Water Use Characteristics of Dactylis glomerata L., Lolium perenne L. and L. multiflorum Lam. Plants

Cocksfoot (Dactylis glomerata L.). perennial ryegrass (Loliumperenne L.) and Italian ryegrass (L. multiflorum Lam.) plantswere grown on deep (75–95 cm) columns of soil in glasshousesand growth rooms with and without irrigation. The species inwhich growth declined least rapidly after water had been withheldwere those which transpired most slowly. During early establishmentin the glasshouse cocksfoot transpired least because of slowroot growth. In the growth room, when root systems were deeperand denser, perennial ryegrass transpired least because of lowleaf water conductance. Results are discussed in relation to(a) drought resistance in the three species; (b) breeding forincreased drought resistance through modifying root distributionand leaf water conductance; and (c) the use of isolated soilcolumns in water relations studies. Dactylis glomerata L., Lolium perenne L., Lolium multiflorum Lam., cocksfoot, perennial ryegrass, Italian ryegrass, transpiration, roots, leaf water conductance     

Initiation of Procambial Strands in Leaf Primordia of Dactylis glomerata L. as an Example of a Temperate Herbage Grass

This study is concerned with the examination of shoots of herbagegrasses, particularly Dactylis glomerata L., for comparisonwith earlier investigations on this species and on the cerealTriticum aestivum L. The main features of procambial strandinitiation are found to be the same in all the herbage grassesexamined and to be very similar to those in Triticum. Thus,in a vegetative shoot, all the procambial strands originatein the leaf primordia independently of the vascular system ofthe older parts of the plant, and extend downwards from theirfirst point of origin. For the median strands, the first pointof origin is in the disc of insertion of the primordium, butfor later strands it is progressively higher, so that the laststrands are initiated well up in the free portion of the primordium.The course of the median and first and second lateral strands,in the first two discs of insertion that they penetrate, isvery regular and predictable. However, two discs of insertionbelow the point of initiation of strands, their course is interruptedby the strands of the primordium directly below (there is onealternating primordium between them), and from this point downwardsvariations, both specific and between individual plants andprimordia, occur. This is the region where connexion with thevascular supply of the rest of the plant is first established.The timing of the arrival of young strands from above and ofthe development of successive nodal plexi from below, via whichmost interconnexions are established, will give some variationto the early development of this region.     

The Effect of Sulphur Dioxide on the Growth of Lolium perenne L., Lolium multiflorum Lam., Dactylis glomerata L., and Phleum pratense L.

Lockyer, D. R. 1985. The effect of sulphur dioxide on the growthof Lolium perenne L., Lolium multiflorum Lam., Dactylis glomerataL., and Phleum pratense L.?J. exp. Bot. 36: 1851-1859. Fouragriculturally important grasses, Lolium perenne L., Loliummultiflorum Lam., Dactylis glomerata L. and Phleum pratenseL. were exposed to sulphur dioxide (SO₂) in a system of exposurechambers. The plants were exposed for a total of 43 d to meanconcentrations of SO₂ in the air of 0,87 or 448 (µg m^–3and herbage was harvested twice. All four grasses showed chloroticlesions after exposure to the highest concentration of SO₂.The effect of SO₂ on the yield of herbage was statisticallysignificant only at the second harvest and at the highest concentration;the dry weights of shoots of D. glomerata and L. perenne werereduced by 33% and 16% respectively. Significant effects ofSO₂ were also found on the 'transpiration coefficients' measuredfor D. glomerata and P. pratense. The grasses differed in theiruptake of sulphur from the atmosphere but this was not relatedto their sensitivity to SO₂. Total–S concentration inthe shoots of L. perenne, L. multiflorum and D. glomerata increasedalmost linearly in response to increasing SO₂ concentration;with P. pratense only the highest SO₂ concentration raised total-Sabove the level in control plants. These increases were almostentirely due to the accumulation of sulphate–S. Key words: Sulphur diozide, Lolium perenne, Lolium multiflorum, Dactylis glomerata, Phleum pratense     

Initiation of Procambial Strands in Leaf Primordia of Bread Wheat, Triticum aestivum L

In Triticum aestivum L. the median and lateral procambial strandsserving the primordia originate independently and in isolationfrom the vascular system of the rest of the plant. The medianstrand is initiated first, followed by a succession of lateralstrands during the next four or so plastochrones. The medianand first lateral strands have their point of origin in theaxis, in the disc of insertion of the primordium. The laterlaterals are initiated up in the primordium. Once initiatedthe procambial strands extend from their point of origin bothacropetally and basipetally, the latter extension eventuallylinking them to strands associated with older leaves. It wouldappear that the materials necessary for the growth of the apicaldome and of the first four leaf primordia are supplied by generaldiffusion and not via direct vascular connexions with the restof the plant.     

