Artículos de revistas: "Plants Angiosperms Dimorphism (Plants)"

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Barrett, Spencer C. H. y Andrea L. Case. "The ecology and evolution of gender strategies in plants: the example of Australian Wurmbea (Colchicaceae)". Australian Journal of Botany 54, n.º 5 (2006): 417. http://dx.doi.org/10.1071/bt05151.

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Angiosperms possess diverse sexual systems, often with different combinations of hermaphroditic, pistillate and staminate flowers. Despite this sexual diversity, most populations are either monomorphic or dimorphic with respect to gender strategy, where gender refers to the relative contribution that individuals make to fitness through female and male function. An important problem in evolutionary biology is to determine how and why variation in gender strategies originates and is maintained. Wurmbea (Colchicaceae), a genus of insect-pollinated geophytes, has recently become the focus of ecological and evolutionary studies aimed at understanding these issues. Phylogenetic reconstructions suggest dispersal from Africa to Australia, then New Zealand, and multiple transitions between monomorphic and dimorphic sexual systems within Australia. Microevolutionary studies of W. dioica and W. biglandulosa, two wide-ranging taxa with monomorphic and dimorphic populations, provide insights into the selective mechanisms governing transitions between sexual systems. Dimorphic populations of these taxa likely comprise independent origins of dimorphism via the gynodioecious pathway by invasion of females into monomorphic populations. Shifts in pollination biology and flower size, and their consequent effects on mating patterns, may have contributed to the evolution of gender dimorphism. Pollinator-mediated selfing and inbreeding depression provide a sufficient fertility advantage for females to be maintained in dimorphic populations. Once dimorphism establishes, increasing gender specialisation is associated with invasion of more arid environments. Inbreeding avoidance, particularly under stressful ecological conditions, is the most likely selective mechanism maintaining gender dimorphism in Wurmbea. We conclude our review by suggesting avenues for future research that might provide a more comprehensive picture of the evolution of gender strategies in Wurmbea.

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Cossard, Guillaume G., Melissa A. Toups y John R. Pannell. "Sexual dimorphism and rapid turnover in gene expression in pre-reproductive seedlings of a dioecious herb". Annals of Botany 123, n.º 7 (4 de octubre de 2018): 1119–31. http://dx.doi.org/10.1093/aob/mcy183.

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Abstract Background and Aims Sexual dimorphism in morphology, physiology or life history traits is common in dioecious plants at reproductive maturity, but it is typically inconspicuous or absent in juveniles. Although plants of different sexes probably begin to diverge in gene expression both before their reproduction commences and before dimorphism becomes readily apparent, to our knowledge transcriptome-wide differential gene expression has yet to be demonstrated for any angiosperm species. Methods The present study documents differences in gene expression in both above- and below-ground tissues of early pre-reproductive individuals of the wind-pollinated dioecious annual herb, Mercurialis annua, which otherwise shows clear sexual dimorphism only at the adult stage. Key Results Whereas males and females differed in their gene expression at the first leaf stage, sex-biased gene expression peaked just prior to, and after, flowering, as might be expected if sexual dimorphism is partly a response to differential costs of reproduction. Sex-biased genes were over-represented among putative sex-linked genes in M. annua but showed no evidence for more rapid evolution than unbiased genes. Conclusions Sex-biased gene expression in M. annua occurs as early as the first whorl of leaves is produced, is highly dynamic during plant development and varies substantially between vegetative tissues

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Carlquist, Sherwin. "How wood evolves: a new synthesis". Botany 90, n.º 10 (octubre de 2012): 901–40. http://dx.doi.org/10.1139/b2012-048.

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Recent advances in wood physiology, molecular phylogeny, and ultrastructure (chiefly scanning electron microscopy, SEM), as well as important new knowledge in traditional fields, provide the basis for a new vision of how wood evolves. Woody angiosperms have, in the main, shifted from conductive safety to conductive efficiency (with many variations and modifications) and from ability to resist cavitation (low vulnerability) to ability to refill vessels. The invention of the vessel was a kind of dimorphism (vessel elements plus tracheids) that permitted division of labor and many kinds of wood repatterning that suit conductive safety–efficiency trade-offs. Angiosperms were primarily adapted to mesic habitats but were not failures or “unstable.” They have survived to the present in such habitats well, along with older structural adaptations (e.g., the scalariform perforation plate) that are still suited to such habitats. These “primitive” features are evident in earlier branchings of phylogenetic trees based on multiple genes. Older features may still be functional and thus persist, although newer formulations are overriding in effect. There are, however, numerous instances of “breakouts” in a number of clades (ecological iterations and bursts of speciation and diversification related to new ways of dealing with water economy), whereas in other branchings, other clades show ecological stasis over long periods of time. Newer physiological and anatomical mechanisms have permitted entry into habitats with marked fluctuation in moisture availability. Wood evolves progressively, and literal character state reversal may be unusual: genomic and developmental information holds answers to these changes. Wood is a complex tissue, and each of the histological components shows polymorphism as an evolutionary mechanism. Cell types within wood evolve collaboratively. Shifts in wood features (e.g., simplification of the scalariform perforation plate) are commonly homoplastic. Manifold changes in habit and in leaf physiology, morphology, and anatomy accompany wood evolution, and wood should be studied with relationship to real-world ecology, information that cannot be gleaned from literature or other secondary sources. Heterochrony (protracted juvenilism, accelerated adulthood) characterizes angiosperm xylem extensively, far more so than in other vascular plants, and these mechanisms have resulted in many remarkable changes (e.g., monocots have permanently juvenile xylem, woody trees represent accelerated adulthood). Understanding the many successful features of angiosperm wood evolution must ultimately rest on syntheses.

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Draper, Jenna T., John G. Conran, Nicholas Crouch, Philip Weinstein y Bradley S. Simpson. "Sexual dimorphism in the dioecious monocot Lomandra leucocephala ssp. robusta and its potential ecosystem and conservation significance". Australian Journal of Botany 68, n.º 4 (2020): 275. http://dx.doi.org/10.1071/bt20006.

