Hanging by a thread? Forests and drought

Science, Journal Year: 2020, Volume and Issue: 368(6488), P. 261 - 266

Published: April 16, 2020

Trees are the living foundations on which most terrestrial biodiversity is built. Central to success of trees their woody bodies, connect elevated photosynthetic canopies with essential belowground activities water and nutrient acquisition. The slow construction these carbon-dense, skeletons leads a generation time, leaving forests highly susceptible rapid changes in climate. Other long-lived, sessile organisms such as corals appear be poorly equipped survive changes, raises questions about vulnerability contemporary future climate change. emerging view that, similar corals, tree species have rather inflexible damage thresholds, particularly terms stress, especially concerning. This Review examines recent progress our understanding how looks for growing hotter drier atmosphere.

Language: Английский

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Mechanisms of woody-plant mortality under rising drought, CO2 and vapour pressure deficit

Nature Reviews Earth & Environment, Journal Year: 2022, Volume and Issue: 3(5), P. 294 - 308

Published: March 29, 2022

Language: Английский

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Soil Rather Than Xylem Vulnerability Controls Stomatal Response to Drought

Trends in Plant Science, Journal Year: 2020, Volume and Issue: 25(9), P. 868 - 880

Published: May 3, 2020

There is an increasing need for mechanistic and predictive models of transpiration stomatal response to drought soil water availability. It has been hypothesized that regulation predictable based on plant hydraulics.The current trend towards a greater consideration hydraulics in earth system science emphasizes xylem vulnerability, neglecting the explicit role root importance hydraulic conductivity status well accepted, but difficult measure.There evidence plants adapt their roots as vicinity, rhizosphere, match conditions atmospheric demand, contributing transpiration. The linking stomata vulnerability. Using soil–plant model, we show vulnerability does not trigger closure medium-wet dry soils propose loss primary driver closure. This finding two key implications: cannot be derived from traits only related soil–root way; interface with soil, are regions can alter efficiently limitations. We conclude connecting below- aboveground necessary fully comprehend responses drought. Stomatal controls most carbon acquisition and, thus, terrestrial productivity at global scale. also regulates fluxes atmosphere through plants. While hydrological cycle, its estimates suffer large uncertainty, spanning 35–80% evapotranspiration [1.Coenders-Gerrits A.M.J. et al.Uncertainties estimates.Nature. 2014; 506: E1-E2Crossref PubMed Scopus (134) Google Scholar, 2.Jasechko S. al.Terrestrial dominated by transpiration.Nature. 2013; 496: 347-350Crossref (764) 3.Schlesinger W.H. Jasechko Transpiration cycle.Agric. For. Meteorol. 189–190: 115-117Crossref (533) Scholar]. uncertainty arises difficulty estimating conductance, particular under stress. Stomata present all land features vascular content Earth. Their function thought prevent cavitation [4.Brodribb T.J. al.Xylem stomata, coordinated time space.Plant Cell Environ. 2017; 40: 872-880Crossref (74) requires respond potential. Two main mechanisms have demonstrated: passive mechanism induced connection between epidermal guard cells; active production hormones, such abscisic acid (ABA) [5.Brodribb McAdam S.A.M. Evolution content.Plant Physiol. 174: 639-649Crossref (105) Sensitivity hormonal signals differs species results varying degrees iso- anisohydricity; these definitions indicate capacity regulate conductance maintain constant (isohydricity) or less (anisohydricity) leaf potential [6.Tardieu F. Davies W.J. Integration chemical signalling control droughted plants.Plant 1993; 16: 341-349Crossref (400) Existing either optimization principles [7.Cowan I.R. Farquhar G.D. relation metabolism environment.Symp. Soc. Exp. Biol. 1977; 31: 471-505PubMed 8.Sperry J.S. al.Pragmatic theory predicts climatic deficits.New Phytol. 2016; 212: 577-589Crossref (131) 9.Wolf A. al.Optimal behavior competition risk impairment.PNAS. 113: E7222-E7230Crossref (144) Scholar] description cell dynamics [10.Buckley T.N. al.A hydromechanical biochemical model conductance.Plant 2003; 26: 1767-1785Crossref (264) Scholar,11.Buckley al.Simple process model: cross-validation against sap flux data.Plant 2012; 35: 1647-1662Crossref (61) Despite great progress [12.Buckley Modeling 572-582Crossref (95) Scholar,13.Mencuccini M. al.Modelling plants: tissues biosphere.New 2019; 0Google Scholar], how drying impacts remains unclear existing empirical [14.Hochberg U. al.Iso/Anisohydry: plant–environment interaction rather than simple trait.Trends Plant Sci. 2018; 23: 112-120Abstract Full Text PDF (184) overestimate during [15.Anderegg W.R.L. al.Plant improves prediction models.PLoS One. 12e0185481Crossref (49) An intriguing hypothesis prevents exceeding supply determined [8.Sperry To accomplish this function, should change (i.e., ∂E∂ψleaf) (see Table 1 definition terms used article). Sperry Love [16.Sperry D.M. What tell us about climate-change droughts.New 2015; 207: 14-27Crossref (258) argued that, view around conductivities area adsorbing roots, it pragmatic assume 'root investment just sufficient approach limit'. Behind assumption, there adjust architecture properties (e.g., texture). follows, authors, cavitation, drying, limits triggers However, were found close much before cavitates; is, which 50% (ψgs50) negative loses (ψx50) follows ψx50 informative predicting closure.Table 1Summary Terms Used ArticleTermDefinitionUnit measurementETranspiration flowm3 s–1gGravitational accelerationm s–2HWater per weight (water head)mhSoil matric potentialmKHydraulic conductancem3 s–1 MPa–1kHydraulic conductivitym s–1KrootRoot conductancecm3 hPa–1ksatSaturated s–1ksoilSoil s–1KxAboveground MPa–1LRoot lengthmqFlux densitym3m–2 s–1ρWater densitykg m–3r0Root radiusmrbRhizosphere radiusmSeSaturation index–SleafDerivative given potentialm3 MPa–1θVolumetric contentm3m–3ψWater volume pressure)MPaψgs50Water 50%MPaψH50Water conductivityMPaψleafLeaf potentialMPaψleaf,predawnPredawn potentialMPaψs50Water conductivityMPaψsoilBulk potentialMpaψx50Water maximal conductivityMPa Open table new tab Here, claim conductivity, more embolism, constraint ψgs50 traits, maximum [17.Henry C. safety-efficiency trade-off constrains dehydration.Nat. Commun. 