The Vascular Pattern of a Rhizomatous Ginger (Alpinia speciosa L. Zingiberaceae). 2. The Rhizome

The vascular system in the underground rhizome of Alpinia speciosaL. (Zingiberaceae) is seen to be arranged in three distinctzones. (1) An inner system of ‘scattered’ vascularbundles which serial cinematography reveals to have an axialpattern conforming to the basic ‘palm’ configuration(a system of upwardly branching leaf traces with interconnections).(2) An intermediate zone comprising a thin perforated cylinderof anastomosing vascular strands having direct contact withboth roots and inner system bundles. (3) An outer system offreely-anastomosing vascular bundles. Connexion of outer andinner system occurs in the form of extensive bridging from innersystem leaf traces as they depart obliquely between the outersystem network. The interrelation of the three systems, plus root and branchinsertion, is illustrated by means of diagrammatic three-dimensionalreconstructions. The intermediate zone is intimately associatedwith root insertions and with the inner system, and is shownto obliviate potential bottlenecks at the point of lateral branchinsertion in this sympodial rhizome system. A comparison ismade with other monocotyle-donous vascular systems. Alpinia speciosa L., shell ginger, rhizome, vascular anatomy     

The Pathway of Assimilate Flow from Source to Sink in Urtica dioica L., Studied with14C under Ambient Atmospheric Conditions

The contribution of individual vascular bundles of the stemto the flow of assimilates from a selected source leaf to thesink regions was investigated inUrtica dioica L., a plant witha decussate leaf arrangement. Two homologous sets of eight vascularstrands were recognized, arranged in mirror symmetry in thestem internodes. In each set, three of the bundles were identifiedas traces of one leaf merging into the vascular system of thestem one node below the origin of the leaf. The main bundleof a stem-half bifurcates at each end of the internode intotwo subdominant bundles, which combine in the next but one nodeto form the dominant bundle again. Each set of vascular strandsalso contains two minor bundles which pass more or less withoutinterruption through the whole stem. The uppermost mature source leaf (leaf number 5 as counted fromthe tip) was exposed to¹⁴CO₂in a closed gas circuit. The concentrationof the carbon-labelled CO₂was maintained at the ambient CO₂levelto maintain the natural source strength of the leaf. By theend of the usual nocturnal dark phase, carbon from the sourceleaf had been imported predominantly by sink leaves of the sameorthostichy. Lesser, but significant amounts of radiocarbonwere also incorporated into the sink leaves of the adjacenttwo orthostichies via the marginal leaf traces. In spite ofthe junction of the vascular strands in the nodes and an interfascicularconnection of the stem bundles, randomization of the photosynthatesfrom individual leaves was minimal in the vascular system ofthe stem in the upward direction, and also low in the flux tothe roots. Substantial amounts of radioactivity were also foundin the lately-formed xylem elements of the vascular strandsand their interfascicular connections, indicating active secondarygrowth. Assimilate distribution; source–sink connections; Urtica dioica ; vascular architecture     

Vascular inter-relationships in someSolanaceae members

Vascular inter-relationships between axillary bud, axillant leaf and axis have been studied in fives pecies of theSolanaceae, Lycopersion lycopersicum (L. )Karsten,Cestrum nocturnum L.,Cestrum diurnum L.,Withania somnifera (L.)Dunal, andDatura innoxia Mill. The phyllotaxy is alternate and the node is unilacunar with one or more leaf trace strands. The bud traces arise either from the trace of the subtending leaf or of the strands flanking the leaf gap. The vascular relationship between the bud, axillant leaf and main axis is discussed.     

Direct Organogenesis and Plant Regeneration in Preconditioned Tissue Cultures of Lathyrus cicera L., L. ochrus (L.)DC. and L. sativus L.

