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Lang W, Chen X, Qian S, Schwartz MD. Temperature variations impacting leaf senescence initiation pathways alter leaf fall timing patterns in northern deciduous forests. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 934:173280. [PMID: 38768721 DOI: 10.1016/j.scitotenv.2024.173280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 04/23/2024] [Accepted: 05/13/2024] [Indexed: 05/22/2024]
Abstract
Simulating the timing of leaf fall in large scale is crucial for accurate estimation of ecosystem carbon sequestration. However, the limited understanding of leaf senescence mechanisms often impedes the accuracy of simulation and prediction. In this study, we employed the advanced process-based models to fit remote sensing-derived end dates of the growing season (EOS) across deciduous broadleaf forests in the Northern Hemisphere, and revealed the spatial pattern associated with two leaf senescence pathways (i.e., either photoperiod- or temperature- initiated leaf senescence) and their potential effects on EOS prediction. The results show that the pixel-specific optimum models effectively fitted all EOS time series. Leaf senescence in 67.6 % and 32.4 % of pixels was initiated by shortening daylength and declining temperature, respectively. Shortening daylength triggered leaf senescence occurs mainly in areas with shorter summer daylength and/or warmer autumns, whereas declining temperature induced leaf senescence appears primarily in areas with longer summer daylength and/or colder autumns. The strong dependence of leaf senescence initiation cues on local temperature conditions implies that the ongoing increase in autumn temperature has the potential to alter the leaf senescence initiation, shifting from temperature cues to photoperiod signals. This shift would occur in 26.2-49.6 % of the areas where leaf senescence is initiated by declining temperature under RCP 4.5 and 8.5 scenarios, while forest areas where leaf senescence is induced by shortening daylength may expand northward. The overall delaying of the currently predicted EOS would therefore slow down by 4.5-10.3 % under the two warming scenarios. This implies that the adaptive nature of plants will reduce the overestimation of changes in carbon exchange capacity between ecosystems and atmosphere. Our study offers novel insights into understanding the mechanism of leaf senescence and improving the estimation of autumn phenology and ecosystem carbon balance in the deciduous broadleaf forests.
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Affiliation(s)
- Weiguang Lang
- College of Urban and Environmental Sciences, Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China
| | - Xiaoqiu Chen
- College of Urban and Environmental Sciences, Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China.
| | - Siwei Qian
- College of Urban and Environmental Sciences, Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China
| | - Mark D Schwartz
- Department of Geography, University of Wisconsin-Milwaukee, Milwaukee, WI 53201-0413, USA
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2
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Tenkanen A, Keinänen M, Oksanen E, Keski-Saari S, Kontunen-Soppela S. Polar day syndrome: differences in growth, photosynthetic traits and sink-size patterns between northern and southern Finnish silver birch (Betula pendula Roth) provenances in native and non-native photoperiods. TREE PHYSIOLOGY 2023; 43:16-30. [PMID: 36049078 PMCID: PMC9833867 DOI: 10.1093/treephys/tpac104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 08/30/2022] [Indexed: 06/15/2023]
Abstract
Continuous light (CL) is available throughout the polar day for plants in the Arctic during the growing season, whereas provenances of the same species experience a very different environment with non-CL (NCL) just a few latitudes to the south. Both provenances need to acclimate to climate warming, yet we lack comprehensive understanding of how their growth, photosynthesis and leaf traits differ. Further, the provenances presumably have morphological and physiological adaptations to their native environments and therefore differ in response to photoperiod. We tested the height growth, leaf longevity, biomass accumulation, biomass allocation and rates of gas exchange of northern (67°N) and southern (61°N) Finnish silver birch (Betula pendula Roth) origins in CL- and NCL-treatments in a 4-month chamber experiment. Irrespective of photoperiod, 67°N had higher area-based photosynthetic rate (Anet), stomatal conductance (gs) and relative height growth rate (RGR), but lower stomatal density and fewer branches and leaves than 61°N. Photoperiod affected height growth cessation, biomass and photosynthetic traits, whereas leaf longevity and many leaf functional traits remained unchanged. In CL, both provenances had lower gs, higher RGR, increased shoot:root ratio and increased sink sizes (more branching, more leaves, increased total plant dry weight) compared with NCL. In NCL, 67°N ceased height growth earlier than in CL, which altered biomass accumulation and distribution patterns. Northern conditions impose challenges for plant growth and physiology. Whether a provenance inhabits and is adapted to an area with or without CL can also affect its response to the changing climate. Northern birches may have adapted to CL and the short growing season with a 'polar day syndrome' of traits, including relatively high gas exchange rates with low leaf biomass and growth traits that are mainly limited by the environment and the earlier growth cessation (to avoid frost damage).