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Dioecious plants constitute 7% of all angiosperm species, yet they occur in many habitat types, partially through the deployment of sexual dimorphisms that assist in reproduction. In the present work, the dioecious monocot Lomandra leucocephala ssp. robusta (Asparagaceae: Lomandroideae) was studied to understand how sexual dimorphisms can assist species conservation and inform us of a species’ potential significance in an ecosystem. Floral display was sexually dimorphic, as male inflorescences were displayed more prominently and more conspicuously in UV range. Male nectar analysed by thin-layer chromatography contained a higher glucose content than female nectar. However, both sexes contained hexose-rich nectar, a common indicator of generalist pollination, which was supported by observations of floral visitors. Floral extract comparison conducted via gas chromatography-mass spectrometry showed that male extracts contained more compounds that potentially convey greater resistance to biotic and abiotic threats. Chemical comparison of leaves by high performance liquid chromatography with peak area ratio analysis revealed this technique could be used as a tool for gender identification of individuals during non-flowering periods. Due to the generalist pollination mechanisms of L. leucocephala ssp. robusta, may have an important role in the conservation and support of local insect populations. The presence of chemical biotic and abiotic resistance may also make L. leucocephala ssp. robusta a significant contributor to the ongoing stabilisation of the sand dunes. Conservation efforts required for L. leucocephala ssp. robusta are likely to be minimal, as pollination services are provided by a diversity of pollinating taxa, including introduced species, which will be abundant regardless of variable flowering periods. Further observational study of L. leucocephala ssp. robusta pollinators and differences in pollinator visitation behaviours between sexes is recommended to better understand efficient pollination for the species, and potentially reveal a greater extent of ecosystem benefit for this species.

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Pignone, Domenico y Karl Hammer. "Parasitic angiosperms as cultivated plants?" Genetic Resources and Crop Evolution 63, n.º 7 (1 de julio de 2016): 1273–84. http://dx.doi.org/10.1007/s10722-016-0416-x.

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Barrett, Spencer C. H. y Josh Hough. "Sexual dimorphism in flowering plants". Journal of Experimental Botany 64, n.º 1 (25 de noviembre de 2012): 67–82. http://dx.doi.org/10.1093/jxb/ers308.

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Mathews, Sarah, Mark D. Clements y Mark A. Beilstein. "A duplicate gene rooting of seed plants and the phylogenetic position of flowering plants". Philosophical Transactions of the Royal Society B: Biological Sciences 365, n.º 1539 (12 de febrero de 2010): 383–95. http://dx.doi.org/10.1098/rstb.2009.0233.

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Flowering plants represent the most significant branch in the tree of land plants, with respect to the number of extant species, their impact on the shaping of modern ecosystems and their economic importance. However, unlike so many persistent phylogenetic problems that have yielded to insights from DNA sequence data, the mystery surrounding the origin of angiosperms has deepened with the advent and advance of molecular systematics. Strong statistical support for competing hypotheses and recent novel trees from molecular data suggest that the accuracy of current molecular trees requires further testing. Analyses of phytochrome amino acids using a duplicate gene-rooting approach yield trees that unite cycads and angiosperms in a clade that is sister to a clade in which Gingko and Cupressophyta are successive sister taxa to gnetophytes plus Pinaceae. Application of a cycads + angiosperms backbone constraint in analyses of a morphological dataset yields better resolved trees than do analyses in which extant gymnosperms are forced to be monophyletic. The results have implications both for our assessment of uncertainty in trees from sequence data and for our use of molecular constraints as a way to integrate insights from morphological and molecular evidence.

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Ribeiro, Ana, Alison M. Berry, Katharina Pawlowski y Patrícia Santos. "Actinorhizal plants". Functional Plant Biology 38, n.º 9 (2011): v. http://dx.doi.org/10.1071/fpv38n9_fo.

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Actinorhizal plants are a group of taxonomically diverse angiosperms with remarkable economic and ecological significance. Most actinorhizal plants are able to thrive under extreme adverse environmental conditions as well as to fix atmospheric nitrogen due to their capacity to establish root nodule symbioses with Frankia bacteria. This special issue of Functional Plant Biology is dedicated to actinorhizal plant research, covering part of the work presented at the 16th International Meeting onFrankia and Actinorhizal Plants, held on 5–8 September 2010, in Oporto, Portugal. The papers (4 reviews and 10 original articles) give an overall picture of the status of actinorhizal plant research and the imposed challenges, covering several aspects of the symbiosis, ecology and molecular tools.

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Jiao, Yuannian, Norman J. Wickett, Saravanaraj Ayyampalayam, André S. Chanderbali, Lena Landherr, Paula E. Ralph, Lynn P. Tomsho et al. "Ancestral polyploidy in seed plants and angiosperms". Nature 473, n.º 7345 (10 de abril de 2011): 97–100. http://dx.doi.org/10.1038/nature09916.

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Yoshida, Hideki, Sayaka Takehara, Masaki Mori, Reynante Lacsamana Ordonio y Makoto Matsuoka. "Evolution of GA Metabolic Enzymes in Land Plants". Plant and Cell Physiology 61, n.º 11 (13 de octubre de 2020): 1919–34. http://dx.doi.org/10.1093/pcp/pcaa126.

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Abstract Gibberellins (GAs) play key roles in various developmental processes in land plants. We studied the evolutionary trends of GA metabolic enzymes through a comprehensive homology search and phylogenetic analyses from bryophytes to angiosperms. Our analyses suggest that, in the process of evolution, plants were able to acquire GA metabolic enzymes in a stepwise manner and that the enzymes had rapidly diversified in angiosperms. As a good example of their rapid diversification, we focused on the GA-deactivating enzyme, GA 2-oxidase (GA2ox). Although the establishment of a GA system first occurred in lycophytes, its inactivation system mediated by GA2oxs was established at a much later time: the rise of gymnosperms and the rise of angiosperms through C19-GA2ox and C20-GA2ox development, respectively, as supported by the results of our direct examination of their enzymatic activities in vitro. Based on these comprehensive studies of GA metabolic enzymes, we discuss here that angiosperms rapidly developed a sophisticated system to delicately control the level of active GAs by increasing their copy numbers for their survival under different challenging environments.

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Caruso, Christina M. "Sexual dimorphism in floral traits of gynodioecious Lobelia siphilitica (Lobeliaceae) is consistent across populations". Botany 90, n.º 12 (diciembre de 2012): 1245–51. http://dx.doi.org/10.1139/b2012-094.

