Development and Histochemistry of the Pistil of the Grape, Vitis vinifera

The development of the grape pistil is followed for a periodof 9 weeks from flower initiation to anthesis. Three phasesof pericarp differentiation are revealed: ring meristem formation;cell proliferation by anticlinal cell divisions; and a maturationphase characterized by periclinal cell division and differentiation.Both the stigma papillae and the transmitting tissue of thestyle originate by periclinal cell divisions. The receptivestigma is of the wet type and comprises many filamentous papillae,each composed of about 20 cells and covered by a loose cuticle.The stigma exudate shows similar cytochemical properties tothe material in the intercellular spaces of the transmittingtissue and is physically continuous with it. After pollinationand coincident with withering of the stigma, a single layerof stylar cells becomes suberized, forming a protective layerof cicatrix. Vitis vinifera, grape, pistil, development, histochemistry     

Pollen-Stigma Interaction in the Leguminosae: Stigma Organization and the Breeding System in Vicia faba L.

As in other papilionoid Leguminosae, the receptive surface ofthe stigma of Vicia faba L. is invested by a detached cuticle.This cuticle, the so-called ‘stigma membrane’ ofplant breeding literature, is lifted away from the epidermisduring development by the accumulation of a lipid-rich secretionreleased into the intercellular spaces of the stigma head bythe epidermal cells and the underlying three to four cell layers.The cuticle is thickened over the prominences left by the epidermalpapillae, thinning out between. Pollen, whether self or cross,cannot hydrate and germinate in contact with the intact stigmasurface, but must await the disruption of the cuticle and therelease of the retained secretion. In most genotypes this takesplace only when the flower is tripped by visiting pollinatorsor in consequence of severe agitation by wind. A comparison of lines differing in their degree of autofertilityin field conditions has revealed various differences in stigmastructure. A highly autofertile line had low papillae at thereceptive tip, with a relatively thin intervening cuticle, whilean autosterile line had longer papillae and a thicker cuticle.A line with partial autofertility was intermediate in thesecharacteristics. These properties of the stigma surface, togetherwith other differences in flower structure, are probably adequateto account for the variation in the degree of autosterility,since no evidence was obtained suggesting the presence of aneffective physiological self-incompatibility system in any ofthe lines studied. Since the rupturing of the stigma cuticle is affected by theturgor pressure of the cells of the stigma and style, some degreeof environmental interaction is to be expected: autofertilityshould be at the highest in conditions of adequate water supply,and lowest where there is water deprivation. Pollen-stigma interaction, Vicia faba L., Leguminosae, breeding system, self-incompatibility     

Structural and Cytochemical Analysis of the Stigma and Style in Tibouchina semidecandra Cogn. (Melastomataceae)

Structural and cytochemical aspects of the pistil of Tibouchinasemidecandra Cogn. were studied. The stigma is of the wet-papillatetype and is structurally divisible into a papillar zone anda stigmatic zone. The papillar zone consists of loosely arrangedpapillae which are matchstick-shaped, unicellular, and producelipid droplets that remain entrapped below the thick cuticle.The bulk of cell volume is made up of large vacuoles rich intannin. The stigmatic zone consists of layers of secretory cellswith dense cytoplasm, actively secreting dictyosomes and numerousrough endoplasmic reticulum (RER) profiles. Free-flowing lipidexudate, produced by these cells, is initially stored in theintercellular spaces, and subsequently extruded out to coverthe surface. The style is solid with a core of transmittingtissue traversing its whole length. The transmitting tissueconsists of loosely arranged cells with numerous organellesand conspicuous intercellular substance rich in polysaccharidesand pectins. Ultrastructural details indicate that the intercellularsecretion is accompanied with fraying of the wall component.Both the transverse and longitudinal walls contain plasmodesmata.Copyright1995, 1999 Academic Press Cytochemistry, stigma and style, ultrastructure, Tibouchina semidecandra     

The Structure and Cytochemistry of the Pistil of Sternbergia lutea (Amaryllidaceae)