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Affiliation(s)
- Antti Tenkanen
- University of Eastern Finland, Department of Environmental and Biological Sciences, Yliopistokatu 7, P.O. Box 111, 80101 Joensuu, Finland
| | - Markku Keinänen
- University of Eastern Finland, Department of Environmental and Biological Sciences, Yliopistokatu 7, P.O. Box 111, 80101 Joensuu, Finland
- University of Eastern Finland, Institute of Photonics, Yliopistokatu 7, PO Box 111, 80101 Joensuu, Finland
| | - Elina Oksanen
- University of Eastern Finland, Department of Environmental and Biological Sciences, Yliopistokatu 7, P.O. Box 111, 80101 Joensuu, Finland
| | - Sarita Keski-Saari
- University of Eastern Finland, Department of Environmental and Biological Sciences, Yliopistokatu 7, P.O. Box 111, 80101 Joensuu, Finland
| | - Sari Kontunen-Soppela
- University of Eastern Finland, Department of Environmental and Biological Sciences, Yliopistokatu 7, P.O. Box 111, 80101 Joensuu, Finland
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3
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Peaucelle M, Peñuelas J, Verbeeck H. Accurate phenology analyses require bud traits and energy budgets. NATURE PLANTS 2022; 8:915-922. [PMID: 35953710 DOI: 10.1038/s41477-022-01209-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
Spring phenology is mainly driven by temperature in extratropical ecosystems. Recent evidence highlighted the key role of micrometeorology and bud temperature on delaying or advancing leaf unfolding. Yet, phenology studies, either using ground-based or remote sensing observations, always substitute plant tissue temperature by air temperature. In fact, temperatures differ substantially between plant tissues and the air because plants absorb and lose energy. Here, we build on recent observations and well-established energy balance theories to discuss how solar radiation, wind and bud traits might affect our interpretation of spring phenology sensitivity to warming. We show that air temperature might be an imprecise and biased predictor of bud temperature. Better characterizing the plants' phenological response to warming will require new observations of bud traits and temperature for accurately quantifying their energy budget. As consistent micrometeorology datasets are still scarce, new approaches coupling energy budget modelling and plant traits could help to improve phenology analyses across scales.
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Affiliation(s)
- Marc Peaucelle
- INRAE, Université de Bordeaux, UMR 1391 ISPA, Villenave-d'Ornon, France.
- Computational and Applied Vegetation Ecology - CAVElab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
| | - Josep Peñuelas
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Barcelona, Spain
- CREAF, Cerdanyola del Vallès, Barcelona, Spain
| | - Hans Verbeeck
- Computational and Applied Vegetation Ecology - CAVElab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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4
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Mannucci A, Scartazza A, Santaniello A, Castagna A, Santin M, Quartacci MF, Ranieri A. Short daily ultraviolet exposure enhances intrinsic water-use efficiency and delays senescence in Micro-Tom tomato plants. FUNCTIONAL PLANT BIOLOGY : FPB 2022; 49:810-821. [PMID: 35598892 DOI: 10.1071/fp22013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Abstract
Ultraviolet (UV) radiation, unless present at high doses, is recognised as a regulator of plant growth and some specific processes. The present study investigated the influence of short daily UV irradiation (15min/day, 11days) on leaf gas exchange and some biochemical and molecular markers of leaf senescence (such as stomata movements, chlorophyll breakdown, anthocyanin production, senescence-associated genes) in Micro-Tom tomato plants. The UV-induced reduction of g s (stomatal conductance) during the treatment was associated with the modified expression of some genes involved in the control of stomatal movements. We hypothesise a two-step regulation of stomatal closure involving salicylic and abscisic acid hormones. The temporal changes of g s and A net (net photosynthetic CO2 assimilation rate) along with the pigment behaviour, suggest a possible delay of leaf senescence in treated plants, confirmed by the expression levels of genes related to senescence such as SAG113 and DFR . The UV potential to induce a persistent partial inhibition of g s without severely affecting A net led to an increased iWUE (intrinsic water-use efficiency) during the 11-day treatment, suggesting a priming effect of short daily UV radiation towards drought conditions potentially useful in reducing the excess water use in agriculture.