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In angiosperms, the evolution of gender dimorphism is often correlated with the evolution of sexual dimorphism in floral traits. The magnitude of sexual dimorphism will reflect both sex-specific selection and constraints on evolution in response to this selection. If the evolution of sexual dimorphism is constrained by genetic correlations, then trait means are predicted to evolve more quickly than the magnitude of sexual dimorphism in the same traits. To test whether mean floral traits evolve more quickly than sexual dimorphism in these traits, I measured flower size and flower number of gynodioecious Lobelia siphilitica L. from 10–14 populations across the species’ range. Females produced more flowers than hermaphrodites, but neither mean flower number nor the magnitude of dimorphism in flower number varied among populations. Pistillate flowers were smaller than perfect flowers, and mean flower size varied among populations. However, the magnitude of dimorphism in flower size did not vary. My results suggest that the evolution of sexual dimorphism in flower size, but not necessarily flower number, could be constrained by within- or between-sex genetic correlations in L. siphilitica.

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Ahmad, Imtiaz, Mohammad Ibrar, Barkatullah y Niaz Ali. "Ethnobotanical Study of Tehsil Kabal, Swat District, KPK, Pakistan". Journal of Botany 2011 (8 de diciembre de 2011): 1–9. http://dx.doi.org/10.1155/2011/368572.

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A total of 140 plants have been reported ethnobotanically from Tehsil Kabal, Swat District. These include the 133 plants (95%) of angiosperms, 3 (2.14%) of gymnosperms, and 2 (1.42%) each of pteridophytes and fungi. The largest family is Lamiaceae represented by 11 species followed by Rosaceae represented by 9 species. Among angiosperms 76 (55.63%) were herbs, 17 (12.78%) were shrubs, and 40 (30.07%) were trees; 127 plants (95.48%) were dicot while 6 plants (4.51%) were monocot. Most of the plants were used for more than one purpose. Generally the plants were used for medicinal, fuel, timber wood, food, and fodder for cattle purposes.

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Cichan, Michael A. "Conductance in the wood of selected Carboniferous plants". Paleobiology 12, n.º 3 (1986): 302–10. http://dx.doi.org/10.1017/s0094837300013804.

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Specific conductance was calculated for secondary xylem in seven Carboniferous stem taxa utilizing an equation derived from the Hagen-Poiseuille relation. Arborescent and lianoid representatives of major pteridophytic (Calamitaceae, Lepidodenraceae, Sphenophyllaceae) and gymnospermous (Cordaitaceae, Medullosaceae) groups were examined. In the calamite Arthropitys communis and the seed plant Cordaites (Cordaixylon sp. and Mesoxylon sp.), conductance corresponded approximately to the low end of the range for both extant conifers and angiosperms. A substantially higher conductance was determined for the wood of Arthropitys deltoides, conforming to the high end of the range for conifers and the low-middle part of the range for angiosperms. The highest conductance values were found in Sphenophyllum plurifoliatum, Medullosa noei, and Paralycopodites brevifolius and corresponded to the middle-high portion of the range for vessel-containing angiosperms. This outcome is particularly significant in light of the fact that tracheary elements in the fossils are imperforate. The results indicate that conductance in secondary xylem of some of the most ancient, woody groups was comparable to that in extant plants and that highly effective conducting tissue developed relatively early in plant evolution. Moreover, it is suggested that the general relationship between wood anatomy, growth habit, and ecology demonstrated for living plants can also be extended back in time to include fossil plants.

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Geber, Monica A. "Fitness effects of sexual dimorphism in plants". Trends in Ecology & Evolution 10, n.º 6 (junio de 1995): 222–23. http://dx.doi.org/10.1016/s0169-5347(00)89068-0.

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Wen, Yin, Wan-li Zhao y Kun-fang Cao. "Global convergence in the balance between leaf water supply and demand across vascular land plants". Functional Plant Biology 47, n.º 10 (2020): 904. http://dx.doi.org/10.1071/fp19101.

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Coordination between the density of veins (water supply) and stomata (demand for water) has been found in the leaves of modern angiosperms and also in ferns. This suggests that this coordinated development is not a unique adaptation of derived angiosperms that enables their high productivity. To test this, we compiled leaf vein and stomatal density data from 520 land vascular plant species including derived angiosperms, basal angiosperms, gymnosperms and ferns. We found global coordination across vascular land plants, although the relationships were not significant in gymnosperms and vessel-less angiosperms. By comparing the evolution of xylem conduit elements with variation in the density of veins and stomata and theoretical stomatal conductance among plant lineages, we found that the physiological advantage of modern angiosperms is associated with the emergence of xylem with low intraconduit resistance and leaves with high vein and stomata densities. Thus our results indicate two major events associated with surges in xylem hydraulic capacity in angiosperms: (1) the origin of vessels and (2) the emergence of vessels with simple perforation plates, which diminished physical limitations on stomatal conductance. These evolutionary innovations may have enabled derived angiosperms to be more productive and adaptive to the changing climate.

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Asker, Sven. "Viewpoints on apornictic and sexual reproduction in angiosperms". Acta Societatis Botanicorum Poloniae 50, n.º 1-2 (2014): 195–99. http://dx.doi.org/10.5586/asbp.1981.031.

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Gametophytic apomixis implies different changes of the reproductive cycle of sexual plants. Each of these "elements of apomixis" occurs in sexual plants, which may even display functional diploid parthenogenesis. Thus, apomixis, like vegetative reproduction, is part of the reproductive behaviour of sexual plants, becoming important when sexual reproduction is impaired. The elements of apomixis are probably to a large extent under polygenic control.

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Herman, A. B., V. V. Kostyleva, P. A. Nikolskii, A. E. Basilyan y A. E. Kotel’nikov. "New data on the late cretaceous flora of the New Siberia island, New Siberian Islands". Стратиграфия 27, n.º 3 (22 de abril de 2019): 53–69. http://dx.doi.org/10.31857/s0869-592x27353-69.

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New plant fossils collected in 2016 from the Derevyannye Gory Formation on the New Siberia Island are studied. Thirty species of fossil plants are identified and illustrated. They belong to liverworts, ferns, ginkgoaleans, conifers and angiosperms. Sixteen of them have not beed found in the New Siberia Flora before. A new angiosperm species Dalembia (?) gracilis Herman is described. The New Siberia Flora is characterised by a moderately high taxonomic diversity, predominance of conifers and angiosperms with large-leafed platanoids and trochodendroids being the most abundant among angiosperms, by predominance of dentate-margined angiosperms and rarity of plants with entire-margined leaves, and by absence of cycadaleans and bennettitaleans. The flora existed during the Turonian–Coniacian time interval and most probably should be dated as Turonian. Plants of the New Siberia Flora experienced a warm-temperate humid climate with warm summers, mild frost-free winters and insignificant seasonality in precipitation.

