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1.
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
2.
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
3.
Calcium Inhibits Ion-Stimulated Stomatal Opening in Epidermal Strips of Commelina communis L. 总被引:2,自引:0,他引:2
Inoue, H. and Katoh, Y. 1987. Calcium inhibitsion-stimulatedstomatal opening in epidermal strips of Commelina communis L.J.exp. Bot. 38: 142149. Ca2+ suppressed both the ion-stimulated stomatal opening andH+ extrusion of pre-illuminated epidermal strips isolated fromCommelina communis L. In the absence of Ca2+, the rate of H+release was 18 nmol H+ cm2 h1 per epidermal stripunit area in 150 mol m3 KCL at pH 7?4. Half-maximum inhibitionof stomatal opening was observed with 220 mmol m3 ofCa2+. The hexavalent dye, ruthenium red, showed concentration-dependentprevention of the inhibition by Ca2+ of the ion-stimulated stomatalopening. The effect of ruthenium red was non-competitive, andthe K1 for the calcium inhibition was found to be 3?6 mmol m3.The calcium inhibition of H+ extrusion was also prevented byruthenium red. These results suggest that Ca2+ inhibits theactivity of electrogenic H+ translocating ATPase of the guardcell plasma membrane and leads to the suppression of stomatalopening. Key words: Calcium, Commelina communis, ruthenium red, stomata 相似文献
4.
Tentoxin and, to a lesser extent, dihydrotentoxin (both at 10mmol m3) reduce stomatal opening in epidermal stripsof Commelina communis in the light but not in darkness. Thiseffect was significantly greater in normal air than in CO2-freeair. Fusicoccin overcame the tentoxin effect. However, tentoxindid not inhibit stomatal opening in the light in epidermal stripsof Paphiopedilum harrisianum, a species which lacks guard cellchloroplasts. It is concluded that tentoxin exerts its actionon stomata not by an ionophorous effect in the plasmalemma ofguard cells but by the inhibition of photophosphorylation intheir chloroplasts. The effects of DCMU and tentoxin on guardcells are discussed in terms of their effects on chloroplastsand the extent to which energy is supplied from this organelleduring stomatal opening in the light. The results indicate thatneither photophosphorylation nor non-cyclic electron transportin guard cell chloroplasts are essential for stomatal opening. Key words: Commelina, epidermal strips, Paphiopedilum, photophosphorylation, stomata, tentoxin 相似文献
5.
Root Growth and Water Uptake by Maize Plants in Drying Soil 总被引:16,自引:0,他引:16
Sharp, R. E and Da vies, W. J. 1985. Root growth and water uptakeby maize plants in drying soil. J. exp. Bot. 36: 14411456. The influence of soil drying on maize (Zea mays L.) root distributionand use of soil water was examined using plants growing in thegreenhouse in soil columns. The roots of plants which were wateredwell throughout the 18 d experimental period penetrated thesoil profile to a depth of 60 cm while the greatest percentageof total root length was between 2040 cm. High soil waterdepletion rates corresponded with these high root densities.Withholding water greatly restricted root proliferation in theupper part of the profile, but resulted in deeper penetrationand higher soil water depletion rates at depth, compared withthe well watered columns. The deep roots of the unwatered plantsexhibited very high soil water depletion rates per unit rootlength. Key words: Maize, roots, water deficit, soil water depletion 相似文献
6.
BREEZE V. G.; WILD A.; HOPPER M. J.; JONES L. H. P. 《Journal of experimental botany》1984,35(8):1210-1221
The effect of phosphate concentration in flowing solution cultureat a range between 0.04 and 32 mmol m3 P on the growthof perennial ryegrass was studied in two experiments, each lastingabout 45 d after sowing. Phosphorus contents of seedlings wereaffected by the concentration in solution within about 5 d fromgermination, and dry weight differences were first observedat about 6 d after this. The rate of uptake of phosphate byseedlings was affected by the concentration in solution beforethe root fresh weight or root/emdash shoot ratio had changed.Young plants (less than 4 weeks old) were more sensitive tophosphate concentration in solution than older ones. In conditionsof high rate of growth, older plants required a solution concentrationbetween 0.1 and 0.4 mmol m3 P to achieve maximum potentialgrowth rate, whereas for plants of similar age but less dryweight, 0.04 mmol m3 P was adequate. Towards the endof the experimental period, plants growing at a nominal solutionconcentration of 0.04 mmol m3 P were able to obtain phosphatefrom a solution of about 0.01 mmol m3P. Phosphate toxicity was not observed, nor were there visual symptoms(other than reduced growth) of phosphate deficiency in plantswhose growth was limited by phosphate concentration in solution. Key words: Lolium perenne, Phosphate uptake 相似文献
7.
