共查询到20条相似文献,搜索用时 15 毫秒
1.
Changes in NMR relaxation times (T1) of water protons and watercontents of leaves of woody plants affected by formation ofinsect galls were studied in Machilus, Zelkova and Cinnamomumparasitized with a gall-midge, an aphid and two different Triozinepsyllids, respectively. The presence of galls in Machilus leavesincreased both T1 and water contents in the galled leaf tissues,while such tissues in Zelkova showed only increases in T1. Similartrends for both parameters were also observed in gall-bearingleaf tissues of Machilus and Cinnamomum, with galls caused bytwo different psyllids. It seems that it is the particular characteristicsof leaf tissues of the host plant that determine whether thesystemic effect of the presence of galls is reflected both inT1 and in water content, or only in T1. Histologic features,including the presence of tannins in and leakage of electrolytesfrom these materials, were compared with those of normal (ungalled)leaves to determine possible causative factors involved in theprolongation of T1 relaxation times that were associated withthe presence of insect galls. The eco-physiological implicationof tannins with respect to the host-parasite relationship isalso discussed. (Received October 27, 1989; Accepted April 24, 1990) 相似文献
2.
A method is described for the accurate measurement of the apparentresistance to water loss from the mesophyll cell walls of plantleaves (rw), and for studying the mechanism underlying thisresistance. The method for distinguishing possible mechanismsinvolves a comparison of the calculated values of rw at differentrates of evaporation. The value of rw remained below 50 s m1at relative water contents greater than 11 ± 3% and 7± 2% for Pelargonium hortorum Bailey and Vicia faba L.respectively. Therefore rw is relatively insignificant at normalphysiological water contents in these species. When rw did increaseit was not sensitive to evaporation rate, suggesting that alowering of the vapour pressure at the evaporating sites wasnot involved. This contrasted with the results for cellulosefilter paper, where rw was more sensitive to evaporative flux. 相似文献
3.
Thermally stimulated depolarization current (TSDC) measurementson plant leaves and stems of six different species in the temperaturerange of 77300 K revealed the existence of three differentdispersions. The first dispersion at low temperatures, whichis attributed to the relaxation of loosely bound water moleculeswas studied in detail in an attempt to obtain information onthe possible structures of water in plant tissue. Its characteristicsdiffer for various plant tissues, indicating a different organizationof water in those plant tissues. The dispersion can be describedby a continuous distribution of relaxation times t with boththe activation energy W and the pre-exponential factor To inthe Arrhenius equation being distributed parameters. The spectrumof W and To was determined for E. globulus and O. europaea leafsamples. The mean values of T and W are larger and that of Tosmaller than the corresponding values for free (bulk) water.The results favour a model of the organization of water in clustersrather than in multilayers and indicate a stronger binding ofwater in living systems. Key words: Dielectric relaxation, distribution of relaxation times, free and bound water 相似文献
4.
Changes in anatomical and physiological features, includingchanges in amount per unit area of anthocyanin and chlorophyll,in leaves of seedling mango (Mangifera indica L. cv. Irwin)trees were determined to understand what controls the rate ofphotosynthesis (Pn) at various stages of development. The youngleaves of seedling trees contained high concentrations of anthocyanin.During enlargement of leaves, the disappearance of anthocyaninand the accumulation of chlorophyll occurred concomitantly;the anthocyanin content began to decrease markedly once theleaf area had reached a maximum. During the early period ofleaf development, the thickness of mesophyll tissue decreasedtemporarily, but when the length of the leaf reached half thatof a mature leaf, the mesophyll began to thicken again. Smallstarch grains appeared in the chloroplasts of the young leavesand chloroplast nucleoids (ct-nuclei) were distributed throughoutthe chloroplasts. When leaves matured, ct-nuclei were displacedto the periphery of chloroplasts because of the accumulationof large starch grains. Compared with young leaves, green andmature leaves contained greater concentrations of ribulose bisphosphatecarboxylase-oxygenase (RuBisCO) protein. The results of immunocytochemicalexamination of RuBisCO under the light microscope reflectedthe results of electrophoresis measurements of RuBisCO. Pn waslow during the chocolate-coloured stage of early leaf development.In green and mature leaves Pn was higher; the average Pn was7·6 mg CO2 dm-2 h-1 under light at intensities above500 µmol m-2 s-1.Copyright 1995, 1999 Academic Press Mangifera indica L., mango leaf, chloroplast nucleoids, chloroplast ultrastructure, starch accumulation, anthocyanin, chlorophyll, DAPI staining, SDS-PAGE, immunocytochemical technique 相似文献
5.