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Zhang, Liangsheng, Fei Chen, Xingtan Zhang, Zhen Li, Yiyong Zhao, Rolf Lohaus, Xiaojun Chang et al. "The water lily genome and the early evolution of flowering plants". Nature 577, n.º 7788 (18 de diciembre de 2019): 79–84. http://dx.doi.org/10.1038/s41586-019-1852-5.

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AbstractWater lilies belong to the angiosperm order Nymphaeales. Amborellales, Nymphaeales and Austrobaileyales together form the so-called ANA-grade of angiosperms, which are extant representatives of lineages that diverged the earliest from the lineage leading to the extant mesangiosperms1–3. Here we report the 409-megabase genome sequence of the blue-petal water lily (Nymphaea colorata). Our phylogenomic analyses support Amborellales and Nymphaeales as successive sister lineages to all other extant angiosperms. The N. colorata genome and 19 other water lily transcriptomes reveal a Nymphaealean whole-genome duplication event, which is shared by Nymphaeaceae and possibly Cabombaceae. Among the genes retained from this whole-genome duplication are homologues of genes that regulate flowering transition and flower development. The broad expression of homologues of floral ABCE genes in N. colorata might support a similarly broadly active ancestral ABCE model of floral organ determination in early angiosperms. Water lilies have evolved attractive floral scents and colours, which are features shared with mesangiosperms, and we identified their putative biosynthetic genes in N. colorata. The chemical compounds and biosynthetic genes behind floral scents suggest that they have evolved in parallel to those in mesangiosperms. Because of its unique phylogenetic position, the N. colorata genome sheds light on the early evolution of angiosperms.

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McKenna, Duane D., Andrea S. Sequeira, Adriana E. Marvaldi y Brian D. Farrell. "Temporal lags and overlap in the diversification of weevils and flowering plants". Proceedings of the National Academy of Sciences 106, n.º 17 (13 de abril de 2009): 7083–88. http://dx.doi.org/10.1073/pnas.0810618106.

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The extraordinary diversity of herbivorous beetles is usually attributed to coevolution with angiosperms. However, the degree and nature of contemporaneity in beetle and angiosperm diversification remain unclear. Here we present a large-scale molecular phylogeny for weevils (herbivorous beetles in the superfamily Curculionoidea), one of the most diverse lineages of insects, based on ≈8 kilobases of DNA sequence data from a worldwide sample including all families and subfamilies. Estimated divergence times derived from the combined molecular and fossil data indicate diversification into most families occurred on gymnosperms in the Jurassic, beginning ≈166 Ma. Subsequent colonization of early crown-group angiosperms occurred during the Early Cretaceous, but this alone evidently did not lead to an immediate and major diversification event in weevils. Comparative trends in weevil diversification and angiosperm dominance reveal that massive diversification began in the mid-Cretaceous (ca.112.0 to 93.5 Ma), when angiosperms first rose to widespread floristic dominance. These and other evidence suggest a deep and complex history of coevolution between weevils and angiosperms, including codiversification, resource tracking, and sequential evolution.

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Kavanagh, P. H., C. A. Lehnebach, M. J. Shea y K. C. Burns. "Allometry of Sexual Size Dimorphism in Dioecious Plants: Do Plants Obey Rensch’s Rule?" American Naturalist 178, n.º 5 (noviembre de 2011): 596–601. http://dx.doi.org/10.1086/662175.

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Sgorbati, Sergio, Marco D'Antraccoli, Sandra Citterio, Rodolfo Gentili y Lorenzo Peruzzi. "Was Charles Darwin right in his explanation of the ‘abominable mystery’?" Italian Botanist 5 (13 de marzo de 2018): 25–30. http://dx.doi.org/10.3897/ib.5.24699.

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The site and time of origin of angiosperms are still debated. The co-occurrence of many of the early branching lineages of flowering plants in a region somewhere between Australia and the SW Pacific islands suggests a possible Gondwanan origin of angiosperms. The recent recognition of Zealandia, a 94% submerged continent in the east of Australia, could explain the discrepancy between molecular clocks and fossil records about the age of angiosperms, supporting the old Darwinian hypothesis of a “lost continent” to explain the “abominable mystery” regarding the origin and rapid radiation of flowering plants.

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Sgorbati, Sergio, Marco D'Antraccoli, Sandra Citterio, Rodolfo Gentili y Lorenzo Peruzzi. "Was Charles Darwin right in his explanation of the ‘abominable mystery’?" Italian Botanist 5 (13 de marzo de 2018): 25–30. http://dx.doi.org/10.3897/italianbotanist.5.24699.

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The site and time of origin of angiosperms are still debated. The co-occurrence of many of the early branching lineages of flowering plants in a region somewhere between Australia and the SW Pacific islands suggests a possible Gondwanan origin of angiosperms. The recent recognition of Zealandia, a 94% submerged continent in the east of Australia, could explain the discrepancy between molecular clocks and fossil records about the age of angiosperms, supporting the old Darwinian hypothesis of a “lost continent” to explain the “abominable mystery” regarding the origin and rapid radiation of flowering plants.

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SHISHKOFF, NINA. "Distribution of the Dimorphic Hypodermis of Roots in Angiosperm Families". Annals of Botany 60, n.º 1 (julio de 1987): 1–15. http://dx.doi.org/10.1093/oxfordjournals.aob.a087413.

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Boyce, C. Kevin, Tim J. Brodribb, Taylor S. Feild y Maciej A. Zwieniecki. "Angiosperm leaf vein evolution was physiologically and environmentally transformative". Proceedings of the Royal Society B: Biological Sciences 276, n.º 1663 (25 de febrero de 2009): 1771–76. http://dx.doi.org/10.1098/rspb.2008.1919.

