Immunocytochemical localization of the allergenic proteins in the pollen of Cryptomeria japonica

Applying an immunocytochemical method, a localization of the protein Cry j I in the Cryptomeria japonica pollen, which is the major allergen responsible for Japanese cedar pollinosis, is investigated with the monoclonal and polyclonal antibodies produced from the protein. The protein that reacts to the polyclonal antibody localizes on the sexine, nexine, between nexine and intine layers, orbicles, cell wall of a generative cell, Golgi body and Golgi vesicles. The allergenic protein contained in the exine and orbicles of Japanese cedar pollen can diffuse or dissolve easily from there into the mucus covering of the eye and nose, causing a response in less than 1 min after exposure. Since the orbicles have a diameter of about 430 nm, they can pass easily through the pores of most protective masks to reach the sensitive tissues of the patient. The proteins react to the monoclonal antibodies (J1BO1 and J1BO7) and localize on the Golgi body, sexine, nexine and orbicles (but not between the nexine and intine layers), and on the generative cell wall. In the young pollen grain, numerous allergenic protein particles contained in the orbicles and sexine layer, but there is only a small amount of the protein between the nexine and intine layers, since the intine layer is not yet complete at this stage. More will be accumulated there during developmental maturation. The allergenic protein is also found on the tapetal materials remaining in the young anther. Since the materials forming the exine layer and orbicles come from tapetal tissue, it is assumed that some of the allergenic protein is produced in the tapetum and localized in the orbicles and pollen wall during maturation, and that the rest of the allergenic protein is produced in the Golgi body in the mature pollen grain.     

Elektronenmikroskopische Untersuchungen zur Frage der verwandtschaftlichen Beziehungen zwischenTheligonum undRubiaceae: Feinbau der Siebelement-Plastiden und Anmerkungen zur Struktur der Pollenexine

Theligonum cynocrambe and 13 species ofRubiaceae contain S-type sieve-element plastids, wide-spread in Dicotyledons. Alignment ofTheligonum toCaryophyllales (Centrospermae), especiallyPhytolaccaceae, is unlikely, because this order is characterized by specific P-type plastids. SEM investigations show the pollen exine ofTheligonum to be microreticulate, with additional supratectate spinules.Asperula and other genera of the tribeRubieae have a tectum perforatum (punctitegillate sexine), also with supratectate verrucae or spinulae.—Thus ultrastructure suggests (but not definitely proves) relationships betweenTheligonum andRubiaceae, while affinities betweenTheligonum andCaryophyllales are excluded.

     

STUDIES OF SEED FERN POLLEN: DEVELOPMENT OF THE EXINE IN MONOLETES (MEDULLOSALES)

Monoletes pollen extracted from the seed fern synangium Dolerotheca sclerotica Baxter illustrate four stages in the development of the sporoderm. In the first stage the grains are up to 100 μm long and possess an apparent homogeneous exine in which there is little differentiation between the nexine and sexine. Numerous nexine lamellae and the initiation of sexine expansion mark stage 2 in exine ontogeny. Further expansion of the sexine continues in the third stage until the ratio between the nexine and sexine is approximately 1:5. The final stage in maturation of the sporoderm shows an expanded alveolate sexine with some of the sporopollenin units broken and disorganized. It is at this stage of development that nexine lamellae are most prominent. The formation of sporoderm layers in the fossil grains is compared with pollen grain development in living cycads (Cycadophyta) and a model proposed to account for the apparent early formation of nexine lamellae in Monoletes. The evolution of exine components in early pollen types is discussed.     

Pollen morphology inParis and its related genera

Pollen grains ofParis, Medeola, andScoliopus have been examined with light, scanning electron, and transmission electron microscopies.P. quadrifolia L.,P. verticillata Bieb.,P. delavayi Franch. andP. polyphylla Smith have monosulcate pollen characterized by psilate, foveolate or reticulate exine sculpture. In contrast to the former species,P. japonica (Fr. et Sav.) Franch. andP. tetraphylla A. Gray have monosulcate pollen with gemmate (rarely rugulate) exine.Medeola has monosulcate pollen with reticulate exine that is distinct from that ofParis. Scoliopus has monosulcate pollen characterized by a peculiar reticulate exine pattern. The palynological evidence suggests thatParis andTrillium are closely related to each other, andMedeola andScoliopus should be separated fromParis andTrillium.     

