Scanning Electron Microscopy Analysis of Exine Patterns in Cultivars of Olive (Olea europaea L.)

Scanning electron microscope analysis of exine patterns in thepollen of nine cultivars of the olive tree (Olea europaea L.)has revealed specific differences between them. The differencesinclude variation in size, form and profile of the meshes andin the thickness of the muri. Every cultivar possesses its ownmorphological characteristics which are constant and are foundin successive years. Olea europaea L, olive, pollen, exine patterns     

Production of total and stainable pollen grains in Olea europaea L

The production of the total and stainable number of pollen grains per flower and per inflorescence of 13 olive cultivars (Olea europaea L.) has been investigated. Grains stainability was evaluated by using the acetic carmine staining method whereas the production of pollen grains was calculated by using a Bürker haemocytometer. All pollen characteristics taken into account varied significantly among the cultivars. The number of flowers per inflorescence ranged from a maximum of 31.3 (‘Cipressino’) to a minimum of 13.0 (‘Leccino’), the number of pollen grains per anther ranged from 123?346 (‘Arbequina’) to 40?975 (‘Sant'Agostino’), and the pollen stainability from 97.6% (‘Cipressino’) to 48.0% (‘Cellina di Nardò’). The number of stainable pollen grains per inflorescence averaged 2?559?512, ranging from a maximum of 3?913?678 (‘Nociara’) to a minimum of 940?143 (‘Sant'Agostino’). All parameters were positively correlated, whereas a linear negative correlation was found between stainability and total pollen grains both per anther and per inflorescence.     

Pollen exine ornamentation in the F2 generation of an interspecific hybrid of Chorisia (Bombacoideae,Malvaceae) in relation to inheritance pattern

Pollen morphology in ten plants of F₂ progeny of an interspecific tree hybrid, Chorisia insignis H. B.& K.×C. speciosa St. Hil (Bombacoideae, Malvaceae) has been studied with a view to have an insight in to the effect of hybridization on the pollen morphological features in F₂ generation. The study is a sequel to an earlier study on the pollen morphology of Chorisia species and their F₁ hybrid, in which case the hybrid pollen uniformly exhibited the apertural features of the male parent and exine features of the female parent. In the F₂ progeny the pollen grains display the apertural feature of the male parent in all the plants. However, with regard to exine ornamentation, variability has been observed. Of the ten plants, two plants exhibit the exine features of the male parent showing empty lumina (without bacula), five plants have their pollen exactly like that of the F₁ plant (showing prominent columellar heads in the lumina of the apocolpium region) and the remaining three plants showing columellae in lumina of both apocolpium and mesocolpium region being different from the above types. It has been inferred that the variability in the exine pattern in F₂ pollen indicates that the pollen exine pattern in hybrids, perhaps, is not unequivocally controlled by sporophytic or gametophytic genomes.     

A palynological study of the genus Nepeta L. (Lamiaceae)

The pollen morphology of forty taxa of the genus Nepeta L. was studied and documented in detail using light microscopy (LM) and scanning electron (SEM) microscopy in this study. Nepeta L. pollen grains are small to large (P = 18.64–63.46 μm, E = 15.62–46.33 μm), suboblate to perprolate (P/E = 0.86–2.09) in shape and hexacolpate (very rarely tetracolpate) with granular membranes. Alternate position of colpi occurs in six Nepeta taxa, N. nuda ssp. glandulifera, N. concolor, N. crinita, N. congesta var. cryptantha, N. stricta var. stricta and N. sibthorpii ssp. tumeniana. In examinations of exine ornamentation with SEM, two types of pollen grains were recognized: (1) type I, with microreticulate sculpture; and (2) type II with bireticulate sculpture, type I and II to be divided into two and five subtypes, respectively. In the two taxa with microreticulate pattern, N. pilinux and N. sulfuriflora, a tendency towards a bireticulum could be recognized due to traces of secondary tectal connections. The bireticulate exine ornamentation is characterized with varying characteristics of the primary muri and secondary reticulum. Pollen morphology within the genus is compared with infrageneric relationships.     