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The veins that irrigate leaves during photosynthesis are demonstrated to be strikingly more abundant in flowering plants than in any other vascular plant lineage. Angiosperm vein densities average 8 mm of vein per mm 2 of leaf area and can reach 25 mm mm −2 , whereas such high densities are absent from all other plants, living or extinct. Leaves of non-angiosperms have consistently averaged close to 2 mm mm −2 throughout 380 million years of evolution despite a complex history that has involved four or more independent origins of laminate leaves with many veins and dramatic changes in climate and atmospheric composition. We further demonstrate that the high leaf vein densities unique to the angiosperms enable unparalleled transpiration rates, extending previous work indicating a strong correlation between vein density and assimilation rates. Because vein density is directly measurable in fossils, these correlations provide new access to the physiology of extinct plants and how they may have impacted their environments. First, the high assimilation rates currently confined to the angiosperms among living plants are likely to have been unique throughout evolutionary history. Second, the transpiration-driven recycling of water that is important for bolstering precipitation in modern tropical rainforests might have been significantly less in a world before the angiosperms.

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Webb, C. J., David G. Lloyd y Lynda F. Delph. "Gender dimorphism in indigenous New Zealand seed plants". New Zealand Journal of Botany 37, n.º 1 (marzo de 1999): 119–30. http://dx.doi.org/10.1080/0028825x.1999.9512618.

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Boldt, Katja M. y Barbara Rank. "Stomata dimorphism in dicotyledonous plants of temperate climate". Feddes Repertorium 121, n.º 5-6 (diciembre de 2010): 167–83. http://dx.doi.org/10.1002/fedr.201000023.

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Crane, Peter R. "Phylogenetic Analysis of Seed Plants and the Origin of Angiosperms". Annals of the Missouri Botanical Garden 72, n.º 4 (1985): 716. http://dx.doi.org/10.2307/2399221.

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Zumajo-Cardona, Cecilia, Alejandra Vasco y Barbara A. Ambrose. "The Evolution of the KANADI Gene Family and Leaf Development in Lycophytes and Ferns". Plants 8, n.º 9 (30 de agosto de 2019): 313. http://dx.doi.org/10.3390/plants8090313.

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Leaves constitute the main photosynthetic plant organ and even though their importance is not debated, the origin and development of leaves still is. The leaf developmental network has been elucidated for angiosperms, from genes controlling leaf initiation, to leaf polarity and shape. There are four KANADI (KAN) paralogs in Arabidopsis thaliana needed for organ polarity with KAN1 and KAN2 specifying abaxial leaf identity. Yet, studies of this gene lineage outside angiosperms are required to better understand the evolutionary patterns of leaf development and the role of KAN homologs. We studied the evolution of KAN genes across vascular plants and their expression by in situ hybridization in the fern, Equisetum hyemale and the lycophyte Selaginella moellendorffii. Our results show that the expression of KAN genes in leaves is similar between ferns and angiosperms. However, the expression patterns observed in the lycophyte S. moellendorffii are significantly different compared to all other vascular plants, suggesting that the KAN function in leaf polarity is likely only conserved across ferns, gymnosperms, and angiosperms. This study indicates that mechanisms for leaf development are different in lycophytes compared to other vascular plants.

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Ran, Jin-Hua, Ting-Ting Shen, Ming-Ming Wang y Xiao-Quan Wang. "Phylogenomics resolves the deep phylogeny of seed plants and indicates partial convergent or homoplastic evolution between Gnetales and angiosperms". Proceedings of the Royal Society B: Biological Sciences 285, n.º 1881 (20 de junio de 2018): 20181012. http://dx.doi.org/10.1098/rspb.2018.1012.

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After decades of molecular phylogenetic studies, the deep phylogeny of gymnosperms has not been resolved, and the phylogenetic placement of Gnetales remains one of the most controversial issues in seed plant evolution. To resolve the deep phylogeny of seed plants and to address the sources of phylogenetic conflict, we conducted a phylotranscriptomic study with a sampling of all 13 families of gymnosperms and main lineages of angiosperms. Multiple datasets containing up to 1 296 042 sites across 1308 loci were analysed, using concatenation and coalescence approaches. Our study generated a consistent and well-resolved phylogeny of seed plants, which places Gnetales as sister to Pinaceae and thus supports the Gnepine hypothesis. Cycads plus Ginkgo is sister to the remaining gymnosperms. We also found that Gnetales and angiosperms have similar molecular evolutionary rates, which are much higher than those of other gymnosperms. This implies that Gnetales and angiosperms might have experienced similar selective pressures in evolutionary histories. Convergent molecular evolution or homoplasy is partially responsible for the phylogenetic conflicts in seed plants. Our study provides a robustly reconstructed backbone phylogeny that is important for future molecular and morphological studies of seed plants, in particular gymnosperms, in the light of evolution.

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30

Puttick, Mark N., James Clark y Philip C. J. Donoghue. "Size is not everything: rates of genome size evolution, not C -value, correlate with speciation in angiosperms". Proceedings of the Royal Society B: Biological Sciences 282, n.º 1820 (7 de diciembre de 2015): 20152289. http://dx.doi.org/10.1098/rspb.2015.2289.

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Angiosperms represent one of the key examples of evolutionary success, and their diversity dwarfs other land plants; this success has been linked, in part, to genome size and phenomena such as whole genome duplication events. However, while angiosperms exhibit a remarkable breadth of genome size, evidence linking overall genome size to diversity is equivocal, at best. Here, we show that the rates of speciation and genome size evolution are tightly correlated across land plants, and angiosperms show the highest rates for both, whereas very slow rates are seen in their comparatively species-poor sister group, the gymnosperms. No evidence is found linking overall genome size and rates of speciation. Within angiosperms, both the monocots and eudicots show the highest rates of speciation and genome size evolution, and these data suggest a potential explanation for the megadiversity of angiosperms. It is difficult to associate high rates of diversification with different types of polyploidy, but it is likely that high rates of evolution correlate with a smaller genome size after genome duplications. The diversity of angiosperms may, in part, be due to an ability to increase evolvability by benefiting from whole genome duplications, transposable elements and general genome plasticity.

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31

Gaff, Donald F. y Melvin Oliver. "The evolution of desiccation tolerance in angiosperm plants: a rare yet common phenomenon". Functional Plant Biology 40, n.º 4 (2013): 315. http://dx.doi.org/10.1071/fp12321.

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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.