Changes in Stomatal Conductance in Intact Ageing Wheat Leaves in Response to Abscisic Acid 总被引:4,自引:0,他引:4
The characteristics of ABA-induced changes in the fluxes ofCO2 and water vapour from whole leaves of spring wheat (Triticumaestivum cv. Wembley) were examined. Aqueous solutions of ABAwere supplied via the transpiration stream to intact leavesof different ages mounted within a gas exchange cuvette. ABA caused a reduction in stomatal conductance (g) that wasproportional to the concentration in the solution fed to theleaf. For the maintenance of a reduction in g there was a requirementfor a continual supply of ABA. At concentrations greater than102 mol m3 ABA reduced g by at least 50% of thecontrol value, while 1.0 mol m3 closed stomata within2 h. Concentrations as low as 103 mol m3 produceda 20% reduction in g. As leaves aged they became less responsiveto applied ABA. The possibility that the stomatal response may change aftera leaf has previously experienced a pulse of ABA was exploredby repeating the exposure of a leaf to 102 mol m3ABA. The first pulse of ABA produced a greater reduction ing than a subsequent exposure the following day. This declinein response of g to ABA on repeated exposure was maintainedwith leaves of different ages. The characteristics of the stomatal response to ABA are discussedin the context of what is known about the location of receptorsfor the hormone. It seems likely that a failure to respond toABA that has previously accumulated in the guard cells shouldbe viewed by means of maximizing the sensitivity to the currentsupply of ABA. It is suggested that the smaller response ofthe stomata of older leaves to ABA makes them more susceptibleto water stress, so that they can act as sensors for decliningwater potentials to give early protection to younger, metabolicallyactive leaves. Key words: Abscisic acid, leaf age, stomatal conductance, Triticum aestivum 相似文献
8.
Does Xylem Sap ABA Control the Stomatal Behaviour of Water-Stressed Sycamore (Acer pseudoplatanus L.) Seedlings? 总被引:3,自引:0,他引:3
Sycamore seedlings were grown with their root systems dividedequally between two containers. Water was withheld from onecontainer while the other container was kept well-watered. Effectsof soil drying on stomatal behaviour, shoot water status, andabscisic acid (ABA) concentration in roots, xylem sap and leaveswere evaluated. At 3 d, root ABA in the drying container increased significantly,while the root ABA in the unstressed container of the same plantsdid not differ from that of the control. The increase in rootABA was associated with the increase in xylem sap ABA and withthe decrease in stomatal conductance without any significantperturbation in shoot water status. At 7 d, despite the continuous increase in root ABA concentration,xylem sap ABA showed a marked decline when soil water contentwas depleted below 013 g g1. This reduction in xylemsap ABA coincided with a partial recovery of stomatal conductance.The results indicate that xylem sap ABA is a function of rootABA as well as the flow rate of water from roots to shoots,and that this ABA can be a sensitive indicator to the shootof the effect of soil drying. Key words: Acer pseudoplatanus L., soil drying, stomatal behaviour, xylem sap ABA 相似文献
9.
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
10.
Perennial ryegrass (Lolium perenne L.) was grown from seed for29 d in flowing solution culture containing 0.1, 0.4 or 6.4mmol m3 P before the concentrations were changed (0.1and 0.4 raised to 6.4; 6.4 lowered to 0.4; controls unchanged)for an experimental period of two weeks to test the hypothesisthat after the seedling stage, the maximum rate of plant growthcould be sustained by a lower concentration of phosphate atthe root/solution interface than was necessary for the maximumrate of seedling growth. During the 29 d seedling period growthwas greatest on 6.4 mmol m3 P achieving 179 mg per plantdry weight compared with 122 and 26 mg on 0.4 and 0.1 mmol m3P respectively. During the experimental period growth on thetreatment 6.4 lowered to 0.4 mmol m3 P continued at thesame rate as the 6.4 control achieving 981 and 983 mg per plantdry weight respectively. Similarly growth of the treatment 0.4raised to 6.4 mol m3 P was unaffected by the change inconcentration and was comparable with the 0.4 control. Bothresults support the hypothesis for seedlings exceeding about100 mg per plant dry weight. In contrast the small plants ofthe treatment 0.1 raised to 6.4 mmol m3 P behaved similarlyto seedlings and responded rapidly to the increased concentrationof phosphate in solution, achieving high rates of phosphateuptake and increasing the growth of shoot more than the growthof root so that the ratio of root: shoot declined from 065 to0.34, a value similar to that for the seedlings grown on 6.4mmol m3 P. Key words: Lolium perenne L, Phosphate concentration, Seedling growth 相似文献
11.