Studies were carried out on structural and cytochemical aspectsof the pistil of Sternbergia lutea (L.) KerGawl. The stigmais of the wet papillate type; the papillae are unicellular andare arranged densely around the rim of a funnel-shaped stigma.The stigma exudate is limited and is confined to the bases ofthe papillae and the inner lining of the stigma. The papillaeare smooth in the distal part and are covered with intact cuticle-pelliclelining. The cuticle is disrupted at places towards the baseof the papillae releasing the exudate. The exudate is rich inpectins and other polysaccharides but poor in proteins and lipids.The papillae show dense cytoplasmic profiles with extensiveendoplasmic reticulum (ER), abundant mitochondria, polyribosomesand active dictyosomes. The style is hollow. The stylar cavityis surrounded by two to four layers of glandular cells. In theyoung pistil the canal is lined with a continuous cuticle, butin the mature pistil the cuticle becomes disrupted and the canalis filled with the secretion produced by the cells of the surroundingglandular tissue. Ultrastructurally, the cells of the glandulartissue are very similar to the stigmatic papillae. The innertangential wall of the cells bordering the canal is uniformlythicker than other walls. The secretion in the stylar canal,as well as the intercellular spaces of the glandular tissue,stain intensely for pectins and polysaccharides but poorly forproteins and lipids. Pollen tubes grow through the stylar canal.Structural and cytochemical details of the pistil of Sternbergiaare compared with other hollow-styled systems. Pistil, Sternbergia lutea (L.) Ker-Gawl., stigma and style, structure and cytochemistry     

Mechanism of Pollination in Gladiolus: Roles of the Stigma and Pollen-tube Guide

Gladiolus has a dry type of stigma. Compatible pollen grainsalight and germinate on the receptive surface of the papillae,penetrate the cuticle and grow towards the style through a sub-cuticularpollen-tube guide of mucilage. This is secreted from epidermalcells of the stylodium and style canal. The cuticle, which coversthe pollen tube guide mucilage, is continuous through the stylecanal to the ovary. The wet stigma of Lilium also has cuticulartissue running through the style canal, covering the mucilage.     

The Structure and Cytochemistry of the Stigma-style Complex ofCorylus avellanaL. 'Tonda Gentile delle Langhe' (Corylaceae)

Structural and cytochemical aspects of the stigma-style complexofCorylus avellanawere studied. In cross section the stigmaticstyle consists of papillae, one or two layers of sub-epidermalcells and a central transmitting tissue. The papillae coverthe style for about 80% of its length, are unicellular and arecoated with a cuticle-pellicle. During development, the cellwalls of the papillae increase in thickness and between them,below the cuticle, lipid bodies are observed. The sub-epidermalcells are similar in cell content to the papillae. The centraltransmitting tissue consists of highly vacuolated cells andthe intercellular spaces are filled with a proteic and polysaccharidicsubstance. Both the transverse and longitudinal walls containplasmodesmata.Copyright 1998 Annals of Botany Company cytochemistry, stigma and style, ultrastructure,Corylus avellana     

Pollen-Stigma Interaction in the Leguminosae: the Organization of the Stigma in Trifolium pratense L.

The intact stigma of Trifolium pratense possesses a smooth receptivesurface fringed by a few ranks of brush hairs. This surfaceis ensheathed by a thin (75–100 nm) but highly impermeablecuticle, which encloses four to five ranks of secretory cellsimmersed in their secretory products. Experimental single-grainpollinations show that pollen cannot become hydrated or germinateon the intact surface. The cuticle is ruptured when the floweris tripped; the secretion is released, and captured pollen-selfor cross-can then germinate. As in other papilionoid Leguminosae,this mechanism provides a guard against premature selling. Thesecretory cells are elongated; they remain in communicationthrough persistent pit-fields as the intercellular spaces fillwith secretion product. The secretion forms a lipid-rich emulsion,with a mucilaginous aqueous phase which reacts cytochemicallyfor protein and carbohydrate and has esterase activity. Duringthe early development of the stigma head, the cells possessa fine-structure appropriate to their secretory function, withabundant ribosomal and smooth endoplasmic reticulum, stratifiedor in the form of ramifying and anastomosing tubules, numerousmitochondria and a well developed Golgi system. Lipid globuli,partly invested in endoplasmic reticulum, are abundant in theyoung cells, but there is as yet no indication of how the lipidis transferred to the intercellular spaces during the secretoryperiod. As the stigma matures, the secretory cells become moribund. Leguminosae, Trifolium pratenseL., pollen-stigma interaction, self-incompatibility, autofertility, stigma secretory system, lipid secretion, cuticle permeability     