This study demonstrates the importance of preconditioning ofsource tissue in regeneration of multiple shoot buds from severalspecies of Lathyrus. Preconditioned multiple shoots of Lathyruscicera L., L. ochrus (L.) DC. and L. sativus L. were obtainedby germinating seeds on Murashige and Skoog (MS) medium containing50 µM N⁵-benzylaminopurine (BAP) for 2 to 3 weeks. Multipleshoot bud formation occurred when epicotyl explants of preconditionedshoots were cultured on MS medium containing 5–50 µMBAP. No shoot regeneration was observed from epicotyl explantswhich were obtained from non-preconditioned shoots. Shoot budswere formed directly on explants without an intervening callusphase after 2 to 3 weeks of culture. Regenerated shoot budsformed healthy shoots which developed prolific and strong rootswhen transferred to MS medium supplemented with 2.5 µMnaphthaleneacetic acid (NAA). Lathyrus cicera L., L. ochrus (L.) DC., Ochrus Vetch, L. sativus L., Lathyrus pea, de novo differentiation, epicotyl, preconditioning with BAP     

Lateral Root Anlage Development in Excised Roots of Vicia faba L., Pisum sativum L., Zea mays L. and Phaseolus vulgaris L.

The development of lateral root primordia has been investigatedin excised roots of Vicia faba, Pisum sativum, Zea mays andPhaseolus vulgaris cultured in White's medium supplemented with2 per cent sucrose and compared with previously published dataon such development in primaries of the corresponding intactplants (control roots). Primordia were produced in each batchof excised roots over the 6 day culture period but at a lowerrate (number day^–1) than in the controls. Such primordia in cultured roots of Zea and Phaseolus completedtheir development and grew out as lateral roots over a periodsimilar in length to that found in the controls, but with acell number of only about 33 per cent of that attained at thetime of secondary emergence in the primaries of the latter roots.These lower cell numbers were at least partly a reflection ofincreases in mean cell doubling time over the period of anlagedevelopment investigated in the excised roots relative to thecorresponding values found in the controls. Primordia initiated in excised roots of Pisum and Vicia didnot complete their development in culture, i.e. no lateral rootsemerged and arrest took place with cell numbers of only 37 (Pisum)and 17 (Vicia) per cent of the numbers determined at the timeof secondary root emergence in the controls. Such arrested primordiahad few nuclei in S and none in mitosis. Moreover, at leastin Pisum, the frequency distribution of the relative DNA contentof the nuclei in the latter primordia approximated that foundin the apical meristem of primary roots following the establishmentof the stationary phase under conditions of carbohydrate starvation. It has also been demonstrated in the course of these investigationsthat lateral root primordium development in all four speciesis at least biphasic and possibly triphasic. Vicia faba L., broad bean, Pisum sativum L., garden pea, Zea mays L., maize, Phaseolus vulgaris L., dwarf bean, root primordia, anlage, cell doubling time, lateral root emergence     

Aspects of the Comparative Physiology of Ranunculus bulbosus L. and Ranunculus repens L.: II. Carbon Dioxide Assimilation and Distribution of Photosynthates

Detailed analysis of the interrelationships between sourcesof photosynthate production and sites of utilization in thetaxonomically closely related species Ranunculus bulbosus L.and R. repens L. showed that leaves whether present on rosette,stem, or stolon had similar levels of ¹⁴CO₂-fixation but thepattern of distribution of radiocarbon to the rest of the plantdiffered. Fruits of R. bulbosus had a lower fixation rate thanleaves but were characterized by total retention of the fixedradiocarbon. Rosette leaves of R. bulbosus supplied the youngleaves, developing apices in the rosette, roots, and corms,whereas the labelled assimilates from cauline leaves were evenlydistributed between reproductive and vegetative parts. The cormwas the major sink both at the flowering and fruiting stages.When plants were treated with ¹⁴CO₂ in the field even higherlevels of radiocarbon moved into the corm than in comparableexperiments under greenhouse conditions. The rosette leaf ofR. repens exported mainly to actively growing stolons in plantswith many stolons bearing rooted ramets although growth of astolon was also substantially supported by photosynthates producedby its own ramets. A proportion of the radiocarbon fixed byleaves of mature ramets was exported and moved in a predominantlyacropetal direction into the stolon apex, stolon axis, and youngramets of the same stolon. The stock in R. repens had a muchlower demand for assimilates than the corm in R. bulbosus. The results are consistent with the concept that R. bulbosusoperates a conservative policy involving the replacement ofthe parent in situ by a daughter from the corm, coupled withextensive fruit production. In R. repens the emphasis is onlateral spread and exploitation of substantial areas of groundby vegetative spread and replacement of the parent by daughtersmany of which may occupy sites some distance from the parent.     