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32

Smith, Stephen A., Nathanael Walker-Hale, Joseph F. Walker y Joseph W. Brown. "Phylogenetic Conflicts, Combinability, and Deep Phylogenomics in Plants". Systematic Biology 69, n.º 3 (20 de noviembre de 2019): 579–92. http://dx.doi.org/10.1093/sysbio/syz078.

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Abstract Studies have demonstrated that pervasive gene tree conflict underlies several important phylogenetic relationships where different species tree methods produce conflicting results. Here, we present a means of dissecting the phylogenetic signal for alternative resolutions within a data set in order to resolve recalcitrant relationships and, importantly, identify what the data set is unable to resolve. These procedures extend upon methods for isolating conflict and concordance involving specific candidate relationships and can be used to identify systematic error and disambiguate sources of conflict among species tree inference methods. We demonstrate these on a large phylogenomic plant data set. Our results support the placement of Amborella as sister to the remaining extant angiosperms, Gnetales as sister to pines, and the monophyly of extant gymnosperms. Several other contentious relationships, including the resolution of relationships within the bryophytes and the eudicots, remain uncertain given the low number of supporting gene trees. To address whether concatenation of filtered genes amplified phylogenetic signal for relationships, we implemented a combinatorial heuristic to test combinability of genes. We found that nested conflicts limited the ability of data filtering methods to fully ameliorate conflicting signal amongst gene trees. These analyses confirmed that the underlying conflicting signal does not support broad concatenation of genes. Our approach provides a means of dissecting a specific data set to address deep phylogenetic relationships while also identifying the inferential boundaries of the data set. [Angiosperms; coalescent; gene-tree conflict; genomics; phylogenetics; phylogenomics.]

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33

Adrian-Romero, Maricela, Gerald Blunden, Asmita V. Patel, Nigel Armstrong, Pablo Meléndez y Alfredo Carabot Cuervo. "Betaines and N-Methylprolines from Venezuelan Plants". Natural Product Communications 2, n.º 8 (agosto de 2007): 1934578X0700200. http://dx.doi.org/10.1177/1934578x0700200815.

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A collection of tropical Angiosperms, mainly collected in Amazonas and Apure States in Venezuela, has been examined for the presence of betaines and N-methylprolines, which were found in 58 out of the 65 species investigated. Betaine yields were generally low, but in the species that contained N-methylprolines, the yields of these compounds were generally in excess of 0.5% of the plant dry weight. N-methylprolines were isolated from four species of Loranthaceae, all four examined species of Miconia (Melastomataceae), Pleonotema variabilis (Bignoniaceae), Gustavia augusta and Lecythis corrugata (Lecythidaceae), and Machaerium humboldtianum (Fabaceae). Trans-4-hydroxyprolinebetaine was isolated in high yields from Amphilophium paniculatum, Arrabidaea candidans and Clytostoma binatum (Bignoniaceae), Combretum laxum (Combretaceae) and Gustavia augusta (Lecythidaceae).

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34

Crawford, NM, JQ Wilkinson y ST Labrie. "Control of Nitrate Reduction in Plants". Functional Plant Biology 19, n.º 4 (1992): 377. http://dx.doi.org/10.1071/pp9920377.

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The reduction of nitrate to nitrite is a critical step in the assimilation of nitrogen for most terrestrial plants. This reaction is catalysed by the enzyme nitrate reductase. Much has been learned about this enzyme over the past 40 years. Biochemical and molecular studies have provided insights into the structure of the enzyme and its prosthetic groups and molybdenum cofactor. Analysis of mutants that are defective in nitrate reduction has shed light on the nature and number of genes required for the synthesis of the nitrate reductase holoenzyme. Physiological studies have revealed an intricate and complex regulatory system that controls the expression of the nitrate reductase gene in response to environmental signals such as nitrate, light and carbon dioxide. In this paper we review what is known about the properties of nitrate reductase and its regulation in angiosperms with special emphasis on Arabidopsis thaliana.

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35

Gauthier, Gregory M. "Dimorphism in Fungal Pathogens of Mammals, Plants, and Insects". PLOS Pathogens 11, n.º 2 (12 de febrero de 2015): e1004608. http://dx.doi.org/10.1371/journal.ppat.1004608.

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36

Miller, J. S. "Polyploidy and the Evolution of Gender Dimorphism in Plants". Science 289, n.º 5488 (29 de septiembre de 2000): 2335–38. http://dx.doi.org/10.1126/science.289.5488.2335.

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37

Charlesworth, Deborah. "Does sexual dimorphism in plants promote sex chromosome evolution?" Environmental and Experimental Botany 146 (febrero de 2018): 5–12. http://dx.doi.org/10.1016/j.envexpbot.2017.11.005.

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38

Kordyum, Elizabeth L. y Sergei L. Mosyakin. "Endosperm of Angiosperms and Genomic Imprinting". Life 10, n.º 7 (3 de julio de 2020): 104. http://dx.doi.org/10.3390/life10070104.

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Modern ideas about the role of epigenetic systems in the regulation of gene expression allow us to understand the mechanisms of vital activities in plants, such as genomic imprinting. It is important that genomic imprinting is known first and foremost for the endosperm, which not only provides an embryo with necessary nutrients, but also plays a special biological role in the formation of seeds and fruits. Available data on genomic imprinting in the endosperm have been obtained only for the triploid endosperm in model plants, which develops after double fertilization in a Polygonum-type embryo sac, the most common type among angiosperms. Here we provide a brief overview of a wide diversity of embryo sacs and endosperm types and ploidy levels, as well as their distribution in the angiosperm families, positioned according to the Angiosperm Phylogeny Group IV (APG IV) phylogenetic classification. Addition of the new, non-model taxa to study gene imprinting in seed development will extend our knowledge about the epigenetic mechanisms underlying angiosperm fertility.

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39

Wilson, Jonathan P. y Andrew H. Knoll. "A physiologically explicit morphospace for tracheid-based water transport in modern and extinct seed plants". Paleobiology 36, n.º 2 (2010): 335–55. http://dx.doi.org/10.1666/08071.1.