POLLEN MORPHOLOGY OF AMPHIANTHUS,ARTANEMA, CURANGA,GLOSSOSTIGMA, AND PEPLIDIUM (SCROPHULARIACEAE-GRATIOLEAE)

Pollen of the scrophulariaceous genera Amphianthus, Artanema, Curanga, Glossostigma, and Peplidium was examined by light and scanning electron microscopy. All have single, isopolar, radially symmetrical pollen grains with equally spaced meridional colpi and columellate exines. Intergeneric differences are established mainly on the differential correlation of colpus number, colpus morphology, and sculpturing of the mesocolpium. The colpi vary in length and range in number from 3 to 6. The colpus membrane can be variously granular, verrucate, rugulate, or spinulose. The exine varies from semitectate and microreticulate or reticulate to tectate and sparsely perforate. It may be psilate or ornamented with supratectal processes ranging from small granules to relatively long spinules or bacules. All the genera examined, with the possible exception of Artanema vs. Amphianthus, are distinguished from one another by pollen morphology, and the grains of both Curanga and Glossostigma have morphotypes not previously reported in tribe Gratioleae. Final taxonomic assessment of the pollen data in the genera examined must await further comparative studies in the Gratioleae and other tribes, but the morphological diversity observed is clearly of potential significance in evaluating specialization levels and clarifying current conflicting interpretations of relationships in these taxa.     

Analysis of the pollen allergen content of twelve olive cultivars grown in Portugal

Olive pollen presents intercultivar variability as regards to its antigenic and allergenic composition. In this study, we report the presence of differences among the SDS-PAGE pollen protein profiles of twelve Portuguese olive cultivars. Though most soluble proteins from these extracts seemed similar, three bands of about 18, 20 and 22 kDa presented sharp differences in intensity among the cultivars analyzed. The dissimilarity of patient’s sera reactivity to these protein extracts and the presence of several allergens already characterized (Ole e 1, Ole e 2, Ole e 5 and Ole e 9) in the extracts were also investigated. Epidemiological data indicated that 53.3 % out of the 428 patients analyzed with reactivity to pollen extracts, presented specific IgE levels to Olea europaea. A representative number of these sera were assayed in immunoblotting experiments. The cultivars ‘Galega’ and ‘Conserva de Elvas’ displayed low reactivity to the sera of atopic patients, whereas the extracts corresponding to the cultivars ‘Cobrançosa’, ‘Ascolana’ and ‘Verdeal de Serpa’ led to higher IgE reactivity. The use of antibodies to the allergens Ole e 1, Ole e 2, Ole e 5 and Ole e 9 in immunoblotting experiments also allowed cultivar discrimination. The cultivar ‘Verdeal de Serpa’ presented the highest Ole e 1, Ole e 5 and Ole e 9 allergen loads but the lowest Ole e 2. ‘Carrasquenha’ was the second cultivar in terms of the higher allergen content. Oppositely, the lowest allergen loads were those of the cultivars ‘Galega’ and ‘Conserva de Elvas’ coincidentally with their low IgE reactivity. These data may help interpret physiological differences in pollen performance for successful olive fertilization and, moreover, to better define future strategies for allergy diagnosis and treatment by specific immunotherapy.     

Pollen morphology of endemic species of the Gonospermum Less., Lugoa DC. and Tanacetum L. complex (Asteraceae: Anthemideae) in the Canary Islands (Spain), and its taxonomical implications

The pollen of nine endemic taxa of the Gonospermum Less., Lugoa DC. and Tanacetum L. complex and of T. parthenium L. (introduced species from the Canary Islands) was studied using light and scanning electron microscopy with the aim of extending the knowledge of their morphology and to investigate whether pollen morphology may help clarifying the controversial taxonomy of these taxa. Twenty six populations in the Canary Islands (Spain) were studied and the following parameters were measured: polar axis (P), equatorial diameter (E), polar exine thickness (Ex1), length (L) and thickness (A) of the spines in the meridional optical section, exine thickness at the centre of the mesocolpium in the interapertural area (Ex2) and distance between spines (De) in the equatorial optical section. The studies show that the pollen of the three genera is very similar regarding shape, apertures, and ornamentation, but may be distinguished by size and exine thickness.     

