Miconia as a key resource for the Neotropical fauna (Research in Context)
Annals of Botany 127: 577–595, 2021
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Current understanding on the ecology and evolution of seed dispersal interactions has been largely founded on studies with Miconia (Melastomataceae), a hyper-diverse plant clade that produces many small berries enclosing numerous tiny seeds within water and sugar-rich pulps. Through an integrative review assessing fruit traits, phenology, frugivory records and gut passage effects on germination, Messeder et al. demonstrate that fruits of Miconia are morphologically, chemically and spatiotemporally available to various animals. The interactions established with birds, mammals, reptiles, fish and ants ensure short- and long-distance seed dispersal and demonstrate that Miconia is a reliable resource that sustains entire frugivore assemblages across Neotropical ecoregions.
Authors: João Vitor Messeder, Fernando Silveira, Tatiana Cornelissen, Lisieux Fuzessy, and Tadeu Guerra
Diversification of Helianthemum in the Canary Islands
Annals of Botany 127: 597–611, 2021
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Albaladejo et al. explore whether a species-rich Canarian lineage belonging to the genus Helianthemum (Cistaceae) diversified along a stepping-stone model of dispersal (with or without ulterior intra-island speciation) vs. a model of inter-island dispersal to similar ecological zones. Their results provide evidence for both inter- and intra-island allopatric speciation driven by ecological niche conservatism as the main force of evolution, underlining also the importance of non-adaptive radiation in island systems. However, emergent ecological niche shifts in some lineages also could have reinforced the rapid diversification process in the archipelago.
Authors: Rafael G. Albaladejo, Sara Martín-Hernanz, J. Alfredo Reyes-Betancort, Arnoldo Santos-Guerra, María Olangua-Corral, and Abelardo Aparicio
For a commentary on this paper, see this issue pp. iii–iv.
Distribution of seed dormancy classes across a fire-prone continent
Annals of Botany 127: 613–620, 2021
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Different seed dormancy classes control the timing of germination via different ecological cues, suggesting that they could be subject to different selective pressures. Colette and Ooi classify the dormancy class of 3390 shrub species from across temperate, fire-prone Australia, investigating how temperature and rainfall seasonality affect dormancy distribution, and whether dormancy class is related to the threat status of plants. Dormancy class is not uniformly distributed, but perhaps most importantly, physiologically dormant species are more likely to be threatened in aseasonal rainfall areas.
Authors: Justin Collette and Mark Ooi
What makes a fig: a comparative study of inflorescence ontogeny in Moraceae
Annals of Botany 127: 621–631, 2021
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An urn-shaped inflorescence named syconium, or fig, with flowers densely arranged on the inner surface of the receptacle, occurs exclusively in Ficus, a genus of the family Moraceae. Other types of inflorescences such as spikes, racemes and heads are also found in this family. Leite et al. compare inflorescence ontology in six Moraceae species. The results identify the changes in the developmental stages that give rise to the unique archictecture of the Ficus syconium. From this, they infer that evolutionary ontogenic changes driven by pollinators (insects, wind) culminate in the enclosure of flowers inside the receptacle.
Authors: Viviane Gonçalves Leite, Finn Kjellberg, Rodrigo Augusto Santinelo Pereira, and Simone Pádua Teixeira
Pollinator isolation by fungus gnats
Annals of Botany 127: 633–644, 2021
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Selective pollination by major insect groups (e.g., bee, hoverfly and moth) has been regarded as an important element of reproductive isolation. Although nematocerans selectively pollinate several plant taxa, their role is understudied partly due to small body size for field observation. Matsumoto et al. examine selective pollination by nematocerans using five Arisaema species (Araceae), which trap all visitors by pitcher-like inflorescence. The five species attracted different fungus gnats both within and outside the sympatric distribution area. Pollinator specificity remained even when anthesis was artificially changed. These results suggest that the specificity of fungus gnats is very stable and potentially contributes to reproductive isolation.