四川雅安地区13种凤仙花属植物花粉形态及其分类学意义

采用扫描电镜观察了中国四川雅安地区13种凤仙花属植物的花粉形态,并对其花粉形态进行了主成分分析和聚类分析,基于孢粉学和SRAP聚类结果的比较,讨论不同孢粉学特征对分类结果的影响。结果显示:(1)雅安地区13种凤仙花属植物花粉粒均为中等大小,花粉粒形状从超扁到扁球形变化,花粉粒极面观形状从矩形和椭圆形到四边形、圆形、三角型变化,且只有湖北凤仙、峨眉凤仙和匙叶凤仙是三沟花粉粒,其余种均为四沟花粉粒;外壁纹饰仅扭萼凤仙和齿萼凤仙为细小网状,其余均为网状纹饰。(2)依据不同指标进行的孢粉学聚类均将13种凤仙花属植物划分为3个类群,而SRAP聚类结果则将13种凤仙花属植物划分为5个类群;不同孢粉学聚类结果的相似率只有30.77%。(3)孢粉学聚类并未与分子聚类显示严格的对应关系,以花粉大小和形状、外壁纹饰为指标进行的孢粉学分类与SRAP分类的相似率最高(69.23%)。研究认为,选择不同的花粉形态特征作指标对分类的准确性影响较大,花粉大小和形状、外壁纹饰这2个指标对凤仙花属植物分类具有意义,而萌发沟的特征则很难作为分类的依据,花粉形态特征在分类上有局限性;进行该属植物孢粉学分类需要选择有价值的分类指标,并结合形态学、分子生物学等综合研究。     

A comparative biochemical study of conifer pollen allergens

In the order Coniferales, only the family Cupressaceae is regarded as being a significant source of airborne allergens, withJuniperus ashei characterized as the most significat aeroallergen. Pollen of the closely related speciesJ. virginiana has been shown to cross-react withJ. ashei pollen, however,J. virginiana pollen is not considered an important aeroallergen. Although there have been several reports of allergies toPinus pollen, the pollen of this genus is regarded as hypoallergenic. Our previous studies have shown that pollen extracts ofJ. ashei, J. virginiana, J. pinchotii, Cupressus macrocarpa, Pinus echinata andP. taeda all contained several proteins with the same molecular weights including the reported allergen ofJ. ashei. The present study compared the biochemistry ofJ. ashei, J. virginiana andP. echinata pollen. A time course experiment ofJ. ashei, J. virginiana andP. echinata showed thatJ. ashei released a greater quantity of protein within the first minute of moistening. SDS-PAGE analyses showed that the reported allergen ofJ. ashei pollen extracts was released in large quantities within the first minute of extraction. It was also determined that individual pollen grains ofP. echinata contained a greater quantity of protein than the pollen ofJ. ashei andJ. virginiana, but due to the large size of pine pollen there was less protein per gram of pollen. Lipid analysis of these three taxa showed that the pollen ofP. echinata contained more lipid per grain and per gram of pollen. Results indicate that the rapid release of the reported allergen fromJ. ashei pollen contributes to the allergenicity of this species compared to bothJ. virginiana andP. echinata.     

The remarkable genus<Emphasis Type="Italic"> Coptosapelta</Emphasis> (Rubiaceae): pollen and orbicule morphology and systematic implications

The pollen morphology and distribution of orbicules were investigated in ten species of the genus Coptosapelta (Rubiaceae) using light, scanning electron and transmission electron microscopy. In general, Coptosapelta pollen is three- to five-pororate and suboblate to oblate-spheroidal. The sexine ornamentation varies from psilate to reticulate, and the pollen-wall stratification lacks columellae. Droplets are observed on the inner nexine surface. Distinct orbicules are found in five species. Orbicules are often lobed and appear to be aggregated and embedded in the tapetal remnants of the locule wall. Ultrastructurally, a single, flattened core is frequently observed. Coptosapelta has a unique pollen type within Rubiaceae and does not resemble possibly related genera. Pollen characteristics provide additional evidence supporting earlier findings that Coptosapelta represents an isolated lineage in Rubiaceae.     