Morphology of pollen and orbicules in the tribe Spiraeeae (Rosaceae) and its systematic implications

This study provides pollen data for 38 representative taxa belonging to all nine genera in the current classification of the tribe Spiraeeae (Rosaceae) including the monotypic Korean endemic genus Pentactina, and considers the distribution of orbicules for the first time. Pollen morphology and wall stratification were investigated using light, scanning electron and transmission electron microscopy. Spiraeeae pollen grains are small to medium in size (P = 6.9–34.0 μm, E = 7.1–28.0 μm), oblate to prolate in shape (P/E = 0.66–1.48) and tri-colporate. Spiraeeae pollen is generally characterised by striate sexine ornamentation, but four ornamentation types are recognised based on the length and direction of the ridge patterns. The observed variation in sexine ornamentation is particularly valuable at the generic level. The exine stratification of the representative Spiraeeae studied is similar and characterised by unbranched columellae and a continuous endexine. Orbicules are present in three genera of the tribe (Luetkea, Sibiraea and Xerospiraea). Orbicule distribution patterns indicate that the absence of orbicules is a synapomorphic condition of the more derived clade, comprising Pentactina + Petrophytum + Kelseya + Spiraea.     

POLLEN MORPHOLOGY AND SYSTEMATIC RELATIONSHIPS AMONG NEW WORLD SPECIES IN TRIBE ANTIRRHINEAE (SCROPHULARIACEAE)

The morphology of mature pollen grains among 12 New World genera in tribe Antirrhineae has been examined with light and scanning electron microscopy. Pollen from 29 American species have mean polar diam that range from 17 to 26 μm, have a tectate structure with perforate, microreticulate, or reticulate surface pattern, and are subspheroidal to prolate, and trizonocolporate with fusiform or narrowly oblong colpi that are free or occasionally fused at the poles. Among the genera, pollen size is positively associated with style length but not haploid chromosome number. Three major morphological categories are recognized based on grain shape, exine structural pattern, and colpus shape. Two of these morphotypes each characterize individual genera (Mohavea, Linaria). The other morphological category includes ten New World genera and has been divided into three subcategories based on variation in lumina diam and intermittent occurrence of fused colpi. Only Antirrhinum and Pseudorontium have species or populations with pollen in more than one subcategory. Concordance of morphological, anatomical, chromosomal, and palynological data suggests that Linaria and Mohavea are best placed in separate subtribes from other native American genera. Compared to Old World taxa in tribe Antirrhineae, the most common pollen type (subspheroidal, microreticulate, apocolpate, fusiform colpi) may be the most primitive. Pollen grains with fused colpi (Antirrhinum p.p., Pseudorontium) and perforate (Mohavea) or reticulate (Holmgrenanthe) structural patterns probably represent derived types.     

部分中国传统月季花粉形态研究

利用扫描电镜观察了15个中国传统月季品种的花粉形态。结果表明:传统月季花粉为单粒花粉,呈长球形或超长球形（P/E为1.92～2.25）,大小为37.59～51.95 μm×17.02～25.33 μm。赤道面观椭圆形或长矩形,极面观三裂圆形,具三孔沟,沿极轴方向等间距环状分布。外壁纹饰条纹型,覆盖层具穿孔,在品种间具有相似性,但变异丰富,划分为4种类型。聚类分析结果表明,花粉大小和外壁纹饰特征在反映传统月季品种的类别上与形态分类基本一致。根据花粉形态演变规律可推断,样品中‘四面镜’可能为最原始的品种类型,‘月月粉’、‘月月红’及‘匍匐红’等品种较为进化。     

Pollen characteristics of the tribes Calycophylleae, Cinchoneae, and Hillieae (Rubiaceae)

