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Italiano SSP, Camarero JJ, Borghetti M, Colangelo M, Rita A, Ripullone F. Drought legacies in mixed Mediterranean forests: Analysing the effects of structural overshoot, functional traits and site factors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 927:172166. [PMID: 38575023 DOI: 10.1016/j.scitotenv.2024.172166] [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: 10/13/2023] [Revised: 03/09/2024] [Accepted: 03/31/2024] [Indexed: 04/06/2024]
Abstract
Previous favorable climate conditions stimulate tree growth making some forests more vulnerable to hotter droughts. This so-called structural overshoot may contribute to forest dieback, but there is little evidence on its relative importance depending on site conditions and tree species because of limited field data. Here, we analyzed remote sensing (NDVI) and tree-ring width data to evaluate the impacts of the 2017 drought on canopy cover and growth in mixed Mediterranean forests (Fraxinus ornus, Quercus pubescens, Acer monspessulanum, Pinus pinaster) located in southern Italy. Legacy effects were assessed by calculating differences between observed and predicted basal area increment (BAI). Overall, the growth response of the study stands to the 2017 drought was contingent on site conditions and species characteristics. Most sites presented BAI and canopy cover reductions during the drought. Growth decline was followed by a quick recovery and positive legacy effects, particularly in the case of F. ornus. However, we found negative drought legacies in some species (e.g., Q. pubescens, A. monspessulanum) and sites. In those sites showing negative legacies, high growth rates prior to drought in response to previous wet winter-spring conditions may have predisposed trees to drought damage. Vice versa, the positive drought legacy found in some F. ornus site was linked to post-drought growth release due to Q. pubescens dieback and mortality. Therefore, we found evidences of structural drought overshoot, but it was restricted to specific sites and species. Our findings highlight the importance of considering site settings such as stand composition, pre-drought conditions and different tree species when studying structural overshoot. Droughts contribute to modify the composition and dynamics in mixed forests.
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Affiliation(s)
- Santain S P Italiano
- Scuola di Scienze Agrarie, Forestali, Alimentari e Ambientali, Università della Basilicata, Viale dell'Ateneo Lucano 10, 85100 Potenza, Italy.
| | - J Julio Camarero
- Instituto Pirenaico de Ecología (IPE-CSIC), Avda. Montañana 1005, E-50192 Zaragoza, Spain.
| | - Marco Borghetti
- Scuola di Scienze Agrarie, Forestali, Alimentari e Ambientali, Università della Basilicata, Viale dell'Ateneo Lucano 10, 85100 Potenza, Italy.
| | - Michele Colangelo
- Scuola di Scienze Agrarie, Forestali, Alimentari e Ambientali, Università della Basilicata, Viale dell'Ateneo Lucano 10, 85100 Potenza, Italy; Instituto Pirenaico de Ecología (IPE-CSIC), Avda. Montañana 1005, E-50192 Zaragoza, Spain.
| | - Angelo Rita
- Dipartimento di Agraria, Università di Napoli Federico II, via Università 100, IT-80055 Portici, Napoli, Italy.
| | - Francesco Ripullone
- Scuola di Scienze Agrarie, Forestali, Alimentari e Ambientali, Università della Basilicata, Viale dell'Ateneo Lucano 10, 85100 Potenza, Italy.