The Effects of Low Concentrations of Sulphur Dioxide on Stomatal Conductance and Epidermal Cell Survival in Field Bean (Vicia faba L.) 总被引:4,自引:0,他引:4
Exposure of 3 week old field bean plants to concentrations ofSO2 from 50500 µg m-3 induced comparable 2025%increases in mean leaf diffusive conductance regardless of whetherthe diffusive conductances were obtained by porometric measurementor calculation from gas exchange data. The stomatal conductancesof the adaxial and abaxial leaf surfaces were both increasedby exposure to SO2. Microscopic examination of epidermal strips from control andpolluted plants revealed that the stomatal opening observedin treated plants was associated with a sharp reduction in theproportion of living epidermal cells adjacent to the stomata.The proportion of surviving adjacent epidermal cells was invariablysmaller on the lower epidermis and appeared to decrease as theSO2 concentration was raised from 50 to 500 µg m3.Although the guard cells appeared to be undamaged at concentrationsbelow 200 µg m3, structural disorganization ordeath of one or both guard cells was observed frequently ator above 500 µg m3. The results are discussed in relation to the controversy concerningthe effects of SO2 on stomatal aperture. 相似文献
12.
An attempt has been made to separate the osmotic effect fromthe ionic effect of KCI in stomatal responses. For this purposeisolated illuminated epidermis from species with and withoutsubsidiary cells were treated with KCI (0-250 mOs kg1)and with mannitol (0-250 mOs kg1). Since osmolarity wasmade the basis of comparison, the effect of mannitol had tobe observed immediately, before guard cell contents could haveleached into the incubation medium. When plotting aperturesagainst osmolarity sigmoid curves were obtained with KCI, butwith mannitol straight lines resulted provided that prior tostripping and incubation leaves were briefly illuminated. Whilst in lower concentrations (60 mOs kg1 for Viciafaba; 90 mOs kg1 for Zantedeschia aethiopica; 190 mOskg1 for Commelina communis) pores were wider in mannitolthan in KCI, in concentrations above these values the situationwas reversed. It appeared therefore that KCI had either an inhibitoryor a promoting effect. Inhibition was most pronounced when atthe beginning of incubation stomata were closed; the inhibitoryeffect on stomata without subsidiary cells occurred at low concentrations(0-60 mOs kg1) whereas when subsidiary cells were presentinhibition occurred at up to 190mOs kg1. Other experiments started with KCI solutions of 50 mOs kg1for Vicia faba, 85 mOs kg1 for Zantedeschia aethiopicaand 115 mOs kg1 for Commelina communism; mannitol wasadditionally used to give the progressive increases in osmolarity.Degrees of opening were then reached which with KCI alone couldonly be attained at the very highest concentrations. Starch disappearance was followed using the periodic-acid-silvertest; by using either 86Rb or 43K it was shown that ion uptakewas restricted to guard cells alone only at osmolarities exceeding200 mOs kg1. On the basis of these observations it was concluded that K transportdoes not represent the major mechanism of stomatal regulation. Key words: Stomata, Potassium, Osmolarity 相似文献
13.
Hydraulic Conductances of the Soil, the Root-Soil Air Gap, and the Root: Changes for Desert Succulents in Drying Soil 总被引:5,自引:0,他引:5
Water movement to and from a root depends on the soil hydraulicconductivity coefficient (Lsoil), the distance across any root-soilair gap, and the hydraulic conductivity coefficient of the root(LP). After analytical equations for the effective conductanceof each part of the pathway are developed, the influences ofsoil drying on the soil water potential and Lsoil are describedduring a 30 d period for a loamy sand in the field. The influencesof soil drying on LP for three desert succulents, Agave deserti,Ferocactus acanthodes, and Opuntia ficus-indica, are also describedfor a 30 d period. To quantify the effects of soil drying onthe development of a root-soil air gap, diameters of 6-week-oldroots of the three species were determined at constant watervapour potentials of 1.0 MPa and 10 MPa as wellas with the water vapour potential decreasing at the same rateas soil drying during a 30 d period. The shrinkage observedfor roots initially 2·0 mm in diameter averaged 19% duringthe 30d period. The predominant limiting factor for water movementwas LP of the root for the first 7 d of soil drying, the root-soilair gap for the next 13 d, and Lsoil thereafter. Compared withthe ease of water uptake from a wet soil, the decrease in conductancesduring soil drying, especially the decrease in Lsoil causedthe overall conductance to decrease by 3 x 103-fold during the30 d period for the three species considered, so relativelylittle water was lost to the dry soil. Such rectifier-like behaviourof water movement in the soil-root system resulted primarilyfrom changes in Lsoil and, presumably, is a general phenomenonamong plants, preventing water loss during drought but facilitatingwater uptake after rainfall. Key words: Agave deserti, Ferocactus acanthodes, Opuntia ficus-indica, rectification, soil water potential, water movement 相似文献
14.