Pollen grains were studied on acetolysed material with the aid of the SEM. They may be classified into four types. Type I is characterized by thick (0.92.1 μm) exine with reticulate surface, by distinct colpi with acute ends, and by distinct ora. It occurs in the genera Alseis, Calycophyllum, Ferdinandusa , and Schizocalyx. Ferdinandusa is further characterized by its lumina being differentiated into two distinct size classes. Type II is characterized by a usually thin (usually 0.7–1.1 μm) exine with foveolate surface, by distinct colpi with obtuse to truncate ends, and by poorly demarcated ora. It occurs in Cinchona, Joosia, Ladenbergia , and Remijia . Pollen grains of Joosia are mostly 4–colporate. Type III is characterized by a thick (1.7–2.0 μm) exine with coarsely reticulate surface, colpi are lacking or short and the ora are clearly demarcated. It occurs only in Capirona . Type IV is characterized by a thin (0.5–0.8 μm) exine with a psilate or foveolate surface and usually indistinct colpi with obtuse ends, and by distinct ora. It occurs in Cosmibuena and Dolicholobium . Pollen grains of Balmea, Hillia, Macrocnemum, Stilpnophyllum , and Wittmackanthus , combining features of Type I and II, do not fit into either of these four groups. It is concluded that both the tribes Calycophylleae and Cinchoneae remain eurypalynous in spite of a recent emendation. It is suggested that pollen characters serve best to characterize genera and small groups of genera. It is further suggested that Type I pollen is plesiomorphic in most or all characteristics.     

Pollen morphology of some taxa of Vicia L. subgenus Vicia (Fabaceae) from Turkey

In this study, the pollen morphology of 11 taxa belonging to Atossa (Alef.) Asch. & Graebner, Hypechusa (Alef.) Asch. & Graebner, Peregrinae Kupicha, Wiggersia (Alef.) Maxted, Vicia L. and Narbonensis (Radzhi) Maxted sections of the genus Vicia L. subgenus Vicia (Fabeae, Fabaceae) naturally growing in Turkey has been studied using Light Microscopy (LM) and Scanning Electron Microscopy (SEM) to evaluate the taxonomic relevance of pollen characters. Twelve morphometric characters are analysed with one-way analysis of variance and Tukey’s honestly significant difference test for multiple comparisons. Of the taxa studied V. narbonensis var. narbonensis (sect. Narbonensis) has the largest pollen grains (P = 51.98 μm × E = 30.52 μm) and V. lathyroides (sect. Wiggersia) has the smallest pollen grains (P = 27.71 μm × E = 20.14 μm). The pollen grains are subprolate to perprolate (P/E = 1.16–2.11), but the prolate shape occurs in the majority of the taxa. The regular pollen grains of all taxa are trizonocolporate, isopolar, and released in monads. Ornamentation of the mesocolpium is psilate-perforate in V. lathyroides (sect. Wiggersia), reticulate-rugulate in V. narbonensis var. narbonensis (sect. Narbonensis), (micro)reticulate in V. sericocarpa var. sericocarpa (sect. Hypechusa), V. sativa subsp. sativa (sect. Vicia) and V. grandiflora var. grandiflora (sect. Vicia), and reticulate-perforate in the remaining taxa. The apocolpium and colpus area are psilate or perforate in all taxa except V. sericocarpa var. sericocarpa (sect. Hypechusa) and V. sativa subsp. sativa (sect. Vicia), which exhibit the obscurely reticulate-perforate pattern. Several palynological features have taxonomic importance in sectional level: polar axis, equatorial diameter, pollen shape (P/E ratio), colpus length, colpus width, size of pori, porus length/width ratio, lumina diameter, muri thickness and ornamentation. The results also indicate that pollen characters can be useful in distinguishing the examined taxa.     

Pollen Characters of Old World Gesneriaceae (Cyrtandroideae)

Pollen of 108 species out of 18 genera (from all tribes of the Old World Gesneriaceae [subf. Cyrtandroideae]) was examined using light, scanning and transmission electron microscopy. The pollen grains are small sized, isopolar and 3-colpate or 3-colporate. In equatorial view they are mostly spheroidal (rarely suboblate or oblate), in polar view circular or subangular. The most variable character is the exine structure and -sculpture. The tectum is perforate, microreticulate, coarsely reticulate or rugulate. Further important characters of the tectum are (a) the presence or absence of conical supratectate sculptural elements, and (b) the width of lumina being either equal or exhibiting different at the apo- and mesocolpium. Ten exine types are distinguished. Some genera and species can be well referred to a special exine type, e.g., Aeschynanthus, Epithema, Stauranthera grandiflora; in other genera several exine types occur, e.g., in the large and heterogeneous genus Didymocarpus. The pollen morphology of the two large subfamilies Cyrtandroideae and Gesnerioideae is compared.     