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Stanfield RC, Forrestel EJ, Elmendorf KE, Bagshaw SB, Bartlett MK. Phloem anatomy predicts berry sugar accumulation across 13 wine-grape cultivars. FRONTIERS IN PLANT SCIENCE 2024; 15:1360381. [PMID: 38576794 PMCID: PMC10991835 DOI: 10.3389/fpls.2024.1360381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 02/19/2024] [Indexed: 04/06/2024]
Abstract
Introduction Climate change is impacting the wine industry by accelerating ripening processes due to warming temperatures, especially in areas of significant grape production like California. Increasing temperatures accelerate the rate of sugar accumulation (measured in ⁰Brix) in grapes, however this presents a problem to wine makers as flavor profiles may need more time to develop properly. To alleviate the mismatch between sugar accumulation and flavor compounds, growers may sync vine cultivars with climates that are most amenable to their distinct growing conditions. However, the traits which control such cultivar specific climate adaptation, especially for ⁰Brix accumulation rate, are poorly understood. Recent studies have shown that higher rates of fruit development and sugar accumulation are predicted by larger phloem areas in different organs of the plant. Methods Here we test this phloem area hypothesis using a common garden experiment in the Central Valley of Northern California using 18 cultivars of the common grapevine (Vitis vinifera) and assess the grape berry sugar accumulation rates as a function of phloem area in leaf and grape organs. Results We find that phloem area in the leaf petiole organ as well as the berry pedicel is a significant predictor of ⁰Brix accumulation rate across 13 cultivars and that grapes from warm climates overall have larger phloem areas than those from hot climates. In contrast, other physiological traits such as photosynthetic assimilation and leaf water potential did not predict berry accumulation rates. Discussion As hot climate cultivars have lower phloem areas which would slow down brix accumulation, growers may have inadvertently been selecting this trait to align flavor development with sugar accumulation across the common cultivars tested. This work highlights a new trait that can be easily phenotyped (i.e., petiole phloem area) and be used for growers to match cultivar more accurately with the temperature specific climate conditions of a growing region to obtain satisfactory sugar accumulation and flavor profiles.
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Affiliation(s)
- Ryan C. Stanfield
- Department of Biological Sciences, California State University, Stanislaus, Turlock, CA, United States
- Department of Viticulture & Enology, University of California Davis, Davis, CA, United States
| | - Elisabeth J. Forrestel
- Department of Viticulture & Enology, University of California Davis, Davis, CA, United States
| | - Kayla E. Elmendorf
- Department of Viticulture & Enology, University of California Davis, Davis, CA, United States
| | - Sophia B. Bagshaw
- Department of Viticulture & Enology, University of California Davis, Davis, CA, United States
| | - Megan K. Bartlett
- Department of Viticulture & Enology, University of California Davis, Davis, CA, United States
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Yule TS, de Oliveira Arruda RDC, Santos MG. Drought-adapted leaves are produced even when more water is available in dry tropical forest. JOURNAL OF PLANT RESEARCH 2024; 137:49-64. [PMID: 37962735 DOI: 10.1007/s10265-023-01505-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 10/19/2023] [Indexed: 11/15/2023]
Abstract
Species in dry environments may adjust their anatomical and physiological behaviors by adopting safer or more efficient strategies. Thus, species distributed across a water availability gradient may possess different phenotypes depending on the specific environmental conditions to which they are subjected. Leaf and vascular tissues are plastic and may vary strongly in response to environmental changes affecting an individual's survival and species distribution. To identify whether and how legumes leaves vary across a water availability gradient in a seasonally dry tropical forest, we quantified leaf construction costs and performed an anatomical study on the leaves of seven legume species. We evaluated seven species, which were divided into three categories of rainfall preference: wet species, which are more abundant in wetter areas; indifferent species, which are more abundant and occur indistinctly under both rainfall conditions; and dry species, which are more abundant in dryer areas. We observed two different patterns based on rainfall preference categories. Contrary to our expectations, wet and indifferent species changed traits in the sense of security when occupying lower rainfall areas, whereas dry species changed some traits when more water was available, such as increasing cuticle and spongy parenchyma thickness, or producing smaller and more numerous stomata. Trischidium molle, the most plastic and wet species, exhibited a similar strategy to the dry species. Our results corroborate the risks to vegetation under future climate change scenarios as stressed species and populations may not endure even more severe conditions.
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Affiliation(s)
- Tamires Soares Yule
- Laboratório de Fisiologia Vegetal, Programa de Pós-Graduação em Biologia Vegetal, Centro de Biociências, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil.
- Laboratório de Anatomia Vegetal, Programa de Pós-Graduação em Biologia Vegetal, Instituto de Biociências, Universidade Federal de Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brazil.