Inherent differences in the responses of stomata on abaxialand adaxial epidermal surfaces of leaves of Commelina communishave previously been suggested to be due to differences in theconcentrations of apoplastic Ca. Adaxial stomata have also beenreported to be more sensitive than abaxial stomata to appliedabscisic acid (ABA). The aims of these experiments were to determinethe validity of these conclusions and to see if xylem sap Cahas a role in determining the response of stomata to ABA. It can be shown from measurements of relative stomatal resistance(determined with a viscous flow porometer) and stomatal conductancethat stomata were more open in plants grown on 8-0 mol m3Ca, than with those grown on 2-0 mol m3 Ca. When attachedleaves were fed with ABA via the transpiration stream neitherthe extent nor the rate with which conductance declined wasdependent on Ca nutrition. The extent of Ca accumulation within both epidermes was relatedto the concentration of Ca in the rhizosphere and in the xylemsap. It did not, however, appear to reflect the apparent differencesin the flux of the transpiration stream between the two epidermes.Plants growing at the lower Ca concentration accumulated proportionallymore epidermal Ca relative to Ca in xylem sap. The evidencepresented suggests that Ca movement from the xylem to the epidermiscannot be simply described by a mass flow model, and that thedistribution of Ca is not an adequate explanation of the differencesin the behaviour of adaxial and abaxial stomata. The potentialrole for changes in xylem sap Ca to act as a regulator of stomatalbehaviour are discussed. Key words: Abscisic acid, calcium, Commelina communis L., stomatal conductance 相似文献
15.
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
16.
Natriuretic Peptides--A New Class of Plant Hormone? 总被引:2,自引:0,他引:2
Recent immunological and functional evidence suggests the presenceof a biologically active natriuretic peptide hormone (NP) systemin plants. The evidence includes specific binding of rat atrialNP [rANP (99126)] to isolated plant membranes and thepromotion of stomatal opening that is concentration and conformationdependent. The native circular molecule is active whereas thelinearized molecule shows no biological activity. Stomatal openingmediated by rANP (99126) is inhibited by LY 83583, anantagonist of guanylate cyclase, while 8-Br-cGMP, a cell permeantcyclic guanosine-3'-5'-monophosphate (cGMP) analogue, mimicsrANP (99126) effects. Most importantly, isolation andimmunoaffinity purification of biologically active plant NP(irPNP) fromHedera helixhas been achieved and immunoaffinitypurified peptide has been shown to induce rapid and specificincreases in cGMP levels inZea maysroot stele. Furthermore,rANP (99126), irPNP and cGMP promote radial water movementsfrom the xylem ofTradescantia multifloraand these NP-inducedand cGMP-dependent increases are prevented by a water channelinhibitor. Taken together, the data are consistent with thepresence of a biologically active NP system that, as in vertebrates,signals via cGMP dependent pathways. The evidence suggests thatthe NP system has a role in maintaining water and salt homeostasisin plants.Copyright 1999 Annals of Botany Company Plant hormones, natriuretic peptides, stomata, cGMP, salt and water homeostasis. 相似文献
17.
Sagebrush (Artemisia tridentata Nutt.) roots maintain nutrient uptake capacity under water stress 总被引:2,自引:0,他引:2
Phosphorus and nitrogen uptake capacities were assessed during3658 d drying cycles to determine whether the abilityof sagebrush (Artemisia tridentata Nutt.) to absorb these nutrientschanged as the roots were subjected to increasing levels ofwater stress. Water was withheld from mature plants in large(6 I) containers and the uptake capacity of excised roots insolution was determined as soil water potentials decreased from0.03 MPa to 5.0 MPa. Phosphorus uptake rates of excised roots at given substrateconcentrations increased as preharvest soil water potentialsdecreased to 5.0 MPa. Vmax and Km also increased as soilwater potentials declined. Declining soil water potentials depressednitrogen uptake at set substrate concentrations, but uptakecapacity, calculated as the sum Vmax for both NH+4+NO3,did not change significantly with drying. The sum Vmax correlatedwith root nitrogen concentration. Root uptake capacity for nitrogen and phosphorus was extremelystable under severe water stress in this aridland shrub. Maintenanceof uptake capacity, coupled with a previously demonstrated abilityto conduct hydraulic lift, may enable A. tridentata better tomaintain nitrogen and phosphorus uptake as soil water availabilitydeclines. These mechanisms may be important in the ability ofA. tridentata to maintain growth, complete reproduction, andgain an advantage against competitors late in the season whenthe soil layers with higher nutrient availability are dry. Key words: Kinetics, nitrogen, phosphorus, roots, water stress 相似文献
18.
