Water use pattern and transpiration of Mongolian pine plantations in relation to stand age on northern Loess Plateau of China

Agricultural and Forest Meteorology, Год журнала: 2023, Номер 330, С. 109320 - 109320

Опубликована: Янв. 17, 2023

Язык: Английский

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Phloem water isotopically different to xylem water: Potential causes and implications for ecohydrological tracing

Ecohydrology, Год журнала: 2022, Номер 15(3)

Опубликована: Март 16, 2022

Abstract The stable isotopes of hydrogen and oxygen in xylem water are often used to investigate tree sources. But this traditional approach does not acknowledge the contribution stored phloem transpiration how may affect source interpretations. Additionally, there is a prevailing assumption that no isotope fractionation during transport. Here, we systematically sampled at daily subdaily resolutions large lysimeter planted with Salix viminalis . Stem diurnal change storage rates were also measured. Our results show significantly less enriched heavy than water. At resolution, observed larger isotopic difference between refilling under periods deficit. These findings contrast expectation heavy‐isotope due downward transport leaf signatures. Because previous evidence aquaporin mediated higher osmotic permeability lighter isotopologues across aquaporins, propose radial xylem–phloem boundary drive relative depletion their enrichment xylem.

Язык: Английский

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Isotopic offsets between bulk plant water and its sources are larger in cool and wet environments

Hydrology and earth system sciences, Год журнала: 2022, Номер 26(15), С. 4125 - 4146

Опубликована: Авг. 8, 2022

Abstract. Isotope-based approaches to study plant water sources rely on the assumption that root uptake and within-plant transport are non-fractionating processes. However, a growing number of studies have reported offsets between source stable isotope composition for wide range ecosystems. These isotopic can result in erroneous attribution used by plants potential overestimations groundwater vegetation. We conducted global meta-analysis quantify magnitude these explored whether their variability could be explained either biotic or abiotic factors. Our database compiled 112 spanning arctic tropical biomes dual (δ2H δ18O) (stem) water, including soil (sampled following various methodologies along variable depths). calculated 2H two ways: line conditioned excess (LC-excess) describes deviation from local meteoric (SW-excess) line, each sampling campaign within study. tested effects climate (air temperature content), class, traits (growth form, leaf habit, wood density, parenchyma fraction mycorrhizal habit) LC-excess SW-excess. Globally, stem was more depleted than (SW-excess < 0) 3.02±0.65 ‰ (P 0.05 according estimates our linear mixed model weighted sample size studies). In 95 % cases where SW-excess negative, indicating had not undergone evaporative enrichment (such as groundwater) unlikely explain observed soil–plant offsets. Soil class did any significant effect negative cold wet sites, whereas it positive warm sites. The climatic suggest methodological artefacts sole cause results would imply may lead inaccuracies when using bulk proxy infer sources.

Язык: Английский

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Snowmelt Water Use at Transpiration Onset: Phenology, Isotope Tracing, and Tree Water Transit Time

Water Resources Research, Год журнала: 2022, Номер 58(9)

Опубликована: Авг. 30, 2022

Abstract Studies of tree water source partitioning have primarily focused on the growing season. However, little is yet known about transpiration before, during, and after snowmelt when trees rehydrate recommence in spring. This study investigates use during spring following tree's winter stem shrinkage. We document three boreal forest species— Pinus banksiana , Picea mariana Larix laricina— by combining observations weekly isotopic signatures ( δ 18 O 2 H) xylem, soil water, rainfall with measurements moisture dynamics, snow depth high‐resolution temporal radius changes sap flow. Our data shows that onset rehydration overlaps for evergreens. During onset, xylem at canopy reflected a constant pre‐melt signature likely showing late fall conditions. As infiltrates recharges matrix, rapid shift to depleted‐snowmelt values. While there was an overlap between timing, values did not onset. showed 1–2‐week delay from clear snowmelt‐depleted evergreen species. appears be controlled transit time order 9–18 days. key

Язык: Английский

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Flushing or mixing? Stable water isotopes reveal differences in arctic forest and peatland soil water seasonality

Hydrological Processes, Год журнала: 2023, Номер 37(1)

Опубликована: Янв. 1, 2023

Abstract Understanding the relative importance of different water sources that replenish soil storage is necessary to assess vulnerability sub‐arctic areas changes in climate and altered rain snow conditions, reflected timing magnitude infiltration. We examine spatiotemporal variability seasonal origin at soil‐vegetation interface Pallas catchment, located northern Finland. The field study was conducted from May 2019 June 2020 over two snowmelt seasons one summer growing season. sampled cores up a 1‐m depth stem dominant tree species four sites forests forested peatlands for stable isotopes. Seasonal rainfall variation late events were well identifiable well‐drained soils areas, while this input signal heavily attenuated wetter, peatland areas. Spatiotemporal forest similar, whereas controlled by extent hydrologic connectivity adjoining pools. A mixture both winter precipitation present during entire period, mineral showed an ephemeral response got nearly fully flushed twice hydrological year. Meltwater after early spring but became displaced isotopically enriched summer. evolution pools not dynamics offset between isotopic signals less pronounced peatlands. This data set uncovered high depth‐resolution, quantifying replenishing sustaining conditions.

