| 1. |
- Fernandez-Martinez, M., et al.
(författare)
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Nutrient scarcity as a selective pressure for mast seeding
- 2019
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Ingår i: Nature Plants. - : Springer Science and Business Media LLC. - 2055-026X .- 2055-0278. ; 5:12
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Tidskriftsartikel (refereegranskat)abstract
- Mast seeding is one of the most intriguing reproductive traits in nature. Despite its potential drawbacks in terms of fitness, the widespread existence of this phenomenon suggests that it should have evolutionary advantages under certain circumstances. Using a global dataset of seed production time series for 219 plant species from all of the continents, we tested whether masting behaviour appears predominantly in species with low foliar nitrogen and phosphorus concentrations when controlling for local climate and productivity. Here, we show that masting intensity is higher in species with low foliar N and P concentrations, and especially in those with imbalanced N/P ratios, and that the evolutionary history of masting behaviour has been linked to that of nutrient economy. Our results support the hypothesis that masting is stronger in species growing under limiting conditions and suggest that this reproductive behaviour might have evolved as an adaptation to nutrient limitations and imbalances.
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| 2. |
- Jonsson, Micael, et al.
(författare)
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Levels of forest ecosystem services depend on specific mixtures of commercial tree species.
- 2019
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Ingår i: Nature Plants. - : Springer Science and Business Media LLC. - 2055-0278 .- 2055-026X. ; 5, s. 141-147
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Tidskriftsartikel (refereegranskat)abstract
- Global and local ecosystem change resulting in diversity loss has motivated efforts to understand relationships between species diversity and ecosystem services. However, it is unclear how such a general understanding can inform policies for the management of ecosystem services in production systems, because these systems are primarily used for food or fibre, and are rarely managed for the conservation of species diversity. Here, using data from a nationwide forest inventory covering an area of 230,000km2, we show that relative abundances of commercial tree species in mixed stands strongly influence the potential to provide ecosystem services. The mixes provided higher levels of ecosystem services compared to respective plant monocultures (overyielding or transgressive overyielding) in 35% of the investigated cases, and lower (underyielding) in 9% of the cases. We further show that relative abundances, not just species richness per se, of specific tree-species mixtures affect the potential of forests to provide multiple ecosystem services, which is crucial information for policy and sustainable forest management.
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| 3. |
- Karady, Michal, et al.
(författare)
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PIN-driven auxin transport emerged early in streptophyte evolution
- 2019
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Ingår i: Nature Plants. - : Springer Science and Business Media LLC. - 2055-026X .- 2055-0278. ; 5, s. 1114-1119
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Tidskriftsartikel (refereegranskat)abstract
- PIN-FORMED (PIN) transporters mediate directional, intercellular movement of the phytohormone auxin in land plants. To elucidate the evolutionary origins of this developmentally crucial mechanism, we analysed the single PIN homologue of a simple green alga Klebsormidium flaccidum. KfPIN functions as a plasma membrane-localized auxin exporter in land plants and heterologous models. While its role in algae remains unclear, PIN-driven auxin export is probably an ancient and conserved trait within streptophytes.
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| 4. |
- Fan, Lei, et al.
(författare)
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Satellite-observed pantropical carbon dynamics
- 2019
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Ingår i: Nature Plants. - : Springer Science and Business Media LLC. - 2055-0278. ; 5:9, s. 944-951
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Tidskriftsartikel (refereegranskat)abstract
- Changes in terrestrial tropical carbon stocks have an important role in the global carbon budget. However, current observational tools do not allow accurate and large-scale monitoring of the spatial distribution and dynamics of carbon stocks1. Here, we used low-frequency L-band passive microwave observations to compute a direct and spatially explicit quantification of annual aboveground carbon (AGC) fluxes and show that the tropical net AGC budget was approximately in balance during 2010 to 2017, the net budget being composed of gross losses of −2.86 PgC yr−1 offset by gross gains of −2.97 PgC yr−1 between continents. Large interannual and spatial fluctuations of tropical AGC were quantified during the wet 2011 La Niña year and throughout the extreme dry and warm 2015–2016 El Niño episode. These interannual fluctuations, controlled predominantly by semiarid biomes, were shown to be closely related to independent global atmospheric CO2 growth-rate anomalies (Pearson’s r = 0.86), highlighting the pivotal role of tropical AGC in the global carbon budget.
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| 5. |
- Hovenden, Mark J., et al.
(författare)
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Globally consistent influences of seasonal precipitation limit grassland biomass response to elevated CO2
- 2019
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Ingår i: Nature Plants. - : Springer Science and Business Media LLC. - 2055-0278. ; 5, s. 167-173
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Tidskriftsartikel (refereegranskat)abstract
- © 2019, The Author(s), under exclusive licence to Springer Nature Limited. Rising atmospheric carbon dioxide concentration should stimulate biomass production directly via biochemical stimulation of carbon assimilation, and indirectly via water savings caused by increased plant water-use efficiency. Because of these water savings, the CO 2 fertilization effect (CFE) should be stronger at drier sites, yet large differences among experiments in grassland biomass response to elevated CO 2 appear to be unrelated to annual precipitation, preventing useful generalizations. Here, we show that, as predicted, the impact of elevated CO 2 on biomass production in 19 globally distributed temperate grassland experiments reduces as mean precipitation in seasons other than spring increases, but that it rises unexpectedly as mean spring precipitation increases. Moreover, because sites with high spring precipitation also tend to have high precipitation at other times, these effects of spring and non-spring precipitation on the CO 2 response offset each other, constraining the response of ecosystem productivity to rising CO 2 . This explains why previous analyses were unable to discern a reliable trend between site dryness and the CFE. Thus, the CFE in temperate grasslands worldwide will be constrained by their natural rainfall seasonality such that the stimulation of biomass by rising CO 2 could be substantially less than anticipated.
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| 6. |
- Li, Tao, et al.
(författare)
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Amplification of plant volatile defence against insect herbivory in a warming Arctic tundra
- 2019
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Ingår i: Nature Plants. - : Springer Science and Business Media LLC. - 2055-0278. ; 5, s. 568-574
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Tidskriftsartikel (refereegranskat)abstract
- Plant-emitted volatile organic compounds (VOCs) play fundamental roles in atmospheric chemistry and ecological processes by contributing to aerosol formation1 and mediating species interactions2. Rising temperatures and the associated shifts in vegetation composition have been shown to be the primary drivers of plant VOC emissions in Arctic ecosystems3. Although herbivorous insects also strongly alter plant VOC emissions2, no studies have addressed the impact of herbivory on plant VOC emissions in the Arctic. Here we show that warming dramatically increases the amount, and alters the blend, of VOCs released in response to herbivory. We observed that a tundra ecosystem subjected to warming, by open-top chambers, for 8 or 18 years showed a fourfold increase in leaf area eaten by insect herbivores. Herbivory by autumnal moth (Epirrita autumnata) larvae, and herbivory-mimicking methyl jasmonate application, on the widespread circumpolar dwarf birch (Betula nana) both substantially increased emissions of terpenoids. The long-term warming treatments and mimicked herbivory caused, on average, a two- and fourfold increase in monoterpene emissions, respectively. When combined, emissions increased 11-fold, revealing a strong synergy between warming and herbivory. The synergistic effect was even more pronounced for homoterpene emissions. These findings suggest that, in the rapidly warming Arctic, insect herbivory may be a primary determinant of VOC emissions during periods of active herbivore feeding.
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