- Instituto de Biociências, Laboratório de Botânica, Universidade Federal de Mato Grosso do Sul, Av. Costa e Silva, s/n, Cidade Universitária, Campo Grande, Mato Grosso do Sul, 79070-900, Brazil.
| | - Rosani do Carmo de Oliveira Arruda
- Laboratório de Anatomia Vegetal, Programa de Pós-Graduação em Biologia Vegetal, Instituto de Biociências, Universidade Federal de Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brazil
| | - Mauro Guida Santos
- Laboratório de Fisiologia Vegetal, Programa de Pós-Graduação em Biologia Vegetal, Centro de Biociências, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
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Petit G, Mencuccini M, Carrer M, Prendin AL, Hölttä T. Axial conduit widening, tree height, and height growth rate set the hydraulic transition of sapwood into heartwood. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:5072-5087. [PMID: 37352139 DOI: 10.1093/jxb/erad227] [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: 01/31/2023] [Accepted: 06/12/2023] [Indexed: 06/25/2023]
Abstract
The size-related xylem adjustments required to maintain a constant leaf-specific sapwood conductance (KLEAF) with increasing height (H) are still under discussion. Alternative hypotheses are that: (i) the conduit hydraulic diameter (Dh) at any position in the stem and/or (ii) the number of sapwood rings at stem base (NSWr) increase with H. In addition, (iii) reduced stem elongation (ΔH) increases the tip-to-base conductance through inner xylem rings, thus possibly the NSWr contributing to KLEAF. A detailed stem analysis showed that Dh increased with the distance from the ring apex (DCA) in all rings of a Picea abies and a Fagus sylvatica tree. Net of DCA effect, Dh did not increase with H. Using sapwood traits from a global dataset, NSWr increased with H, decreased with ΔH, and the mean sapwood ring width (SWrw) increased with ΔH. A numerical model based on anatomical patterns predicted the effects of H and ΔH on the conductance of inner xylem rings. Our results suggest that the sapwood/heartwood transition depends on both H and ΔH, and is set when the carbon allocation to maintenance respiration of living cells in inner sapwood rings produces a lower gain in total conductance than investing the same carbon in new vascular conduits.
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Affiliation(s)
- Giai Petit
- Università degli Studi di Padova, Dept. TeSAF, Viale dell'Università 16, 35020 Legnaro (PD), Italy
| | - Maurizio Mencuccini
- CREAF, Bellaterra (Cerdanyola del Vallès), E08193, Spain
- ICREA, Pg. Lluís Companys 23, Barcelona, 08010, Spain
| | - Marco Carrer
- Università degli Studi di Padova, Dept. TeSAF, Viale dell'Università 16, 35020 Legnaro (PD), Italy
| | - Angela Luisa Prendin
- Università degli Studi di Padova, Dept. TeSAF, Viale dell'Università 16, 35020 Legnaro (PD), Italy
- Department of Biology, Ecoinformatics and Biodiversity, Aarhus University, Ny Munkegade 114-116, building 1540, 8000 Aarhus C, Denmark University of Aarhus, Denmark
| | - Teemu Hölttä
- Institute for Atmospheric and Earth System Research/ Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, FI 00014 Helsinki, Finland
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Shtein I, Gričar J, Lev-Yadun S, Oskolski A, Pace MR, Rosell JA, Crivellaro A. Priorities for Bark Anatomical Research: Study Venues and Open Questions. PLANTS (BASEL, SWITZERLAND) 2023; 12:1985. [PMID: 37653902 PMCID: PMC10221070 DOI: 10.3390/plants12101985] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 04/16/2023] [Accepted: 04/20/2023] [Indexed: 09/02/2023]
Abstract
The bark fulfils several essential functions in vascular plants and yields a wealth of raw materials, but the understanding of bark structure and function strongly lags behind our knowledge with respect to other plant tissues. The recent technological advances in sampling and preparation of barks for anatomical studies, along with the establishment of an agreed bark terminology, paved the way for more bark anatomical research. Whilst datasets reveal bark's taxonomic and functional diversity in various ecosystems, a better understanding of the bark can advance the understanding of plants' physiological and environmental challenges and solutions. We propose a set of priorities for understanding and further developing bark anatomical studies, including periderm structure in woody plants, phloem phenology, methods in bark anatomy research, bark functional ecology, relationships between bark macroscopic appearance, and its microscopic structure and discuss how to achieve these ambitious goals.