Tissue Development in the Stigma of Prunus avium L.

The tissue inside the stigma of Prunus avium L, through whichpollen tubes grow, undergoes a specific pattern of developmentwhich is different from that of the papillae on the stigmaticsurface or the transmitting tissue of the style in several importantaspects An elaborate system of intercellular spaces developsconsisting of small lacunae and aerenchymatous tissue The majorityof spaces contain no intercellular substances and appear tobe air canals, although the small lacunae may participate insecretion Aerenchymatous tissue on the peripheral regions ofthe stigma is characterized by several cytological featureswhich change during ontogeny, such as nuclear inclusions, amyloplastinclusions, dumbbell-shaped mitochondria, cytoplasmic sequestrationand isolated segments of endoplasmic reticulum Occasional clustersof amyloplasts were also observed Prunus avium L, sweet cherry, stigma, cytology, ultrastructure     

Pollen--stigma Interaction in the Leguminosae: the Secretory System of the Style in Trifolium pratense L.

The canal that traverses the upper part of the style of Trifoliumpratense is derived lysigenously. The core tissue of the veryyoung style consists of elongated cells similar to those ofthe transmitting tissue of solid-style families such as theSolanaceae; as the style matures, these cells separate to formthe canal, which receives secretions both from the core tissueand the inner wall cells. The early secretion of proteins intothe intercellular spaces is associated with the presence ofparamural bodies (lomasomes) in the adjacent cells. In the cellsin the immediate vicinity of the canal, vesicles, probably derivedfrom the Golgi system enlarge during later development and accumulatea protein-carbohydrate content, which is later passed into thecytoplasm where it forms densely packed fibrillar nodules. Withthe dissolution of the cell membranes, this material is passedinto the canal, where it is progressively diluted by continuedingress of water until the cavity reaches its final volume. Leguminosae, Trifolium pratense L., pollen—stigma interaction, self-incompatibility, stylar secretion, protein secretion     

Modification of Leaf Formation by Cytokinin and Chlormequat (CCC) in Vitis

Application of the cytokinin, 6-(benzylamino)-9-(2-tetrahydropyrany1)-9H-purine(PBA, 1mM) and 2-chloroethyl trimethyl ammonium chloride (chlormequat;3 mM), a growth retardant, to grapevines induced the formationof fused leaves (two laminae and two petioles) and double leaves(two separate petioles each with a single lamina). Double leaveswere found in Vitis vinifera L. seedlings, in Vitis ripariaand in Muscadinia (Vitis) rotundifolia. In some of the treatedvines, leaves arose with opposite phyllotaxy. Other anomaliesincluded production of two opposite axillary buds in axils ofopposite leaves and production of two tendrils per node. Sometendrils grew into shoots. In Muscat of Alexandria, applicationof GA₃ (3 µM, 15 µM), followed by an applicationof chlormequat (0.4 mM, 1.2 mM), led to a marked reduction inthe extension growth of axillary shoots. Vitis vinifera L., Vitis riparia, Muscadinia (Vitis) rotundifolia, grapevines, leaf formation, cytokinin, chloromequat     

