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- Antonelli, Alexandre, 1978
(författare)
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The rise and fall of Neotropical biodiversity
- 2022
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Ingår i: Botanical Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 199:1, s. 8-24
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Tidskriftsartikel (refereegranskat)abstract
- The exceptional levels of biodiversity found today in the American tropics are the outcome of tens of millions of years of evolution, shaped by the tumultuous geological history of the region, its heterogeneous habitats, climate change, ecological interactions and, in recent millennia, human influence. Although our understanding of diversity patterns and their underlying processes grows steadily in breadth and depth, Neotropical biodiversity is rapidly breaking down. Here, I contrast the long-term evolution of Neotropical biodiversity with its recent and rapid deterioration due to anthropogenic factors. I consider the impacts of the early arrival of humans to the region and the modern intensification of land-use change (primarily driven by agriculture) and other drivers of biodiversity loss, such as direct exploitation, invasive species and climate change. Together, these threats have led to 33% of all Neotropical species for which sufficient data are available being currently threatened with extinction. I outline emerging opportunities for conservation and restoration under the post-2020 Global Biodiversity Framework and call for urgent action from the biodiversity community, for the benefit of people and nature.
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| 2. |
- Bacon, Christine D., et al.
(författare)
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Genomic and niche divergence in an Amazonian palm species complex
- 2021
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Ingår i: Botanical Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 197:4, s. 498-512
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Tidskriftsartikel (refereegranskat)abstract
- Environmental heterogeneity across the landscape can cause lineage divergence and speciation. The Geonoina macrostachys (Arecaceae) species complex has been proposed as a candidate case of ecological speciation in Amazonia due to evidence of habitat partitioning and pre-zygotic reproductive barriers between co-occurring morphotypes at a local scale. In this study, we provide a continent-wide perspective of the divergence patterns in a macrostachys by integrating data from morphological traits, target sequence capture, climate, soil and reproductive biology. A morphometric analysis revealed four morphogroups, defined by traits related to leaf shape. A coalescence-based phylogenetic analysis did not recover the morphogroups as monophyletic, indicating independent evolution of leaf shape across geographical space. We demonstrate scale-dependent habitat differentiation for two of the morphogroups, in which segregation driven mostly by climate was complete at the regional scale but incomplete at the continental scale. Contrary to previous evidence of reproductive isolation in the form of different pollinators and flowering times between sympatric G. macrostachys forms in Peru and Ecuador, these were not found in Colombia, suggesting reproductive barriers have evolved multiple times across its geographical range. Taken together, our findings suggest that ecological divergence and local adaptation is driving diversification in G. macrostachys, and that hyperdiverse regions such as Amazonia are probable arenas for ecological divergence in sympatry.
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| 3. |
- Bisang, Irene, et al.
(författare)
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Sex expression and genotypic sex ratio vary with region and environment in the wetland moss Drepanocladus lycopodioides
- 2020
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Ingår i: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 192:2, s. 421-434
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Tidskriftsartikel (refereegranskat)abstract
- Sex ratio variation is common among organisms with separate sexes. In bryophytes, sex chromosome segregation at meiosis suggests a balanced progeny sex ratio. However, most bryophyte populations exhibit female-biased phenotypic sex ratios based on the presence of reproductive structures on gametophytes. Many bryophyte populations do not form sexual organs, and genotypic sex ratio variation in such populations is mostly unknown. We tested sex expression, and phenotypic and genotypic sex ratios against environmental parameters in natural populations of the unisexual wetland moss Drepanocladus lycopodiodes at 11 sites in each of three regions in southern Sweden. We identified sex in 660 individual ramets, based on sexual structures, when present, or with a specifically designed molecular marker, when absent. All regions exhibited a female bias in phenotypic and genotypic sex ratios. Sex ratio biases and sex expression differed between regions. Sex ratios were less female-biased in larger patches. Wetter patches exhibited a stronger female bias in genotypic sex ratio and lower sex expression. This is the first evidence of environmental effects on genotypic sex ratio in mosses. A higher frequency of females in wet patches could be due to higher female resource demands for sporophyte production or higher male sensitivity to wetness. A higher incidence of females than males in moister sites aligns with female flowering plants, but differs from reproductive bryophytes in drier environments. Taken together with previous results, our data indicate that sex ratio variation and its drivers differ among species, their life histories and environments.
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| 4. |
- Cousins-Westerberg, Ruben, et al.
