scholarly journals The evolution of desiccation tolerance in angiosperm plants: a rare yet common phenomenon

2013 ◽  
Vol 40 (4) ◽  
pp. 315 ◽  
Author(s):  
Donald F. Gaff ◽  
Melvin Oliver
Keyword(s):  
Desiccation Tolerance ◽  
Seed Plants ◽  
Common Phenomenon ◽  
Vegetative Tissue ◽  
Vegetative Cells ◽  
Evolutionary Path ◽  
Reproductive Structures ◽  
Drought Avoidance ◽  
Angiosperm Species ◽  
Derivatives Of

In a minute proportion of angiosperm species, rehydrating foliage can revive from airdryness or even from equilibration with air of ~0% RH. Such desiccation tolerance is known from vegetative cells of some species of algae and of major groups close to the evolutionary path of the angiosperms. It is also found in the reproductive structures of some algae, moss spores and probably the aerial spores of other terrestrial cryptogamic taxa. The occurrence of desiccation tolerance in the seed plants is overwhelmingly in the aerial reproductive structures; the pollen and seed embryos. Spatially and temporally, pollen and embryos are close ontogenetic derivatives of the angiosperm microspores and megaspores respectively. This suggests that the desiccation tolerance of pollen and embryos derives from the desiccation tolerance of the spores of antecedent taxa and that the basic pollen/embryo mechanism of desiccation tolerance has eventually become expressed also in the vegetative tissue of certain angiosperm species whose drought avoidance is inadequate in micro-habitats that suffer extremely xeric episodes. The protective compounds and processes that contribute to desiccation tolerance in angiosperms are found in the modern groups related to the evolutionary path leading to the angiosperms and are also present in the algae and in the cyanobacteria. The mechanism of desiccation tolerance in the angiosperms thus appears to have its origins in algal ancestors and possibly in the endosymbiotic cyanobacteria-related progenitor of chloroplasts and the bacteria-related progenitor of mitochondria. The mechanism may involve the regulation and timing of the accumulation of protective compounds and of other contributing substances and processes.

Actin During Pollen Germination

1986 ◽  
Vol 86 (1) ◽  
pp. 1-8
Author(s):  
J. HESLOP-HARRISON ◽  
Y. HESLOP-HARRISON ◽  
M. CRESTI ◽  
A. TIEZZI ◽  
F. CIAMPOLINI
Keyword(s):  
Medium Release ◽  
Pollen Tube ◽  
Vegetative Cell ◽  
Pollen Germination ◽  
Pollen Grain ◽  
Actin Microfilaments ◽  
Vegetative Cells ◽  
Stage Of Development ◽  
Angiosperm Species

The cytoplasm of the vegetative cell of the ungerminated pollen grain of Endymton non-scriplus and other angiosperm species contains numerous fusiform bodies sometimes exceeding 15μm in length and 2.5 μm in width, which bind fluorescent-labelled phalloidin and are likely therefore to constitute a storage form of actin. The bodies are dispersed during the activation of the pollen, being replaced by aggregates of slender phalloidin-binding fibrils, which converge towards the germination apertures and are present in the emerging pollen tube. The storage bodies appear to be homologous with crystalline-fibrillar structures, shown in an earlier paper to be abundantly present in the vegetative cells of Nicotiana pollen. These are composed of massive aggregates of linearly disposed units with individual widths of 4–7 nm, probably to be interpreted as actin microfilaments. Vegetative-cell protoplasts from mature but ungerminated pollen disrupted in osmotically balancing medium release extended phalloidin-binding fibrils of a kind not observed in the intact grain. It is suggested that these are derived by the rapid dissociation of the compact actin storage bodies present in the vegetative cell at this stage of development.