The Pollen-stigma Interaction: Pollen-tube Penetration in Crocus

In a compatible pollination in Crocus, pollen tube tips enterthe stigma papillae after the enzymic erosion of the cuticle,and the tubes continue downward growth towards the ovary betweenthe cuticle and the underlying pectocellulosic wall. The cuticleof the receptive zone of the stigma papilla is chambered, thechambers containing a secretion accumulated during the maturationof the stigma. Pollen exudates contain various acid hydrolases,but are incapable alone of eroding stigma cutin. Furthermore,there is no penetration when the proteins of the wall-held stigmasecretions are degraded enzymically. These facts are taken toindicate that the pollen contributes a ‘cutinase’precursor which is activated by a factor or factors held inthe stigma secretion. Pollens of certain Cruciferae producetubes capable of penetrating the Crocus stigma cuticle, suggestingthat notwithstanding the taxonomic remoteness of Cruciferaeand Iridaceae the enzyme activation systems are quite similar.     

Reproduction in Seagrasses: Nature of the Pollen and Receptive Surface of the Stigma in the Hydrocharitaceae

This paper describes the characteristics of the pollen and thereceptive surfaces of the stigmas in the three marine angiospermsincluded in the Hydrocharitaceae. The pollen in Enhalus acoroidesand Thalassia hemprichii is spherical and has an ornamentedexine. An exine layer is not found in Halophila stipulacea wherereniform pollen grains are contained within transparent moniliformtubes. Cytochemical tests show that the pollen wall in the threespecies contains acidic and neutral polysaccharides and acidhydrolase acitivity is detected in the intine of H. stipulaceaand T. hemprichii. In Thalassia, one of the intine enzymes,acid phosphatase, is unambiguously associated with cytoplasmicinclusions. Flowering in Thalassia is coincident with the spring tides andthe pollen is released as a mass suspended in a thecal slimewhich contains approximately 5 per cent by weight carbohydrate,the principal mono-saccharide being mannose. Electrophoreticanalysis of the pollen-free slime shows a single glycoproteincomponent. The stigmas of the three seagrasses are papillate and of the‘dry’ type possessing a continuous protein-aceouspellicle subtended by a cuticle. The stigma pellicle exhibitscytochemically detectable esterase activity and binds the lectinconcanavalin A. Acid phosphatase activity is localized beneaththe cuticle at the tips of the stigma papillae. The discoveries show that the characteristics of the pollenand stigmas in the seagrasses are comparable with those foundin terrestrial flowering plants. The similarity in enzymaticproperites of the pollen wall and stigma pellicle suggests that,intriguingly, a similar mechanism of cuticle erosion might wellfollow compatible pollination both on land and in the sea. Enhalus acoroides, Thalassia hemprichii, Halophila stipulacea, Halophila decipiens, seagrasses pollen wall, stigma surface, hydrolytic enzymes     

Structure and Cytochemistry of the Stigma and Pollen--Pistil Interaction in Zephyranthes

The stigma in Zephyranthes candida and Z. citrina is of thedry type with a continuous cuticle—pellicle. In some papillae,however, the terminal portion of the cuticle—pellicleis lifted upwards and occasionally even disrupted by the accumulationof a secretion product below it. Both non-specific esterasesand acid phosphatases are present on the stigma surface. Thestyle is solid with a central core of transmitting tissue whichhas conspicuous intercellular spaces containing a matrix thatincludes proteins, polysaccharides and pectic substances. Zephyranthes citrina is self-compatible while Z. candida isself-incompatible. Followng incompatible pollination in Z. candida,pollen germination is normal but pollen tube growth is inhibitedat the junction of the stigma and style. Self-incompatibilitycan be overcome by bud pollination. Protein synthesis is necessaryfor pollen germination in both species. Concanavalin A bindsto the stigma surface of both species, but does not affect pollentube penetration in Z. candida. In crosses between the two speciestypical unilateral incompatibility is observed when Z. candidais used as the pistillate parent. Zephyranthes, stigma-surface enzymes, dry stigma, pollen-pistil interaction, self-incompatibility, unilateral-incompatibility     