Язык: Английский

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Water sources used by artificial Salix psammophila in stands of different ages based on stable isotope analysis in northeastern Mu Us Sandy Land

CATENA, Год журнала: 2023, Номер 226, С. 107087 - 107087

Опубликована: Март 27, 2023

Язык: Английский

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Introduction of broadleaf tree species can promote the resource use efficiency and gross primary productivity of pure forests

Plant Cell & Environment, Год журнала: 2024, Номер 47(12), С. 5252 - 5264

Опубликована: Авг. 23, 2024

Long-term pure forest (PF) management and successive planting has result resulted in "low-efficiency artificial forests" large areas. However, controversy persists over the promoting effect of introduction broadleaf tree species on production efficiency PF. This study hypothesised that introduced can significantly promote both water-nutrient use gross primary productivity (GPP)of Tree ring chronologies, water source, GPP were analysed coniferous Cunninghamia lanceolata broadleaved Phoebe zhennan growing past three decades. The P. into C. plantations inter-specific competition for water, probably because similarity main source these two species. absorbed more with a higher nutrient level from 40-60-cm soil layer mixed forests (MF). Although co-existing limited basal area increment growth rates MF plots, acquisition dissolved nutrients fertile topsoil enhanced; this increased plots. To achieve better ecological benefits GPP, MFs should be constructed southern China.

Язык: Английский

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Sapwood and heartwood are not isolated compartments: Consequences for isotope ecohydrology

Ecohydrology, Год журнала: 2022, Номер 15(8)

Опубликована: Сен. 7, 2022

Abstract In most tree species, xylem consists of two different functional parts: sapwood and heartwood. While sapwood, as the flowpath for sap, has received more attention in isotope studies assessing water sources accessed by trees (e.g. soil from depths, groundwater, stream or a mixture these), much remains unknown about heartwood possible exchange between parts. We investigated four species ( Fagus sylvatica , Quercus petraea Pseudotsuga menziesii Picea abies ) characterised anatomy timing physiological activity to evaluate degree differentiation isotopic composition on biweekly time scale. found that all displayed concurrent variation their throughout growing season day‐night scale suggesting are not isolated compartments. parts display consistent difference conifers, they similar values broadleaved higher exchange. Furthermore, we have also observed progressive change with sampling depth rather than xylem. Our study highlights value accounting radial variation, which might potentially lead uncertainties concerning origin extracted uptake studies.

Язык: Английский

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Xylem water in riparian willow trees (&lt;i&gt;Salix alba&lt;/i&gt;) reveals shallow sources of root water uptake by in situ monitoring of stable water isotopes

Hydrology and earth system sciences, Год журнала: 2022, Номер 26(8), С. 2073 - 2092

Опубликована: Апрель 27, 2022

Abstract. Root water uptake (RWU) is an important critical zone process, as plants can tap various sources and transpire these back into the atmosphere. However, knowledge about spatial temporal dynamics of RWU associated at both high resolution (e.g. daily) over longer time periods seasonal) still limited. We used cavity ring-down spectroscopy (CRDS) for continuous in situ monitoring stable isotopes soil xylem two riparian willow (Salix alba) trees growing season (May to October) 2020. This was complemented by isotopic sampling local precipitation, groundwater, stream order help constrain potential RWU. A eddy flux tower, together with sap flow monitoring, moisture measurements, dendrometry, also provide hydroclimatic ecohydrological contexts isotope monitoring. In addition, respective bulk twig samples were collected corroborate data. The period characterised frequent inputs interspersed warm dry periods, which resulted variable storage upper 20 cm profile dynamic signatures. variability greatly damped 40 cm, composition subsoil groundwater relatively stable. very similar those soil, analysis using a Bayesian mixing model inferred that overall ∼90 % derived from profile. while signatures, direct equilibrium method showed good comparability results, water, cryogenic extractions signatures only moderately or not all comparable. Sap dendrometry data indicated availability did seriously limit transpiration during study period, though it seemed deeper (>40 cm) provided higher proportion (∼30 %) drier late summer. demonstrates utility prolonged real-time natural abundance soil–vegetation systems, has great further understanding partitioning under changing conditions.

Язык: Английский

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Causes and Factors of Cryogenic Extraction Biases on Isotopes of Xylem Water

Water Resources Research, Год журнала: 2022, Номер 58(8)

Опубликована: Авг. 1, 2022

Abstract Cryogenic vacuum extraction (CVE) has been considered as the standard technique for analysis of plant water stable isotopes in ecohydrological research. Recent studies reported that CVE can introduce significant bias isotope analyses, yet causes and influencing factors CVE‐induced deuterium offsets remain poorly understood. Here, we performed rehydration experiments on samples from two species three organs with distinct‐isotopic spiking waters. Centrifugation high‐pressure mechanical squeezing were used to separate sap tissue analyses. Plant waters extracted by differed significantly reference δ 2 H, but not 18 O. The H was linearly correlated xylem content, this relationship is affected organs/species isotopic signature water. Moreover, induced (−8.52 ± 0.90‰) greater than difference between (−3.33 0.76‰) apple stems possessing similar contents. Thus, hydrogen‐exchange organics water, heterogeneity within plants both contribute negative bias, former dominant cause. multiple governing make it difficult establish a unified correction equation. Our results question usefulness cryogenic extraction.

Язык: Английский

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