10: 1-9Crossref (79) ψx50, depends hydraulics. In particular, when drops rapidly increase support opinion data literature covering different flow across (Figure 1, Key Figure). Water flows soil–plant–atmosphere continuum driven gradient potential, rate pathways. set short timescale, regulated opening closing. components variable: vessels stems, leaves cavitate lose potentials ranging –1 –8 MPa [18.Brodersen C.R. al.Functional time.Annu. Rev. 70: 407-433Crossref Scholar,19.Tyree M.T. Vulnerability embolism.Annu. Mol. 1989; 19-36Crossref (here referred radial pathway) decreases anatomical development due suberization [20.Steudle E. Peterson C.A. How get roots?.J. Bot. 1998; 49: 775-788Google formation Casparian bands [21.Zimmermann H.M. al.Chemical composition apoplastic transport barriers corn (Zea mays L.).Planta. 2000; 210: 302-311Crossref (142) Scholar]; reversibly aquaporin (AQP) expression [22.Rodríguez-Gamir J. al.Aquaporin Pinus radiata stress.Plant 42: 717-729Crossref (37) Scholar,23.Caldeira C.F. al.Circadian rhythms growth enhanced improve performance.Nat. 5: 5365Crossref (108) root–soil variable expected decrease shrink contact [24.Carminati al.Do mind gap?.Plant Soil. 367: 651-661Crossref (69) Root hairs contribute matrix [25.Carminati al.Root enable high rates soils.New 216: 771-781Crossref (78) they might break tensile force low potentials. arguably region greatest strongly types. Soil dramatically unsaturated cross-sectional higher tortuosity flowpaths. One important characteristic (increase decrease) instantaneous. means contrast other losses plant, usually reversible upon rehydration. A remarkable exception reversibility where root-secreted mucilage causes strong hysteresis rhizosphere [26.Carminati al.Dynamics rhizosphere.Plant 2010; 332: 163-176Crossref (257) Figure 2A illustrates typical curves types compares them 40 deciduous evergreen [27.Kröber W. al.Linking economics spectrum—a cross-species study 39 broadleaved subtropical tree species.PLoS ONE. 9e109211Crossref (36) range (~0.02–1.5 MPa), differ five orders magnitude, dropping (units discussed Box SI2 supplemental information online). ksoil (cm s–1) decreasing (MPa) geometry single root, density q toward surface, cause nonlinearly surface. These gradients calculated solving equation surface [28.Schroeder T. al.Effect local drop using three-dimensional uptake model.Vadose Zone 2008; 7: 1089-1098Crossref (40) (Box 1). For (7–10–7 cm s–1), bulk negligible wet conductive soils, becomes increasingly steeper 2b). Specifically, each type critical (and relative content) beyond very values faster reaction min h [29.Vico G. al.Effects delays gas exchange intermittent light regimes.New 2011; 192: 640-652Crossref (100) Scholar,30.Katul describe effects CO2 photosynthesis transpiration.Ann. 105: 431-442Crossref (219) Scholar]) 2C). reached hour largely varies ranges –0.1 –1.45 MPa. threshold value –1.2 MPa) would fail promptly protect soils. Therefore, evolution, must developed efficient fast reduction adapting type.Box 1Soil–Plant Hydraulic ModelWe provides xylem, steady-state equalize leaves. Other researchers similar approaches represent (supply function) Scholar].Water ψ (MPa), E (m3 conductance's (Kroot Kx) (ksoil) series. Under steady-rate represented Equation I:q=−ksoilψmρg∂ψ∂r,[I] (m (Pa), ρ density, g gravitational acceleration, r coordinate (m) [50.Gardner W.R. Dynamic aspects availability plants.Soil 1960; 89: 63-73Crossref (582) nonlinear ψm 1A text). Assuming uniform distribution along system, according II:qr0=E2πr0L,[II] r0 radius L length roots. length. Kirchhoff transformation, I solved find ψsr ψsoil SI1 online).In III:E=−Krootψx,r−ψsr.[III] III collar ψx, Kroot MPa–1), conductance. simplicity, here constant, assumption easily replaced complex relation, once known.The IV:E=−Kxψψleaf−ψx,r,[IV] ψleaf Kx MPa–1) Cavitation included describing dependency V:Kxψ=Krootψψ0x−τx,[V] nonlimiting assumed. Equations [IV], [V] (Equation S5 online) yields ψleaf. known. Solving equations 1) gives relationship (cm3 3A ). Presenting E(ψsoil,ψleaf) fundamental insights into reconciles views physiologists 3B) scientists 3C) relations. represents physically possible states plant. When equal, no drive null. soil), linear starts deviate because Whereas, dries out, already moderate conductivity. Xylem embolism determines shape while belowground processes (namely length) (examples shown S1 At any deviates define stress onset limit (SOL), divides zones (red line 3A). SOL 2) point slope E(ψleaf,ψsoil) ψsoil, Sleaf=∂E∂ψleafψsoil, reaches 80% value. zone (green 3A), neither nor subject reductions (in brown generates region, whereas slight Note transition continuous.Box 2Onset Nonlinearity Definition Critical Potential ψs50We trajectory text), separates E(ψleaf) parts: SOL. calculate iso-potential I:Sleafψleafψsoil=∂E∂ψleafψsoil.[I] Sleaf occurs = null-transpiration called Sleaf, max(ψsoil). ratio Sleaf. consider significantly small transpiration, shown, instance II:SleafψleafψsoilSleaf,maxψsoil<80%.[II] arbitrary, taking 70% 90% little sensitivity SOL.ψH50 defined ψs50, ψs50 up Emax sustained. corresponds (not constrained stress). flow, III):ϕs50=12Emax2πr0Lr02−r0rb2lnrb/r0rb2−r02,[III] S3 online, assuming infinitely negative, so null, Emax. obtained S2 doing so, obtain Emax/2 length, factors conductance) micrometeorological intensity, vapor pressure deficit, wind). ψH50 3 shows exemplary (E,ψsoil) (E,ψleaf) planes. From perspective displays universal Scholar,31.Rodriguez-Dominguez C.M. Brodribb Declining drives olive stress.New 2020; 225: 126-134Crossref (73) 3B), consistent well-accepted observations [32.Gardner Ehlig influence plants.J. Geophys. Res. 1963; 68: 5719-5724Crossref Given marked nonlinearity E(ψsoil,ψleaf), optimal strategy undergoing approached able sense ∂ψleaf∂E. enables independently environmental known thus outstanding question.