(författare)
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Evolution of cold tolerance in the highly stress-tolerant samphires and relatives (Salicornieae: Amaranthaceae) : Amaranthaceae)
- 2023
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Ingår i: Botanical journal of the Linnean Society. - 0024-4074 .- 1095-8339. ; 203:1, s. 20-36
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Tidskriftsartikel (refereegranskat)abstract
- Low temperature constitutes one of the main barriers to plant distributions, confining many clades to their ancestrally tropical biome. However, recent evidence suggests that transitions from tropical to temperate biomes may be more frequent than previously thought. Here, we study the evolution of cold and frost tolerance in the globally distributed and highly stress-tolerant Salicornieae (Salicornioideae, Amaranthaceae s.l.). We first generate a phylogenetic tree comprising almost all known species (85-90%), using newly generated (n = 106) and published nuclear-ribosomal and plastid sequences. Next, we use geographical occurrence data to document in which clades and geographical regions cold-tolerant species occur and reconstruct how cold tolerance evolved. Finally, we test for correlated evolution between frost tolerance and the annual life form. We find that frost tolerance has evolved independently in up to four Northern Hemisphere lineages but that annuals are no more likely to evolve frost tolerance than perennials, indicating the presence of different strategies for adapting to cold environments. Our findings add to mounting evidence for multiple independent out-of-the-tropics transitions among close relatives of flowering plants and raise new questions about the ecological and physiological mechanism(s) of adaptation to low temperatures in Salicornieae.
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| 7. |
- Frohlich, Michael W., et al.
(författare)
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Molecular phylogenetics of Euploca (Boraginaceae) : homoplasy in many characters, including the C-4 photosynthetic pathway
- 2022
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Ingår i: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 199:2, s. 497-537
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Tidskriftsartikel (refereegranskat)abstract
- We present a phylogenetic analysis using plastid (matK, rbcL) and nuclear (nrITS) DNA for diverse Euploca spp. (formerly Heliotropium section Orthostachys) from the worldwide distribution of a genus and including species encompassing the wide physiological and morphological diversity of the genus. Our results indicate that some remarkably complex features arose multiple times in parallel in Euploca, including attributes of its subsections under section Orthostachys, notably plants that, above ground, consist almost entirely of inflorescences. To elucidate in greater detail the distribution of C-4 species in Euploca and Heliotropium s.s., we made > 800 delta C-13 determinations, including some from the traditional genus Tournefortia. We greatly increase the number of proven C-4 species in Euploca, but found none outside Euploca. Of the tested Euploca spp., c. 28% are C-3 or intermediate in carbon fixation pathway. Our phylogenetic results indicate four parallel/convergent acquisitions of C-4 photosynthesis or fewer origins with subsequent loss in some species.
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| 9. |
- Löfstrand, Stefan D., et al.
(författare)
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Phylogenetic relationships, infrageneric classification and species limits in the Neotropical genus Faramea (Coussareeae: Rubiaceae)
- 2021
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Ingår i: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 197, s. 478-497
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Tidskriftsartikel (refereegranskat)abstract
- Faramea is characterized by white or blue, tetramerous corollas and blue-black, fleshy fruits with a single, large pyrene. Both infrageneric relationships and species boundaries are poorly understood in the genus. This study represents the first broad-scale phylogenetic study of Faramea, with 80 of the c. 170 species sampled, 24 by two or more specimens. We aimed to include specimens representing the entire geographical, morphological and ecological ranges of the genus. Morphological characters historically utilized to delimit infrageneric sections in Faramea (e.g. bract and pyrene forms) were also evaluated. Only one of the currently accepted infrageneric sections was recovered as monophyletic (within a complex of species from other sections) and none of the morphological features traditionally utilized to determine infrageneric relationships in the genus was found to be uniquely diagnostic of a larger clade. Some Faramea lineages appear to be geographically isolated, with several clades containing solely specimens collected in the Atlantic Forest biomes. Of the 24 species represented by at least two specimens, 11 were supported as monophyletic, ten as non-monophyletic and three were not resolved as either monophyletic nor non-monophyletic. The results of the present study constitute a good basis for future studies of taxonomy, biogeography and ecology of Faramea.
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| 10. |
- Maksimova (Evkaikina), Anastasiia, et al.
(författare)
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What can the phylogeny of class I KNOX genes and their expression patterns in land plants tell us about the evolution of shoot development?
- 2021
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Ingår i: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 195:3, s. 254-280
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Forskningsöversikt (refereegranskat)abstract
- KNOX genes encode transcription factors (TFs), several of which act non-cell-autonomously. KNOX genes evolved in algae, and two classes, class I KNOX and class II KNOX genes, were already present in charophytes. In tracheophytes, class I KNOX genes are expressed in shoot apical meristems (SAMs) and thought to inhibit cell differentiation, whereas class II KNOX genes are expressed in mature organs regulating differentiation. In this review, we summarize the data available on gene families and expression patterns of class I and class II KNOX genes in embryophytes. The expression patterns of class I KNOX genes should be seen in the context of SAM structure and of leaf primordium development where the inhibition of cell differentiation needs to be lifted. Although the SAMs of angiosperms and gnetophytes almost always belong to the duplex type, several other types are distributed in gymnosperms, ferns, lycopods and bryophytes. KNOX gene families remained small (maximally five genes) in the representatives of bryophytes, lycopods and ferns examined thus far; however, they expanded to some extent in gymnosperms and, independently and much more strongly, in angiosperms. The growing sophistication of mechanisms to repress and re-induce class KNOX I expression played a major role in the evolution of leaf shape.
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