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Affiliation(s)
- Ilana Shtein
- Department of Molecular Biology, Milken Campus, Ariel University, Ariel 40700, Israel
- Eastern R&D Center, Milken Campus, Ariel 40700, Israel
| | - Jožica Gričar
- Department of Forest Physiology and Genetics, Slovenian Forestry Institute, 1000 Ljubljana, Slovenia
| | - Simcha Lev-Yadun
- Department of Biology & Environment, Faculty of Natural Sciences, University of Haifa-Oranim, Tivon 36006, Israel
| | - Alexei Oskolski
- Department of Botany and Plant Biotechnology, University of Johannesburg, Auckland Park, Johannesburg 2006, South Africa
- Komarov Botanical Institute, Russian Academy of Science, Prof. Popov Str. 2, 197376 St. Petersburg, Russia
| | - Marcelo R. Pace
- Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Julieta A. Rosell
- Laboratorio Nacional de Ciencias de la Sostenibilidad, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Alan Crivellaro
- Forest Biometrics Laboratory, Faculty of Forestry, “Stefan cel Mare” University of Suceava, Str. Universitatii 13, 720229 Suceava, Romania
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6
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Tang Y, Yin S, Pace MR, Gerolamo CS, Nogueira A, Zuntini AR, Lohmann LG, Plath M, Liesche J. Diameters of phloem sieve elements can predict stem growth rates of woody plants. TREE PHYSIOLOGY 2022; 42:1560-1569. [PMID: 35218199 DOI: 10.1093/treephys/tpac022] [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: 09/10/2021] [Accepted: 02/18/2022] [Indexed: 06/14/2023]
Abstract
Understanding forest dynamics is crucial to addressing climate change and reforestation challenges. Plant anatomy can help predict growth rates of woody plants, contributing key information on forest dynamics. Although features of the water-transport system (xylem) have long been used to predict plant growth, the potential contribution of carbon-transporting tissue (phloem) remains virtually unexplored. Here, we use data from 347 woody plant species to investigate whether species-specific stem diameter growth rates can be predicted by the diameter of both the xylem and phloem conducting cells when corrected for phylogenetic relatedness. We found positive correlations between growth rate, phloem sieve element diameter and xylem vessel diameter in liana species sampled in the field. Moreover, we obtained similar results for data extracted from the Xylem Database, an online repository of functional, anatomical and image data for woody plant species. Information from this database confirmed the correlation of sieve element diameter and growth rate across woody plants of various growth forms. Furthermore, we used data subsets to explore potential influences of biomes, growth forms and botanical family association. Subsequently, we combined anatomical and geoclimatic data to train an artificial neural network to predict growth rates. Our results demonstrate that sugar transport architecture is associated with growth rate to a similar degree as water-transport architecture. Furthermore, our results illustrate the potential value of artificial neural networks for modeling plant growth under future climatic scenarios.
