaris)leaves or to isolated leaf discs inhibits light-stimulated cellenlargement This effect may be obtained with 104 molm3 ABA, but is more significant at higher concentrations.The inhibition of disc expansion by ABA is greater for discsprovided with an external supply of sucrose than for discs providedwith KC1, and may be completely overcome by increasing the KC1concentration externally to 50 mol m3. Decreased growthrate of ABA-treated tissue is not correlated with loss of solutesfrom growing cells, but is correlated with a decrease in cellwall extensibility. ABA does not prevent light-stimulated acidificationof the leaf surface, and stimulates the acidification of theexternal solution by leaf pieces. However, the capacity of thecell walls to undergo acid-induced wall loosening is diminishedby ABA-treatment. The possibility that ABA acts directly byinhibiting growth processes at the cellular level, or indirectlyby causing stomatal closure, is discussed. Key words: Phaseolus vulgaris, ABA, Inhibition, Leaf expansion 相似文献
8.
Benzoic acid and its o-, m- and p-hydroxy derivatives appliedon excised leaves of Cassia fasciculata modified the dark-induced(scotonasty) and light-induced (photonasty) leaflet movements.Benzoic acid inhibited the scotonastic closure in a dose-dependentmanner from 104M to 103M and promoted the photonasticopening at optimum concentration of 5.104M. These effectswere dependent upon the position of hydroxyl group on the benzoicring, the o-derivative inducing a stronger effect than the m-and p-derivatives. Experiments showed that treatment with o-hydroxybenzoicacid had not to exceed 3060 min and that the maximumeffect was obtained at pH 5.5. (Received September 16, 1986; Accepted June 22, 1987) 相似文献
9.
We isolated a mutant from Vicia faba L. cv. House Ryousai. Itwilts easily under strong light and high temperature conditions,suggesting that its stomatal movement may be disturbed. We determinedresponses of mutant guard cells to some environmental stimuli.Mutant guard cells demonstrated an impaired ability to respondto ABA in 0.1 mM CaCl2 and stomata did not close in thepresence of up to 1 mM ABA, whereas wild-type stomata closedwhen exposed to 10 µM ABA. Elevating external Ca2+caused a similar degree of stomatal closure in the wild typeand the mutant. A high concentration of CO2 (700 µlliter1) induced stomatal closure in the wild type, butnot in the mutant. On the basis of these results, we proposethe working hypothesis that the mutation occurs in the regiondownstream of CO2 and ABA sensing and in the region upstreamof Ca2+ elevation. The mutant is named fia (fava bean impairedin ABA-induced stomatal closure).
3 Corresponding author: E-mail, smoiwai{at}agri.kagoshima-u.ac.jp;Fax, +81-99-285-8556. 相似文献
10.
Effect of Elevated CO2 on Stomatal Density and Distribution in a C4 Grass and a C3 Forb under Field Conditions 总被引:1,自引:0,他引:1
Knapp Alan K.; Cocke Meagan; Hamerlynck Erik P.; Owensby Clenton E. 《Annals of botany》1994,74(6):595-599
Two common tallgrass prairie species, Andropogon gerardii, thedominant C4 grass in this North American grassland, and Salviapitcheri, a C3 forb, were exposed to ambient and elevated (twiceambient) CO2 within open-top chambers throughout the 1993 growingseason. After full canopy development, stomatal density on abaxialand adaxial surfaces, guard cell length and specific leaf mass(SLM; mg cm-2) were determined for plants in the chambers aswell as in adjacent unchambered plots. Record high rainfallamounts during the 1993 growing season minimized water stressin these plants (leaf xylem pressure potential was usually >-1·5 MPa in A. gerardii) and also minimized differencesin water status among treatments. In A. gerardii, stomatal densitywas significantly higher (190 ± 7 mm-2; mean ±s.e.) in plants grown outside of the chambers compared to plantsthat developed inside the ambient CO2 chambers (161 ±5 mm-2). Thus, there was a significant 'chamber effect' on stomataldensity. At elevated levels of CO2, stomatal density was evenlower (P < 0·05; 121 ± 5 mm-2). Most stomatawere on abaxial leaf surfaces in this grass, but the ratio ofadaxial to abaxial stomatal density was greater at elevatedlevels of CO2. In S. pitcheri, stomatal density was also significantlylower when plants were grown in the open-top chambers (235 ±10 mm-2 outside vs. 140 ± 6 mm-2 in the ambient CO2 chamber).However, stomatal density was greater at elevated CO2 (218 ±12 mm-2) compared to plants from the ambient CO2 chamber. Theratio of stomata on adaxial vs. abaxial surfaces did not varysignificantly in this herb. Guard cell lengths were not significantlyaffected by growth in the chambers or by elevated CO2 for eitherspecies. Growth within the chambers resulted in lower SLM inS. pitcheri, but CO2 concentration had no effect. In A. gerardii,SLM was lower at elevated CO2. These results indicate that stomataland leaf responses to elevated CO2 are species specific, andreinforce the need to assess chamber effects along with treatmenteffects (CO2) when using open-top chambers.Copyright 1994, 1999Academic Press Andropogon gerardii, elevated CO2, Salvia pitcheri, stomatal density, tallgrass prairie 相似文献
11.
