Moderate Water Content Research Articles

Integrated Effects of Soil Moisture on Wheat Hydraulic Properties and Stomatal Regulation.

The development of water-saving management relies on understanding the physiological response of crops to soil drought. The coordinated regulation of hydraulics and stomatal conductance in plant water relations has steadily received attention. However, research focusing on grain crops, such as winter wheat, remains limited. In this study, three soil water supply treatments, including high (H), moderate (M), and low (L) soil water contents, were conducted with potted winter wheat. Leaf water potential (Ψleaf), leaf hydraulic conductance (Kleaf), and stomatal conductance (gs), as well as leaf biochemical parameters and stomatal traits were measured. Results showed that, compared to H, predawn leaf water potential (ΨPD) significantly reduced by 48.10% and 47.91%, midday leaf water potential (ΨMD) reduced by 40.71% and 43.20%, Kleaf reduced by 64.80% and 65.61%, and gs reduced by 21.20% and 43.41%, respectively, under M and L conditions. Although gs showed a significant difference between M and L, Ψleaf and Kleaf did not show significant differences between these treatments. The maximum carboxylation rate (Vcmax) and maximum electron transfer rate (Jmax) under L significantly decreased by 23.11% and 28.10%, stomatal density (SD) and stomatal pore area index (SPI) under L on the abaxial side increased by 59.80% and 52.30%, respectively, compared to H. The leaf water potential at 50% hydraulic conduction loss (P50) under L was not significantly reduced. The gs was positively correlated with ΨMD and Kleaf, but it was negatively correlated with abscisic acid (ABA) and SD. A threshold relationship between gs and Kleaf was observed, with rapid and linear reduction in gs occurring only when Kleaf fell below 8.70 mmol m-2 s-1 MPa-1. Our findings demonstrate that wheat leaves adapt stomatal regulation strategies from anisohydric to isohydric in response to reduced soil water content. These results enrich the theory of trade-offs between the carbon assimilation and hydraulic safety in crops and also provide a theoretical basis for water management practices based on stomatal regulation strategies under varying soil water conditions.

Green Synthesis of MOF-Based Materials for Electrochemical Reduction of Carbon Dioxide.

Porous ZIF-8 and ZIF-67 were synthesized via a green steam-assisted dry-gel technique and investigated as potential catalysts for CO2 electroreduction. The synthesis conditions are found to significantly influence the growth of these metal-organic frameworks (MOFs). Notably, the water content employed during synthesis plays a crucial role in shaping the morphological properties of ZIF-8. Specifically, a moderate water content results in the formation of uniform ZIF-8 with a size distribution ranging from 240-440 nm. During CO2 electroreduction, these morphological properties exert substantial effects on the selectivity for CO formation, thereby facilitating the production of syngas with adjustable CO: H2 ratios. This feature holds promise for the widespread adoption of syngas as a clean alternative to fossil fuels, offering potential benefits for electricity generation and liquid fuel production. Despite sharing similar structural properties with ZIF-8, ZIF-67 exhibits distinct performance characterized by its limited selectivity for CO2 electroreduction. This discrepancy is attributed to the different metal centers of the two MOFs, resulting in the distinct activation of CO2 and H2O molecules and their further reduction. This finding highlights the critical role of metal centers in MOF-based materials for electrocatalysis application.

A formation pathway for terrestrial planets with moderate water content involving atmospheric-volatile recycling

Of the many recently discovered terrestrial exoplanets, some are expected to harbor moderate water mass fractions of a few percent. The formation pathways that can produce planets with these water mass fractions are not fully understood. Here, we use the code chemcomp which consists of a semi-analytical 1D protoplanetary disk model harboring a migrating and accreting planet, to model the growth and composition of planets with moderate water mass fractions by pebble accretion in a protoplanetary disk around a TRAPPIST-1 analog star. This star is accompanied by seven terrestrial planets, of which the outer four planets likely contain water mass fractions of between 1<!PCT!> and 10<!PCT!>. We adopt a published model that considers the evaporation of pebbles in the planetary envelope, from where recycling flows can transport the volatile vapor back into the disk. We find that with this model, the planetary water content depends on the influx rate of pebbles onto the planet. A decreasing pebble influx with time reduces the envelope temperature and consequently allows the formation of planets with moderate water mass fractions as inferred for the outer TRAPPIST-1 planets for a number of different simulation configurations. This is further evidence that the recycling of vapor is an important component of planet formation needed to explain the vast and diverse population of exoplanets.

