Spheroidal Pollen Grains Research Articles

Molecular, micromorphological and anatomical study of rangeland species of Atriplex (Chenopodiaceae) in Iran

Atriplex, as the largest genus of the Chenopodiaceae, is well known for its taxonomic complexity resulting from overlapping morphological characters. This halophytic perennial is distributed in salty and dry soils of Eurasia, America and Australia. Atriplex is one of the most widely cultivated rangeland species in Iran, which improves and revitalizes the rangelands. These unique characteristics of Atriplex make it a valuable plant. The present study is the first micromorphological investigation of this genus in Iran. In this study, the molecular evidence, micromorphological and anatomical structure of four species of Atriplex have been considered to evaluate their relationships. The basic shape of the pollen grains in most taxa is subprolate, however prolate and spheroidal pollen grains were recorded for A. lentiformis and A. canescens. One type of trichome (glandular) is described. Here, among the glandular trichomes, density and size of trichomes are considered as valuable characteristics. Micromorphology of epidermis illustrated three types of epidermal cells including puzzle-shaped, polygonal and irregular. Stem cross sections showed rounded shape, but the margins are diff erent between four species. Using nuclear and plastid markers (nrDNA ITS and rpl32-trnL(UAG)), we reconstructed phylogenetic relationships within four species of Atriplex. This data set was analyzed by phylogenetic methods including Bayesian inference, maximum likelihood and maximum parsimony. In phylogenetic analyses, all members of four species formed a well-supported clade (PP = 1; ML/BS = 100/100), divided into three major subclades (I, II and III). The results of the present study showed the usefulness of micromorphological, anatomical and molecular characteristics in taxon delimitation at specific levels.

Molecular, micromorphological and anatomical study of rangeland species of Atriplex (Chenopodiaceae) in Iran

Atriplex, as the largest genus of the Chenopodiaceae, is well known for its taxonomic complexity resulting from overlapping morphological characters. This halophytic perennial is distributed in salty and dry soils of Eurasia, America and Australia. Atriplex is one of the most widely cultivated rangeland species in Iran, which improves and revitalizes the rangelands. These unique characteristics of Atriplex make it a valuable plant. The present study is the first micromorphological investigation of this genus in Iran. In this study, the molecular evidence, micromorphological and anatomical structure of four species of Atriplex have been considered to evaluate their relationships. The basic shape of the pollen grains in most taxa is subprolate, however prolate and spheroidal pollen grains were recorded for A. lentiformis and A. canescens. One type of trichome (glandular) is described. Here, among the glandular trichomes, density and size of trichomes are considered as valuable characteristics. Micromorphology of epidermis illustrated three types of epidermal cells including puzzle-shaped, polygonal and irregular. Stem cross sections showed rounded shape, but the margins are diff erent between four species. Using nuclear and plastid markers (nrDNA ITS and rpl32-trnL(UAG)), we reconstructed phylogenetic relationships within four species of Atriplex. This data set was analyzed by phylogenetic methods including Bayesian inference, maximum likelihood and maximum parsimony. In phylogenetic analyses, all members of four species formed a well-supported clade (PP = 1; ML/BS = 100/100), divided into three major subclades (I, II and III). The results of the present study showed the usefulness of micromorphological, anatomical and molecular characteristics in taxon delimitation at specific levels.

Palynotaxonomy of Aechmea subgenus Ortgiesia (Regel) Mez (Bromeliaceae, Bromelioideae)