Pollenfertility and seed formation in theOrnithogalum umbellatum/angustifolium complex (Liliaceae/Scilloideae)

The pollen fertility and seed formation of six species of theOrnithogalum umbellatum/angustifolium complex and of seven related species were studied. Four types of pollen grains could be recognized. The pollen fertility varied greatly in this complex and is not related to the ploidy level. The seed formation ofO. umbellatum showed an adaptation to a subcontinental-Mediterranean climate, that ofO. angustifolium to an Atlantic climate. In both cases raindrops seem to be important for pollination, in view of the absence of insect pollinators. After open pollination 113 seedlings were obtained in four species. Their chromosome numbers were determined. Nearly all the cultivated seedlings were aneuploid, which points to a positive selection of euploids in nature, because aneuploid individuals are rare in the wild.Biosystematic Studies on theOrnithogalum umbellatum/angustifolium Complex III.—Previous parts of this series are Part I: Taxonomy. Proceeding Kon. Ned. Acad. Wet. series C,85 (4), 563–574 (1982) andvan Raamsdonk (1984).     

Pollen morphology of Microstachys (Euphorbiaceae) with emphasis on neotropical species

Abstract

In Euphorbiaceae tribe Hippomaneae is the pantropical genus Microstachys, comprised by 24 species, mostly from Brazil. Palynological studies with several representatives of the genus are scarce. The purpose of this study was to describe the pollen morphology of Microstachys and find possible differentiating characteristics between its species. Ten species of the genus were analysed, represented by 21 herbarium collections. Their pollen grains were acetolysed, measured and photographed under light microscopy (LM) and scanning electron microscopy (SEM). The analysed species possess pollen in monads, of small to medium size, isopolars, amb distincticly trilobed, oblate-spheroidal, prolate-spheroidal or subprolate, tricolporate with narrow and very long colpi, almost fused at the poles sometimes forming an invagination with tapering ends and margo of the colporus wide to very wide and psilate; endoapertures lalongate to very lalongate with tapering ends, presence of a narrow costae distinct in the endoaperture; exine microreticulate homobrochate, walls with simple columella; at the mesocolpus the sexine separates from the nexine forming cavea; and sexine always thicker than the nexine. Microstachys is a stenopalynous genus, despite its species varying in pollen size, shape and width of the cavea, margo of the colporus, and length of the endoapertures, demonstrating taxonomic value, and indicating a contribution towards future systematic analyses.     

Stylar trimorphism in four functionally andromonoeciousProsopis species (Mimosaceae)

The reproductive system ofProsopis chilensis, P. pugionata, P. flexuosa, andP. torquata is described. Observations were made of floral morphology, stigmatic receptivity, pollen grain viability, and the nature of pollen reserves. Scanning electrone microscopy and statistical analysis were carried out. The results allow us to conclude that: 1) The studied species have three distinct floral morphs characterized by significantly different style lengths and, to a lesser extent, different stamen lengths; 2) style precocity found in all species does not indicate protogyny; 3) flowers with shortest styles are not receptive; 4) the pollen grains of all floral morphs showed high viability; 5) peroxidase is present in both the pollen and pistil; 6) viable pollen grains invariably have both starch and pollenkitt; 7) the studied species are andromonoecious.     

The systematic relationships ofAegialitis (Plumbaginaceae) as revealed by pollen morphology

Light and first SEM observations on the pollen ofAegialitis indicate that the two species of the genus are clearly distinguishable from all other genera of the tribeStaticeae to whichAegialitis presently is relegated. Intraspecific exine or aperture dimorphism which appears frequently in this tribe, is not recorded in this genus.A. annulata andA. rotundifolia have distinct monomorphic pollen and show a great resemblance in exine features with the tribePlumbagineae, particularly species ofPlumbago. Considering these and other features, separate subtribal status forAegialitis within thePlumbagineae is proposed.     