Regeneration of transgenic plants of grapevine (Vitis vinifera L.) via Agrobacterium rhizogenesmediated transformation of embryogenic calli

Genetically transformed roots and calli were induced from leafsegments of grapevine (Vitis vinifera L. cv. Koshusanjaku) afterco-cultivation with wild-type Agrobacterium rhizogenes strains,but plant regenera tion from them was not achieved. On the otherhand, transgenlc grapevine plants were obtained via somaticembryogenesis after co-cultivation of embryogenic calli withan engineered A. rhizogenes strain including both the neomycinphosphotransferase II (NPT II) and the ß-glucuronidase(GUS) genes, followed by selection of secondary embryos forkanamycin resistance. All these plants showed GUS gene expressionrevealed by histochemical assay. Southern blot analysis revealedthe stable integration of the GUS cording region in their genome.Transformants containing Ri T-DNA exhibited various phenotypes:most of them showed a typical Ri-transformed phenotype suchas wrinkled leaves, while the others looked normal. Key words: Agrobacterium rhizogenes, grapevine, transgenic plants, Vitis vinifera     

Pistil Exudate Production and Pollen Tube Growth in Lilium longiflorum Thunb.

Exudate production in the pistil of Lilium longiflorum was studiedin relation to pollen tube growth, using scanning electron microscopy(SEM), transmission electron microscopy and light microscopy.In contrast with conventional fixation for SEM, during whichthe exudate of L. longiflorum largely washes away, the exudateremains present through freezing in case of cryo-SEM. Usingthe latter method we observed that exudate production on thestigma and in the style started before anthesis. Just underneaththe stigma the exudate was first accumulated at the top of eachsecretory cell, followed by a merging of those accumulationsas exudate production proceeded. Exudate is also produced bythe placenta. It was however not possible to determine whetherany of this fluid originated from the micropyle. Apart fromthe cell shape and the cuticle present in between the secretorycells, the ultrastructure of the secretory cells covering theplacenta was comparable to those of the stylar canal. The transferwall of the secretory cells of the placenta originated fromfusing Golgi vesicles but the endoplasmic reticulum seemed tohave an important role as well. After pollination the pollen tubes grew across the stigma andentered the style through one of the slits in the three stigmalobes. The pollen tubes grew straight downward through the styleand were covered by exudate. As the pollen tubes approachedthe ovary their growth was restricted to the areas with secretorycells. In the cavity the pollen tubes formed a bundle and theybent from this bundle in between the ovules towards the micropylarside. There they bent again to stay close to the secretory cells.After bud pollination the pollen tube growth was retarded. Laterarriving pollen tubes had a tendency to grow close to the secretorycells of the style, which resulted in a growth between thesecells and preceding pollen tubes. If there was still a littleexudate produced, it resulted in a lifting up of the pollentubes, out of the exudate. The relationship between exudateproduction and pollen tube growth is discussed. Both the speedand the guidance of the pollen tube seemed determined by theproperties of the exudate.Copyright 1994, 1999 Academic Press Cryo-scanning electron microscopy, exudate, Lilium longiflorum, lily, ovary, pollination, pollen tube growth, secretory cell, stigma, style     

The development of the grape berry cuticle in relation to susceptibility to bunch rot disease

Some physical and morphological factors of grape berry cuticlewere investigated at different developmental stages of threeclones ofVitis vinifera cv. Pinot noir. The surface morphologyof grape berries was examined by scanning electron microscopyand cuticle anatomy was examined by light and transmission electronmicroscopy. During the period from flowering to maturity, thecomposition of the cuticular waxes changed, corresponding withan increase of waxy deposits and significant modifications ofthe wax surface morphology. The content in cutin per unit surfacedecreased more than 2.5-fold between berry set (16 d after anthesis)and veraison of the grape berries, and might predispose thegrape berry to fungal infection. This result was correlatedwith the differentiation of the cuticle layers and particularlywith a decrease in the thickness of the primary cuticle at harvest. Key words: Botrytis cinerea, cuticle, cutin, epicuticular waxes, Vitis vinifera L     

