Supposedly Colpate Pollen Grains from the Jurassic

AbstractSome Mesozoic spores and pollen grains claimed in a recent publication to exhibit angiosperm-like features are discussed. It is suggested that Poroplanites Pflug, is actually a trilete fern spore. The “ germinal apparatus ” of the Poroplanites type is simply an optical section of the characteristic folding of a lobe of a trilete spore, flattened along the polar axis and seen in equatorial view. It is shown that Pflug's Poroplanites type can be reproduced almost exactly in the trilete spores of a living tree fern. Classopollis Pflug, Circumpollis Pflug, and Canalopollis Pflug are pollen grains with distinct annular thickening, similar to the pollen grains of the Jurassic araucarian, Pagiophyllum connivens Kendall.

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Impact of mid Eocene greenhouse warming on America’s southernmost floras

Communications Biology ◽

10.1038/s42003-021-01701-5 ◽

2021 ◽

Vol 4 (1) ◽

Cited By ~ 1

Author(s):

Damián A. Fernández ◽

Luis Palazzesi ◽

M. Sol González Estebenet ◽

M. Cristina Tellería ◽

Viviana D. Barreda

Keyword(s):

Middle Eocene ◽

Pollen Grains ◽

Late Eocene ◽

Significant Rise ◽

Spores And Pollen ◽

Deep Time ◽

Nonparametric Estimators ◽

Southern Patagonia ◽

Marine Realm ◽

High Diversity

AbstractA major climate shift took place about 40 Myr ago—the Middle Eocene Climatic Optimum or MECO—triggered by a significant rise of atmospheric CO2 concentrations. The biotic response to this MECO is well documented in the marine realm, but poorly explored in adjacent landmasses. Here, we quantify the response of the floras from America’s southernmost latitudes based on the analysis of terrestrially derived spores and pollen grains from the mid-late Eocene (~46–34 Myr) of southern Patagonia. Robust nonparametric estimators indicate that floras in southern Patagonia were in average ~40% more diverse during the MECO than pre-MECO and post-MECO intervals. The high atmospheric CO2 and increasing temperatures may have favored the combination of neotropical migrants with Gondwanan species, explaining in part the high diversity that we observed during the MECO. Our reconstructed biota reflects a greenhouse world and offers a climatic and ecological deep time scenario of an ice-free sub-Antarctic realm.

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An inverse relationship between moisture and grazing intensity in an arid mountain-basin system

Progress in Physical Geography Earth and Environment ◽

10.1177/03091333211060000 ◽

2021 ◽

pp. 030913332110600

Author(s):

Jun Zhang ◽

Xiao-zhong Huang ◽

Jia-le Wang ◽

Richard HW Bradshaw ◽

Tao Wang ◽

...

Keyword(s):

Arid Region ◽

Influencing Factor ◽

Regional Climate ◽

Fungal Spores ◽

Grazing Intensity ◽

Pollen Grains ◽

High Mountains ◽

Spores And Pollen ◽

The North ◽

Basin System

Precipitation has been suggested as a crucial influencing factor in the primary productivity in arid and semi-arid regions, yet how moisture fluctuation in an arid mountain-basin system of the north Qinghai–Tibetan Plateau has affected human activities is poorly understood. Here, we reconstruct the variations of grazing intensity in high elevations and regional humidity based on independent and high-resolution records of Sporormiella-type coprophilous fungal spores and pollen grains in the same well-dated sediment core from Lake Tian’E in the western Qilian Mountains over the past 3500 years. We find that stronger grazing activity was associated with low regional effective moisture, and propose that the drier regional climate pushed people and their livestock into the mountainous areas. A notable exception was a reduction of human and grazing activities in arid region with high mountains during 380–580 CE caused by centennial-length dry and cold conditions. In addition, it is also noteworthy that intensified grazing activity occurred during 580–720 CE and after ∼1920 CE, corresponding to a warmer and wetter climate and diverse subsistence strategies with social developments in the lowlands of the Hexi Corridor. Our findings potentially provide a historical reference for understanding how ancient people adapted to the climate change in arid region with high mountains.

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Pollen morphology and availability of pollen and stigma in Syzygium (Myrtaceae)

Revista Brasileira de Fruticultura ◽

10.1590/0100-29452019485 ◽

2019 ◽

Vol 41 (6) ◽

Author(s):

Guilherme Nacata ◽

Talita Kely Belonsi ◽

Eduardo Custódio Gasparino ◽

Renata Aparecida de Andrade

Keyword(s):

Flower Development ◽

Pollen Morphology ◽

Pollen Grains ◽

Scanning Microscopy ◽

Stigma Receptivity ◽

Equatorial View ◽

Equatorial Diameter ◽

Species Overlap ◽

Polar Diameter

Abstract The present study aimed to describe the pollen morphology in three species of Syzygium, to test pollen availability and stigma receptivity. The pollen was analyzed by light and scanning microscopy to show the detailed ornamentation of the pollen grains. Pollen availability was measured according to two protocols. Stigmatic receptivity was tested at different stages of flower development. There are differences among the pollen morphology for the species studied; when the polar and equatorial diameters are measured in the equatorial view of the pollen grains, it is observed that S. jambos is the largest species concerning the two values of the diameters, S. malaccense is the smallest species and S. aqueum, the largest species in relation to the polar diameter in the equatorial view. For the equatorial diameter in equatorial view, S. aqueum showed the smallest diameters and S. malaccense, the major diameters, but the two species overlap in the values of the measured diameters. There are variations in the number of apertures in the pollen grains. Alexander’s stain is more sensitive to estimate pollen availability and the species S. aqueum and S. jambos have the same schedules of pollen availability and stigma receptivity.