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We present a morphometric analysis of water transport cells within a physiologically explicit three-dimensional space. Previous work has shown that cell length, diameter, and pit resistance govern the hydraulic resistance of individual conducting cells; thus, we use these three parameters as axes for our morphospace. We compare living and extinct plants within this space to investigate how patterns of plant conductivity have changed over evolutionary time. Extinct coniferophytes fall within the range of living conifers, despite differences in tracheid-level anatomy. Living cycads, Ginkgo biloba, the Miocene fossil Ginkgo beckii, and extinct cycadeoids overlap with both conifers and vesselless angiosperms. Three Paleozoic seed plants, however, occur in a portion of the morphospace that no living seed plant occupies. Lyginopteris, Callistophyton, and, especially, Medullosa evolved tracheids with high conductivities similar to those of some vessel-bearing angiosperms. Such fossils indicate that extinct seed plants evolved a structural and functional diversity of xylem architectures broader, in some ways, than the range observable in living seed plants.

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40

Andrews, M. Y., J. J. Ague y R. A. Berner. "Weathering of soil minerals by angiosperm and gymnosperm trees". Mineralogical Magazine 72, n.º 1 (febrero de 2008): 11–14. http://dx.doi.org/10.1180/minmag.2008.072.1.11.

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AbstractWeathering of terrestrial Ca- and Mg-bearing silicate minerals is an important control on atmospheric CO2 on geological time scales. It has been determined that vascular plants can accelerate mineral weathering as compared to non-vascular plants or non-vegetated surfaces. This indicates that the evolution of vascular plants, particularly the deep-rooted trees, may play a large role in the long-term carbon cycle and its regulation of the atmosphere. The weathering impact of the separate evolutionary appearances of the gymnosperms in the Palaeozoic and the angiosperms in the Mesozoic, and the shifting ecological dominance from the former to the latter, is currently poorly understood. This study aims to contribute to our understanding of the quantitative weathering rates of the angiosperms and gymnosperms by examining plant-mineral interactions of the two tree types in a temperate field setting underlain by granodiorite. Results include determinations of soil element fluxes and etching of minerals. The observed root-mineral interactions resulted in only slightly more weathering of Ca-bearing minerals by the angiosperms. However, we observed significantly more weathering of the Mg-bearing minerals by the gymnosperms. These results suggest that increasing dominance of the angiosperms in forests in the Mesozoic may have had a small or neutral impact on accelerating overall mineral weathering and regulating CO2, but that this impact may be lithology-dependent.

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41

Wirminghaus, J. O. "A checklist of the plants of the Karkloof Forest, Natal midlands". Bothalia 20, n.º 2 (17 de octubre de 1990): 159–65. http://dx.doi.org/10.4102/abc.v20i2.910.

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A checklist of the plants of the Karkloof Forest is presented. Of the 400 taxa recorded, seven are bryophytes, 69 are pteridophytes. four are gyninosperms and 320 are angiosperms At least 17 of the plants recorded are localized or uncommon in Natal. Two of these are endemic to the area.

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42

Du, Zhi-Yuan y Qing-Feng Wang. "Phylogenetic tree of vascular plants reveals the origins of aquatic angiosperms". Journal of Systematics and Evolution 54, n.º 4 (26 de octubre de 2015): 342–48. http://dx.doi.org/10.1111/jse.12182.

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43

Carlquist, Sherwin. "Fibre dimorphism: cell type diversification as an evolutionary strategy in angiosperm woods". Botanical Journal of the Linnean Society 174, n.º 1 (7 de noviembre de 2013): 44–67. http://dx.doi.org/10.1111/boj.12107.

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44

Lupia, Richard, Scott Lidgard y Peter R. Crane. "Comparing palynological abundance and diversity: implications for biotic replacement during the Cretaceous angiosperm radiation". Paleobiology 25, n.º 3 (1999): 305–40. http://dx.doi.org/10.1017/s009483730002131x.

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The Cretaceous radiation of angiosperms initiated a major reorganization of terrestrial plant communities as dominance by pteridophytic and gymnospermic groups eventually gave way to dominance by angiosperms. Previously, patterns of biotic replacement have been assessed using measures based on taxonomic diversity data. However, using measures of both abundance and diversity to investigate replacement patterns provides more information about macroecological change in the fossil record than either can provide alone. Analyses of an updated and expanded database of North American palynological samples from Cretaceous sediments document a rapid increase in angiosperm diversity and abundance within individual fossil palynofloras (representing local/subregional vegetation). New analyses of floristic diversity patterns support previous results and indicate that the decline of free-sporing plants is more pronounced than the decline of gymnosperms. In contrast, analyses of abundance data appear to show that the decline of gymnosperms is far more pronounced than the decline of free-sporing plants. Detailed examination of both data sets segregated by paleolatitude shows that this apparent contradiction reflects biogeographical differences in the patterns of vegetational change (e.g., free-sporing plants declined in abundance at lower latitudes) as well as sampling bias (e.g., greater sampling in the northern region in the Late Cretaceous). Analyses accounting for these biases support the conclusion that as angiosperms radiated, free-sporing plants rather than gymnosperms (in this case, mainly conifers) experienced the most pronounced decline. A thorough understanding of the Cretaceous radiation of angiosperms will require both abundance and diversity data. It also will require expanding the analyses presented here into other geographic regions as well as sampling more completely at all spatial scales.

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45

Tucker, Matthew R. y Anna M. G. Koltunow. "Sexual and asexual (apomictic) seed development in flowering plants: molecular, morphological and evolutionary relationships". Functional Plant Biology 36, n.º 6 (2009): 490. http://dx.doi.org/10.1071/fp09078.

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Reproduction in the flowering plants (angiosperms) is a dynamic process that relies upon the formation of inflorescences, flowers and eventually seed. Most angiosperms reproduce sexually by generating gametes via meiosis that fuse during fertilisation to initiate embryo and seed development, thereby perpetuating the processes of adaptation and evolution. Despite this, sex is not a ubiquitous reproductive strategy. Some angiosperms have evolved an alternate form of reproduction termed apomixis, which avoids meiosis during gamete formation and leads to the production of embryos without paternal contribution. Therefore, apomixis results in the production of clonal progeny through seed. The molecular nature and evolutionary origin of apomixis remain unclear, but recent studies suggest that apomixis evolved from the same molecular framework supporting sex. In this review, we consider physical and molecular relationships between the two pathways, with a particular focus on the initial stages of female reproduction where apomixis deviates from the sexual pathway. We also consider theories that explain the origin of apomictic processes from sexual progenitors. Detailed characterisation of the relationship between sex and apomixis in an evolutionary and developmental sense is an important step towards understanding how apomixis might be successfully integrated into agriculturally important, but currently sexual crops.

