scholarly journals Poaceae pollen grains from southern Brazilian grasslands: Pollen grain size in species from dry and humid environments

2018 ◽  
Vol 13 (2) ◽  
Author(s):  
Jefferson Nunes Radaeski ◽  
Soraia Girardi Bauermann
Keyword(s):  
Grain Size ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Poaceae Pollen ◽  
Pollen Grain Size

scholarly journals Palynology of the Genus Stachytarpheta Vahl. (Verbenaceae)

2010 ◽  
Vol 2 (4) ◽  
pp. 27-33
Author(s):  
Olubukola ADEDEJI
Keyword(s):  
Cluster Analysis ◽  
Grain Size ◽  
Evolutionary History ◽  
Pollen Grains ◽  
Pollen Grain ◽  
The Other ◽  
Pollen Grain Size ◽  
Pollen Diameter ◽  
Stachytarpheta Cayennensis ◽  
Exine Morphology

The exine morphology of pollen grains of Stachytarpheta indica (Linn.) Vahl, Stachytarpheta cayennensis (Rich.) Vahl and Stachytarpheta angustifolia (Mill.) Vahl is reported. This study was carried out with a light microscope. Pollen grains from fresh anthers were collected and aceolysed. Statistical analysis used to analyse the data collected include cluster analysis, correlation analysis, similarity and distance indices. The pollen grains are spheroidal to oblate to sub-oblate in shape. They are aperturate, both colpate and porate. Tricolpate types occur most frequently, acolpate, monocolpate, bicolpate and tetracolpate types less frequently. The multicolpate and multiporate attributes in all the species indicate that the genus is not primitive in evolutionary history and this species probably, evolved around in the same time. According to the size, the pollen grains of the genus falls into groups permagna (pollen diameter 100-200 μm) and giganta (pollen diameter greater than 200 μm). S. cayennensis and S. anguistifolia belong to group permagna and S. indica only in the group giganta. This separates S. indica from the other two species. The large pollen grain size in the genus clearly supports the fact that the flowers in the genus are more insect-and-bird pollinated than wind pollinated. The similarity and distance indices of the species showed that S. cayennensis and S. angustifolia are the closest. S. indica is closer to S. angustifolia but farther from S. cayennensis.

scholarly journals Differences in stomatal and pollen grain dimensions and pollen viability between Paspalum rawitscheri populations

2020 ◽  
Vol 42 ◽  
pp. e46
Author(s):  
Jéssica Mena Barreto De Freitas ◽  
Andrielle Wouters Kuhn ◽  
Viviane Dal-Souto Frescura ◽  
Liliana Essi ◽  
Solange Bosio Tedesco
Keyword(s):  
Grain Size ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Low Fertility ◽  
Leaf Epidermis ◽  
Stomatal Size ◽  
Pollen Grain Size ◽  
Different Populations ◽  
Santa Maria

The objective of this study was to evaluate stomatal and pollen grain size and to estimate pollen viability of individuals from different populations of Paspalum rawitscheri (Parodi) Chase ex G.H. Rua Valls. To analyze stomatal size, slides were made of the adaxial leaf epidermis using the epidermal impression method. The height and width of 100 stomata per population were analyzed. Pollen was obtained from inflorescences to evaluate pollen grain size and pollen viability. Pollen grains were stained with 2% acetic orcein, 2% acetic carmine, or Alexander’s reactive stain. Per population, 1600 grains of pollen were observed for viability, and 50 grains of pollen were measured. There were significant differences between populations in stomatal height and pollen grain height and width. The populations also differed in pollen viability, with the Santa Maria population showing the lowest viability. The differences in stomatal and pollen grain size suggest genetic variability in the evaluated populations. Moreover, low pollen viability in one population indicates that its decline may be related to low fertility. Keywords: Grass. Ploidy. Fertility. Threatened species.

scholarly journals Male gametophytic generation and a possible approach for selective pollination in carnation (Dianthus) breeding program

2011 ◽  
Vol 48 (No. 8) ◽  
pp. 368-375
Author(s):  
Tejaswini
Keyword(s):  
Grain Size ◽  
Pollen Tube ◽  
Dianthus Caryophyllus ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Breeding Program ◽  
Germination Capacity ◽  
Causal Organism ◽  
Pollen Tube Growth Rate ◽  
Pollen Grain Size

Present study focuses on making best possible use of male gametophytic generation in carnation breeding program. Exploration of pollen population revealed the existence of variability in terms of pollen morphology and histochemical content among as well as within varieties and species of Dianthus caryophyllus and D. chinensis sufficient to make selection. Pollen grain size and histochemical content were found to be associated with germination capacity and pollen tube growth rate. In addition, pollen germination capacity and elongation of pollen tube in response to presence of culture filtrate from F. oxysporum. f.sp. dianthi causal organism of fusarium wilt in carnation was found to be governed by pollen grain size and histochemical content of pollen grains. Entire result suggests the possibility of selecting the desired pollen grains from a pollen population and possibility of attempting selective pollination in carnation breeding program.

scholarly journals Palyno-morphology of Hedera L. (The ivy genus, araliaceae) and their systematics implications

Genetika ◽  
2021 ◽  
Vol 53 (2) ◽  
pp. 851-865
Author(s):  
Fahimeh Fallah ◽  
Farrokh Ghahremaninejad
Keyword(s):  
Grain Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Hedera Helix ◽  
Transmission Electron ◽  
Pollen Grain Size ◽  
The Relationship ◽  
Scanning Electron