Mind the gap: Distinguishing disc substructures and their impact on the inner disc composition

Improved observational technologies have enabled the resolution of substructures and the measurement of chemical abundances in protoplanetary discs. Understanding the chemical composition of the inner disc allows us to infer the building blocks available for planet formation. Recently, the depletion of water in the inner disc has been suggested to be linked to the presence of substructures, such as gaps and rings, further out in the disc. We investigate this hypothesis further by running 1D semi-analytical models of a protoplanetary disc with a gap to understand the combined effects of disc viscosity, gap depth, gap location, and gap formation timescales on the composition of the inner disc (water abundance, C/O, O/H, and C/H ratios). Our results show that for a specific value of disc viscosity, the simulation outcome can be classified into three regimes: shallow gap, 'traffic jam', and deep gap. While deep gaps may already be distinguishable with moderate-resolution (FWHM sim 10 AU) techniques, it is still challenging to resolve shallow gaps with the current capabilities. On the other hand, discs with traffic jams have a higher chance of being resolved when observed with a high resolution (FWHM lesssim 5 AU), but they may appear as an intensity enhancement or even featureless when observed with moderate to low angular resolution (FWHM gtrsim 10 AU). In this regard, information on the inner disc composition is useful because it can help to infer the existence of traffic jams or distinguish them from deep gaps: discs with deep gaps are expected to have a low water content -- and thus high C/O ratio in the inner disc due to the effective blocking of pebbles -- while discs with shallow gaps would demonstrate the opposite trend (water-rich and low C/O ratio). Furthermore, discs with a traffic jam would have a constant (albeit low) inward flux of water-rich pebbles resulting in a moderate water content and sub-stellar C/O ratios. Finally, we find that the effectiveness of gaps as pebble barriers diminishes quickly when they form late $(t_ gap Myr )$, as most of the pebbles have already drifted inwards.

KAJIAN DISTRIBUSI C ORGANIK DAN KADAR AIR TAHAN DI LAHAN KOPI ROBUSTA KABUPATEN JEMBER DENGAN KETINGGIAN BERBEDA PADA AKHIR MUSIM PENGHUJAN

Coffee (Coffea spp.) is one of the leading commodities, which contributed 42.98 percent to the export value of the annual crop agricultural sector in 2013-2020. The productivity of Robusta coffee plants in the Jember region has tended to decrease significantly over the last 5 years. Geographic Information Systems (GIS) can be used to determine the distribution of organic C and soil water content as a basis for proper land management. The results showed that the percentage of ideal distribution area for organic C content was 94.94%, and the soil water content was at a value of 6.92-18.68%, where the status of moderate soil water content dominated by 59% of the total land. The results of simple linear regression analysis showed that the organic C variable (X1) had an effect of 29% and soil water content (X2) 10% productivity values. In addition, multiple linear regression analysis showed a strong influence of 63% on the value of productivity. The age factor also has an effect of 57% on the value of productivity.

Intrinsic Anti-Freezing and Unique Phosphorescence of Glassy Hydrogels with Ultrahigh Stiffness and Toughness at Low Temperatures.

