Morphological, developmental and ultrastructural comparison of Osmunda regalis L. spores with spore mimics

Moore, Susannah; Gabarayeva, Nina I.; Hemsley, Alan R.

doi:10.1016/j.revpalbo.2008.12.010

Cited by 22 publications

(7 citation statements)

References 16 publications

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“…; Moore et al, 2009: Osmunda regalis L.; Blackmore et al, 2010: Compositae;Gabarayeva & Grigorjeva, 2010: Chamaedorea microspadix Burret, Swida alba (L.) Opiz in Bercht. et Opiz, Magnolia sieboldii K.Koch).…”

Section: Modelling Of Exine 243unclassified

“…However, the best proof of this hypothesis would be experimental modelling of spore and microspore sporoderm-like patterns in vitro. The first series of such experiments was undertaken by Hemsley and co-authors (Hemsley et al, 1996(Hemsley et al, , 2003Griffiths & Hemsley, 2001;Moore et al, 2009). These authors used special techniques for their experiments and selected a number of components, including polystyrene in place of SP .…”

Section: Modelling Of Exine 243mentioning

confidence: 99%

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Experimental modelling of exine-like structures

Gabarayeva

Grigorjeva

2013

Grana

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Section: Modelling Of Exine 243unclassified

Section: Modelling Of Exine 243mentioning

confidence: 99%

Experimental modelling of exine-like structures

Gabarayeva

Grigorjeva

2013

Grana

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“…Summarizing the results from previous experiments modelling spore‐like patterns (Hemsley et al ., 1996b, 1998, 2003; Hemsley and Griffiths, 2000; Griffiths and Hemsley, 2001; Moore et al ., 2009), from computational modelling experiments (Lavrentovich et al ., 2016; Plourde et al ., 2019; Radja et al ., 2019), from our previous experimental data (Gabarayeva and Grigorjeva, 2013, 2016, 2017; Gabarayeva et al ., 2019a,c) and from the data in this study, the evidence suggests that previously underestimated physical processes play a considerable role in pollen wall development alongside the role of the genome.…”

Section: Resultsmentioning

confidence: 99%

An integral insight into pollen wall development: involvement of physical processes in exine ontogeny inCalycanthus floridusL., with an experimental approach

Gabarayeva

Grigorjeva

2020

The Plant Journal

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Summary We aimed to understand the underlying mechanisms of development in the sporopollenin‐containing part of the pollen wall, the exine, one of the most complex cell walls in plants. Our hypothesis is that distinct physical processes, phase separation and micellar self‐assembly, underpinexine development by taking the molecular building blocks, determined and synthesised by the genome, through several phase transitions. To test this hypothesis, we traced each stage of microspore development in Calycanthus floridus with transmission electron microscopy and then generated in vitro experimental simulations corresponding to every developmental stage. The sequence of structures observed within the periplasmic space around developing microspores starts with spherical units, which are rearranged into columns to then form rod‐like units (the young columellae) and, finally, white line centred endexine lamellae. Phase separation precedes each developmental stage. The set of experimental simulations, obtained as self‐assembled micellar mesophases formed at the interface between lipid and water compartments, was the same: spherical micelles; columns of spherical micelles; cylindrical micelles; and laminate micelles, separated by gaps, resembling white‐lined lamellae. Thus, patterns simulating structures observed at the main stages of exine development in C. floridus were obtained from in vitro experiments, and hence purely physicochemical processes can construct exine‐like patterns. This highlights the important part played by physical processes that are not under direct genomic control and share influence on the emerging ultrastructure with the genome during exine development. These findings suggest that a new approach to ontogenetic studies, including a consideration of physical factors, is required for a better understanding of developmental processes.

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“…The hypothesis was based on earlier self-assembly ideas (Hemsley et al 1992;Gabarayeva 1993), on reconsideration of our results from the study of the pollen wall ontogeny of a number of angiosperms and gymnosperms performed before 2006 and on experiments modelling artificial sporoderm (Hemsley et al 1996a(Hemsley et al , 1998Moore et al 2009). The hypothesis was supported (Blackmore et al 2007) and shared (Blackmore et al 2010).…”

Section: Tapetum Developmentmentioning

confidence: 93%

“…This idea was worked out in the field of sporoderm development (Gerasimova-Navashina 1973;van Uffelen 1991;Hemsley et al 1992;Collinson et al 1993;Gabarayeva 1993; and received some confirmation in modelling experiments (Hemsley et al 1996a(Hemsley et al , b, 1998(Hemsley et al , 2003Griffiths and Hemsley 2001;Moore et al 2009). Our recent hypothesis develops the self-assembling idea in that all the processes of exine development in the periplasmic space are based on unfolding the sequence of the micellar mesophase of surface-active substances (Gabarayeva and Hemsley 2006;Hemsley and Gabarayeva 2007).…”

Section: Introductionmentioning

confidence: 96%

I. Primexine development in Passiflora racemosa Brot.: overlooked aspects of development

2013

Self Cite

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Developmental stages during the tetrad period were examined in detail by transmission electron microscopy with an emphasis on substructure. Our purpose was to find out whether the sequence of sporoderm developmental events provides additional evidence for our recent hypothesis on the underlying cause of exine ontogeny as a sequence of self-assembling micellar mesophases initiated by genomically given physicochemical parameters. Osmiophilic globules encrusting the surface of postmeiotic microspores and tapetal cells are temporary prepattern units which come first. The second prepattern structures are highly ordered bundles of microfilaments and microtubules which determine the position of microspore surface invaginations and clusters of the glycocalyx inside them. The first glycocalyx units are microgranules which during the middle tetrad stage rearrange into radially oriented rodlike units. The latter form lens-like clusters of the glycocalyx-1, located inside the invaginations. These clusters predestine the position of the future luminae in the exine reticulum. The second glycocalyx layer is laid down as a continuous layer over the whole microspore surface and has similar substructure, that is radial rods. Glycocalyx-2 is a framework for procolumellae which appear at the late tetrad stage. Therefore, the sequence of substructural units in the primexine is: globules, microgranules, rod-like units, and layers of radially oriented rods tightly packed in the periplasmic space. This sequence corresponds to the first three mesophases of self-assembling micelles: spherical micelles, cylindrical micelles, and layers of hexagonally packed cylindrical micelles (middle mesophase). We observed the same sequence in other species during primexine development, and the findings of this study provide new evidence for our hypothesis.

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Morphological, developmental and ultrastructural comparison of Osmunda regalis L. spores with spore mimics

Cited by 22 publications

References 16 publications

Experimental modelling of exine-like structures

Experimental modelling of exine-like structures

An integral insight into pollen wall development: involvement of physical processes in exine ontogeny inCalycanthus floridusL., with an experimental approach

I. Primexine development in Passiflora racemosa Brot.: overlooked aspects of development

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