Effects of Intercropping on Growth and Reproductive Capacity of Late-emerging Senecio vulgaris L., with Special Reference to Competition for Light

Due to increased emphasis on long-term management of weed populationsin cropping systems with a reduced reliance on herbicides, theproduction of seeds by weeds that emerge after the criticalperiod for weed control is increasingly important. It was hypothesizedthat increased soil cover and light interception by a crop canopywould shorten the critical period for weed control and reducegrowth and fecundity of late-emerging weeds. This hypothesiswas tested in a series of field and glasshouse experiments inwhich competition for light was manipulated. Senecio vulgaris,an important weed in vegetable production systems, was chosenas the target plant, and canopies of pure and mixed stands ofleek and celery were used to provide shade. The time courseof light interception differed among the crop canopies. Increasingcompetition for light caused morphological changes to S. vulgaris,including a vertical shift in leaf area distribution. Increasedshading reduced biomass, capitula:shoot ratio and seed productionof S. vulgaris. However, the viability of seeds produced bythe shaded weed plants was not affected. Results indicate thatintercropping can increase light interception in a weakly competitivecrop such as leek and can contribute to weed suppression ina long-term strategy for weed management. Copyright 2001 Annalsof Botany Company Competition for light, late-emerging weeds, critical period, Apium graveolens L., celery, Allium porrum L., leek, Senecio vulgaris L., common groundsel, seed production, weed management, intercropping     

Effect of Temperature on Growth of Crotalaria juncea L. and Crotalaria sericea Retz.

Growth performances of Crotalaria juncea L. and C. sericea Retz.have been compared at two controlled temperatures, 16–20°C, and 28–32 °C, with respect to increase ind. wt and leaf area, relative growth rate, leaf area ratio,specific leaf area, leaf weight ratio, net assimilation rate,the ratio of mean relative growth rate to mean relative rateof leaf area increase () and shoot/root ratios. Both the speciesgrew better at the higher temperature; however the relativegrowth rate was more affected by temperature in C. sericea thanin C. juncea. Further, it was observed to be more dependenton net assimilation rate than on the leaf area ratio. Crotalaria juncea L., Crotalaria sericea Retz., relative growth rate, leaf area ratio, specific leaf area, leaf weight ratio, leaf area increase, net assimilation rate, shoot/root ratio     

Electron-probe Microanalysis Studies of Silicon in the Epicarp Hairs of the Caryopses of Hordeum sativum Jess., Avena sativa L., Secale cereale L. and Triticum aestivum L.

Silicon deposits in the epicarp hairs of the caryopses of mature,field-grown specimens of Hordeum sativum, Avena sativa, Secalecereale and Triticum aestivum were investigated using electron-probemicroanalysis. In all four cereals, silicon was most concentratedat the extreme tips of the hairs. In barley, it was the onlyelement detected; in the other three cereals potassium and calciumwere located below the tip. In wheat, chlorine was also detected. The hair bases of the different cereals displayed variationin the elements detected. Silicon and polassium were presentin all four and calcium present in all except rye. The hairbases of wheat also contained chlorine; phosphorus and zincwere located in barley. The latter alone showed variation ofelements between hair bases. Scanning electron microscopy revealed heavy striations of thehair tips of barley and oats. In rye and wheat, the tips weresmooth but there were slight surface markings below the tip. The results are discussed in relation to the possible functionsand significance of the epicarp hairs and their silicification. Avena sativa L., Hordeum sativum Jess., Secale cereale L., Triticum aestivum L., oat, barley, rye, wheat, epicarp hairs, silicon, electron-probe microanalysis, scanning electron microscopy     

Cuticular permeability of the three tree species Prunus Iaurocerasus L., Ginkgo biloba L. and Juglans regia L.: comparative investigation of the transport properties of intact leaves, isolated cuticles and reconstituted cuticular waxes