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The molecular structure of plant sporopollenin

10.1101/415612 ◽

2018 ◽

Author(s):

Fu-Shuang Li ◽

Pyae Phyo ◽

Joseph Jacobowitz ◽

Mei Hong ◽

Jing-Ke Weng

Keyword(s):

Molecular Structure ◽

Minor Component ◽

Pollen Grains ◽

Outer Wall ◽

Land Plant ◽

Spores And Pollen ◽

Biomimetic Polymers ◽

Wide Range ◽

Nmr Techniques ◽

A Minor

Sporopollenin is a ubiquitous and extremely chemically inert biopolymer that constitutes the outer wall of all land-plant spores and pollen grains. Sporopollenin protects the vulnerable plant gametes against a wide range of environmental assaults, and is considered as a prerequisite for the migration of early plants onto land. Despite its importance, the chemical structure of plant sporopollenin has remained elusive. Using a newly developed thioacidolysis degradative method together with state-of-the-art solid-state NMR techniques, we determined the detailed molecular structure of pine sporopollenin. We show that pine sporopollenin is primarily composed of aliphatic-polyketide-derived polyvinyl alcohol units and 7-O-p-coumaroylated C16 aliphatic units, crosslinked through a distinctive m-dioxane moiety featuring an acetal. Naringenin was also identified as a minor component of pine sporopollenin. This discovery answers the long-standing question about the chemical makeup of plant sporopollenin, laying the foundation for future investigations of sporopollenin biosynthesis and for design of new biomimetic polymers with desirable inert properties.

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Flowering Biology of Rhododendron pulchrum

Horticulturae ◽

10.3390/horticulturae7110508 ◽

2021 ◽

Vol 7 (11) ◽

pp. 508

Author(s):

Jie Qiu ◽

Chao Gao ◽

Hongli Wei ◽

Biao Wang ◽

Yang Hu ◽

...

Keyword(s):

Colorimetric Assay ◽

Pollen Viability ◽

Pollen Grains ◽

Experimental Period ◽

Polar Axis ◽

Flowering Phenology ◽

Mtt Colorimetric Assay ◽

Single Flower ◽

Axis Length ◽

To Receive

To study the flowering biology of Rhododendron pulchrum, we used scanning electron microscopy (SEM) and paraffin sectioning to observe the microstructures of its floral organs, a methyl thiazolyl tetrazolium (MTT) colorimetric assay to detect pollen viability in different periods, continuous observations to study flowering phenology, and artificial pollination and a benzidine-hydrogen peroxide method to determine stigma receptivity. R. pulchrum exhibited a centralized flowering phenology. The protogynous stigmas of R. pulchrum were able to receive pollen before flowering. The pollen grains of R. pulchrum fused into tetrads, the average ratio of the polar axis length to the equatorial axis length (P/E) was 1.05, and the pollen viability was highest in the initial flowering period, reaching 88.98%. The pollen/ovule (P/O) ratio was 266–328, and the outcrossing index (OCI) was 4; the vitality of R. pulchrum pollen remained high in the initial flowering and blooming periods. Compared with the lifespan of a single flower, pollen vitality remained high for most of the experimental period, thereby improving male fitness. The P/O ratio suggests that R. pulchrum may have a facultative outcrossing breeding system. The OCI estimation suggests that R. pulchrum is partially self-compatible, most likely requiring pollinators to complete pollination.

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Pollen morphology of the Balkan-Carpathian endemic Campanula lingulata Waldst. & Kit. (Campanulaceae)

Zbornik Matice srpske za prirodne nauke ◽

10.2298/zmspn1630075m ◽

2016 ◽

pp. 75-82

Author(s):

Marina Macukanovic-Jocic ◽

Snezana Jaric

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Light Microscopy ◽

Endemic Species ◽

Pollen Morphology ◽

Average Length ◽

Pollen Grains ◽

Polar Axis ◽

First Time ◽

Scanning Electron

Palynomorphological characteristics of Campanula lingulata, the Balkan-Carpathian endemic species growing in Serbia, have been investigated using light microscopy and scanning electron microscopy for the first time, in order to provide some information helpful for a better understanding of the taxonomic position of this species within the genus, as well as to contribute to the pollen atlas of Serbian apiflora. The pollen grains are radially symmetrical, isopolar, 3-zonoporate and medium-sized monads oblate-sphaeroidal in shape. Mean of the polar axis (P) is 27.6?1.9 ?m, while the average length of the equatorial axis (E) is 28.8?1.6 ?m. The apertures are operculate. The sculpturing pattern of the exine is microre?ticulate-microechinatae. The exine surface is covered with evenly distributed supratectal spinules of variable length and sparse granules. The longest supratectal spinules are 0.64?0.05 ?m in length and the smallest sculptural elements are less than 0.2 ?m high. The microechinae density per sample area of 5 ?m x 5 ?m averages 17.4?2.4.