Most hydrogels become frozen at subzero temperatures, leading to degraded properties and limited applications. Cryoprotectants are massively employed to improve anti-freezing property of hydrogels; however, there are accompanied disadvantages, such as varied networks, reduced mechanical properties, and the risk of cryoprotectant leakage in aqueous conditions. Reported here is the glassy hydrogel having intrinsic anti-freezing capacity and excellent optical and mechanical properties at ultra-low temperatures. Supramolecular hydrogel of poly(acrylamide-co-methacrylic acid) with moderate water content (≈50 wt.%) and dense hydrogen-bond associations is in a glassy state at room temperature. Since hydrogen bonds become strengthened as the temperature decreases, this gel becomes stronger and stiffer, yet still ductile, with Young's modulus of 900MPa, tensile strength of 30MPa, and breaking strain of 35% at -45°C. This gel retains high transparency even in liquid nitrogen. It also exhibits unique phosphorescence due to presence of carbonyl clusters, which is further enhanced at subzero temperatures. Further investigations elucidate that the intrinsic anti-freezing property is related to a fact that most water molecules are tightly bound and confined in the glassy matrix and become non-freezable. This correlation, as validated in several systems, provides a roadmap to develop intrinsic anti-freezing hydrogels for widespread applications at extreme conditions.

Permeability evolution of methane and water vapor when simultaneously transporting in shale

Methane and water vapor transport in shale (mud rocks) is important in many resource and environmental issues, e.g., effectively exploiting shale gas and clearly understanding water and methane global cycles. To investigate methane and water vapor permeability in shale, a new permeability determination method was proposed using a linearization approach based on previous studies. The experimental samples are crushed Carboniferous shale from the eastern Qaidam Basin in China. Simultaneous methane and water vapor transport experiments in shale were performed. Water vapor was derived through deionized water evaporation under different methane pressures. The relative humidity dynamically changed during the experiment. The methane and water vapor transport processes were observed and recorded, and the methane and water vapor permeability in the shale matrix was calculated. Both the methane and water vapor permeabilities temporally varied, and a critical abrupt point occurred in the decreasing process over time. After the abrupt point, the permeability rapidly decreased, which was mainly due to capillary condensation plugging at high relative humidities. Pore throat closure could dramatically affect permeability. The relationship between permeability and water saturation (Sw) conformed to an exponential equation. Methane permeability was sensitive to water saturation variation at very low or high levels (Sw <20 % or Sw >50 %, respectively) and relatively insensitive at a moderate water content. Water vapor permeability variation with water saturation was similar to that in methane but basically remained stable at a moderate water saturation (10 % <Sw < 50%). At high water saturations, water vapor permeability reduction was more sensitive than that in methane.

Breakdown of the anodized nanostructured anatase for photovoltaic devices: The effect of water content in the electrolyte on preparation of large surfaces of nanotubes

Many researchers are heavily involved in attempts to optimise the course of the electrochemical anodization for preparing nanostructured anatase thin-films. Particularly challenging is to prepare vertically aligned arrays of ordered nanotubes of anatase for application in the photovoltaic (PV) systems which require preparing larger homogeneous crack-free surfaces without the need for pre- or post-treatments. Having previously optimised the anodization cell geometry and electrical settings, here we focus on the electrolyte contribution during the anodization, specifically water content. It was elucidated that the water content can influence the equilibrium and the mechanisms behind several competing processes responsible for the formation of nanotubes (NT): (i) titania formation, (ii) NT formation over intermediate titanium hexafluoride, and (iii) etching of the mentioned phases. We employed broad structural, microstructural, electrochemical, and spectroscopic characterisation tools to shed more light on the development of the system with respect to water presence. Namely, water presence built up conductivity of the electrolyte, and consequently allowed faster oxidation of Ti and subsequently faster etching. Water content increase also facilitated the dissolution of the titanium hexafluoride which is the only water-soluble phase in the system. At moderate water content, the synergy of these processes facilitated: (I) forming the initial titania protective layer (titania prevented short circuits and thus eliminated the need for pre-deposition of protective layers), (II) growth of NT (upgraded the charge transfer), and (III) diminishing the residual nanoformations at the surface of residual titanium oxide or hydroxide phases (fewer nanoformations at surface and fewer residues increased charge transfer and apparent transparency and thus eliminated the need for post-treatment). The highest water content promoted excessive oxidation/etching where first NT with expanded tip were formed (crown-like NT), and then wormholes arose. Similarly, disproportioning in dissolution/oxidation/etching occurred at the lowest water contents resulted in less perfect NTs. The bottlenecks of the whole anodization process were identified proving the feasibility of the compositionally novel preparing procedure for obtaining perfect NT. Specifically for the solar cell application, 12% of water in the electrolyte will facilitate growth of the large-scale crack-free TNTs, with other parameters constant. In the course of the investigation, it was evidenced electrolyte can be utilised as a useful tool for controlling anatase to rutile occurrence and vertical distribution.