Language: Английский

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Drought response of European beech (Fagus sylvatica L.)—A review

Perspectives in Plant Ecology Evolution and Systematics, Journal Year: 2020, Volume and Issue: 47, P. 125576 - 125576

Published: Oct. 11, 2020

Language: Английский

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Developing drought‐smart, ready‐to‐grow future crops

The Plant Genome, Journal Year: 2022, Volume and Issue: 16(1)

Published: Nov. 10, 2022

Breeding crop plants with increased yield potential and improved tolerance to stressful environments is critical for global food security. Drought stress (DS) adversely affects agricultural productivity worldwide expected rise in the coming years. Therefore, it vital understand physiological, biochemical, molecular, ecological mechanisms associated DS. This review examines recent advances plant responses DS expand our understanding of DS-associated mechanisms. Suboptimal water sources affect growth yields through physical impairments, physiological disturbances, biochemical modifications, molecular adjustments. To control devastating effect plants, important its consequences, mechanisms, agronomic genetic basis sustainable production. In addition responses, we highlight several mitigation options such as omics approaches, transgenics breeding, genome editing, mechanical methods (foliar treatments, seed priming, conventional practices). Further, have also presented scope speed breeding platforms helping develop drought-smart future crops. short, recommend incorporating multi-omics, traditional strategies, cultivars achieve 'zero hunger' goal.