The pollen morphology of 16 species of Aechmea subgenus Ortgiesia is characterised, represented by 59 specimens including original data provided for A. kleinii, A. pimenti-velosoi, A. winkleri, Aechmea sp1 and Aechmea sp2. The pollen grains are monads, subisopolar, amb ellipsoidal, slightly flattened/convex in equatorial view, presenting some spheroidal pollen grains at a small percentage, 2(3)-porate, with small to large pores, pore shape circular or elliptic. The exine on the central area of the pollen grain varied from ‘reticulate’ to ‘predominantly microreticulate’ and less frequently from ‘foveolate’ to ‘microreticulate’. Ortgiesia may be considered stenopalynous by the porate aperture pattern and reticulate sculpturing in most cases. However, some secondary details of the exine ornamentation, such as the size variations of the lumina near the pores, as well as the size and shape of the lumina and muri in the central area of the pollen grain, helped to recognise some groups. Multivariate analyses, based on the pollen grain metric variables, similarly grouped species that are morphologically and taxonomically related by their vegetative and reproductive characteristics, such as A. calyculata and A. kleinii, and A. gamosepala and A. cylindrata, while in the remaining species the palynological similarity was less or null, such as in A. blumenavii and A. kertezsiae; A. blumenavii and A. calyculata; A. caudata and A. coelestis; A organensis and A. coelestis, A. gracilis and A. coelestis. Our results allowed an improved morphological characterisation of Ortgiesia and brought to light important data to complement the palynotaxonomy of the subgenus.

Pollen morphology and variability of Sambucus nigra L. – Adoxaceae

The objective of this study was to investigate the pollen morphology and the ranges of intraspecific and interindividual variability of Sambucus nigra L. S. nigra inflorescences were collected randomly from 66 natural elderberry sites in Poland, Germany and Lithuania. Each individual (shrub) was represented by 30 pollen grains. In total, 1980 pollen grains were measured. Nine quantitative and three qualitative features of the pollen grains were analysed. The diagnostic features of the pollen grains for the studied species were: exine ornamentation (microreticulate-heterobrochate), the length of the polar axis (small pollen) and the pollen shape (ca. 80% prolate-spheroidal and spheroidal pollen grains). These features should be treated as auxiliary because they fail to differentiate individual samples, although they can be helpful in distinguishing groups of samples. For the first time, the intraspecific and interindividual variability of the pollen grains of S. nigra were investigated. Statistically significant differences were found among particular individuals (shrubs) in all pollen grain features, although the most different were the pollen grains from samples (individuals) 7, 8 and 9 collected in Łubiana. There were significant relationships observed between the pollen grain traits and the geographical location of the collection sites.

Pollen micromorphological analysis of tribe Acacieae (Mimosaceae) with LM and SEM techniques.

The morphology of pollen grains of the 06 species of tribe Acacieae (Mimosaceae) belonging to one genus were investigated using scanning electron microscopic (SEM) and light microscopic (LM) approach. Lactic acid acetolysis method was used for (LM) while non-acetolysis for (SEM). The species were examined for the both qualitative and quantitative palynological features. Qualitatively the pollen was studied for the shape, exine sculpturing, pollen shape, and pollen type. Oblate spheroidal shape of pollen was observed in Accacia modesta. Subprolate shape in Accaca nilotica. In Accacia farnesiana, prolate pollen was examined while prolate spheroidal in Acacia tortilis and spheroidal pollen grains were studied in Acacia catechu, respectively. Pollen exine sculpturing of the studied tribe possesses novel variation. Foveolate, reticulate, foveolate-psilate, faint reticulate, fossulate, perforate, and scrabate exine sculpturing were noticed. Colpi were absent in all species. Excessive variation was observed in both qualitative and quantitative character of pollen. SPSS software was use for the quantitative measurement of the pollen grains. The current study will be helpful for the identification of the problematic species and phylogenetic studies of family Mimosaceae.

Rubus huagaoxiensis and R. lingtianus (Rosaceae), two new species from Sichuan, China

Rubus huagaoxiensis and R. lingtianus, two new species of Rosaceae from Sichuan, Southwest China, are described and illustrated. Rubus huagaoxiensis is morphologically similar to R. setchuenensis, but differs from the latter by gray tomentose branchlets, thicker leaves which are usually adaxially pubescent, larger and subflabellate stipules, 0.3–0.5 cm long pedicels, sepals which are triangular to ovate and abaxially densely gray tomentose-villous, white petals which are abaxially and adaxially villous along midrib, villous styles, and spheroidal pollen grains. Rubus lingtianus is morphologically similar to R. setchuenensis and R. huagaoxiensis, but differs from R. setchuenensis by having leathery leaves, acute lobes of leaf blade, larger and subflabellate stipules, broadly ovate sepals with acute or obtuse apex, white flowers, red fruits, and subprolate pollen grains with verrucate-striate-perforate ornamentation. Rubus lingtianus differs from R. huagaoxiensis by having leathery leaves, mature leaf blade which is adaxially glabrous or soft-hairy along veins only, usually glabrous petals, styles base with few soft hairs, red fruits, and subprolate pollen grains with verrucate-striate-perforate ornamentation. Morphological comparison among these three species is given.