Engineering performance and microstructure characteristics of natural marine sediment stabilized with quicklime-activated GGBS under different lime proportions

The safe treatment of marine sediment has been a global-scale challenge. To reduce the environmental impacts associated with Portland cement (PC), an environment-friendly binder consisting of quicklime and ground granulated blast-furnace slag (GGBS) was used in the stabilization/solidification of natural marine sediment. Although the combination of lime and GGBS is used to stabilize the sediment with very low water content or moderate water content in previous studies, the natural marine sediment with such a high water content has not been treated by the quicklime–GGBS binder up to now. Therefore, a series of tests were performed to study the physicochemical, mechanical, and microstructural characteristics of quicklime–GGBS stabilized sediments. The results indicated that the quicklime–GGBS solidified/stabilized sediment had a similarly low water content at a proper quicklime-binder ratio to that of PC-stabilized sediments. The pH of quicklime–GGBS solidified sediments gradually decreased as the quicklime-binder ratio decreased and the curing period increased. The unconfined compressive strength (UCS) of quicklime–GGBS stabilized sediments was 1.4 times higher than that of the corresponding PC-stabilized sediments using the same test conditions. The hydration products effectively bonded the sediment particles and filled the pores between the sediment particles, facilitating the improvement of the UCS of the quicklime–GGBS stabilized sediment. The findings indicated that the use of GGBS and a small amount of quicklime can replace PC to stabilize natural marine sediment with high water content. This would be to provide binder dosage and component proportion for the field application of quicklime–GGBS binder and to significantly improve the economical and environmental effects of the treatment of high water content sediment. HIGHLIGHTS Innovative lime-activated GGBS is used as a binder in the improvement of sediment with ultrahigh water content. The water content, pH, and UCS of lime–GGBS stabilized sediments are contrastively studied. The engineering performances of lime-GGBS stabilized sediments are better than those of PC-stabilized sediment. An optimal and appropriate lime-binder ratio is suggested. Microstructure mechanism of lime–GGBS stabilized sediment is revealed through series of micro-tests.

Modelling the mechanical behaviours of glassy hydrogels

Our recent works show that poly(methacrylamide-co-methacrylic acid) (P(MAAm-co-MAAc)) hydrogels with moderate water content (50–70 wt%) exhibit similar glass transition behaviours as in dry polymers. In the glassy state, these gels exhibit a modulus of several hundred megapascals and a failure strength of tens of megapascals, which are much higher than other reported tough gels. In this work, we apply a viscoplastic model to describe the temperature-dependent and rate-dependent mechanical behaviours of the P(MAAm-co-MAAc) gels. It is found that the viscoplastic model developed for dry polymers can also describe the stress-strain responses of gels including yielding and strain softening. It can also capture the stress relaxation behaviours. This work confirms that the glass transition in the gels and dry polymers shares a similar physical mechanism. Meanwhile, it indicates the classic viscoelastic/viscoplastic models can be readily applied for this new type of tough gels.

Emplacement and eruptive style of high-grade ignimbrites from fissure vents: The Las Mellizas Ignimbrite, Caviahue-Copahue volcanic complex, southern Andes