Pollination ofOpuntia lindheimeri and related species

The large, yellow, bowl-shaped flowers ofOpuntia lindheimeri, O. discata, O. phaeacantha major, andO. compressa in Texas are visited by various species of beetles and bees. The beetles and small bees (Perdita, Dialictus) are pollen thieves. The pollinators are the medium-sized and larger bees (Melissodes, Diadasia, Lithurge, Megachile, Agapostemon, etc.). Different species of theOpuntia lindheimeri group have the same pollination system and there is no evidence of any floral isolation between them. The pollination system of these species ofOpuntia in Texas is essentially the same as that ofEchinocereus fasciculatus andFerocactus wislizeni in Arizona.Pollination of North American Cacti, II.—SeeGrant & Grant (1979).     

POLLEN MORPHOLOGY AND ULTRASTRUCTURE OF THE CABOMBACEAE: CORRELATIONS WITH POLLINATION BIOLOGY

Of all species comprising the two genera of the Cabombaceae, only Brasenia schreberi J. F. Gmel. and Cabomba caroliniana Gray have been critically investigated with regard to their pollination biology. Brasenia schreberi has been shown to be anemophilous, while C. caroliniana has an entomophilous (myophilous) pollination syndrome. In the present paper, a number of pollen and pollen-related characters, including pollen size, shape, quantity, terminal settling velocity, pollen-ovule ratios, and overall exine architecture of B. schreberi and C. caroliniana are evaluated. Pollen from both species is elliptic, monosulcate, and has a tectate-columellate sporoderm with supratectal surface ornamentation. Grains of B. schreberi are small, produced in copious amounts, and settle relatively slowly. Flowers of this species have large pollen-ovule ratios. The exine of B. schreberi pollen is scabrate, relatively thin, has a uniformly thick sexine composed of a two-zoned (homogeneous/granular) tectum and distinct columellae, and a homogeneous nexine. Pollen of C. caroliniana is relatively large, produced in small quantities, and has a rapid terminal settling velocity. Flowers exhibit small pollen-ovule ratios. Exine organization of C. caroliniana pollen is typically two times thicker than that of B. schreberi; ornamentation is striate. Nonapertural sexine regions have a thick tectum and well-defined columellae, with both sexine components traversed by a dense system of channels. The nexine is relatively thin. All of the palynological characters examined correlate well with the anemophilous and entomophilous syndromes of B. schreberi and C. caroliniana, respectively. Moreover, several other parameters of exine ultrastructure from each species exhibit positive correlations with the respective pollination mechanisms, including: tectum thickness, columellae diameter, tectum-nexine ratios, and the consistency, distribution, and total amount of pollenkitt present. Overall exine ultrastructure is also discussed from a historical perspective as well as with respect to its phylogenetic significance.     

THE ULTRASTRUCTURE OF SAHNIA POLLEN (PENTOXYLALES)

The micromorphology and fine structure of in situ pentoxylalean pollen are described from the holotype of Sahnia laxiphora Drinnan and Chambers 1985 collected from the Lower Cretaceous (Valanginian-Aptian) of Victoria, southeastern Australia. Pollen grains are ovoid, monosulcate, and relatively small, averaging 26 μm in length. Exine ornamentation is psilate. The sporoderm is two-parted with the sexine staining lightly throughout and approximately six times the thickness of the more darkly staining nexine. The exine over the sulcus is typically strongly invaginated, and may or may not include an extremely thin sexine layer. The outer part of the sexine is homogeneous, while the inner part is composed of relatively large granules separated by irregular lacunae of various sizes; lacunae are most pronounced at the sexinenexine interface. Faint lamellae characterize the nexine in both apertural and nonapertural regions. Granular orbicules are often associated with the exine surfaces and also occur appressed to pollen sac walls along with lamellated tapetal membranes. Sporoderm ultrastructure is compared to that of nonsaccate pollen of other groups, and particularly to pollen of Bennettitales, Gnetales, angiosperms, and similar plants, to which the Pentoxylales have been thought to be closely related. Although Sahnia laxiphora pollen is not identical to that of any of these taxa, the strongest similarity is with pollen of Bennettitales.     