Monitoring Stress Sensitivity by Water Proton NMR Relaxation Times in Leaves of Azaleas That Originated in Different Ecological Habitats 总被引:1,自引:0,他引:1
Responses of the leaves of five species of azalea to environmentalstresses, such as freezing, dehydration, high temperature andsalt spray, were measured in terms of water proton NMR relaxationtimes (T1), supercooling ability, and water content. Three subtropicalspecies (R. scabrum cv. Shounoshin, R. eriocarpum and R. tashiroivar. lasiophyllum) and two northern species (R. indicum cv.Kumano-satsuki and R. yedoense f. poukhanense), which originatedin different ecological habitats, showed characteristic behaviorsin terms of T1 relaxation times. In general, a species witha large change in T1 is more stress-sensitive than a speciesshowing the opposite tendency. The relative sensitivity to variousstresses of each species appears to be related to the severityof conditions in its natural habitat. It seems possible thatthose species of azalea with higher sensitivity to a particularsingle stress may also exhibit higher sensitivity to severalor even most stresses, and vice versa. (Received August 27, 1992; Accepted February 26, 1993) 相似文献
6.
The mechanisms underlying the drought tolerance of Peperomiacarnevalii Steyermark (Piperaceae), a succulent herb growingin the understorey of seasonally dry forests, were examined.Crassulacean acid metabolism (CAM) was studied in the fieldand laboratory, and measurements of water status were made inplants subjected to drought in the greenhouse. Nocturnal acidaccumulation and day and night-time CO2assimilation rates weregreatest in watered plants and decreased in drought. The proportionof CO2recycled through CAM in droughted plants, with nocturnalCO2uptake close to zero, was higher than in watered plants.Maximum quantum yield of chlorophyll fluorescence remained unchangedduring drought, but the PSII quantum yield at the photosyntheticphoton flux density at which the plants were grown was significantlydecreased. Leaf anatomy consists of a chlorophyll-less hydrenchymalocated beneath the upper epidermis, and a two-layered mesophyll.Leaves nearer to the apex are thinner than those nearer to thebase of the shoot. Drought caused a reduction in leaf thicknessdue to shrinkage of the hydrenchyma, but not of the mesophyll.This was associated with the occurrence of a gradient of osmoticpotential between these tissues. Comparison of water loss fromthin leaves of watered and droughted plants, either partly defoliatedat the lower nodes or intact, suggested that water moved fromthe thick to the thin leaves. This process was related to theoccurrence of a gradient of water potential between the thickand the thin leaves. Drought tolerance in P. carnevalii is achievedby the operation of CAM and the occurrence of water movementwithin and between leaves. Copyright 2000 Annals of Botany Company Crassulacean acid metabolism, fluorescence, hydrenchyma, mesophyll, Peperomia carnevalii, water relations 相似文献
7.
Thermal hysteresis of longitudinal relaxation times (T1) ofwater protons in hypocotyls of etiolated Vigna radiata and V.mungo seedlings was investigated by pulse nuclear magnetic resonance(NMR) spectroscopy. Various lengths of chilling exposures duringa cool-warm cycle between 20 and 0?C (below 10?C, about 4 h)for the T1 hysteresis measurement did not cause any visibleinjury symptoms in hypocotyls. However, the profiles of T1 hysteresisvaried as a result of different chilling exposures. The sumsof the T1 ratio (for detail see Introduction) reflecting T1prolongation or shortening upon the warming process were a goodquantitative index for the extent of T1 hysteresis, and thewide dispersion of this value ranging on the "minus" side (T1prolongation upon warming) suggested the occurrence of a primaryresponse of cells to chilling stress before obvious visiblesymptoms occur while the T1 ratio sums on the "plus" side (T1shortening upon warming) corresponded to a response of seriousvisible injury. Therefore, the sums of the T1 ratio can be usedas a non-destructive diagnostic tool for monitoring the primaryevent of chilling injury when lacking any visible injury symptoms.The data indicate that the critical temperature for the occurrenceof primary response for chilling stress was around 7.5?C forV. radiata and 12.5?C for V. mungo. (Received February 1, 1988; Accepted June 1, 1988) 相似文献
8.