The Pliocene to Recent Caviahue – Copahue volcanic complex is located in the Southern Volcanic Zone of the Andes. The Las Mellizas Ignimbrite is widely distributed in the intra-caldera region of the previously formed Caviahue caldera. Detailed field work led us to identify four facies associations for Las Mellizas Ignimbrite and to characterize the pyroclastic facies as dominantly vitrophyric, eutaxitic and rheomorphic, with limited occurrences of welded agglomerates and lithic breccias. Pyroclastic dykes with subvertical eutaxitic fabric were found and interpreted as fissure vents of this ignimbrite. Their orientations follow either the southern Caviahue caldera rim, or approximately the current extension direction as determined by previous neotectonic studies. Thermobarometry and hygrometry estimations were carried out based on compositional analyses of minerals (plagioclase, ortho- and clinopyroxenes, FeTi oxides) and glass. We interpret that Las Mellizas Ignimbrite was deposited from high-temperature and concentrated pyroclastic density currents, formed by almost fully collapsed low eruptive columns (pyroclastic fountaining). Low pre-eruptive pressures (0.04–0.06 GPa) and moderate water content (2.0–3.4 wt%) plus the low crystallinity of the magma (<10 vol% of phenocrysts) points to a shallow magma chamber and shallow fragmentation level, which is also supported by lithic clast composition. The eruption trigger is interpreted as mainly due to magmatic processes, and aided by tectonic activity. The presence of topographic scarps, outcrops distribution and stratigraphic discontinuities north of the Copahue volcano, in addition to co-ignimbritic lithic breccias, suggest that a small collapse may have occurred, nested on the western Caviahue caldera rim. In this context, the fissure vents represent peripheral extra-caldera pyroclastic conduits.

Geothermobarometry and geochemical modeling of Archean charnockites from Carajás Province, Amazonian craton, Brazil

Orthopyroxene-bearing tonalites/trondhjemites with scarce quartz diorites comprise the Café enderbite that crops out in three Neoarchean plutons in the central portion of the Canaã dos Carajás domain, Carajás Province, northern Brazil. Intrinsic parameters based on the mineral chemistry of plagioclase, biotite, amphibole, and pyroxene constrain crystallization conditions to 1150–850°C and 750–600 MPa, moderate water content in the melt (4.8–5.6 wt.%) and relatively oxidizing conditions, between the fayalite–magnetite–quartz (FMQ) and nickel– nickel oxide (NNO) + 1.7 buffers. Geochemical modeling indicates that the Café enderbite evolved via at least two fractional crystallization stages – quartz diorite to orthopyroxene tonalite and orthopyroxene tonalite to orthopyroxene trondhjemite – with high crystal content (45–60%, or even higher). This high crystal content during fractional crystallization was the key factor to the preservation of orthopyroxene in the magmatic system as it left only a relatively small proportion of melt to react with early-formed orthopyroxene.

Shock-induced H loss from pyroxene and maskelynite in a Martian meteorite and the mantle source δD of enriched shergottites

Assessing the water abundance and hydrogen isotopic signature (δD) of the Martian interior dictates our understanding of the formation of inner solar-system planets, the origin of their volatiles, Martian volcanic history, and the potential for life-bearing environments on the surface of the red planet. Although several Martian meteorites, representing the planet's crust, have been analyzed before for this assessment, little is known about the effect of shock on recorded hydrogen (H) in their mineral phases. Here, hydrogen contents and isotopes are measured by secondary ion mass spectrometry (SIMS) in an enriched olivine-phyric shergottite, Larkman Nunatak (LAR) 06319, containing impact-melted zones. Systematic 100 μm-long traverses in pyroxene and maskelynite grains reveal decreases of hundreds of µg/g H2O and increases in δD of thousands of ‰ towards the contact with impact-melted zones, which is interpreted as H diffusive loss during shock-melting. Diffusion modeling reveals that temperatures high enough to permit H diffusion following shock were maintained near the impact-melted zone for a few minutes. By comparison, the interior of pyroxenes > 200 μm away from impact-melted zones have some of the highest H content with 170–480 µg/g H2O and the lowest δD with ∼ 300‰. The latter values, obtained on the most Mg-rich, i.e. earliest crystallized pyroxenes, are used to estimate that the enriched shergottite mantle source contains 300–1000 µg/g H2O and has a δD of ∼ 300‰. This δD is similar to that of depleted shergottite and nakhlite mantle sources, but higher than Earth’s upper mantle, suggesting slightly different water source materials for the two planets. The enriched shergottite mantle source has ∼ 10 times more water than that inferred for the depleted shergottite source and for Earth’s upper mantle. The high water content and wide range of δD in olivine (from 90 µg/g H2O and 2700‰ to 1350 µg/g H2O and −14‰) is interpreted as overprinting by a combination of Martian and terrestrial surface alteration. Finally, the high δD recorded in the impact-melt produced glass (3350–4700‰), its moderate water content (100–230 µg/g H2O), and the presence of vesicles, are likely the result of incorporation of Martian surficial material (ice and atmospheric gases) and degassing during shock melting. This study shows that shock can induce H loss from minerals, accompanied by > 1000‰ δD increases. Additionally, although it confirms that the Martian mantle may be heterogeneous in its water content, it implies that the Martian mantle is homogeneous within uncertainties for δD.