Microscopic Studies, Phytochemical and Biological Screenings of <i>Ocimum canum</i>

It has been reported that more than 80% of the African population uses traditional medicine to primary healthcare. The aim of the study was to determine the histological elements, the phytochemical composition and evaluate the bioactivities of <i>Ocimum canum</i> in order to promote this plant used in Congolese traditional medicine. The earthworms were collected from the ponds of the secondary forest of Monastère Prieure Notre Dame de l’Assomption in Kinshasa city and the blood used in this study was provided by the Centre de Médecine Mixte et d’Anémie SS in Yolo-Sud quarter, Kinshasa, Democratic Republic of the Congo. The histological elements were determined by microscopic examination while different metabolites were determined using thin layer chromatography. Microscopic examination revealed the presence of crystalliferous fibres, fragment of parenchyma, grandular and non-glandular pluricellular trichomes, spheroidal pollen grains, diacytic stomata, spiral vessels. With regard to chromatographic analysis, phytochemicals identified were anthocyanins, coumarins, flavonoids, terpenoids and iridoids. The extracts from <i>O. canum</i> showed good antihelminthic, antisickling and antioxidant activities related to their phytochemicalsAll these findings constitute a scientific evidence validating the use of this medicinal plant for the management of various ailments in the Democratic Republic of the Congo.

Sporogenesis, gametogenesis and pollen morphology of Solanum japonense and S. septemlobum (Solanaceae)

Solanum japonense Nakai and S. septemlobum Bunge are medicinal plants used chaotically in traditional Chinese medicine because they have the same Chinese name, Shuyangquan. In this study, anther wall development, microsporogenesis, male gametophyte development, megasporogenesis and female gametophyte development of S. japonense and S. septemlobum were studied using traditional paraffin section technology for the first time, and their pollen morphologies were compared using scanning electron microscopy. The results showed that both species exhibit dicotyledonous anther wall development, dual tapetum origination, secretory tapetum development, simultaneous microsporocyte cytokinesis, tetrahedral tetrad, coexistent 2-celled and 3-celled mature spheroidal pollen grains that are circular along the equatorial view and have tricolporate groves, 2 locules per ovary, axial placenta, anatropous, unitegmic and tenuinucellate ovule, linear megaspore tetrad, as well as monosporic Polygonum type of embryo sac, where the chalazal megaspore develops into the functional megaspore and the other three megaspores degenerate. However, the pollen grains of S. japonense are circular along the polar view, while those of S. septemlobum are triangular; the pollen surface ornamentation of S. japonense is granulate-verrucate-punctate, while that of S. septemlobum is granulate-punctate-fossula. These results enrich the embryological data of Solanum and provide palynological bases for the classification of these two species. https://doi.org/10.2298/ABS170724048L Received: July 24, 2017; Revised: October 20, 2017; Accepted: November 9, 2017; Published online: November 22, 2017 How to cite this article: Liu Y, Gu L, Liu J. Sporogenesis, gametogenesis and pollen morphology of Solanum japonense and S. septemlobum (Solanaceae). Arch Biol Sci. 2018;70(2):313-20.

Pollen diversity in Brazilian species of Monnina (Polygalaceae)

Monnina is subordinated to the Polygalaceae family, which consists of 19 genera and approximately 1300 species widely distributed throughout the continents. The current study aims to characterize pollen grains in the genera to provide the basis for their taxonomy. Thus, 13 species were analyzed: subg. Monninopsis (M. insignis and M. malmeana), subg. Pterocayra (M. cardiocarpa, M. cuneata, M. dictyocarpa, M. exalata, M. goiana, M. itapoanensis, M. oblongifolia, M. resedoides, M. richardiana, M. stenophylla, M. tristaniana). The shape of the species widely varied: M. insignis and M. malmeana showed prolate pollen grains; M. cardiocarpa, M. resedoides and M. richardiana showed subprolate pollen grains; and M. itapoanensis, M. stenophylla, and M. tristaniana showed oblate spheroidal and prolate spheroidal pollen grains in most of the species. According to data obtained in the current study, it can be concluded that it is possible to differentiate the species based on pollen attributes. Another important feature in the characterization of the species was the number of apertures, which varied from 10 to19 colporate ones.