Percurrent proliferations in fungi, algae, and mosses

1971 ◽  
Vol 49 (2) ◽  
pp. 215-231 ◽  
Author(s):  
S. J. Hughes
Keyword(s):  
Red Algae ◽  
Common Phenomenon ◽  
Reproductive Structures

The production of new reproductive structures at the apex of successive percurrent proliferations is a common phenomenon in fungi. Successive sporangia and conidia in Phycomycetes, successive asci, conidia, phialides, and possibly 'gemmae' in Ascomycetes, and successive probasidia, basidia, and apparently urediniospores in Basidiomycetes, can be produced in this way. Examples of these are given from published accounts and some personal observations. Successive reproductive structures of various kinds are also formed on percurrent proliferations in 'green,' brown, and red algae. In the red algae successive antheridia can develop within empty ones by this method; it is concluded that such antheridia are not phialides. Successive gemmae in some mosses are formed terminally on percurrent proliferations.

scholarly journals Upper Carboniferous seed fern (Pteridospermophyta) pollen organs from Silesia (Poland) and related evolution considerations

2014 ◽  
Vol 100 ◽  
pp. 1-81 ◽  
Author(s):  
Grzegorz Pacyna ◽  
Danuta Zdebska
Keyword(s):  
New Species ◽  
New Genus ◽  
Radial Symmetry ◽  
Seed Plants ◽  
New Genus And Species ◽  
Typical Species ◽  
Reproductive Structures ◽  
The North ◽  
Compound Pollen ◽  
First Time

Extinct seed ferns (Pteridospermophyta) fill a key position in the evolutionary tree of seed plants. Their reproductive structures enable to recognition of the interrelationship within seed ferns and other seed plants descending from them. Seed fern reproductive structures from Poland are very rarely found and very poorly known, especially the pollen organs to which this paper is dedicated. A new genus and species <em>Silesiatheca formosa</em><em> </em>Pacyna &amp; Zdebska, gen. et sp. nov. of lyginopteridalean aggregated synangia was recognized based on specimens preserved within sideritic nodules from Sosnowiec. The genus <em>Codonotheca </em>is recognized from European Carboniferous for the first time. The least evolutionarily advanced species of <em>Codonotheca</em><em> </em>− <em>Codonotheca</em><em> silesiaca</em><em> </em>Pacyna &amp; Zdebska sp. nov., is described based on specimens with weakly expressed radial symmetry and slight fusion of the sporangia. this species matches the hitherto hypothetical simplest species of <em>Codonotheca </em>very well, constituting the initial form for all the more compound pollen organs of Medullosales. For the first time in the European Carboniferous the North American species <em>Aulacotheca campbellii </em>(White, 1900) Halle, 1933 is recognized. A new emended diagnosis for the typical species <em>Boulayatheca fertilis </em>(Kidston, 1914) Taylor &amp; Kurmann, 1985 is proposed, based on specimens from Poland. Two new species of genus <em>Boulayatheca </em>Taylor &amp; Kurmann, 1985 are recognized. <em>Boulayatheca ciliata </em>Pacyna &amp; Zdebska, sp. nov. with a synangium surface covered with hairs (a feature hitherto unknown in the <em>Boulayatheca </em>genus) and <em>Boulayatheca saganii </em>Pacyna &amp; Zdebska, sp. nov<em>. </em>with a markedly elongated synangium. Occurrence of <em>Whittleseya </em>Newberry, 1853a emend. Halle, 1933 typical species <em>− Whittleseya elegans </em>Newberry, 1853a was confirmed in Lower Silesia based on new specimens. Some specimens referred to earlier in the literature as <em>W. elegans </em>were ascribed here to the new species <em>W. silesiaca</em><em> </em>Pacyna &amp; Zdebska, sp. nov<em>.</em>, which differs from typical species in synangium shape and sporangia clustering into groups. The new species <em>Whittleseya campanulata </em>Pacyna &amp; Zdebska, sp. nov<em>. </em>has a large synangium and sporangia clustering into groups. Heterogeneity within the genus <em>Whittleseya </em>is recognized, where some species, including those new described here, probably formed compound synangia. The aggregated synangia of Medullosales are recognized in thecompression state of preservation for the first time they are the base for establishing a new genus and species <em>Kotasotheca annaeadamii </em>Pacyna &amp; Zdebska, gen. et sp. nov. The genus <em>Dolerotheca</em><em> </em>Halle, 1933 was recognized in the Polish Carboniferous for the first time and a new species <em>Dolerotheca migierii</em><em> </em>Pacyna &amp; Zdebska, sp. nov. was described. T.N. Taylor’s model of evolution of medullosalean pollen organs was confirmed, and the new taxa described were included within it.