The Effects of Partially Drying Part of the Root System of Helianthus annuus on the Abscisic Acid Content of the Roots, Xylem Sap and Leaves 总被引:7,自引:0,他引:7
Plants of Helianthus annuus were grown in soil in pots suchthat approximately 30% of the root system protruded throughthe base of the pot. After 7 d further growth in aerated nutrientsolution, the attached, protruding roots were air-dried for1015 min and thereafter surrounded with moist still air,in the dark, for 49 h, whilst the soil was kept at field capacity.The roots of the control plants remained in the nutrient solutionthroughout the experiment. This treatment rapidly reduced the water content of protrudingroots from 20.5 to 17.8 g g1 dry mass (DM), which remainedless than that of the control roots for the rest of the experiment.This treatment also reduced root turgor and water potential.The abscisic acid (ABA) concentrations in the protruding roots,xylem sap and leaves of the treated plants increased significantly,compared to values recorded for control plants. In treated roots, the ABA concentration was significantly increased4 h after treatment, with a maximum of 4.4+0.1 nmol g1(DM) after 25 h. The ABA concentration in the xylem sap of thetreated plants was significantly greater than in the controls25 h, 30 h, and 49 h after the partial drying of the roots,with a maximum concentration of approximately 970 pmol ABA cm-3at 49 h. Initially, the ABA concentration in the leaves was0.45 nmol g1 (DM) which increased significantly to 1.1±0.1 nmol g1 at 25 h, to 1.7±0.3 nmol g1at 49 h. Leaf conductance was significantly less in plants with air-driedroots than in the controls 8 h after the start of the treatmentand thereafter. The water relations of the leaves of the treatedplants did not differ from those of the control plants. These results confirm previous reports that ABA is rapidly generatedin partially-dried and attached root systems and demonstratesa concomitant large increase in the ABA content of the xylemsap. It is suggested that partial dehydration of some of theroots of Helianthus annuus, increases ABA concentration in thetranspiration stream and decreases leaf conductance in the absenceof changes in leaf water status. As these responses were initiatedin free-growing roots the stimulus is independent of any increasesin soil shear strength that are associated with soil drying. Key words: Soil drying, roots, ABA, leaf conductance, water relations 相似文献
19.
Epidermal strips from either well-watered or water-stressedplants of Commelina communis L. were subjected to a range ofABA concentrations (106103 mol m3)in the presence (330 parts 106 in air) or virtual absence(3 parts 106 in air) of CO2. The stomatal response toCO2 was greater in epidermis from water-stressed plants, althoughthere was a distinct CO2 response in epidermis from well-wateredplants. Additions of ABA via the incubation medium had littleeffect on the relative CO2 response. Stomata responded to ABAboth in the presence and virtual absence of CO2, but the relativeresponse to ABA was greatest in the high CO2 treatment. Whenwell-watered plants were sprayed with a 101 mol m3ABA solution 1 d prior to use, the stomatal response of detachedepidermis to both CO2 and ABA was very similar to that of epidermisdetached from water-stressed leaves. It is hypothesized thata prolonged exposure to ABA is necessary before there is anymodification of the CO2 response of stomata. 相似文献
20.
The effects of H$ and fusicoccin (FC) on stomatal opening inthe dark were investigated using epidermal strips of Commelinacommunis and Vicia faba cv. Ryosai Issun. Citrate-phosphatebuffer induced maximal opening of stomata at pH 3.0 when testedover the range of 2.7 to 5.0. HCl at 1 mM also induced stomatalopening without appreciable accumulation of K$ in the guardcells. After 4 hr treatment with 10 µM FC, stomata openedwith concomitant accumulation of K$ in the guard cells, although12 hr treatment caused opening without concomitant K$increase. These results suggest that stomatal opening can be caused bysalt accumulation and/or changes of the physicochemical conditionsin the cell wall of the guard cells due to high acidity.
1 Present address: Biological Laboratory, Faculty of Education,Nagasaki University, Nagasski 852, Japan. (Received April 30, 1982; Accepted July 17, 1982) 相似文献