Cuticular transport properties of intact leaves, isolated cuticularmembranes and reconstituted cuticular waxes of the three treespecies Prunus laurocerasus L., Ginkgo biloba L. and Juglansregia L. were measured using six different ¹⁴C-labelled compounds,benzoic acid, salicylic acid, 2,4-dichlorophenoxy acid, metribuzin,4-nitrophenol, and atrazine. For the same compound and the samespecies, the permeance of the intact leaf and the isolated cuticlewas equal. This provides strong evidence demonstrating thattransport properties of cuticles are not altered during isolation.Additionally, diffusion coefficients of the ¹⁴C-labelled compoundsin isolated and subsequently reconstituted cuticular wax ofthe three tree species were measured. Permeances of intact leavesand isolated cuticles could be predicted from diffusion coefficients,wax/water partition coefficients and the thickness of the transport-limitingwax layer with a mean deviation of about 1.7. This providesevidence that transport properties of recrystallized cuticularwaxes do indeed reflect barrier properties of isolated cuticularmembranes and intact leaves with in situ waxes. Thus, it canbe concluded that the investigation of cuticular permeabilityusing the three independent experimental systems of differentcomplexity give comparable results. Finally, it was observedthat permeances and diffusion coefficients measured with P.laurocerasus were always significantly lower than those measuredwith G. biloba and J. regia. This is interpreted as an ecologicaladaptation of the respective species. The evergreen speciesP. laurocerasus must be more adapted to environmental stresssuch as drought and frost injury compared to the two deciduousspecies G. biloba and J. regia. Key words: Cuticular permeability, diffusion coefficient, leaf surface, permeance, plant cuticle, transport     

Electron Microscopic Observations of the Structure of Sieve-connexions in the Phloem of Angiosperms and Gymnosperms

The sieve elements of Pinus silvestris L., Sorbus aucupariaL., Vitis vinifera L., and Cucurbita pepo L. have been examinedelectron microscopically in ultra-thin section, and the structuresof the corresponding sieve areas or sieve plates have been describedand compared. In Pinus the sieve areas contain groups of connectingstrands which enter the wall from the lumen side as individualsbut coalesce within it in the median cavity. This cavity hasdeveloped by wall breakdown in the middle lamella and primarywall region and corresponds to the median nodule visible undera light microscope. Neither in this nor in the other speciesobserved is there any visible closing membrane. Structural differences between the four species are shown tosuggest that the major evolutionary trend in the evolution ofspecialized conducting strands has been the enlargement of theconnecting strands from groups of small separate strands toa smaller number of larger strands as the median cavity becomesenlarged to form a canal through the wall. The connecting strands appear invariably to be dense, highlyosmiophilic and continuous with the cytoplasmic surface of thecell. No signs of micropores or of other tubular structure inthe strands have been found. The structures thus revealed aremore nearly compatible with active transport of materials acrossthe sieve plate than they are with any purely physical mechanism.It is suggested that they are incompatible with any mass flowhypothesis.     

Structure and Function in the Grass Ligule: the Newly-initiated Ligule of Lolium temulentum L., a Light and Electron Microscope Study

Initiation and early development of the membranous ligule ofLolium temulentum L. was studied by light and transmission electronmicroscopy. The ligule appeared to be derived solely from theleaf adaxial epidermis and at this stage had a structure andultrastructure typical of a meristematic tissue. Cells of thefuture collar region of the leaf appear to be initiated at thesame time as the ligule. The siting of the ligule upon the leafis briefly discussed. Darnel, ligule (initiation), Lolium temulentum L., Poaceae, ultrastructure     

Low Temperature Affects Pattern of Leaf Growth and Structure of Cell Walls in Winter Oilseed Rape (Brassica napus L., var. oleifera L.)

Three-week acclimation of winter oilseed rape (Brassica napusL. var. oleifera L.) plants in the cold (2 °C) resultedin a modified pattern of leaf cell enlargement, indicated bythe increased thickness of young leaf blades and modified dimensionsof mesophyll cells, as compared with non-acclimated tissuesgrown at 20/15 °C (day/night). The thickness of leaf cellwalls also increased markedly during cold acclimation but itdecreased in response to a transient freezing event (5 °Cfor 18 h followed by 6 or 24 h at 2 °C, in the dark). Cellwalls of the upper (adaxial) epidermis were most affected. Theirultrastructure was modified by cold and freezing treatmentsin different ways, as revealed by electron microscopy. Possiblereasons for the cold- and freezing-induced modifications inthe leaf and cell wall morphology and their role in plant acclimationto low temperature conditions are discussed. Copyright 1999Annals of Botany Company Acclimation, Brassica napus var. oleifera, cell wall ultrastructure, cold, freezing, leaf structure, winter oilseed rape.     