Pollen morphology of the tribe Rhinantheae (Orobanchaceae) and its systematic significances

Pollen morphology of 36 species representing 14 genera within the tribe Rhinantheae in the family Orobanchaceae was studied and illustrated with light microscopy (LM) and scanning electron microscopy (SEM). Five major pollen types were recognized on the basis of exine ornamentation. Within these major types, minor types (subtypes) were distinguished based on exine surface pattern, size, shape, amb form, colpi and colpus membrane. These types and subtypes are as follows: type I. retipilate: subtype Ia. regular retipilate: (1) pollen size < 27 μm, (2) pollen size > 27 μm, subtype Ib. irregular retipilate; type II. verrucate: subtype IIa. macro-verrucate, subtype IIb. verrucate, subtype IIc. sparse verrucate; type III. retirugulate; type IV. granulate; type V. micro-reticulate. A key to pollen morphology of genera studied within the Rhinantheae was made based on pollen morphology from our study and earlier work. Combining with other sources of information on the Rhinantheae, the systematic relationships of this tribe are discussed. Rhinantheae pollen displays considerable variation between genera and species, with taxonomically significant characters at genus and species level. Palynological characteristics provide evidence for interpreting the conflicting views concerning the “Pterygiella Complex”. The evolutionary trend in exine sculpture of Rhinantheae could be proposed, namely that retipilate sculpturing which is the most widespread type is more primitive than the other types (such as foveolate, granulate, regulate, reticulate, retirugulate and verrucate). The pollen data in present study and the view of Hong (1986), as well as the molecular data from Bennett and Mathews (2006) indicated that Asia and related regions were likely to the origin centre of the tribe Rhinantheae.     

Pollen morphology and its systematic implications for the genera<Emphasis Type="Italic">Keiskea</Emphasis> miq. and<Emphasis Type="Italic">Collinsonia</Emphasis> L. (Elsholtzieae-Lamiaceae)

The pollen morphology of six species ofKeiskea and three representative taxa ofCollinsonia was studied in detail using LM, SEM, and TEM. In both genera, pollen grains are monad, hexa-colpate, and mostly medium in size [P = 28.0 to 37.0 μm, E = 24.3 to 30.7 μm (Keiskea); P = 30.0 to 45.0 μm, E = 26.0 to 39.0 μm (Collinsonia)]. Polar outlines are of circular or ellipsoid form. Shapes range from primarily oblate-spheroidal to prolate-spheroidal to subprolate, and rarely prolate in the equatorial view. Their exine, including the inline characters, are clearly distinct from each other:Keiskea, well-developed bi-reticulate, often forming large lumina by supratectal ridges, unbranched columellae, one-third to one-half of the total exine thickness; versusCollinsonia, mostly perforate without supratectal ridges or a faint/very weak bi-reticulate appearance without supratectal ridges, seemingly branched columellae, ca. two-thirds of the total exine thickness. As demonstrated by these current data, the pollen morphology of the two genera is well distinguished, easily supporting the separation ofKeiskea fromCollinsonia.     

我国特有珍稀濒危植物银缕梅(Parrotia subaequalis)的花粉形态研究

采用光学显微镜和扫描电镜对产自安徽省大别山金缕梅科银缕梅(Parrotia subaequalis)的花粉进行了观察和研究。银缕梅花粉粒近球形或长球形,P/E(极轴/赤道轴)=1.27(1.14-1.32),赤道面观椭圆形,极面观圆三角形或三裂圆形,大小为37.3(32.0～41.0)×29.4(25.0～36.0)μm。具3沟,沟狭长,几达两极。花粉外壁厚2.0～2.4μm,外层与内层近等厚,柱状层基柱发达。外壁纹饰在光镜下为细网状,在扫描电镜下为粗网状纹饰,网脊上有刺瘤。现生银缕梅具有鲜明的生境和分布格局特点,本研究为利用地层中银缕梅化石花粉重建古环境、古气候等提供了现代孢粉学参考依据,也为研究金缕梅科的起源、演化和现代地理分布提供了科学依据。     