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Affiliation(s)
- Alessia Mannucci
- Department of Agriculture, Food and Environment, University of Pisa, Pisa, PI, Italy
| | - Andrea Scartazza
- Institute of Research on Terrestrial Ecosystems, National Research Council, Pisa, PI, Italy
| | | | - Antonella Castagna
- Department of Agriculture, Food and Environment, University of Pisa, Pisa, PI, Italy
| | - Marco Santin
- Department of Agriculture, Food and Environment, University of Pisa, Pisa, PI, Italy
| | - Mike Frank Quartacci
- Department of Agriculture, Food and Environment, University of Pisa, Pisa, PI, Italy
| | - Annamaria Ranieri
- Department of Agriculture, Food and Environment, University of Pisa, Pisa, PI, Italy
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5
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Brelsford CC, Trasser M, Paris T, Hartikainen SM, Robson TM. Understorey light quality affects leaf pigments and leaf phenology in different plant functional types. PHYSIOLOGIA PLANTARUM 2022; 174:e13723. [PMID: 35606930 PMCID: PMC9328371 DOI: 10.1111/ppl.13723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/29/2022] [Accepted: 05/22/2022] [Indexed: 05/12/2023]
Abstract
Forest understorey plants receive most sunlight in springtime before canopy closure, and in autumn following leaf-fall. We hypothesised that plant species must adjust their phenological and photoprotective strategies in response to large changes in the spectral composition of the sunlight they receive. Here, we identified how plant species growing in northern deciduous and evergreen forest understoreys differ in their response to blue light and ultraviolet (UV) radiation according to their functional strategy. We installed filters in a forest understorey in southern Finland, to create the following treatments attenuating: UV radiation below 350 nm, all UV radiation (< 400 nm), all blue light and UV radiation (< 500 nm), and a transparent control. In eight species, representing different functional strategies, we assessed leaf optical properties, phenology, and epidermal flavonoid contents over two years. Blue light accelerated leaf senescence in all species measured in the understorey, apart from Quercus robur seedlings, whereas UV radiation only accelerated leaf senescence in Acer platanoides seedlings. More light-demanding species accumulated flavonols in response to seasonal changes in light quality compared to shade-tolerant and wintergreen species and were particularly responsive to blue light. Reduction of blue and UV radiation under shade reveals an important role for microclimatic effects on autumn phenology and leaf photoprotection. An extension of canopy cover under climate change, and its associated suppression of understorey blue light and UV radiation, may delay leaf senescence for understorey species with an autumn niche.
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Affiliation(s)
- Craig C. Brelsford
- Yield SystemsEspooFinland
- Organismal and Evolutionary Biology (OEB), Viikki Plant Science Centre (ViPS), Faculty of Biological and Environmental SciencesUniversity of HelsinkiHelsinkiFinland
| | - Marieke Trasser
- Gregor Mendel Institute of Molecular Plant BiologyViennaAustria
- Vienna BioCenter PhD ProgramDoctoral School of the University of Vienna and Medical University of ViennaViennaAustria
| | - Tom Paris
- EcodivNormandie Université, UNIROUENRouenFrance
| | - Saara M. Hartikainen
- Organismal and Evolutionary Biology (OEB), Viikki Plant Science Centre (ViPS), Faculty of Biological and Environmental SciencesUniversity of HelsinkiHelsinkiFinland
| | - T. Matthew Robson
- Organismal and Evolutionary Biology (OEB), Viikki Plant Science Centre (ViPS), Faculty of Biological and Environmental SciencesUniversity of HelsinkiHelsinkiFinland
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6
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Long-Term Vegetation Phenology Changes and Responses to Preseason Temperature and Precipitation in Northern China. REMOTE SENSING 2022. [DOI: 10.3390/rs14061396] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Due to the complex coupling between phenology and climatic factors, the influence mechanism of climate, especially preseason temperature and preseason precipitation, on vegetation phenology is still unclear. In the present study, we explored the long-term trends of phenological parameters of different vegetation types in China north of 30°N from 1982 to 2014 and their comprehensive responses to preseason temperature and precipitation. Simultaneously, annual double-season phenological stages were considered. Results show that the satellite-based phenological data were corresponding with the ground-based phenological data. Our analyses confirmed that the preseason temperature has a strong controlling effect on vegetation phenology. The start date of the growing season (SOS) had a significant advanced trend for 13.5% of the study area, and the end date of the growing season (EOS) showed a significant delayed trend for 23.1% of the study area. The impact of preseason precipitation on EOS was overall stronger than that on SOS, and different vegetation types had different responses. Compared with other vegetation types, SOS and EOS of crops were greatly affected by human activities while the preseason precipitation had less impact. This study will help us to make a scientific decision to tackle global climate change and regulate ecological engineering.