Hybridization and evolution inCardamine (Brassicaceae) at Urnerboden, Central Switzerland: Biosystematic and molecular evidence

Hybridization between two diploid (2n = 2x = 16) species ofBrassicaceae, Cardamine rivularis andC. amara, at Urnerboden, Central Switzerland, resulted in the rather unusual triploid hybridC. insueta (2n = 3x = 24), and later on in the amphiploidC. schulzii (2n = 6x = 48). The hybrid and the neopolyploid species colonized successfully some man-made biotopes. Plants ofC. insueta are mostly functional females with non-dehiscent anthers, but true hermaphrodite individuals with partly sterile pollen grains also occur within the population. Analyses of cpDNA and nuclear DNA permitted to establish the parentage of the hybrid: the maternal parent which contributed unreduced egg cells proved to beC. rivularis whereas the normally reduced pollen originated fromC. amara. The pronounced genetic variability inC. insueta revealed by isozyme and RAPD analyses, at variance with the polarized segregation, heterogamy and strong vegetative reproduction of the hybrid, is possibly influenced by recurrent formation ofC. insueta which party results from backcrosses betweenC. insueta andC. rivularis but may also proceed by other pathways. The amphiploidCardamine schulzii has normally developed anthers but its pollen is sometimes highly sterile. The surprisingly uniform genetic make-up of the new amphiploid species might be related to its possible monotopic origin and/or young phylogenetic age but should be further assessed. Site management seems to be very important to a further development of hybridogenous populations and their parent species. In conclusion, the evolution at Urnerboden is discussed in the context of the traditional concept of multiple plant origins.     

Pollen morphology and ultrastructure of Marathrum schiedeanum (Podostemaceae)

The Podostemaceae, or river-weeds, comprise 46 genera and 270 species of dicots and are the largest family of strictly aquatic angiosperms. Despite the large size, specialized habitats, and enigmatic morphology of the family, relatively little is known about the palynology of Podostemaceae. In the current paper, pollen morphology and ultrastructure of Marathrum schiedeanum are described. Pollen grains are relatively small, spheroidal, and tricolpate to spiraperturate. The exine has a microechinate ornament, a tectate-granular sexine and a relatively thick nexine in non-apertural regions, and a semitectate sexine and thinner nexine in apertural regions. Although aperture variation occurs in the family, this is the first report of the spiral aperture type in Podostemaceae. The spiraperturate condition appears to be derived in river-weeds, as does the granular pollen wall, which represents a reduction of the typical columellae found in eudicots.     

Pollen morphology and ultrastructure of the Bennettitales: In situ pollen of Cycadeoidea

The micromorphology and ultrastructure of in situ pollen from Cycadeoidea dacotensis are described from permineralized specimens collected from the Lower Cretaceous of North America. Pollen grains are ovoid and relatively small, averaging 25 μm in length and 12 μm in width. Grains are monosulcate with the exine typically invaginated in apertural regions. Exine ornamentation ranges from punctate to psilate. The exine averages 0.73 μm in thickness and is composed of a light-staining sexine and a dark-staining nexine. The sexine consists of a thin, homogeneous tectum, typically with a well-defined inner boundary, and a thicker granular infratectum. The infratectal granules are relatively uniform in size, however, variation occurs in the arrangement of granules. In some grains, the sexine appears homogeneous because there is little lacunal space between the individual granules. The granular infratectum is in direct contact with the underlying nexine. The nexine is uniform in thickness in both apertural and nonapertural regions, and it lacks lamellae throughout. Pollen morphology and ultrastructure are compared with those of the bennettitalean genus Leguminanthus and the dispersed genus Monosulcites. In addition, the fine structure of Cycadeoidea pollen is compared to that of the gymnosperm groups with which the Bennettitales are regarded to be most closely related, including Gnetales, Pentoxylales, and Eucommiidites-type pollen-producing plants.     