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Affiliation(s)
- Yunjia Tang
- Northwest A&F University, College of Life Sciences, Yangling 712100, China
| | - Shijiao Yin
- Northwest A&F University, College of Life Sciences, Yangling 712100, China
- Biomass Energy Center for Arid Lands, Northwest A & F University, Yangling 712100, China
- State Key Laboratory of Stress Biology for Arid Areas, Northwest A&F University, Yangling 712100, China
| | - Marcelo R Pace
- Universidad Nacional Autónoma de México, Instituto de Biología, Departamento de Botánica, Circuito Zona Deportiva s.n., Apartado Postal 70-367, Ciudad Universitaria, Coyoacán, Mexico City 04510, Mexico
| | - Caian S Gerolamo
- Universidade de São Paulo, Instituto de Biociências, Departamento de Botânica, Rua do Matão, 277, Cidade Universitária, São Paulo, SP 05508-090, Brazil
| | - Anselmo Nogueira
- Universidade Federal do ABC, Centro de Ciências Naturais e Humanas (CCNH), Rua Arcturus, 03, São Bernardo do Campo, SP 09606-070, Brazil
| | | | - Lúcia G Lohmann
- Universidade de São Paulo, Instituto de Biociências, Departamento de Botânica, Rua do Matão, 277, Cidade Universitária, São Paulo, SP 05508-090, Brazil
| | - Martin Plath
- Northwest A&F University, College of Animal Science and Technology, Yangling 712100, China
| | - Johannes Liesche
- Northwest A&F University, College of Life Sciences, Yangling 712100, China
- Biomass Energy Center for Arid Lands, Northwest A & F University, Yangling 712100, China
- State Key Laboratory of Stress Biology for Arid Areas, Northwest A&F University, Yangling 712100, China
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Petit G, Zambonini D, Hesse BD, Häberle K. No xylem phenotypic plasticity in mature Picea abies and Fagus sylvatica trees after 5 years of throughfall precipitation exclusion. GLOBAL CHANGE BIOLOGY 2022; 28:4668-4683. [PMID: 35555836 PMCID: PMC9325500 DOI: 10.1111/gcb.16232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 05/03/2022] [Indexed: 06/15/2023]
Abstract
Forest trees are experiencing increasing frequency and intensity of drought events with climate change. We investigated xylem and phloem traits from mature Fagus sylvatica and Picea abies trees after 5 years of complete exclusion of throughfall precipitation during the growing season. Xylem and phloem anatomy, leaf and branch biomass were analysed along top branches of ~1.5 m lenght in 5 throughfall precipitation excluded (TE) and 5 control (CO) trees of both beech and spruce. Xylem traits were analysed on wood cores extracted from the stem at breast height. In the top branches of both species, the lumen diameter (or area) of xylem and phloem conduits did not differ between TE and CO trees. At breast height, TE trees of both species produced narrower xylem rings and conduits. While allocation to branch (BM) and needle biomass (LM) did not change between TE and CO in P. abies, TE F. sylvatica trees allocated proportionally more biomass to leaves (LM) than BM compared with CO. Despite artificial drought increased the mortality in the TE plots, our results revealed no changes in both xylem and phloem anatomies, undermining the hypothesis that successful acclimation to drought would primarily involve increased resistance against air embolism.
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Affiliation(s)
- Giai Petit
- Dipartimento Territorio e Sistemi Agro‐Forestali (TESAF)University of PadovaPadovaItaly
| | - Dario Zambonini
- Dipartimento Territorio e Sistemi Agro‐Forestali (TESAF)University of PadovaPadovaItaly
| | - Benjamin D. Hesse
- Land Surface‐Atmosphere InteractionsTechnical University of Munich, School of Life SciencesFreisingGermany
| | - Karl‐Heinz Häberle
- Chair of Restoration EcologyTechnical University of Munich, School of Life SciencesFreisingGermany
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Gričar J, Jevšenak J, Hafner P, Prislan P, Ferlan M, Lavrič M, Vodnik D, Eler K. Climatic regulation of leaf and cambial phenology in Quercus pubescens: Their interlinkage and impact on xylem and phloem conduits. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 802:149968. [PMID: 34525737 DOI: 10.1016/j.scitotenv.2021.149968] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 08/05/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
Increased frequency and severity of stressful events affects the growth patterns and functioning of trees which adjust their phenology to given conditions. Here, we analysed environmental effects (temperature, precipitation, VPD and SWC) on the timing of leaf phenology, seasonal stem radial growth patterns, and xylem and phloem anatomy of Quercus pubescens in the sub-Mediterranean in the period 2014-2019, when various adverse weather events occurred, i.e. spring drought in 2015, summer fire in 2016 and summer drought in 2017. Results showed that the timings of leaf and cambium phenology do not occur simultaneously in Q. pubescens, reflecting different environmental and internal constraints. Although year-to-year variability in the timings of leaf and cambial phenology exists, their chronological sequence is fairly fixed. Different effects of weather conditions on different stages of leaf development in spring were observed. Common climatic drivers (i.e., negative effect of hot and dry summers and a positive effect of increasing moisture availability in winter and summer) were found to affect the widths of xylem and phloem increments with more pronounced effect on late formed parts. A legacy effect of the timing of leaf and cambial phenology of the previous growing season on the timing of phenology of the following spring was confirmed. Rarely available phloem data permitted a comprehensive insight into the interlinkage of the timing of cambium and leaf phenology and adjustment strategies of vascular tissues in Mediterranean pubescent oak to various environmental constraints, including frequent extreme events (drought, fire). Our results suggest that predicted changes in autumn/winter and spring climatic conditions for this area could affect the timings of leaf and stem cambial phenology of Q. pubescens in the coming years, which would affect stem xylem and phloem structure and hydraulic properties, and ultimately its performance.