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Influence of Replacement of Sodium Lamps in Park Luminaires with LED Sources of Different Closest Color Temperature on the Effect of Light Pollution and Energy Efficiency. ENERGIES 2021. [DOI: 10.3390/en14196383] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
According to the European Union (EU) regulations, EU members are obligated, among others, to improve the energy efficiency in the outdoor lighting sector. One of the ways to consider this fact is to install LED sources in luminaires. Due to the reasonable lighting requirements for the lighting of squares and parks, the cheapest way to modernize lighting is to replace conventional discharge lamps with LED sources in park luminaires. Using nine typical park luminaires, the influence of replacing classic sodium lamps with LED sources on the effect of light pollution and energy efficiency was analyzed. Using data, such as a photometric solid and a relative spectral distribution, simulation calculations were carried out in DIALux software and our own calculation tool to consider this issue. The studies considered 156 LED sources of different spectral distributions and a wide range of color temperatures from 1000 K to 9753 K as well as different color rendering index (CRI) values. The conducted studies showed that the replacement of sodium lamps with LED sources is not necessarily associated with an increased negative impact on the effect of light pollution. It was also found also that the CRI value has an influence on the degree of light pollution.
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8
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Quantitative genetic architecture of adaptive phenology traits in the deciduous tree, Populus trichocarpa (Torr. and Gray). Heredity (Edinb) 2020; 125:449-458. [PMID: 32901141 PMCID: PMC7784687 DOI: 10.1038/s41437-020-00363-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 08/26/2020] [Accepted: 08/27/2020] [Indexed: 12/02/2022] Open
Abstract
In a warming climate, the ability to accurately predict and track shifting environmental conditions will be fundamental for plant survival. Environmental cues define the transitions between growth and dormancy as plants synchronise development with favourable environmental conditions, however these cues are predicted to change under future climate projections which may have profound impacts on tree survival and growth. Here, we use a quantitative genetic approach to estimate the genetic basis of spring and autumn phenology in Populus trichocarpa to determine this species capacity for climate adaptation. We measured bud burst, leaf coloration, and leaf senescence traits across two years (2017–2018) and combine these observations with measures of lifetime growth to determine how genetic correlations between phenology and growth may facilitate or constrain adaptation. Timing of transitions differed between years, although we found strong cross year genetic correlations in all traits, suggesting that genotypes respond in consistent ways to seasonal cues. Spring and autumn phenology were correlated with lifetime growth, where genotypes that burst leaves early and shed them late had the highest lifetime growth. We also identified substantial heritable variation in the timing of all phenological transitions (h2 = 0.5–0.8) and in lifetime growth (h2 = 0.8). The combination of additive variation and favourable genetic correlations in phenology traits suggests that populations of cultivated varieties of P. Trichocarpa may have the capability to adapt their phenology to climatic changes without negative impacts on growth.
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9
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The Complex Issue of Urban Trees—Stress Factor Accumulation and Ecological Service Possibilities. FORESTS 2020. [DOI: 10.3390/f11090932] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This review paper is the first that summarizes many aspects of the ecological role of trees in urban landscapes while considering their growth conditions. Research Highlights are: (i) Plant growth conditions in cities are worsening due to high urbanization rates and new stress factors; (ii) Urban trees are capable of alleviating the stress factors they are exposed to; (iii) The size and vitality of trees is related to the ecological services they can provide. Our review shows, in a clear way, that the phenomenon of human-related environmental degradation, which generates urban tree stress, can be effectively alleviated by the presence of trees. The first section reviews concerns related to urban environment degradation and its influence on trees. Intense urbanization affects the environment of plants, raising the mortality rate of urban trees. The second part deals with the dieback of city trees, its causes and scale. The average life expectancy of urban trees is relatively low and depends on factors such as the specific location, proper care and community involvement, among others. The third part concerns the ecological and economic advantages of trees in the city structure. Trees affect citizen safety and health, but also improve the soil and air environment. Finally, we present the drawbacks of tree planting and discuss if they are caused by the tree itself or rather by improper tree management. We collect the latest reports on the complicated state of urban trees, presenting new insights on the complex issue of trees situated in cities, struggling with stress factors. These stressors have evolved over the decades and emphasize the importance of tree presence in the city structure.