The palynomorphological characteristics of 5 species belonging to Hedera of the Araliaceae family were studied in detail. These plant species were collected from various phytogeographical regions of Iran and Hungary. The palynological investigation was accomplished using Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM). Pollen grains of the species are reticulate, prolate, sub-prolate, tricolporate, isopolar, radially symmetrical, and monad. The largest pollen grain was in the Hedera colchica species (72.24?1.6 ?m) and the smallest pollen grain was in Hedera helix (28.63?2.1 ?m). The research carried out by the TEM showed that the species were different in terms of exine thickness, tectum thickness, foot layer thickness, the diameter and length of the Columella, the thickness and shape of the Caput, the tectum to foot layer )T/F( ratio, the absence or presence of the Endexine and the thickness of the Intine layers. The main purpose of this study was the importance of the relationship between pollen grain size and the number of chromosomes and ploidy level in Hedera species.

scholarly journals Pollen grain size associated with pollinator feeding strategy

2020 ◽  
Vol 287 (1933) ◽  
pp. 20201191 ◽  
Author(s):  
Kai Hao ◽  
Zhi-Xi Tian ◽  
Zi-Chen Wang ◽  
Shuang-Quan Huang
Keyword(s):  
Grain Size ◽  
Feeding Strategy ◽  
Pollen Grains ◽  
Field Studies ◽  
Interspecific Variation ◽  
Pollen Grain ◽  
Pollen Foraging ◽  
Pollinator Behaviour ◽  
Trade Offs ◽  
Pollen Grain Size

Angiosperm pollen grain diameter varies greatly from a few microns to over 100, but the selective forces driving the interspecific variation in pollen size remain unclear. Although both pre- and post-pollination hypotheses have been proposed, empirical evidence remains scarce. Here we propose that visits by pollen-foraging pollinators have selected against large pollen grains. An association between pollinator behaviour and pollen grain size was confirmed by field studies of 80 flowering species in natural communities, showing that pollinators positively collected pollen in those species with relatively smaller pollen grains but rarely did so in species with larger ones. Allowing for the confounding effects of pollinator type, flower size or style length and pollen grain number, we found a significant effect of pollen-foraging behaviour on variation in pollen grain size, particularly in bee-pollinated plants. While these results suggest that many plant species whose pollen is collected or consumed by pollinators produce small pollen grains, it remains unclear whether pollen grain size is directly affected by pollinator foraging habit or indirectly mediated by pollen number trade-offs.

scholarly journals Interaction between Bees and the Tristylous Flowers ofOxalis cytisoidesMart. & Zucc. (Oxalidaceae)

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Cristiane Krug ◽  
Cláudia Inês Silva ◽  
Isabel Alves-dos-Santos
Keyword(s):  
Grain Size ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Santa Catarina ◽  
Semideciduous Forest ◽  
Pollen Loads ◽  
Pollen Grain Size ◽  
Flower Visiting ◽  
Santa Catarina State

The interaction of bees with the tristylous flowers ofOxalis cytisoidesMart. & Zucc. (Oxalidaceae) was evaluated. The study was conducted in a semideciduous forest at the Fritz Plaumann State Park in Concórdia, Santa Catarina state. TwoOxalis cytisoidesaggregations were found and the flower visiting bees were observed. The 3 floral morphs were found at the following proportions: 16 long-, 37 mid-, and 34 shortstyled individuals (n=87). Anthesis lasted one day (6:30 AM to 3 PM). No fruit was formed in the autogamy test; thus, pollination was dependent on the visitors. The pollen grain size varied between the stamens and morphs and formed subsets in accordance with the stigma height (long/mid/short). We collected 165 bees from 30 species visiting the flowers.Hypanthium divaricatumwas the most abundant bee species (34%) and the males were often observed patrolling the flowers in search of females for mating. Analysis of the pollen loads from 34 females showed that 27 carriedO. cytisoidespollen. The most frequent bees that carriedO. cytisoidespollen grains on their bodies were considered pollinator agents, responsible for transferring pollen grains among the floral morphs.

scholarly journals Pollen tube branching in the ovary of five species of Oenothera

2014 ◽  
Vol 65 (1-2) ◽  
pp. 111-116 ◽  
Author(s):  
Renata Śnieżko
Keyword(s):  
Grain Size ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Morphology ◽  
Pollen Grains ◽  
Growth Direction ◽  
Pollen Grain ◽  
Tube Growth ◽  
Oenothera Hookeri ◽  
Pollen Grain Size

Flowers of <em>Oenothera hookeri</em> Torr. et Gray, <em>Oe. brevistylis</em> and <em>Oe. lamarkiana</em> de Vries were pollinated after anthesis by insects. <em>Oe. biennis</em> L., <em>Oe. suaveolens</em> Desf and sulfurea were selfpollinated in the buds. Pollen morphology was slightly different: <em>Oe. hookeri</em> have regular, triporated pollen, often germinating through two pores; in <em>Oe. suaveolens</em> many pollen grains had callose patches on the intine; in <em>Oe. brevistylis</em> tetraporated pollen were more often than in other species; in <em>Oe. lamarckiana</em> many pollen grains were empty; in <em>Oe. biennis</em> and <em>Oe. suaveolens</em> pollen grain size and viability varied. The pollen tube growth and fertilization were similar in 5 species and can be considered as typical for <em>Oenothera</em>. In the ovary pollen tubes branched and changed their growth direction. Near micropyle they formed short branches to the inner integument. In the nucellus the pollen tube became swollen.

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