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Affiliation(s)
- Jožica Gričar
- Department of Yield and Silviculture, Slovenian Forestry Institute, Vecna pot 2, SI-1000 Ljubljana, Slovenia.
| | - Jernej Jevšenak
- Department of Yield and Silviculture, Slovenian Forestry Institute, Vecna pot 2, SI-1000 Ljubljana, Slovenia
| | - Polona Hafner
- Department of Yield and Silviculture, Slovenian Forestry Institute, Vecna pot 2, SI-1000 Ljubljana, Slovenia
| | - Peter Prislan
- Department of Forest Techniques and Economics, Slovenian Forestry Institute, Vecna pot 2, SI-1000 Ljubljana, Slovenia
| | - Mitja Ferlan
- Department of Forest Ecology, Slovenian Forestry Institute, Vecna pot 2, SI-1000 Ljubljana, Slovenia
| | - Martina Lavrič
- Department of Yield and Silviculture, Slovenian Forestry Institute, Vecna pot 2, SI-1000 Ljubljana, Slovenia
| | - Dominik Vodnik
- Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia
| | - Klemen Eler
- Department of Forest Ecology, Slovenian Forestry Institute, Vecna pot 2, SI-1000 Ljubljana, Slovenia; Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia
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9
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Olson ME, Anfodillo T, Gleason SM, McCulloh KA. Tip-to-base xylem conduit widening as an adaptation: causes, consequences, and empirical priorities. THE NEW PHYTOLOGIST 2021; 229:1877-1893. [PMID: 32984967 DOI: 10.1111/nph.16961] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/14/2020] [Indexed: 06/11/2023]
Abstract
In the stems of terrestrial vascular plants studied to date, the diameter of xylem water-conducting conduits D widens predictably with distance from the stem tip L approximating D ∝ Lb , with b ≈ 0.2. Because conduit diameter is central for conductance, it is essential to understand the cause of this remarkably pervasive pattern. We give reason to suspect that tip-to-base conduit widening is an adaptation, favored by natural selection because widening helps minimize the increase in hydraulic resistance that would otherwise occur as an individual stem grows longer and conductive path length increases. Evidence consistent with adaptation includes optimality models that predict the 0.2 exponent. The fact that this prediction can be made with a simple model of a single capillary, omitting much biological detail, itself makes numerous important predictions, e.g. that pit resistance must scale isometrically with conduit resistance. The idea that tip-to-base conduit widening has a nonadaptive cause, with temperature, drought, or turgor limiting the conduit diameters that plants are able to produce, is less consistent with the data than an adaptive explanation. We identify empirical priorities for testing the cause of tip-to-base conduit widening and underscore the need to study plant hydraulic systems leaf to root as integrated wholes.