Dislocation Creep of Olivine and Amphibole in Amphibole Peridotites from Åheim, Norway

Amphibole peridotite samples from Åheim, Norway, were analyzed to understand the deformation mechanism and microstructural evolution of olivine and amphibole through the Scandian Orogeny and subsequent exhumation process. Three Åheim amphibole peridotite samples were selected for detailed microstructural analysis. The Åheim amphibole peridotites exhibit porphyroclastic texture, abundant subgrain boundaries in olivine, and the evidence of localized shear deformation in the tremolite-rich layer. Two different types of olivine lattice preferred orientations (LPOs) were observed: B- and A-type LPOs. Electron backscatter diffraction (EBSD) mapping and transmission electron microscopy (TEM) observations revealed that most subgrain boundaries in olivine consist of dislocations with a (001)[100] slip system. The subgrain boundaries in olivine may have resulted from the deformation of olivine with moderate water content. In addition, TEM observations using a thickness-fringe method showed that the free dislocations of olivine with the (010)[100] slip system were dominant in the peridotites. Our data suggest that the subgrain boundaries and free dislocations in olivine represent a product of later-stage deformation associated with the exhumation process. EBSD mapping of the tremolite-rich layer revealed intracrystalline plasticity in amphibole, which can be interpreted as the activation of the (100)[001] slip system.

Unravelling the influence of water content, reaction time, and temperature on the heterogeneous synthesis of methyl formate

The atomic efficient synthesis of the fuel additive, methyl formate (MF), was performed with the ion exchange resin Amberlyst™ A26OH, acting as a heterogeneous catalyst. CO gas feed for the carbonylation reaction of methanol contained 65 vol% of N2. A 33 central composite design was applied to investigate the influence of temperature, reaction time and water content, as well as their interactions on the MF yield. Moderate temperatures (30–55 °C), pressures (2.0–4.5 MPa), water content (0.01–0.1 vol%), and short reaction times (0.5–2 h) were chosen for enquiry. The global optimum, reaching 61.7 ± 3.5%, was detected at 55 °C after 2 h with the lowest water content of 0.01 vol%. Under optimal reaction condition the reusability of A26 was confirmed and a five times higher MF yield was obtained in comparison to the homogenous catalyst NaOCH3. MF was selectively (≤99.9%) formed in all experiments. The results confirm that the heterogeneous carbonylation simplifies and reduces energy expenditure of MF synthesis. Furthermore, the shown suitability as a downstream process of biomass gasification contributes to the zero-waste emission goal in transport and chemical sector.

Highly sensitive and chemically stable NH3 sensors based on an organic acid-sensitized cross-linked hydrogel for exhaled breath analysis

Due to interference by the high moisture content and complicated compositions of human exhaled breath, the trace-level detection of ammonia (NH3) with desirable selectivity and stability is a large challenge for exhaled breath analysis. Carboxyl-sensitized hydrogels can be activated by moisture to exhibit a significant response and excellent selectivity to NH3. However, the high activity of carboxyl groups in hydrogels is a double-edged sword, resulting in poor chemical stability during NH3 detection. Herein, organic acids were embedded into a cross-linked poly(ethylene glycol) diacrylate (PEGDA) hydrogel via thiol−ene photochemistry to form stable hydrogels for NH3 detection in a humid atmosphere. As a result, under high humidity conditions (80% RH), the optimal sensors exhibited superior selectivity to NH3 among various interfering gas species, a remarkably high NH3 response (Za/Zg=6.20) towards 20 ppm NH3, and an extremely low actual detection limit (50 ppb) at room temperature. Moreover, the sensors exhibited excellent chemical stability due to the moderate equilibrium water content of the hydrogel composites and acid dissociation constant of the acid groups. The moisture-activated NH3 sensing mechanism was thoroughly investigated by complex impedance spectroscopy (CIS), quartz crystal microbalance (QCM) measurements, Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). To explore the application prospects of cross-linked hydrogel sensors for detecting NH3 in exhaled breath, a simulated exhaled breath test was also performed.