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46

Miller, Naomi F. "Plants and Humans in the Near East and the Caucasus: Ancient and Traditional Uses of Plants as Food and Medicine, a Diachronic Ethnobotanical Review". Ethnobiology Letters 5 (10 de febrero de 2014): 22–23. http://dx.doi.org/10.14237/ebl.5.2014.139.

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Review of Plants and Humans in the Near East and the Caucasus: Ancient and Traditional Uses of Plants as Food and Medicine, a Diachronic Ethnobotanical Review (2 vols). Vol. 1: The Landscapes. The Plants: Ferns and Gymnosperms. Vol. 2: The Plants: Angiosperms. Diego Rivera Núñez, Gonzalo Matilla Séiquer, Concepción Obón, Francisco Alcaraz Ariza. 2011. Ediciones de la Unverisdad de Murcia. Pp. 1056. EUR 23.76 (paperback). ISBN 978-84-15463-07-08 (2 vols.), 978-84-15463-05-4 (vol. 1), 978-84-15463-06-1 (vol. 2).

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47

Silva, G. G., A. J. Green, V. Weber, P. Hoffmann, Á. Lovas-Kiss, C. Stenert y L. Maltchik. "Whole angiosperms Wolffia columbiana disperse by gut passage through wildfowl in South America". Biology Letters 14, n.º 12 (diciembre de 2018): 20180703. http://dx.doi.org/10.1098/rsbl.2018.0703.

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For the first time to our knowledge, we demonstrate that whole angiosperm individuals can survive gut passage through birds, and that this occurs in the field. Floating plants of the genus Wolffia are the smallest of all flowering plants. Fresh droppings of white-faced whistling duck Dendrocygna viduata ( n = 49) and coscoroba swan Coscoroba coscoroba ( n = 22) were collected from Brazilian wetlands. Intact Wolffia columbiana were recovered from 16% of D. viduata and 32% of Coscoroba samples (total = 164 plantlets). The viability of plants was tested, and asexual reproduction was confirmed. Wolffia columbiana is an expanding alien in Europe. Avian endozoochory of asexual angiosperm propagules may be an important, overlooked dispersal means for aquatic plants, and may contribute to the invasive character of alien species.

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48

Romanova, Marina A., Anastasiia I. Maksimova, Katharina Pawlowski y Olga V. Voitsekhovskaja. "YABBY Genes in the Development and Evolution of Land Plants". International Journal of Molecular Sciences 22, n.º 8 (16 de abril de 2021): 4139. http://dx.doi.org/10.3390/ijms22084139.

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Mounting evidence from genomic and transcriptomic studies suggests that most genetic networks regulating the morphogenesis of land plant sporophytes were co-opted and modified from those already present in streptophyte algae and gametophytes of bryophytes sensu lato. However, thus far, no candidate genes have been identified that could be responsible for “planation”, a conversion from a three-dimensional to a two-dimensional growth pattern. According to the telome theory, “planation” was required for the genesis of the leaf blade in the course of leaf evolution. The key transcription factors responsible for leaf blade development in angiosperms are YABBY proteins, which until recently were thought to be unique for seed plants. Yet, identification of a YABBY homologue in a green alga and the recent findings of YABBY homologues in lycophytes and hornworts suggest that YABBY proteins were already present in the last common ancestor of land plants. Thus, these transcriptional factors could have been involved in “planation”, which fosters our understanding of the origin of leaves. Here, we summarise the current data on functions of YABBY proteins in the vegetative and reproductive development of diverse angiosperms and gymnosperms as well as in the development of lycophytes. Furthermore, we discuss a putative role of YABBY proteins in the genesis of multicellular shoot apical meristems and in the evolution of leaves in early divergent terrestrial plants.

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49

Nepi, Massimo, Daniele Calabrese, Massimo Guarnieri y Emanuele Giordano. "Evolutionary and Ecological Considerations on Nectar-Mediated Tripartite Interactions in Angiosperms and Their Relevance in the Mediterranean Basin". Plants 10, n.º 3 (9 de marzo de 2021): 507. http://dx.doi.org/10.3390/plants10030507.

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The Mediterranean basin hosts a high diversity of plants and bees, and it is considered one of the world’s biodiversity hotspots. Insect pollination, i.e., pollen transfer from male reproductive structures to conspecific female ones, was classically thought to be a mutualistic relationship that links these two groups of organisms, giving rise to an admirable and complex network of interactions. Although nectar is often involved in mediating these interactions, relatively little is known about modifications in its chemical traits during the evolution of plants. Here, we examine how the current sucrose-dominated floral nectar of most Mediterranean plants could have arisen in the course of evolution of angiosperms. The transition from hexose-rich to sucrose-rich nectar secretion was probably triggered by increasing temperature and aridity during the Cretaceous period, when most angiosperms were radiating. This transition may have opened new ecological niches for new groups of insects that were co-diversifying with angiosperms and for specific nectar-dwelling yeasts that originated later (i.e., Metschnikowiaceae). Our hypothesis embeds recent discoveries in nectar biology, such as the involvement of nectar microbiota and nectar secondary metabolites in shaping interactions with pollinators, and it suggests a complex, multifaceted ecological and evolutionary scenario that we are just beginning to discover.

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50

Kevan, Paeter G., Robert W. Longair y Randy M. Gadawski. "Dioecy and pollen dimorphism in Vitis riparia (Vitaceae)". Canadian Journal of Botany 63, n.º 12 (1 de diciembre de 1985): 2263–67. http://dx.doi.org/10.1139/b85-321.

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The breeding system of Vitis riparia Michx. hitherto has not been investigated. Field observations indicated that two morphs exist, one that produces fruit, and another that does not. Through experimental cross- and self-pollinations it was found that V. riparia is functionally dioecious in southern Ontario. Further, it was found that male plants produce functional spherical tricolporate pollen, whereas female plants produce inaperturate pollen of the same diameter, 23 μm, that cannot bring about fertilization. The sex ratios found at seven locations were skewed slightly, but significantly, in favour of male plants (average 0.567). Pollination is brought about by wind, probably supplemented to a greater or lesser extent by insects which feed on the cytoplasm-filled pollen of both sexes.

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