ROMERO-ARANDA R.; BONDADA B. R.; SYVERTSEN J. P.; GROSSER J. W. 《Annals of botany》1997,79(2):153-160
The effect of tetraploidy on leaf characteristics and net gasexchange was studied in diploid (2x ) and autotetraploid (4x) Valencia sweet orange (Citrus sinensis (L.)Osb.) and Femminello lemon (Citrus limon (L.)Burm. f.) leaves. Comparisons between ploidy levels were madeunder high irradiance (I) in a growth chamber or low total Iin a glasshouse. Tetraploids of both species had thicker leaves,larger mesophyll cell volume and lower light transmittance thandiploids regardless of growth I. Mesophyll surface area perunit leaf area of 2x leaves was 515% greater than on4x leaves. Leaf thickness and mesophyll cell volume were greaterin high I leaves than low I leaves. In high I, average leafarea was similar for 2x and 4x leaves, whereas in low I it was30% greater in 4x than in 2x leaves. Nitrogen and chlorophyllconcentration per cell increased with ploidy level in both growthconditions. The ratio of chlorophyll a:b was 25% greater in2x than in 4x leaves. When net CO2assimilation rate (ACO2) wasbased on leaf area, 4x orange leaves had 2435% lowerACO2than their diploids. There were no significant differencesin ACO2between 2x and 4x orange or lemon leaves when expressedon a per cell basis. Overall, lower ACO2per unit leaf area oftetraploids was related to increase in leaf thickness, largermesophyll cell volume, the decrease in mesophyll area exposedto internal air spaces, and the lower ratio between cell surfaceto cell volume. Such changes probably increased the resistanceto CO2diffusion to the site of carboyxlation in the chloroplasts. Cell volume; chlorophyll; irradiance; leaf thickness; nitrogen; photosynthesis; ploidy; Citrus limon ; C. sinensis ; Valencia sweet orange; Femminello lemon 相似文献
9.
Transverse Relaxation Time of Leaf Water Protons and Membrane Injury in Wheat (Triticum aestivum L.) in Response to High Temperature 总被引:2,自引:0,他引:2
MAHESWARI M.; JOSHI D. K.; SAHA R.; NAGARAJAN S.; GAMBHIR P. N. 《Annals of botany》1999,84(6):741-745
The relationship between high temperature stress injury andtemperature dependence of the transverse relaxation time (T2)of leaf water was examined using NMR in four cultivars of wheatdiffering in their sensitivity to high temperature stress. TheT2declined with increasing temperature between 25 and 35 °C.A comparison of relative injury based on electrolyte leakageand T2, between 40 and 50 °C, indicated that while membranepermeability increased with increasing temperature there wasan increase in T2until 44 and 48 °C in susceptible and tolerantcultivars respectively, followed by a sharp decline. This patternof change in T2with increasing temperature was consistent whetherthe same or different samples were used for each treatment temperature.Loss of temperature dependence of T2after heat killing indicatedirreversible changes in T2, probably due to the loss of membraneintegrity. Heat tolerant varieties, which suffered less membraneinjury, had a higher T2compared to susceptible varieties. Tolerantvarieties also maintained the T2of leaf water protons to highertemperatures than did sensitive varieties. This NMR-based, non-invasive,rapid technique could be used to efficiently detect heat injuryin leaf tissues. Copyright 1999 Annals of Botany Company Membrane integrity, transverse relaxation time, high temperature stress, Triticum aestivum L. 相似文献
10.
The longitudinal relaxation time (T1) of water protons in floretsof R. ? akebono flower buds was measured with a pulse NMR spectrometerto determine the relationship of T1 to water content and coldhardiness (supercooling ability). Seasonal changes of T1 inflorets were closely correlated with water content and supercoolingability of florets. T1 of florets was short for acclimated budshaving a low water content and long for non-acclimated budshaving a high water content. Flower buds collected in Novemberand stored at 0 and 5?C for 4 weeks had shorter T1 values thanbuds stored at 10?C even though the floret water content andsupercooling ability were similar. Thus, the short T1 of coldacclimated buds hardened naturally or by storage at low temperaturesis due to a combination of both reduced water content and temperature. (Received August 27, 1983; Accepted May 26, 1984) 相似文献
11.