Analysis of Low-temperature Tolerance of a Tomato (Lycopersicon esculentum) Cybrid with Chloroplasts from a more Chilling-tolerant L. hirsutum Accession

Growth and photosynthesis of an alloplasmic tomato (cybrid),i.e. line AH47, containing the nuclear genome of the chilling-sensitivecytoplasmic albino mutant of L. esculentum Mill. ‘LargeRed Cherry’ (LRC) and the plastome of a more chilling-toleranthigh-altitude accession of the related wild species L. hirsutumHumb. & Bonpl. LA 1777, were investigated at an optimal(25/20°C) and suboptimal (16/14°C) day/night temperatureregime and their performance compared with that of both euplasmicparents. The cybrid shoot had a similar biomass and developmentrate to the nuclear tomato (L. esculentum) parent at both temperatureregimes. Compared with the biomass production of shoots grownat optimal temperature, the reduction in shoot biomass at suboptimaltemperature was smaller for L. hirsutum than for L. esculentumand the cybrid. This difference was related to a stronger inhibitionof leaf area expansion in L. esculentum and the cybrid in thesuboptimal temperature regime than in L. hirsutum. Irrespectiveof the temperature regime under which the plants were grown,photosynthetic performance and leaf pigment, carbohydrate andsoluble-protein contents of the cybrid resembled those of thenuclear parent. No advantages of the alien L. hirsutum chloroplastwith respect to growth and photosynthesis-related characteristicswere observed in the cybrid in the suboptimal temperature regime,indicating that the temperature sensitivity of the photosyntheticapparatus is regulated by nuclear genes. An adverse consequenceof interspecific chloroplast transfer was the increased susceptibilityto chill-induced photoinhibition of the cybrid. It is concludedthat cybridization is not a useful tool for improving low-temperaturetolerance of tomato. Copyright 2000 Annals of Botany Company Alloplasmic tomato, chloroplast, cybrid(ization), growth, low-temperature tolerance, Lycopersicon esculentum, L. hirsutum, photosynthesis, plastome, tomato     

Bud Structure in Relation to Shoot Morphology and Position on the Vegetative Annual Shoots of Juglans regia L. (Juglandaceae)

The length and basal diameter of all lateral and terminal budsof vegetative annual shoots of 7-year-oldJuglans regia treeswere measured. All buds were dissected and numbers of cataphylls,embryonic leaves and leaf primordia were recorded. Each axillarybud was ranked according to the position of its associated leaffrom the apex to the base of its parent shoot. Bud size andcontent were analysed in relation to bud position and were comparedwith the size and number of leaves of shoots in equivalent positionswhich extended during the following growing season. Length andbasal diameter of axillary buds varied according to their positionon the parent shoot. Terminal buds contained more embryonicleaves than any axillary bud. The number of leaves was smallerfor apical and basal axillary buds than for buds in intermediatepositions on the parent shoot only. All new extended shootswere entirely preformed in the buds that gave rise to them.Lateral shoots were formed in the median part of the parentshoot. These lateral shoots derived from buds which were largerthan both apical and basal ones. Copyright 2001 Annals of BotanyCompany Juglans regia L., Persian walnut tree, branching pattern, preformation, bud content, shoot morphology     

Cellular Interactions in the Development of Stomatal Patterns in Vinca major L

The development of the leaf epidermis of Vinca major L. wasfollowed in situ by epi-illumination microscopy and evidencewas sought for cellular interactions. Stomata were often foundto be initiated in adjoining cells. The epidermal cells whichseparated such stomata when they had matured were formed fromthe same cells as the stomatal complexes themselves. The presenceof developing and mature stomata may influence only the orientationof divisions in neighbouring cells, and not the initiation andmaturation of stomata. There is great variability in the relativeorientation, timing and number of divisions which intervenebetween the first unequal division and the maturation of a stomaas well as the location of stomata relative to the spongy mesophylland minor veins. The results indicate that continuous short-rangeinteractions between the future guard cells and the adjoiningcells, rather than interactions between future stomata or afixed programme of development, are essential for the formationof the pattern of functional stomata in the mature leaf. Vinca major L., cell lineage, cellular interactions, development of stomata, epi-illumination microscopy, meristemoids, patterned differentiation, stomata