Ontogenesis, Differentiation and Precocious Germination in Anther-derived Somatic Embryos of Grapevine (Vitis vinifera L.): Proembryogenesis

Histological steps of callogenesis and proembryogenesis in anthercultures ofVitis vinifera L. ‘Grenache noir’ aredescribed. Embryogenic calli were obtained on Nitsch and Nitschmedium supplemented with 1mgl^-12,4-dichlorophenoxyacetic acid(2,4-D) and 0.25mgl^-1benzylaminopurine (BAP). Calli were initiatedfrom anther connective cells only and no division of microsporesoccurred. The embryos were hence of somatic origin. Proembryosdeveloped either directly (i.e. without intervening callus)from the endothecium, or indirectly from the connective-derivedcallus. In both cases, proembryos originated from single cells.They developed from starchy differentiated cells of a predeterminedtype. The polarity of the somatic proembryo was establishedfrom the first divisions and it was marked by precocious developmentof an easily recognizable suspensor. Other analogies with thedevelopment of the zygote are also emphasised. Vitis vinifera L.; grapevine; somatic embryogenesis; proembryogenesis; histology     

Influence of Endomycorrhizal Infection on Root Morphology in a Micropropagated Woody Plant Species (Vitis vinifera L.)

The influence of vesicular-arbuscular (VA) endomycorrhizal infectionon root morphology and architecture of a woody micropropagatedplant, Vitis vinifera L., has been investigated using morphologicalanalysis, modelling and topological methods. Endomycorrhizaformation caused increases in lateral root number and consequentlytotal root length but did not alter the number of root axes.The rate of production of any order lateral roots was higherin mycorrhizal than non-mycorrhizal controls. The number offirst- and second-order laterals increased linearly with timein mycorrhizal plants whilst in control plants both fitted alogistic function. Topological analysis indicated similar patternsof root branching in the early stages of growth, but the rootsystem of non-mycorrhizal plants adopted a more herringbonepattern after 8 weeks, whereas that of mycorrhizal plants retaineda more dichotomous pattern with repeated bifurcation. Althoughthe root system pattern of non-mycorrhizal vines is more efficientin exploring soil, it is more expensive for the plant in termsof energy cost versus return benefit (nutrient acquisition).In contrast mycorrhizal plants develop a more economical rootsystem which is rendered more efficient by the direct role ofthe mycorrhizal fungus in assisting nutrient absorption. Vitis vinifera L., vine, root system, modelling, topology, vesicular-arbuscular mycorrhizae     

Functional Characterization of Two Ripening-related Sucrose Transporters from Grape Berries

The ripening of grape (Vitis vinifera L.) berries is associatedwith a large accumulation of glucose and fructose in the vacuolesof the fruit cells. These hexoses are derived from sucrose,which is released from the phloem and may be taken up by parenchymacells prior to hydrolysis. We have expressed two putative ripening-relatedsucrose transporters from grape berries, VvSUC11 (synonymouswith VvSUT1) and VvSUC12, in an invertase deficient yeast strainto characterize their transport activities. Sucrose was takenup by yeast transformed with either transporter at an optimumpH of <4.5 and with a Michaelis constant (K_m) of 0.9–1.4m M. The uptake of sucrose through VvSUC11 and VvSUC12 was inhibitedby protonophores and by vanadate. This is consistent with anactive uptake mechanism involving proton cotransport, typicalof sucrose/H⁺symporters. The transporters from grape berrieswere functionally similar to Scr1, a sucrose transporter fromRicinus cotyledons. It is likely that in grape berries VvSUC11and VvSUC12 facilitate the loading of sucrose from the apoplastinto the parenchyma cells. Copyright 2001 Annals of Botany Company Fruit, grape berries, plasma membrane, sugars, sucrose transporters, Vitis vinifera