Nhiri Mohamed; Bakrim Naima; Pacquit Valerie; Hachimi-Messouak Zakia El; Osuna Lidia; Vidal Jean 《Plant & cell physiology》1998,39(2):241-46
Calcium-dependent phosphoenolpyruvate carboxylase protein kinasewas copurified with C4 phosphoenolpyruvate carboxylase (C4 PEPC)from illuminated Sorghum leaves during purification by variousprocedures. Isolated mesophyll cell protoplasts contained bothcalcium-dependent and -independent protein kinases. The latterwas induced by light and weak bases and was found to be themajor protein kinase phosphorylating C4 PEPC in the mesophyll. (Received July 29, 1997; Accepted November 28, 1997) 相似文献
12.
When leaves of Vicia faba were treated with H2O2 or visiblelight in the presence of methyl viologen (MV), the orange-redcompound dopachrome was formed transiently and melanin was accumulated.With the darkening of leaves, the level of 3,4-dihydroxyphenylalanine(DOPA) decreased and then recovered to the original level uponaddition of 1 mM H2O2. However, if leaves were incubated inthe presence of 10 mM H2O2, the level of DOPA decreased againafter the increase. The time course of the changes in levelsof DOPA observed during the accumulation of melanin as a resultof illumination in the presence of MV was very similar to thatobserved after the addition of 10 mM H2O2. Illumination of leavesin the absence of MV did not result in any accumulation of melanin,but the level of DOPA changed slightly. When isolated mesophyllcells were incubated in the dark, the level of DOPA decreased.Illumination of the cells stimulated this decrease. Tropolone,an inhibitor of phenol oxidase, did not inhibit and actuallystimulated the H2O2- and light-induced oxidation of DOPA andaccumulation of melanin in leaves. Tropolone also stimulatedthe decrease in the levels of DOPA both in the dark and in thelight in isolated mesophyll cells. These data suggest that aperoxidase-H2O2 system, and not phenol oxidase, participatesin the oxidation of DOPA. When DOPA was oxidized by a basicperoxidase isolated from V.faba leaves, an intermediate, whichwas perhaps dopaquinone and which was reducible by ascorbate,was formed. Based on the data, a discussion is presented ofthe physiological significance of the oxidation of DOPA by peroxidasein vacuoles. (Received March 4, 1991; Accepted May 21, 1991) 相似文献
13.
Quantitative anatomical and other measurements were made onfully expanded flag leaves of a series of diploid, tetraploidand hexaploid Triticum and Aegilops species, and photosyntheticrates per unit leaf area were measured at light saturation (Pmax). Diploids had the highest Pmax, hexaploids the lowest with tetraploidsbeing intermediate. The anatomical features of tetraploids andhexaploids were generally similar, but different from the diploids.The diploids had thinner leaves with less dry matter and chlorophyllper unit area. The surface area of the mesophyll cells per unitvolume of mesophyll tissue was similar for all ploidy levels,as was the ratio mesophyil cell surface area per unit leaf area.It is argued that while these anatomical features are unlikelyto account for the observed variation in Pmax, it is possiblethat other structural factors with which they are correlatedmay causally influence Pmax. One such feature is the averagediffusion path length from the plasmalemma at the cell surfaceto the sites of carboxylation. Anatomy, photosynthesis, mesophyll, cell size, Triticum, Aegilops, polyploidy 相似文献
14.
Stomatal Responses and the Senescence of Leaves 总被引:1,自引:0,他引:1
Guard cell responses were examined in green and senescing leavesof Victa faba using detached epidermal strips to eliminate influencesfrom the mesophyll. Stomatal opening was greater in epidermalstrips from mature leaves than from senescing leaves althoughthe latter still retained the ability to respond to CO2 andto kinetin. It was concluded that the decline in stomatal activityduring senescence is an independent but parallel process tochanges occurring in the mesophyll. Vicia faba, leaf senescence, stomata, kinetin 相似文献
15.