Changes in lipid composition, water relations and gas exchange in leaves of two young ‘Chemlali’ and ‘Chetoui’ olive trees in response to water stress

The comparative responses of two young olive trees (Olea europaea L. ‘Chemlali’ and ‘Chetoui’) to drought stress were investigated during 1 month. Three-month-old own-rooted plants were subjected to two irrigation treatments: WW (well watered plants that were irrigated with fresh water to maintain a soil water content close to field capacity), and WS (water stressed plants by withholding water). Leaf water potential, gas exchange and leaf lipid composition were studied. ‘Chemlali’ was able to maintain higher leaf CO₂ assimilation rate and leaf stomatal conductance throughout the drought cycle compared to ‘Chetoui’. Water stress induced a larger decrease in the total lipid content in ‘Chetoui’ than in ‘Chemlali’. Interestingly, the constitution of different lipid classes was highly altered in ‘Chetoui’. Lipid changes in Chemlali, a drought tolerant cultivar, revealed more stability of its cellular membranes to drought stress as compared to the drought susceptible olive cultivar, Chétoui. Furthermore, in comparison to the controls, drought stressed plants showed an increase in the degree of unsaturation of leaf lipids in the two olive cultivars. Moreover, the results observed in Chemlali showed that besides changes in lipids composition this cultivar may have an efficient defence strategy which can be related on antioxidative production against oxidative stress.     

Effect of AMF application on growth, productivity and susceptibility to Verticillium wilt of olives grown under desert conditions

The effect of arbuscular mycorrhizal fungi (AMF) on olive (Olea europaea) growth and development was followed for 4 years after transplanting in irrigated commercial orchards under arid conditions. Sites I and II were irrigated with saline water (EC?=?4.5 dS/m). In site I, the soil was infested with Verticillium dahliae and olive varieties ‘Picual’ (Verticillium susceptible) and ‘Barnea’ (relatively Verticillium tolerant) were tested. In site II, the soil was virgin soil (previously non-cultivated soil) and olive varieties ‘Souri’ and ‘Barnea’ were tested. Plants for all sites were inoculated in the nursery with Glomus intraradices alone or in a mixture with G. mosseae. Relative to non-inoculated trees, AMF colonization enhanced vegetative growth, expressed as tree height and trunk circumference, at all sites. At first commercial harvest, AMF-treated trees had higher fruit and oil yields than non-mycorrhitic controls. Under saline water irrigation, differences between inoculated and non-inoculated treatments were reduced in the slow-growing ‘Souri’ but remained apparent in the modern fast-growing ‘Barnea’. AMF colonization did not appear to improve tolerance of either ‘Picual’ or ‘Barnea’ to V. dahliae, and both were more susceptible than the non-inoculated controls. Thus inoculation of olive plants with AMF improves transplant growth and adaptation in arid areas during the first 3 years of growth and until the first commercial harvesting season.     

Using palynomorphological characteristics for the identification of species of Alsinoideae (Caryophyllaceae): a systematic approach

Palynological characters of 18 species belonging to seven genera of the traditional subfamily Alsinoideae including Arenaria, Cerastium, Eremogone, Lepyrodiclis, Minuartia, Sabulina and Stellaria were studied in detail using light and scanning electron microscopy. Pollen grains of subfamily Alsinoideae are subspheroidal or prolate, pantoporate and 20.04 to 51.4 µm in size, prominent and sunken apertures uniformly distributed on the pollen surface. Two types of pollen grain ornamentation were observed, i.e. microechinate-punctate or microechinate-perforate. Echini are present on the surface of the pollen of all investigated species with medium, dense, or sparse echinodensity. These species exhibit variation in polar view, equatorial diameter, number of apertures, exine thickness, diameter of pore, appendages per pore, pore ornamentation, echini arrangement, echinidensity and shape of pollen. Based on qualitative characters, a dichotomous key has been developed for quick and easy identification. The present investigation contributes to the systematic approach using palynological characteristics and correct identification of species for members of subfamily Alsinoideae (Caryophyllaceae).