Ineffectiveness of Abscisic Acid in Stomatal Closure of Yellow Lupin, Lupinus luteus var. Weiko III 总被引:4,自引:0,他引:4
Stomata of yellow lupin leaves are remarkably insensitive toabscisic acid (ABA). Stomatal resistance was monitored usingboth a viscous now porometer and a diffusion porometer. Resultswere confirmed with scanning electron microscopy. When exogenousABA solutions were supplied via petioles, 106 M solutionshad no effect on stomatal resistance. Upper (adaxial) stomatawere not affected by 105 M ABA but lower stomata showed3-fold more resistance after 2 h. Stomata of both surfaces closedafter 30 min in 104 M ABA. Isolated epidermal peels of lupin leaves were floated on ABAsolutions yet upper surface peels showed no stomatal closingin 104 M ABA, while lower surface stomata closed to abarely significant extent. Stomata of intact leaves were not very sensitive to darkness,showing at most a doubling in resistance after 6 h darkness.Complete stomatal closure, however, was readily produced bywilting leaves. Hence, lupin stomata are physically capableof closing. Endogenous ABA levels of water-stressed leaves increased approximately10-fold, which corresponds to concentrations below 10 µMABA. It is concluded that ABA is unlikely to play a role incontrolling short-term stomatal response of lupins. 相似文献
12.
Seedlings of Zea mays L. (John Innes hybrid) were grown withroots divided between two containers such that part of the rootsystem could reduce the water potential of the soil in its immediatevicinity while the rest of the root system was well suppliedwith water. When compared to plants rooted in two pots of moistsoil, drying of part of the root system resulted in partialclosure of stomata, even though leaf water potential, turgorand abscisic acid (ABA) content remained unaffected. When leafpieces were removed from the two groups of plants and incubatedunder conditions favourable for stomatal opening, stomata ofthe half-watered plants still showed restrictedapertures. Incubation in kinetin (10 mmol m3) or zeatin(100 mmol m3) reversed the closure of stomata stimulatedby soil drying. These results suggest that a continuous supplyof cytokinin from roots may be necessary to sustain maximalstomatal opening and an interruption of this supply due to soildrying may act as an indicator of inhibited root activity, resultingin restricted stomatal opening and thereby restricted wateruse. Key words: Zea mays L., Soil drying, Stomata, Roots 相似文献
13.
Source-Sink Relationship: Control of Photosynthesis in the Flag Leaf by the Panicle in Wheat 总被引:2,自引:0,他引:2
If the sink organs regulate the metabolic activity of the sourceorgans through the transmission of a signal and that signalis chemical in nature, then it should be present among the substancescoming out of the panicle. When flag leaf respiration and photosynthesisof wheat (Tritcum aestivum L.) cv. HP 1459 were measured withan infrared gas analyser after feeding the flag leaves withthe diffusate coming out of the panicle, it was observed thatwhile respiration was unaffected, photosynthesis was sharplyinhibited; the inhibition decreased with increasing age of thepanicle. Among the known plant growth regulators none couldsatisfy the requirements of this role with the exception ofabscisic acid which was found to inhibit photosynthesis by morethan 50% even at 107 M, when respiration was affectedby only 8%. Apparently, abscisic acid inhibited photosynthesisthrough its effects on stomatal movement. (Received September 2, 1986; Accepted May 1, 1987) 相似文献
14.