为探究秋季枫叶呈色的关键生理因素,该文以转色期叶色为绿色、黄色和红色的枫香单株为试材,研究了L*、a*、b*值变化与叶片色素、可溶性糖及可溶性蛋白质含量变化的相关性。结果表明:(1)在变色期,3种色彩枫香叶片叶绿素a、叶绿素b、总叶绿素和类胡萝卜素均大量降解,花色素苷不同程度积累。(2)绿色叶单株叶绿素和类胡萝卜素始终保持较高含量,花色素苷含量上升4.2倍,叶片内色素含量比值始终保持稳定; 黄色叶单株叶绿素和类胡萝卜素含量最低,花色素苷含量上升4.4倍,b*值与叶绿素含量极显著负相关,与类胡萝卜素含量显著负相关,与花色素苷/类胡萝卜素含量比值极显著正相关; 红色叶单株叶绿素和类胡萝卜素含量略高于黄色叶单株,花色素苷含量上升27.2倍,a*值与叶绿素含量、类胡萝卜素含量极显著负相关,与花色素苷含量显著正相关,与色素含量比值无显著相关性。(3)红色叶单株具有较高的可溶性糖含量和可溶性蛋白质含量。因此,在枫香叶片变色期,保持较高的叶绿素和类胡萝卜素含量,维持色素含量比值稳定使叶片呈现绿色; 叶绿素和类胡萝卜素的大量降解,以及花色素苷/类胡萝卜素含量比值的升高使叶片呈现黄色; 叶绿素的降解和花色素苷的大量合成使叶片呈现红色。 相似文献
16.
Mitochondria were isolated from mesophyll protoplasts and bundlesheath protoplasts or strands which were obtained by enzymaticdigestion of six C4 species: Zea mays, Sorghum bicolor, Panicummiliaceum, Panicum capillare, Panicum maximum and Chloris gayana,representative of three C4 types. Photorespiratory glycine oxidationand related enzyme activities of mesophyll and bundle sheathmitochondria were compared. Mesophyll mitochondria showed good P/O ratios with malate andsuccinate as substrate but lacked the ability to oxidize glycine.On the other hand, mitochondria isolated from bundle sheathprotoplasts of P. miliaceum and bundle sheath strands of Z.mays possessed glycine oxidation activity similar to that ofmitochondria from C3 plant leaves. The two enzymes involvedin glycine metabolism in mitochondria, serine hydroxymethyltransferaseand glycine decarboxylase, were also assayed in the mitochondriaof the two cell types. The activities of the two enzymes inbundle sheath mitochondria were in the range found in C3 mitochondria.In contrast, the activities in mesophyll mitochondria were eithernot detectable or far lower than those in bundle sheath mitochondriaand ascribed to contaminating bundle sheath mitochondria. The present results indicate the deficiency of a complete glycineoxidation system in mesophyll mitochondria and also a differentiationbetween mesophyll and bundle sheath cells of C4 plants withrespect to the photorespiratory activities of the mitochondria. (Received June 8, 1983; Accepted August 29, 1983) 相似文献
17.
Temperature dependence of longitudinal relaxation times (T1)of water protons in flower buds of six azalea species differingin cold hardiness and ecological distribution was investigatedby pulse nuclear magnetic resonance spectroscopy. Thermal hysteresiswas observed for T1 following a slow freeze-thaw cycle. TheT1 ratio (the ratio obtained from the difference between theoriginal T1 value in an unfrozen sample and the final T1 aftera freeze-thaw treatment, both at 20C, divided by the originalT1) was closely correlated with the viability of florets innon-acclimated buds of R. kiusianum. If the buds were frozento a lethal temperature and then thawed to 20C, the T1 ratioincreased. The T1 ratios of acclimated winter buds for the sixspecies used were correlated with the level of cold hardiness(supercooling ability of florets determined by differentialthermal analysis). The T1 ratio of deacclimated spring buds,especially those from hardier species, markedly increased uponcooling to a lethal temperature. Species differences observedin acclimated winter buds disappeared upon deacclimation. TheT1 ratio appears to be related to the viability of florets andthe degree of freezing damage (membrane disruption) in florets. (Received December 28, 1984; Accepted May 24, 1985) 相似文献
18.