Colourful cones: how did flower colour first evolve?

2019 ◽  
Vol 71 (3) ◽  
pp. 759-767 ◽  
Author(s):  
Paula J Rudall
Keyword(s):  
Colour Vision ◽  
Flower Colour ◽  
Flowering Plants ◽  
Seed Plants ◽  
Plant Tissues ◽  
Secondary Effect ◽  
Reproductive Structures ◽  
Seed Cone ◽  
Evolutionary Pathways ◽  
Flower Pigments

Abstract Angiosperms that are biotically pollinated typically produce flowers with bright and contrasting colours that help to attract pollinators and hence contribute to the reproductive success of the species. This colourful array contrasts with the much less multicoloured reproductive structures of the four living gymnosperm lineages, which are mostly wind pollinated, though cycads and Gnetales are predominantly pollinated by insects that feed on surface fluids from the pollination drops. This review examines the possible evolutionary pathways and cryptic clues for flower colour in both living and fossil seed plants. It investigates how the ancestral flowering plants could have overcome the inevitable trade-off that exists between attracting pollinators and minimizing herbivory, and explores the possible evolutionary and biological inferences from the colours that occur in some living gymnosperms. The red colours present in the seed-cone bracts of some living conifers result from accumulation of anthocyanin pigments; their likely primary function is to help protect the growing plant tissues under particular environmental conditions. Thus, the visual cue provided by colour in flower petals could have first evolved as a secondary effect, probably post-dating the evolution of bee colour vision but occurring before the subsequent functional accumulation of a range of different flower pigments.

scholarly journals Highly Conserved Evolution of Aquaporin PIPs and TIPs Confers Their Crucial Contribution to Flowering Process in Plants

2022 ◽  
Vol 12 ◽  
Author(s):  
Qi Li ◽  
Tao Tong ◽  
Wei Jiang ◽  
Jianhui Cheng ◽  
Fenglin Deng ◽  
...  
Keyword(s):  
Small Molecules ◽  
Expression Profiling ◽  
Transmembrane Proteins ◽  
Evolutionary Conservation ◽  
Seed Plants ◽  
Genome Wide Analysis ◽  
Genome Wide ◽  
Angiosperm Species ◽  
Opening And Closing ◽  
Flowering Process

Flowering is the key process for the sexual reproduction in seed plants. In gramineous crops, the process of flowering, which includes the actions of both glume opening and glume closing, is directly driven by the swelling and withering of lodicules due to the water flow into and out of lodicule cells. All these processes are considered to be controlled by aquaporins, which are the essential transmembrane proteins that facilitate the transport of water and other small molecules across the biological membranes. In the present study, the evolution of aquaporins and their contribution to flowering process in plants were investigated via an integration of genome-wide analysis and gene expression profiling. Across the barley genome, we found that HvTIP1;1, HvTIP1;2, HvTIP2;3, and HvPIP2;1 were the predominant aquaporin genes in lodicules and significantly upregulated in responding to glume opening and closing, suggesting the importance of them in the flowering process of barley. Likewise, the putative homologs of the above four aquaporin genes were also abundantly expressed in lodicules of the other monocots like rice and maize and in petals of eudicots like cotton, tobacco, and tomato. Furthermore, all of them were mostly upregulated in responding to the process of floret opening, indicating a conserved function of these aquaporin proteins in plant flowering. The phylogenetic analysis based on the OneKP database revealed that the homologs of TIP1;1, TIP1;2, TIP2;3, and PIP2;1 were highly conserved during the evolution, especially in the angiosperm species, in line with their conserved function in controlling the flowering process. Taken together, it could be concluded that the highly evolutionary conservation of TIP1;1, TIP1;2, TIP2;3 and PIP2;1 plays important roles in the flowering process for both monocots and eudicots.

scholarly journals An interactive key (Lucid) for the identifying of the genera of seed plants from the Ducke Reserve, Manaus, AM, Brazil