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10
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Marchand LJ, Dox I, Gričar J, Prislan P, Leys S, Van den Bulcke J, Fonti P, Lange H, Matthysen E, Peñuelas J, Zuccarini P, Campioli M. Inter-individual variability in spring phenology of temperate deciduous trees depends on species, tree size and previous year autumn phenology. AGRICULTURAL AND FOREST METEOROLOGY 2020; 290:108031. [PMID: 32817727 PMCID: PMC7304479 DOI: 10.1016/j.agrformet.2020.108031] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 05/05/2020] [Accepted: 05/06/2020] [Indexed: 05/27/2023]
Abstract
We explored the inter-individual variability in bud-burst and its potential drivers, in homogeneous mature stands of temperate deciduous trees. Phenological observations of leaves and wood formation were performed weekly from summer 2017 to summer 2018 for pedunculate oak, European beech and silver birch in Belgium. The variability of bud-burst was correlated to previous' year autumn phenology (i.e. the onset of leaf senescence and the cessation of wood formation) and tree size but with important differences among species. In fact, variability of bud-burst was primarily related to onset of leaf senescence, cessation of wood formation and tree height for oak, beech and birch, respectively. The inter-individual variability of onset of leaf senescence was not related to the tree characteristics considered and was much larger than the inter-individual variability in bud-burst. Multi-species multivariate models could explain up to 66% of the bud-burst variability. These findings represent an important advance in our fundamental understanding and modelling of phenology and tree functioning of deciduous tree species.
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Affiliation(s)
- Lorène Julia Marchand
- Centre of Excellence PLECO (Plants and Ecosystems), Department of Biology, University of Antwerp, 2160Wilrijk, Belgium
- UMR 6553 ECOBIO (Ecosystèmes, Biodiversité, Evolution), Université de Rennes 1, CNRS, 263 Av. du Général Leclerc, 35042Rennes, France
| | - Inge Dox
- Centre of Excellence PLECO (Plants and Ecosystems), Department of Biology, University of Antwerp, 2160Wilrijk, Belgium
| | - Jožica Gričar
- Department of Yield and Silviculture, Slovenian Forestry Institute, Vecna pot 2, 1000Ljubljana, Slovenia
| | - Peter Prislan
- Department of Yield and Silviculture, Slovenian Forestry Institute, Vecna pot 2, 1000Ljubljana, Slovenia
| | - Sebastien Leys
- Centre of Excellence PLECO (Plants and Ecosystems), Department of Biology, University of Antwerp, 2160Wilrijk, Belgium
| | - Jan Van den Bulcke
- Laboratory of Wood Technology, UGent-Woodlab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000Gent, Belgium
| | - Patrick Fonti
- Swiss Federal Research Institute WSL, Zürcherstrasse 111, 8903Birmensdorf, Switzerland
| | - Holger Lange
- NIBIO (Norwegian Institute of Bioeconomy Research), Division of Environment and Natural Resources, Høgskoleveien 8, 1433Ås, Norway
| | - Erik Matthysen
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, 2160Wilrijk, Belgium
| | - Josep Peñuelas
- Centre for Research on Ecology and Forestry Applications (CREAF), Cerdanyola del Vallès, Barcelona, Spain
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra 08193, Spain
| | - Paolo Zuccarini
- Centre for Research on Ecology and Forestry Applications (CREAF), Cerdanyola del Vallès, Barcelona, Spain
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra 08193, Spain
| | - Matteo Campioli
- Centre of Excellence PLECO (Plants and Ecosystems), Department of Biology, University of Antwerp, 2160Wilrijk, Belgium
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11
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Peaucelle M, Janssens IA, Stocker BD, Descals Ferrando A, Fu YH, Molowny-Horas R, Ciais P, Peñuelas J. Spatial variance of spring phenology in temperate deciduous forests is constrained by background climatic conditions. Nat Commun 2019; 10:5388. [PMID: 31772185 PMCID: PMC6879605 DOI: 10.1038/s41467-019-13365-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 11/04/2019] [Indexed: 11/26/2022] Open
Abstract
Leaf unfolding in temperate forests is driven by spring temperature, but little is known about the spatial variance of that temperature dependency. Here we use in situ leaf unfolding observations for eight deciduous tree species to show that the two factors that control chilling (number of cold days) and heat requirement (growing degree days at leaf unfolding, GDDreq) only explain 30% of the spatial variance of leaf unfolding. Radiation and aridity differences among sites together explain 10% of the spatial variance of leaf unfolding date, and 40% of the variation in GDDreq. Radiation intensity is positively correlated with GDDreq and aridity is negatively correlated with GDDreq spatial variance. These results suggest that leaf unfolding of temperate deciduous trees is adapted to local mean climate, including water and light availability, through altered sensitivity to spring temperature. Such adaptation of heat requirement to background climate would imply that models using constant temperature response are inherently inaccurate at local scale.