Green Light Drives CO2 Fixation Deep within Leaves 总被引:5,自引:0,他引:5
Maximal l4CO2-fixation in spinach occurs in the middle of thepalisade mesophyll [Nishio et al. (1993) Plant Cell 5: 953],however, ninety percent of the blue and red light is attenuatedin the upper twenty percent of a spinach leaf [Cui et al. (1991)Plant Cell Environ. 14: 493]. In this report, we showed thatgreen light drives 14CO2-fixation deep within spinach leavescompared to red and blue light. Blue light caused fixation mainlyin the palisade mesophyll of the leaf, whereas red light drovefixation slightly deeper into the leaf than did blue light.14CO2-fixation measured under green light resulted in less fixationin the upper epidermal layer (guard cells) and upper most palisademesophyll compared to red and blue light, but led to more fixationdeeper in the leaf than that caused by either red or blue light.Saturating white, red, or green light resulted in similar maximal14CO2-fixation rates, whereas under the highest irradiance ofblue light given, carbon fixation was not saturated, but itasymptotically approached the maximal 14CO2-fixation rates attainedunder the other types of light. The importance of green lightin photosynthesis is discussed.
1Supported in part by grants from Competitive Research GrantsOffice, U.S. Department of Agriculture (Nos. 91-37100-6672 and93-37100-8855). 相似文献
19.
Relationship between Leaf Structure and Gas Exchange in Wheat Leaves at Different Insertion Levels 总被引:3,自引:0,他引:3
Net photosynthesis rate (Pn), stomatal conductance to CO2 andresidual conductance to CO2 were measured in the last six leaves(the sixth or flag leaf and the preceding five leaves) of Triticumaestivum L. cv. Kolibri plants grown in Mediterranean conditions.Recently fully expanded leaves of well-watered plants were alwaysused. Measurements were made at saturating photosynthetic photonflux density, and at ambient CO2 and O2 levels. The specificleaf area, total organic nitrogen content, some anatomical characteristics,and other parameters, were measured on the same leaves usedfor gas exchange experiments. A progressive xeromorphic adaptation in the leaf structure wasobserved with increasing leaf insertion levels. Furthermore,mesophyll cell volume per unit leaf area (Vmes/A) decreasedby 52·6% from the first leaf to the flag leaf. Mesophyllcell area per unit leaf area also decreased, but only by 24·5%.However, nitrogen content per unit mesophyll cell volume increasedby 50·6% from the first leaf to the flag leaf. This increasecould be associated to an observed higher number of chloroplastcross-sections per mm2 of mesophyll cell cross-sectional areain the flag leaf: values of 23000 in the first leaf and 48000in the flag leaf were obtained. Pn per unit leaf area remainedfairly constant at the different insertion levels: values of33·83±0·93 mg dm2 h1 and32·32±1·61 mg dm2 h1 wereobtained for the first leaf and the flag leaf, respectively.Residual conductance, however, decreased by 18·2% fromthe first leaf to the flag leaf. Stomatal conductance increasedby 41·7%. The steadiness in Pn per unit leaf area across the leaf insertionlevels could be mainly accounted for by an opposing effect betweena decrease in Vmes/A and a more closely packed arrangement ofphotosynthetic apparatus. Adaptative significance of structuralchanges with increasing leaf insertion levels and the steadinessin Pn per unit leaf area was studied. Key words: Photosynthesis, structure, wheat 相似文献
20.
Stomatal Responses of Variegated Leaves to CO2 Enrichment 总被引:1,自引:0,他引:1
The responses of stomatal density and stomatal index of fivespecies of ornamental plants with variegated leaves grown attwo mole fractions of atmospheric CO2 (350 and 700 µmolmol-1) were measured. The use of variegated leaves allowed anypotential effects of mesophyll photosynthetic capacity to beuncoupled from the responses of stomatal density to changesin atmospheric CO2 concentration. There was a decrease in stomataldensity and stomatal index with CO2 enrichment on both white(unpigmented) and green (pigmented) leaf areas. A similar responseof stomatal density and index was also observed on areas ofleaves with pigmentation other than green indicating that anydifferences in metabolic processes associated with colouredleaves are not influencing the responses of stomatal densityto CO2 concentrations. Therefore the carboxylation capacityof mesophyll tissue has no direct influence on stomatal densityand index responses as suggested previously (Friend and Woodward1990 Advances in Ecological Research 20: 59-124), instead theresponses were related to leaf structure. The stomatal characteristics(density and index) of homobaric variegated leaves showed agreater sensitivity to CO2 on green portions, whereas heterobaricleaves showed a greater sensitivity on white areas. These resultsprovide evidence that leaf structure may play an important rolein determining the magnitude of stomatal density and index responsesto CO2 concentrations.Copyright 1995, 1999 Academic Press Leaf structure, photosynthesis, stomatal conductance, CO2, stomatal density, stomatal index 相似文献