Pollen morphology of Iranian species of Anemone L. & Pulsatilla Mill. (Ranunculaceae) and its implications

In this study, pollen analyses of Iranian species of Anemone L. and Pulsatilla Mill. were conducted through light microscopy and scanning electron microscopy. Two pollen classes were observed in these species: trizonocolpate and pantoporate. The trizonocolpate class consists of only Anemone caucasica species, which are isopolar and prolate with microechinate ornamentations, and the pantoporate class consists of four other Anemone taxa and Pulsatilla albana, which have isopolar and spheroidal pollen grains, with 8–18 circular pores and microechinate ornamentations. Some characters show variations between/within species and populations and must be regarded in taxonomic studies. It is necessary to write a key for the porate pollen grains of Ranunculaceae, especially Anemone species. Pollen character evolution of these species is not clear.

Pollen morphology of 14 species of Abutilon and Hibiscus of the family Malvaceae (sensu stricto)

Pollen morphology and the degree of pollen variability within the fourteen species belonging to the two genera, Abutilon Mill. and Hibiscus L. of the family Malvaceae was studied and documented in detail using light microscopy (LM) and scanning electron microscopy (SEM). Two distinct pollen types were recognized based on polarity, shape, diameter and spine index of the pollen grains. The genus, Hibiscus is characterized by apolar, pantoporate and globose to spheroidal pollen grains whereas Abutilon is delimited by isopolar, 3-zonoporate and suboblate-spheroidal pollen grains. The wall of a mature pollen was composed of unremitting intine and exine overspread with spines of variable width and height. The character of spine index was used for the first time to describe Malvaceous pollen and was found to be of significant taxonomic importance. An artificial key is given for all studied taxa based on palynomorphological characters. Key words: Pollen morphology, Hibiscus, Abutilon, Malvaceae.

Pollen morphological survey of Pentas (Rubiaceae–Rubioideae) and its closest allies

Pollen descriptions, based on LM and SEM observations, are provided for the Pentas complex, an African alliance within the Hedyotideae–Spermacoceae alliance, which includes the genera Pentas, Otomeria, Batopedina, Parapentas, and Chamaepentas. The close relationship among these genera is confirmed by pollen morphological data. The observed variation in pollen character states agrees well with the existing genera and subgenera. The combination of small spheroidal pollen grains with narrow, acute endocolpi, and a small apocolpium index distinguishes Batopedina from Otomeria and Pentas. Parapentas differs from Batopedina in having broad endocolpi with vague ends. Two of the three subgenera of Otomeria, Neotomeria and Volubilis, are supported by pollen data. Pollen of the subgenus Otomeria, however, is less differentiated and is similar to pollen of Pentas subgenus Pentas. The exact relationship between the genera Otomeria and Pentas remains unclear, and molecular data are needed to interpret the observed morphological variation. Chamaepentas has pollen that is nearly identical to that of the Pentas subgenus Chamaepentadoides and of the subgenus Megapentas, i.e. large spheroidal pollen grains with three, medium-length colpi and endocolpi with acute ends. Pollen morphology provides additional support for a close affinity between Pentas subgenus Phyllopentas and Pentas subgenus Vignaldiopsis.

Pollen Production and Seed Development in the White Sapote

1. In the white sapote (Casimiroa edulis Llav. and Lex.) all the flowers observed were structurally hermaphroditic. 2. The anthers in the Dade and Blumenthal varieties differed markedly in appearance from those in the other varieties and seedlings studied and contained no normal pollen grains. 3. The other varieties and seedlings studied were found to produce an abundance of spheroidal pollen grains measuring 25-37 μ in diameter and containing three germ pores.