Authors: Tetsuya K. Matsumoto, Muneto Hirobe, Masahiro Sueyoshi, and Yuko Miyazaki
Chlorophyllous plant species cheat on fungi forming Paris-type arbuscular mycorrhiza
Annals of Botany 127: 645–653, 2021
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Mycorrhizae are considered to be mutualistic, with plants serving as carbon providers for fungi. Mycoheterotrophic plants turn the tables by taking carbon from their fungal symbionts, Arbuscular mycorrhiza (AM) achlorophyllous mycoheterotrophs always occur with Paris-morphotype AM. Here, Giesemann et al. investigate whether or not chlorophyllous Paris-type plant species are cheating on fungal carbon too. In a literature survey, they compare multi-element stable isotope abundance of 135 AM species, including representatives like chlorophyllous Arum maculatum (Arum-type) and Paris quadrifolia (Paris-type) and the achlorophyllous species (Paris-type). The majority of chlorophyllous Paris-type AM species were identified as partially mycoheterotrophic.
Authors: Philipp Giesemann, Hanne N. Rasmussen, and Gerhard Gebauer
Rapid local adaptation in monkeyflowers
Annals of Botany 127: 655–668, 2021
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Lack of sexual reproduction may slow or prevent local adaptation. Here, Simón-Porcar et al. compare the facultatively asexual monkeyflower, Mimulus guttatus (Phrymaceae), against its recently evolved (<200 years) obligately asexual hybrid derivative, M. × robertsii, to test for local adaptation. They conducted reciprocal transplants across the latitudinal extremes of Great Britain and common garden experiments to measure phenotypic plasticity and both sexual and clonal performance of local vs. foreign genotypes. They found evidence of local adaptation in both M. guttatus and in asexual M. × robertsii. This study supports the hypothesis that even strictly asexual species can rapidly adapt to novel environments.
Authors: Violeta Simón-Porcar, Jose Silva, and Mario Vallejo-Marin
Effects of decreased precipitation on habitat islands in the coastal Atacama Desert
Annals of Botany 127: 669–680, 2021
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Increased aridity threatens ecosystems globally. Working in the driest desert on Earth, the Atacama Desert, Stotz et al. test whether fog-driven habitat islands (Lomas communities) prevent the loss of individual, species and functional diversity that is often associated with increased aridity. While preventing the loss of the less stress-tolerant species and individuals as precipitation decreased, Lomas became increasingly isolated, which led to the stochastic loss of species and individuals. However, only functionally redundant species and individuals were lost, resulting in the maintenance of functional diversity. Results suggest that microclimatic conditions and functional redundancy may determine the conservation of functional diversity.
Authors: Gisela Stotz, Cristian Salgado-Luarte, Alonso Vigil, Henry J. De La Cruz, Víctor Pastén-Marambio, and Ernesto Gianoli
Evolution of living fossils
Annals of Botany 127: 681–695, 2021
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Plant groups with long fossil histories are a key to understanding land plant evolution. Christenhusz et al. study the biogeographic history of all 18 extant horsetail species using fossils to calibrate the phylogenetic tree. Extant Equisetum diversified in the Early Carboniferous, with the first major split in the Jurassic, coinciding with the breakup of Pangaea. The Laurasian clade, including most extant species, diverged in the mid-Cretaceous. Flow cytometry reveals that, despite the same chromosome number, species in subgenus Hippochaete have larger genome sizes, possibly related to their greater number of sperm-cell flagellae.
Authors: Maarten Christenhusz, Mark Chase, Michael Fay, Oriane Hidalgo, Ilia Leitch, Jaume Pellicer, and Juan Viruel
Plastome phylogenomics of plum-yew (Cephalotaxus) and related genera
Annals of Botany 127: 697–708, 2021
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The economically and ecologically important Cephalotaxus is the only genus of the gymnosperm family Cephalotaxaceae. However, relationships between Cephalotaxus and closely related genera in Taxaceae have long been controversial. Ji et al. sequenced the plastomes of all Cephalotaxus species to address this controversy. Phylogenetic analyses of plastome data show that Cephalotaxaceae is a monotypic family and that there is a clear-cut delineation between Cephalotaxaceae and Taxaceae. They also reveal that extant Cephalotaxus species are derived from recent divergence events associated with the establishment of monsoonal climates in East Asia and Pleistocene climatic fluctuations, and thus are not the evolutionary relics they usually thought to be.
Authors: Yunheng Ji, Changkun Liu, Jacob B Landis, Min Deng, and Jiahui Chen