Experiments have examined the effect of phenylmercuric acetate(PMA) on the guard cells of Commelina communis. In one series,PMA was supplied to the leaf surface; after different time intervalsthe epidermis was removed and the ability of the stomata toopen was determined. In the other series, different concentrationsof PMA were included in the medium used for inccubating epidermalstrips with which ion-stimulated stomatal opening was assayed.At concentrations of 10-54 M and above the effect of PMA wassevere and the structural integrity of the guard cells was affected;they were unable to accumulate neutral red. At concentrationsarpound 10-6 M the guard cells were less affected and PMA broughtabout a transient stimulation of stomatal opening by releasingsubsidiary-cell turgor pressure. A solution of 5 x 10-4 M PMA applied to leaves reduced by halfthe photosynthetic 14CO2 incorporation into C. communis mesophyll.In Zea mays it increased the CO2 compensation point and alsothe resistance to diffusion in the gas phase (RA, but therewas a proportionately greater increase in the apparent liquidphase resistance (Rt). This direct inhibition of mesophyll photosynthesisundermines one of the major objectives of applying anatitranspirants,and for this reason it is suggested that PMA is unsuitable forgeneral application to crops. 相似文献
15.
The effects of three morphactins, chlorflurenol, flurenol andEMD 7301 W, were examined on the stomatal aperture using isolatedepidermal strips of Commelina benghalensis. Morphactins produced,a striking decrease in the stomatal opening in light but hadno effect on stomatal closure in darkness. Various catalystsand inhibitors of photophosphorylation had no influence on themorphactin-induced stomatal closure. The stimulatory effectsof ATP, pyruvate and KC1 on stomatal opening were suppressedby the morphactins. The cytokinin, benzyladenine stimulatedthe stomatal opening even in the presence of a morphactin. Theinfluence of morphactins on the stomatal aperture closely resembledthe effect of abscisic acid.
1Present address: Central Plantation Crops Research Institute,Regional Station, Vittal 574243, Karnataka, India. (Received September 16, 1975; ) 相似文献
16.
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
17.
Stornata of leaves of non-stressed yellow lupin plants wereclosed with phenylmercuric acetate (PMA) and viscous flow resistanceand apparent diffusive resistance were measured for both leafsurfaces. Viscous flow resistance was proportional to the ythpower of apparent diffusive resistance with y = 1.19 ±0.10 for the upper surface and y = 1.58 ± 0.11 for thelower surface, i.e. viscous flow resistance changed faster thanapparent diffusive resistance. However, in three separate experiments where lupin plants werewatered with 104 M abscisic acid (ABA) for 1 week, they values were between 0.29 and 0.59 for the upper surface andbetween 0.18 and 1.00 for the lower surface. Similarly, drought-hardened plants showed y values between 0.45and 0.52 for the upper surface, and between 0.43 and 0.88 forthe lower surface. Both ABA. and drought-induced changes iny values were statistically different from PMA results at the1% confidence level. Upon rewatering, drought-stressed plants and ABA-treated plantsrecovered within 2 and 5 d respectively. Thus with both treatments there was a considerable increasein apparent diffusive resistance (and thus a decrease in transpiration)which could not be accounted for by a comparable increase inviscous flow resistance (i.e. stomatal closure). These results suggest that drought stress and ABA treatmentcause an extrastomatal resistance to transpiration in the leavesof yellow lupin plants. 相似文献
18.