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Affiliation(s)
- Marc Peaucelle
- CREAF, Cerdanyola del Vallès, Barcelona, 08193, CA, Spain.
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Barcelona, 08193, CA, Spain.
- Computational and Applied Vegetation Ecology - CAVElab, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium.
| | - Ivan A Janssens
- Department of Biology, University of Antwerp, Wilrijk, 2610, Belgium
| | - Benjamin D Stocker
- CREAF, Cerdanyola del Vallès, Barcelona, 08193, CA, Spain
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Barcelona, 08193, CA, Spain
- Institute of Agricultural Sciences, Department for Environmental Systems Science, ETH Zürich, Universitätsstrasse 2, 8006, Zürich, Switzerland
| | - Adrià Descals Ferrando
- CREAF, Cerdanyola del Vallès, Barcelona, 08193, CA, Spain
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Barcelona, 08193, CA, Spain
| | - Yongshuo H Fu
- College of Water Sciences, Beijing Normal University Beijing, Beijing, China
| | | | - Philippe Ciais
- Laboratoire des Sciences du Climat et de l'Environnement, UMR 1572 CEA-CNRS UVSQ, 91191, Gif sur Yvette, France
| | - Josep Peñuelas
- CREAF, Cerdanyola del Vallès, Barcelona, 08193, CA, Spain
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Barcelona, 08193, CA, Spain
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12
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Robson TM, Aphalo PJ. Transmission of ultraviolet, visible and near-infrared solar radiation to plants within a seasonal snow pack. Photochem Photobiol Sci 2019; 18:1963-1971. [PMID: 31342042 DOI: 10.1039/c9pp00197b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sunlight is strongly attenuated by the snowpack, causing irradiance to decrease exponentially with depth. The strength of attenuation is wavelength dependent across the spectrum. Changes in received irradiance and its spectral composition are used by plants as cues for the timing of phenology, and it is known that at shallow depths in the snowpack there is sufficient light for plants to photosynthesize if conditions are otherwise favourable. The spectral composition of solar radiation under snow in the visible region was already determined in the 1970s using scanning spectroradiometers, but spectral attenuation within the ultraviolet region (UV-B 280-315 nm, UV-A 315-400 nm) has not been well characterised because it is difficult to measure. We measured vertical transects of spectral irradiance (290-900 nm) transmitted through a settled seasonal snowpack. The peak transmission of radiation was in the UV-A region in the upper centimetres of the snowpack and transmittance generally declined at longer wavelengths. Given the known action spectra of plant photoreceptors, these results illustrate the possibility that changing UV-A : visible and red : far-red radiation ratios under the snowpack may serve as spectral cues for plants; potentially priming plants for the less stable environment they experience following snowmelt. Array spectrometers open opportunities for rapid and continuous measurement of irradiance in challenging environments, e.g. beneath the snowpack, and capturing changing light conditions for plants. Future research is needed to couple the spectral transmittance of snowpacks differing in their longevity and crystal structure with measurements of the perception and response to radiation by plants under snow.
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Affiliation(s)
- T Matthew Robson
- Organismal and Evolutionary Biology (OEB), Viikki Plant Science Centre (ViPS), P.O. Box 65, Faculty of Biological and Environmental Science, 00014, University of Helsinki, Finland.
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