含笑花药发育的超微结构研究

对含笑花药发育中的超微结构变化进行观察,结果显示:(1)花粉发育中有三次液泡变化过程——第一次是小孢子母细胞在形成时内部出现了液泡,这可能与胼胝质壁的形成有关;第二次是在小孢子母细胞减数分裂之前,细胞内壁纤维素降解区域形成液泡,它的功能可能是消化原有的纤维素细胞壁;第三次是在小孢子液泡化时期,形成的大液泡将细胞核挤到边缘,产生极性。(2)含笑花粉在小孢子早期形成花粉外壁外层,花粉外壁内层在小孢子晚期形成,而花粉内壁是在二胞花粉早期形成;花粉成熟时,表面上沉积了绒毡层细胞的降解物而形成了花粉覆盖物。研究认为,含笑花粉原外壁的形成可能与母细胞胼胝质壁有关,而由绒毡层细胞提供的孢粉素物质按一定结构建成了花粉覆盖物。     

Stamen movements in flowers ofOpuntia (Cactaceae) favour oligolectic pollinators

Opuntia brunneogemmia andO. viridirubra occur sympatrically in the Serra do Sudeste, Rio Grande do Sul, Brazil. Their flowers have 450–600 thigmonastic stamens and provide large amounts of pollen and nectar for bees. Bees of 41 species were registered at the flowers ofO. brunneogemmia and 30 at the flowers ofO. viridirubra. Females of three oligolectic species are the only effective pollinators:Ptilothrix fructifera (Anthophoridae),Lithurgus rufiventris (Megachilidae), andCephalocolletes rugata (Colletidae). During their visits inOpuntia-flowers, bees touch the filaments and stimulate the movement of the stamens to the centre of the flower. At the end of this movement, the anthers are densely packed around the style. As a consequence the pollen is presented in an easily accessible upper layer of anthers and various, nearly inaccessible lower layers. The lower layers contain about 80% of the pollen reward. Only females of the three oligolectic pollinators exploit the pollen from the lower layers and reach the nectar furrow. Therefore, through their stamen movements,Opuntia flowers hide most of their pollen from flower visitors but favour effectively pollinating, oligolectic bees.     

The PELPIII glycoproteins in Solanaceae: stylar expression and transfer into pollen tube walls

The class III pistil-specific extensin-like proteins (PELPIII) of Nicotiana tabacum accumulate in the intercellular matrix (IM) of the style transmitting tissue (TT). After pollination, the 110–140 kDa PELPIII is translocated from the IM into the pollen tube walls. PELPIII-like sequences have been found in several solanaceous species. These sequences are expressed in mature non-pollinated styles at both RNA and protein level. Of the genus Nicotiana, the species N. alata, N. x sanderae and N. sylvestris (section Alatae), and N. tomentosiformis and N. otophora (section Tomentosae) showed an expression level of PELPIII homologues similar to that in mature styles of N. tabacum. PELPIII genes were absent in the most ancient species studied, namely N. trigonophylla (section Trigonophyllae). To study the species dependence of the translocation of PELPIII into the pollen tube wall in tobacco, interspecific pollinations on N. tabacum pistils were carried out with pollen from the incongruous species N. rustica, N. trigonophylla and Petunia hybrida, where PELPIII homologues are absent in the style. Immunocytological tests showed that the N. tabacum PELPIII is translocated into the pollen tube walls of all three species. Thus, the pollen tube walls of these species do not form a barrier for IM compounds such as the 110–140 kDa PELPIII and the absence of any possible effect of PELPIII on pollen tube growth cannot be due to failure of PELPIII transport through the wall. The importance of these findings is discussed with respect to the evolutionary origin of PELPIII, the pollen pistil interaction, the function of style TT-specific proteins and the physical properties of pollen tube walls.