Willmer, C. M., Wilson, A. B. and Jones, H. G. 1988. Changingresponses of stomata to abscisic acid and CO2 as leaves andplants age.J. exp. Bot. 39: 401410. Stomatal conductances were measured in ageing leaves of Commelinacommunis L. as plants developed; stomatal responses to CO2 andabscisic acid (ABA) in epidermal strips of C. communis takenfrom ageing leaves of developing plants and in epidermal stripsfrom the same-aged leaves (the first fully-expanded leaf) ofdeveloping plants were also monitored. Stomatal behaviour wascorrelated with parallel measurements of photosynthesis andleaf ABA concentrations. Stomatal conductance in intact leavesdecreased from a maximum of 0-9 cm s 1 at full leaf expansionto zero about 30 d later when leaves were very senescent. Conductancesdeclined more slowly with age in unshaded leaves. Photosynthesisof leaf slices also declined with age from a maximum at fullleaf expansion until about 30 d later when no O2 exchange wasdetectable. Exogenously applied ABA (0.1 mol m 3) didnot affect respiration or photosynthesis. In epidermal stripstaken from ageing leaves the widest stomatal apertures occurredabout 10 d after full leaf expansion (just before floweringbegan) and then decreased with age; this decrease was less dramaticin unshaded leaves. The inhibitory effects of ABA on stomatalopening in epidermal strips decreased as leaves aged and wasgreater in the presence of CO2 than in its absence. When leaveswere almost fully-senescent stomata were still able to open.At this stage, guard cells remained healthy-looking with greenchloroplasts while mesophyll cells were senescing and theirchloroplasts were yellow. Similar data were obtained for stomatain epidermal strips taken from the same-aged leaves of ageingplants. The inhibitory effects of ABA on stomatal opening alsodecreased with plant age. In ageing leaves both free and conjugated ABA concentrationsremained low before increasing dramatically about 30 d afterfull leaf expansion when senescence was well advanced. Concentrationsof free and conjugated ABA remained similar to each other atall times. It is concluded that the restriction of stomatal movements inintact leaves as the leaves and plants age is due mainly toa fall in photosynthetic capacity of the leaves which affectsintracellular CO2 levels rather than to an inherent inabilityof the stomata to function normally. Since stomatal aperturein epidermal strips declines with plant and leaf age and stomatabecome less responsive to ABA (while endogenous leaf ABA levelsremain fairly constant until leaf senescence) it is suggestedthat some signal, other than ABA, is transmitted from the leafor other parts of the plant to the stomata and influences theirbehaviour. Key words: Abscisic acid, CO2, Commelina, leaf age, senescence, stomatal sensitivity 相似文献
19.
Leaf abscisic acid (ABA) levels of chilled P. vulgaris weremeasured after 18 h chilling at 5°C, at a saturation deficitof 1.24 g m3 (SD), and after chilling in a water-saturatedatmosphere. Changes were also followed during a chill hardeningperiod of 4 d at 12°C, 2.1 g m3 SD. It was foundthat hardening resulted in an almost 5. fold increase in ABAlevels after 3 d at 12°C, and this decreased to approximatelycontrol levels on the fourth day. Subsequent chilling of hardenedplants produced no change in ABA levels from that of controlplants (22° C). In contrast, non-hardened plants chilledat 1.24 g m3 SD had ABA levels almost 3 times the levelof control plants. However, chilling in a water-saturated atmosphereresulted in a decrease in ABA levels. In addition, the response of leaf diffusion resistance (LDR)to exogenous ABA fed via the transpiration stream was measuredat 5 ° C and 22° C in hardened and non-hardened plants.Use of tritium-labelled ABA was made to calculate the stomatalsensitivity to ABA. It was found that exogenous ABA caused anincreased in LDR at 22°C in both hardened and non-hardenedplants. However, the sensitivity of the hardened plants to ABAwas greater in terms of rate of closure and amount of ABA requiredto close the stomata. At 5°C, however, ABA caused stomatalopening and the maintainance of open stomata in non-hardenedplants. In hardened plants, ABA caused stomatal closure at 5°C.These results are discussed in relation to the locking-openresponse of chilled P. vulgaris stomata. Key words: Chilling, Stomata, ABA, Phaseolus vulgaris 相似文献
20.
Kitahara Yoshio; Yanagawa Hiroshi; Kato Tadahiro; Takahashi Norindo 《Plant & cell physiology》1972,13(5):923-925
Yellow prisms of asparagusic acid, with a molecular formulaof C4H6O2S2 were isolated from etiolated asparagus tissues (Asparagusofficinalis L.). This acid inhibits growth in lettuce and otherseedlings when applied in concentrations of 6.67x107Mto 6.67xl07M. The extent of activity was very similarto that of abscisic acid.
1 A well known shift reagent in the NMR spectrum (1). (Received April 12, 1972; ) 相似文献