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Affiliation(s)
- Mark E Olson
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Mexico City, 04510, Mexico
| | - Tommaso Anfodillo
- Department Territorio e Sistemi Agro-Forestali, University of Padova, Legnaro (PD), 35020, Italy
| | - Sean M Gleason
- Water Management and Systems Research Unit, United States Department of Agriculture, Agricultural Research Service, Fort Collins, CO, 80526, USA
- Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, CO, 80523, USA
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Timeline of Leaf and Cambial Phenology in Relation to Development of Initial Conduits in Xylem and Phloem in Three Coexisting Sub-Mediterranean Deciduous Tree Species. FORESTS 2020. [DOI: 10.3390/f11101104] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
It is unclear how the anticipated climate change will affect the timing of phenology of different tree organs/tissues and thus the whole-tree functioning. We examined the timing of leaf phenology and secondary growth in three coexisting deciduous tree species (Quercus pubescens Willd., Fraxinus ornus L. and Ostrya carpinifolia Scop) from a sub-Mediterranean region in 2019. In addition, we investigated the relationship between leaf and cambial phenology and the onset of the potential functioning of initial conduits, as determined by the completed differentiation process (vessels) or final size (sieve tubes). For this purpose, leaf development was monitored and the microcores of cambium and the youngest phloem and xylem increments were repeatedly collected at 7–10-day intervals during the growing season. The results revealed differences in the timing of leaf development and seasonal radial growth patterns in spring among the studied tree species, depending on wood porosity. We found that cambial cell production started in all cases in the first half of March. However, in ring-porous Q. pubescens and F. ornus, radial growth in the stem occurred more than a month before buds were swollen, whereas in diffuse-porous O. carpinifolia, these two events were detected at almost the same time. The end of cambial cell production occurred earliest in F. ornus (mid-July) and two weeks later also in the other two species. The widest initial earlywood vessels and early phloem sieve tubes were found in Q. pubescens, the narrowest initial earlywood vessels in O. carpinifolia and the narrowest early phloem sieve tubes in F. ornus. This indicates differences in the efficiency of conducting systems among the studied species. This novel approach of studying phloem phenology and anatomy in relation to leaf and xylem development contributes to a better understanding of how different tree species adapt their structure of secondary vascular tissues in response to environmental change.
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11
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Kiorapostolou N, Camarero JJ, Carrer M, Sterck F, Brigita B, Sangüesa-Barreda G, Petit G. Scots pine trees react to drought by increasing xylem and phloem conductivities. TREE PHYSIOLOGY 2020; 40:774-781. [PMID: 32186730 DOI: 10.1093/treephys/tpaa033] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 02/29/2020] [Accepted: 03/12/2020] [Indexed: 06/10/2023]
Abstract
Drought limits the long-distance transport of water in the xylem due to the reduced leaf-to-soil water potential difference and possible embolism-related losses of conductance and of sugars in the phloem due to the higher viscosity of the dehydrated sugary solution. This condition can have cascading effects in water and carbon (C) fluxes that may ultimately cause tree death. We hypothesize that the maintenance of xylem and phloem conductances is fundamental for survival also under reduced resource availability, when trees may produce effective and low C cost anatomical adjustments in the xylem and phloem close to the treetop where most of the hydraulic resistance is concentrated. We analyzed the treetop xylem and phloem anatomical characteristics in coexisting Scots pine trees, symptomatic and non-symptomatic of drought-induced dieback. We selected the topmost 55 cm of the main stem and selected several sampling positions at different distances from the stem apex to test for differences in the axial patterns between the two groups of trees. We measured the annual ring area, the tracheid hydraulic diameter (Dh) and cell wall thickness (CWT), the conductive phloem area and the average lumen diameter of the 20 largest phloem sieve cells (Dph). Declining trees grew less than the non-declining ones, and despite the similar axial scaling of anatomical traits, had larger Dh and lower CWT. Moreover, declining trees had wider Dph. Our results demonstrate that even under drought stress, maintenance of xylem and phloem efficiencies is of primary importance for survival, even if producing fewer larger tracheids may lead to a xylem more vulnerable to embolism formation.