Language: Английский

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Rapid hydraulic collapse as cause of drought-induced mortality in conifers

Proceedings of the National Academy of Sciences, Journal Year: 2021, Volume and Issue: 118(16)

Published: April 12, 2021

Understanding the vulnerability of trees to drought-induced mortality is key predicting fate forests in a future climate with more frequent and intense droughts, although underlying mechanisms are difficult study adult trees. Here, we explored dynamic changes water relations limits hydraulic function dying adults Norway spruce (Picea abies L.) during progression record-breaking 2018 Central European drought. In on trajectory mortality, observed rapid, nonlinear declines xylem pressure that commenced at early onset cavitation caused complete loss conductance within very short time. We also severe depletions nonstructural carbohydrates, though carbon starvation could be ruled out as cause tree death, both surviving showed these metabolic limitations. Our observations provide striking field-based evidence for fast dehydration collapse spruce. The decline suggests considering temporal dynamics critical death. system time demonstrates can rapidly pushed zone safety summary, our findings point toward higher risk than previously assumed, which line current reports unprecedented levels this major species.

Language: Английский

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From the comfort zone to crown dieback: Sequence of physiological stress thresholds in mature European beech trees across progressive drought

The Science of The Total Environment, Journal Year: 2020, Volume and Issue: 753, P. 141792 - 141792

Published: Aug. 21, 2020

Language: Английский

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Root hydraulic phenotypes impacting water uptake in drying soils

Plant Cell & Environment, Journal Year: 2022, Volume and Issue: 45(3), P. 650 - 663

Published: Jan. 17, 2022

Soil drying is a limiting factor for crop production worldwide. Yet, it not clear how soil impacts water uptake across different soils, species, and root phenotypes. Here we ask (1) what phenotypes improve the use from soils? (2) hydraulic properties impact flow soil-plant continuum? The main objective to propose framework investigate interplay between on uptake. We collected highly resolved data transpiration, leaf potential 11 crops 10 contrasting textures. In drop in at soil-root interface resulted rapid decrease conductance, especially higher transpiration rates. analysis reveals that was limited by within wide range of (-6 -1000 kPa), depending both textures phenotype with low long roots and/or dense hairs postpones limitation soils. consequence these discussed.

Language: Английский

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Towards a unified theory of plant photosynthesis and hydraulics

Nature Plants, Journal Year: 2022, Volume and Issue: 8(11), P. 1304 - 1316

Published: Oct. 27, 2022

The global carbon and water cycles are governed by the coupling of CO2 vapour exchanges through leaves terrestrial plants, controlled plant adaptations to balance gains hydraulic risks. We introduce a trait-based optimality theory that unifies treatment stomatal responses biochemical acclimation plants environments changing on multiple timescales. Tested with experimental data from 18 species, our model successfully predicts simultaneous decline in assimilation rate, conductance photosynthetic capacity during progressive soil drought. It also correctly dependencies gas exchange atmospheric pressure deficit, temperature CO2. Model predictions consistent widely observed empirical patterns, such as distribution strategies. Our unified opens new avenues for reliably modelling interactive effects drying rising photosynthesis transpiration. Using environments, this study builds leaves. This assimilation, droughts.

Language: Английский

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Burning questions for a warming and changing world: 15 unknowns in plant abiotic stress

The Plant Cell, Journal Year: 2022, Volume and Issue: 35(1), P. 67 - 108

Published: Aug. 26, 2022

We present unresolved questions in plant abiotic stress biology as posed by 15 research groups with expertise spanning eco-physiology to cell and molecular biology. Common themes of these include the need better understand how plants detect water availability, temperature, salinity, rising carbon dioxide (CO2) levels; environmental signals interface endogenous signaling development (e.g. circadian clock flowering time); this integrated controls downstream responses stomatal regulation, proline metabolism, growth versus defense balance). The plasma membrane comes up frequently a site key transport events mechanosensing lipid-derived signaling, aquaporins). Adaptation extremes CO2 affects hydraulic architecture transpiration, well root shoot morphology, ways not fully understood. Environmental adaptation involves tradeoffs that limit ecological distribution crop resilience face changing increasingly unpredictable environments. Exploration diversity within among species can help us know which represent fundamental limits ones be circumvented bringing new trait combinations together. Better defining what constitutes beneficial resistance different contexts making connections between genes phenotypes, laboratory field observations, are overarching challenges.

Language: Английский

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