Pollen grains associated with gymnospermous mesofossils from the Jurassic of Uzbekistan

Zavialova, Natalia; Nosova, Natalya; Гаврилова, О. А.

doi:10.1016/j.revpalbo.2016.07.009

Cited by 10 publications

(4 citation statements)

References 17 publications

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“…As a result, we were not sure by LM observations whether the pollen grains are monosulcate or trisulcate (Figs. A–D), also keeping in mind that TEM observations revealed certain similarities to some trisulcate pollen grains of the Eucommiidites ‐type (Zavialova et al ., ). Surprisingly, TEM observations did not solve the problem, because it was difficult to differentiate between repeatedly folded exines of individual pollen grains (Fig.…”

Section: Resultsmentioning

confidence: 97%

“…We were able to measure roughly the exine thickness in the apertural and nonapertural areas even in a mechanically damaged pollen grain. The measurements of the total exine thickness in apertural and nonapertural regions obtained by CLSM do not contradict to those obtained by TEM (Zavialova et al ., ). However, CLSM did not reveal the exine sublayers as well as their ultrastructure and relative thicknesses: the three‐layered ectexine of a thick solid tectum, a thinner alveolate infratectum, a very thin foot layer and a homogeneous endexine were detected by TEM (Fig.…”

Section: Resultsmentioning

confidence: 97%

“…of the pollen grain, and to make measurements of some sculpture elements and, for some objects, exine layers. The main advantage of CLSM for such objects is its capacity to detect the exact location of all visible and concealed (inner) pollen structures in the sporoderm; this helps to correct description of the taxon and to choose necessary directions of further ultrathin sectioning for a TEM study, as it has been shown for modern and fossil angiosperms, particularly for pollen grains with a complicated morphology and for deformed pollen grains Zavialova et al, 2016).…”

Section: Application Of Clsm To Palynological Objectsmentioning

confidence: 99%

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Potential of CLSM in studying some modern and fossil palynological objects

Гаврилова

Zavialova

Tekleva

et al. 2017

Journal of Microscopy

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We have tested possibilities and limitations of confocal laser scanning microscopy to study the morphology of pollen and spores and inner structure of sporoderms. As test objects, we used pollen grains of the modern angiosperm Ribes niveum (Grossulariaceae) and Datura metel (Solanaceae), fossil angiosperm pollen grains of Pseudointegricorpus clarireticulatum and Wodehouseia spinata dated to the Late Cretaceous, fossil gymnosperm pollen grains of Cycadopites-type dated to the Middle Jurassic, and fossil megaspores Maexisporites rugulaeferus, M. grosstriletus, and Trileites sp. dated to the Early Triassic. For comparative purpose, we studied the same objects with application of conventional light, scanning electron (to entire pollen grains and spores or to semithin sections of their walls), or transmission electron microscopy. The resolution of confocal microscope is much lower than that of electron microscopes, as are its abilities to reconstruct the surface patterns and inner structure. On the other hand, it can provide information that is unreachable by other microscopical methods. Thus, the structure of endoapertures in angiosperm pollen grains can be directly observed. It is also helpful in studies of asymmetrical pollen and pollen grains bearing various appendages and having complicated exine structure, because rotation of 3-D reconstructions allows one to examine all sides and structures of the pollen grain. The exact location of all visible and concealed structures in the sporoderm can be detected; this information helps to describe the morphology and inner structure of pollen grains and to choose necessary directions of further ultrathin sectioning for a transmission electron microscopical study. In studies of fossil pollen grains that are preserved in clumps and stuck to cuticles, confocal microscope is useful in determining the number of apertures in individual pollen grains. This can be done by means of virtual sections through 3-D reconstructions of pollen grains. Fossil megaspores are too large and too thick-walled objects for a confocal study; however, confocal microscope was able to reveal a degree of compression of fossil megaspores, the presence of a cavity between the outer and inner sporoderm layers, and to get some information about sporoderm inner structure.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 97%

Section: Application Of Clsm To Palynological Objectsmentioning

confidence: 99%

See 1 more Smart Citation

Potential of CLSM in studying some modern and fossil palynological objects

Гаврилова

Zavialova

Tekleva

et al. 2017

Journal of Microscopy

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“…Determining the ecological significance of this shift is challenging, given that monosulcate pollen are produced by a range of unrelated plant groups (i.e. cycads, bennettites, ginkgophytes and 'seed-ferns' [Balme 1995]), covering a wide spectrum of ecological preferences (Zavialova et al 2016;Pott et al 2017). However, ginkgophyte macrofossils have been documented from the Karamay Formation (underlying the Huangshanjie Formation) of the Dalongkou Section (Zhou and Zhou 1986;Shi et al 2014Shi et al , 2015, and ginkgophyte and bennettite macrofossils have been recorded from the Huangshanjie Formation of a different locality (Sun et al 2001(Sun et al , 2010.…”

Section: Discussionmentioning

confidence: 99%

A Late Triassic vegetation record from the Huangshanjie Formation, Junggar Basin, China: possible evidence for the Carnian Pluvial Episode

Peng

Slater

Vajda

2022

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The Carnian Pluvial Episode (CPE; ∼234‒232 million years ago) is characterized by an accelerated hydrological cycle, global warming and a period of elevated biotic turnover. Using spores and pollen, we reconstruct vegetation and climate changes through a Carnian‒Norian (Upper Triassic) interval of the Huangshanjie Formation from the Junggar Basin, China. Four palynofloras were identified, representing distinct vegetation communities. Among these palynofloras, we observed a prominent shift from a conifer-dominated climax forest community, with common ginkgophytes and bennettites, to a fern-dominated community, suggestive of an environmental perturbation. We interpret this change as a regional shift in vegetation, likely caused by increased humidity, consistent with the CPE. Our records represent the first indication of a possible CPE-induced vegetation response in the Junggar Basin and highlight how this event likely affected floral communities of inland Laurasia.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5738637

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The morphology and ultrastructure of Jurassic in situ ginkgoalean pollen

Zavialova

Nosova

2019

Geobios

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Pollen grains associated with gymnospermous mesofossils from the Jurassic of Uzbekistan

Cited by 10 publications

References 17 publications

Potential of CLSM in studying some modern and fossil palynological objects

Potential of CLSM in studying some modern and fossil palynological objects

A Late Triassic vegetation record from the Huangshanjie Formation, Junggar Basin, China: possible evidence for the Carnian Pluvial Episode

The morphology and ultrastructure of Jurassic in situ ginkgoalean pollen

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