Rodriguésia ◽  
2012 ◽  
Vol 63 (1) ◽  
pp. 055-064 ◽  
Author(s):  
Volker Bittrich ◽  
Clara Sampaio D. Souza ◽  
Rubens L.G. Coelho ◽  
Milena V. Martins ◽  
Michael J.G. Hopkins ◽  
...  
Keyword(s):  
Seed Plants ◽  
Seed Plant ◽  
Electronic Publication ◽  
Field Guide ◽  
Reproductive Structures ◽  
The Poor ◽  
On Line ◽  
Vegetative Characters ◽  
Amazonian Brazil ◽  
Reproductive Characters

The identification of Amazonian plants is still difficult for many reasons, one being the lack of collections over large areas of the region. As a consequence of the poor knowledge on the Amazonian flora, many taxonomic publications (revisions and floristic treatments) become out of date within a few years. In this context, the on-line publication of taxonomic treatises has been suggested, since it allows constant data updates; and this type of publication should therefore be more valued by the scientific community. An excellent field guide for the Ducke Reserve (Manaus, central Amazonian Brazil) was published, based exclusively on vegetative characters. However, the presence of reproductive structures in the collected material does not facilitate identification with this type of field guide. Furthermore, as in any printed key, the text cannot be updated, except through a new edition. As an example of a way to facilitate the identification of Amazonian plants, an interactive, multiple-entry key to the seed plant genera that occur in the Ducke Reserve was created using the program Lucid 3.5. The key includes vegetative and reproductive characters and many illustrations, and is available on-line. We discuss here the peculiarities and advantages of this type of electronic publication.

scholarly journals Caracterización preliminar de una secuencia homóloga del gen LEAFY en gimnospermas (Pinus radiata Lemm.)

2017 ◽  
pp. 7
Author(s):  
Liz Y. Izquierdo ◽  
Rosalinda Tapia ◽  
Francisco Vergara ◽  
Elena Álvarez-Buylla
Keyword(s):  
Dna Sequences ◽  
Genomic Dna ◽  
Higher Plants ◽  
Structural Complexity ◽  
Homologous Sequence ◽  
Seed Plants ◽  
Seed Plant ◽  
Inflorescence Development ◽  
Reproductive Structures ◽  
Molecular Components

A fragment from an homologous sequence of LEAFY (LFY) gene that encodes for a transcription factor involved in early events during inflorescence development was cloned from genomic DNA of P. radiata, a non flowering seed plant. Using PCR technic we amplified an 85 bp fragment flanked by two primers designed from some DNA sequences obtained from different species of angiosperms. The fragment obtained was.highly similar to A. thaliana gene LFY between 5077 and 5143 bases and hybridized with a LFY clone from this species. This result suggests that sorne molecular components of the functional and structural complexity of the development of reproductive structures in higher plants are an ancestral property of seed plants and not a novelty in the angiosperm lineage.

scholarly journals Areas of Endemism of Selected Seed Plants in Southcentral and Southwestern USA

2021 ◽  
Author(s):  
Anna Saghatelyan
Keyword(s):  
Spatial Patterns ◽  
Large Scale ◽  
Seed Plants ◽  
Native Seed ◽  
Areas Of Endemism ◽  
Southwestern Usa ◽  
Plant Spatial Patterns ◽  
Angiosperm Species ◽  
North America North ◽  
Plant Specimen

Areas of endemism (AEs) are fundamental entities of analysis in biogeography and a key step for biogeographical regionalization. Even though many studies have contributed to the biogeographical knowledge of southern USA flora, no endemicity analysis (EA) has been conducted that would include a large number of native seed plant species from different families. A new analysis of plant spatial patterns is important as a first step for a future updated floristic regionalization of North America North of Mexico. It has become easier to accomplish owing to the increased availability of large-scale digitized distributional data and statistical methods of biogeographic analysis. Here we identify the AEs in SC/SW USA using digitized plant specimen data available from IDigBio. We built a database with 81,851-specimen point records of 400 selected mostly angiosperm species and applied the NDM/VNDM method of endemicity analysis. We then compare the established 26 AEs in the area of study with the floristic provinces in two comparatively recent regionalization systems of USA. To understand the spatial patterns, we also pay attention to the information on relationships of the endemic species found in phylogenetic literature.

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