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The Nossa Senhora da Luz flora from the Early Cretaceous (early Aptian-late Albian) of Juncal in the western Portuguese Basin

Acta Palaeobotanica ◽

10.2478/acpa-2018-0015 ◽

2018 ◽

Vol 58 (2) ◽

pp. 159-174 ◽

Cited By ~ 2

Author(s):

Mário Miguel Mendes ◽

Else Marie Friis

Keyword(s):

Early Cretaceous ◽

Pollen Grains ◽

Fossil Flora ◽

Spores And Pollen ◽

Fossil Assemblage ◽

Seasonally Dry ◽

Palynological Assemblage ◽

Conifer Seeds ◽

Angiosperm Pollen ◽

The Village

AbstractA new fossil flora is described from the Early Cretaceous of the western Portuguese Basin, based on a combined palynological-mesofossil study. The fossil specimens were extracted from samples collected in the Nossa Senhora da Luz opencast clay pit complex near the village of Juncal in the Estremadura region. The plant-bearing sediments belong to the Famalicão Member of the Figueira da Foz Formation, considered late Aptianearly Albian in age. The palynological assemblage is diverse, including 588 spores and pollen grains assigned to 30 genera and 48 species. The palynoflora is dominated by fern spores and conifer pollen. Angiosperm pollen is also present, but subordinate. The mesofossil flora is less diverse, including 175 specimens ascribed to 17 species, and is dominated by angiosperm fruits and seeds. The mesofossil flora also contains conifer seeds and twigs as well as fossils with selaginellaceous affinity. The fossil assemblage indicates a warm and seasonally dry climate for the Nossa Senhora da Luz flora.

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A LATE CRETACEOUS PLANT ASSEMBLAGE FROM EAST-CENTRAL BRITISH COLUMBIA: I, FOSSIL LEAVES

Canadian Journal of Earth Sciences ◽

10.1139/e67-080 ◽

1967 ◽

Vol 4 (6) ◽

pp. 1185-1197 ◽

Cited By ~ 10

Author(s):

G. E. Rouse

Keyword(s):

Pollen Grains ◽

Rocky Mountain ◽

The United States ◽

Spores And Pollen ◽

East Central ◽

Mountain Ranges ◽

Plant Assemblage ◽

The Pacific ◽

Fossil Leaves ◽

The Pacific Ocean

Leaf compressions, spores, and pollen grains referrable to about 45 species were collected from a series of fine silts and coal stringers in the Parsnip River valley of the Rocky Mountain Trench. The leaf assemblage described in this paper indicates a late Maestrichtian to Danian age, somewhat younger than generally comparable assemblages previously reported from the lower part of the Edmonton Formation of Alberta, and from the Hell Creek, Lance, and Fox Hills Formations in the western interior of the United States. It also contains several species reported from the Nanaimo Group on eastern Vancouver Island. Plant microfossils (to be described in a later paper) include species of Glyptostrobus, Sciadopitys, Aquilapollenites, Pistillipollenites, Alnus, Myrica, Tilia, Pterocarya, and Carya, together with tricolpate pollen of uncertain affiliation. The combined leaf and microfossil assemblages indicate a warm mesothermal and humid paleoecological setting of low relief, suggesting absence of major mountain ranges westward to the Pacific Ocean.

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Pollen morphology of chestnut cultivars in southern China by using scanning electron microscope

Bangladesh Journal of Botany ◽

10.3329/bjb.v49i1.49089 ◽

2020 ◽

Vol 49 (1) ◽

pp. 39-46

Author(s):

Huan Xiong ◽

De-Yi Yuan ◽

Ya Chen ◽

Genhua Niu ◽

Feng Zou

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

Southern China ◽

Morphological Characteristics ◽

Pollen Grains ◽

Polar Axis ◽

Upgma Tree ◽

Equatorial Diameter ◽

Components Analysis ◽

Scanning Electron

The morphological characteristics of pollen grains of 16 cultivars belonging to two species of the genus Castanea (Castanea mollissima and C. henryi) collected from southern China were observed by using scanning electron microscope (SEM). The length of polar axis (PL), the equatorial diameter (ED), the length of colpus (CL) of grain, P/E ratio (polar axis to equatorial diameter), P/C ratio (polar axis to colpus length), and C/E ratio (colpus length to equatorial diameter) were measured and their variations were compared among studied taxa. The result of this study indicated that chestnut pollen grain was a tricolporate in aperture type, and aperprolate type in equatorial view. The morphological characteristics were mainly represented by PL, ED and CL as revealed by principal components analysis, which accounted for 99.56% of the total variations. The cluster analysis by the UPGMA tree divided the taxa into three groups and showed a great morphological affinity among the 16 cultivars.

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