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Affiliation(s)
- Natasa Kiorapostolou
- Dip. Territorio e Sistemi Agro-Forestali, Università di Padova, Viale dell'Università 16, Legnaro, PD 35020, Italy
| | - J Julio Camarero
- Depto. Conservación de Ecosistemas, Instituto Pirenaico de Ecologia (IPE-CSIC), Avda Montanana 1005, Zaragoza 50059, Spain
| | - Marco Carrer
- Dip. Territorio e Sistemi Agro-Forestali, Università di Padova, Viale dell'Università 16, Legnaro, PD 35020, Italy
| | - Frank Sterck
- Department of Environmental Sciences, Wageningen University, Droevendaalsesteeg 3, NL 6700 AA Wageningen, The Netherlands
| | - Brigita Brigita
- Department of Environmental Sciences, Wageningen University, Droevendaalsesteeg 3, NL 6700 AA Wageningen, The Netherlands
| | - Gabriel Sangüesa-Barreda
- Depto. Conservación de Ecosistemas, Instituto Pirenaico de Ecologia (IPE-CSIC), Avda Montanana 1005, Zaragoza 50059, Spain
- Depto Ciencias Agroforestales, iuFOR-EiFAB, University of Valladolid, Campus Duques de Soria s/n, Soria E-42004, Spain
| | - Giai Petit
- Dip. Territorio e Sistemi Agro-Forestali, Università di Padova, Viale dell'Università 16, Legnaro, PD 35020, Italy
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Zhang L, Chen Y, Hao G, Ma K, Bongers F, Sterck FJ. Conifer and broadleaved trees differ in branch allometry but maintain similar functional balances. TREE PHYSIOLOGY 2020; 40:511-519. [PMID: 31976531 DOI: 10.1093/treephys/tpz139] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 11/28/2019] [Accepted: 12/18/2019] [Indexed: 05/29/2023]
Abstract
Conifers and broadleaved trees coexist in temperate forests and are expected to differ in partitioning strategies between leaf and stem. We compare functional balances between water loss and water supply, and between sugar production and sugar transport/storage, and associate these with xylem growth to better understand how they contribute to these life form strategies. We sampled canopy branches from 14 common species in a temperate forest in northeast China and measured xylem area, phloem area, ray area, ray percentage, dry wood density, xylem conductivity and mean xylem growth rate for branch stems, and the leaf area and specific leaf area for leaves, and calculated the leaf-specific conductivity. Conifers and broadleaved trees did not differ significantly in tissue areas, xylem growth rate and the relation between phloem area and leaf area. Conifers had higher xylem area but lower ray area relative to leaf area. For the same xylem conductivity, phloem area and ray parenchyma area did not differ between conifers and broadleaved trees. Xylem growth rate was similar relative to leaf area and phloem area. Our results indicate that conifers tend to develop more xylem area per leaf area and more tracheid area at the cost of ray parenchyma area, probably to compensate for the low water transport ability of tracheid-based xylem. The divergent strategies between conifers and broadleaved tree species in leaf area and xylem area partitioning probably lead to the convergence of partitioning between leaf area and phloem area. Consequently, conifers tend to consume rather than store carbon to achieve a similar xylem expansion per year as coexisting broadleaved trees.
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Affiliation(s)
- Lan Zhang
- Forest Ecology and Forest Management Group, Wageningen University and Research Centre, PO Box 47, Wageningen, 6700 AA, The Netherlands
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan, Beijing 100093, China
| | - Yajun Chen
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China
- Yuanjiang Savanna Ecosystem Research Station, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Pupiao Villiage Yuanjiang, Yunnan 666303, China
| | - Guangyou Hao
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, 72 Wenhua Road, Shenhe District Shenyang, Liaoning 110016, China
| | - Keping Ma
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan, Beijing 100093, China
| | - Frans Bongers
- Forest Ecology and Forest Management Group, Wageningen University and Research Centre, PO Box 47, Wageningen, 6700 AA, The Netherlands
| | - Frank J Sterck
- Forest Ecology and Forest Management Group, Wageningen University and Research Centre, PO Box 47, Wageningen, 6700 AA, The Netherlands
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