Analysis on water use efficiency of Populus euphratica forest ecosystem in arid area

Water use efficiency (WUE, the ratio of gross primary productivity (GPP) to evapotranspiration (ET)) reflects the coupled relationship between water loss and carbon gain in the process of plant photosynthetic carbon assimilation. As a dominant tree species in arid area, Populus euphratica plays an important ecological role in slowing desertification. Here, continuous observations of carbon, water, and energy fluxes were carried out in Populus euphratica forest with eddy covariance (EC) technique in 2018. We systematically explained the variation characteristics of energy fluxes and WUE at different time scales, and explored the main controlling factors of WUE in drought-stressed environment based on the synchronous meteorological data. Results showed that the carbon exchange of the Populus euphratica forest ecosystem occurred mainly during the growing seasons (April–October). During this period, the entire ecosystem appeared as a carbon sink with the potential to sequester atmospheric carbon dioxide. The average daily WUE was 2.2 g C/kg H2O, which was lower than other temperate forests (2.57–6.07 g C/kg H2O) but higher than grassland, wetland, and cropland. We also concluded that an increase in carbon dioxide concentration (CCO2) and air relative humidity (RH) could promote the increase of WUE. Nevertheless, WUE was negatively correlated with air temperature (Ta), photosynthetically active radiation (PAR), and normalized difference vegetation index (NDVI). Additionally, WUE increased under moderate soil water content (SWC), but decreased due to the continuously rising SWC. WUE was more strongly affected by factors affecting water consumption than carbon uptake. Under the conditions of high temperature, strong radiation and low humidity in the summer, the growth rate of ET was much larger than that of GPP. This study not only contributes to our understanding of the carbon, water, and energy dynamics of the Populus euphratica forest ecosystem but also provides an important reference for ecological conservation and ecological restoration in arid regions.

Mild water intake orients crystal formation imparting high tolerance on unencapsulated halide perovskite solar cells

The irreversible phase transition by water incorporation, along with thermal decomposition, has long been thought to be the dominant degradation pathway to deteriorate electronic and optoelectronic properties of perovskite devices. However, comprehensive characterization and insightful understanding of beneficial effect of water incorporation remains scarce. Here, we capture the phase transformation of perovskite in situ from its precursor stage to the final film upon thermal annealing as a function of relative humidity (RH) by grazing-incident wide-angle X-ray scattering. Quantitative structural analyses show that a moderate water content (RH 40%) enhances the texture orientation of the perovskite. A consequence of the guided water-incorporated treatment is that the unencapsulated device, without any sophisticated instability-mitigation approaches, exhibits excellent tolerance to long-term, light soaking and high-temperature aging, retaining more than 80% of the peak power-conversion efficiency under constant 1-sun illumination or heating at 65°C for more than 1,000 h, respectively.

Licorice (Glycyrrhiza glabra)—Growth and Phytochemical Compound Secretion in Degraded Lands under Drought Stress

Water deficiency restricts plant productivity, while excessive soil moisture may also have an adverse impact. In light of this background, field trials were conducted in secondary saline soil (EC 6.5 dS m−1) at the experimental station of Tashkent State Agrarian University (TSAU), Uzbekistan to determine drought tolerance of licorice (Glycyrrhiza glabra) by exposure to four levels of water deficit, namely control (70–80%), moderate (50–60%), strong (30–40%) and intense (10–20%) relative water content (WC) in the soil. The moderate drought stress exhibited positive effects on the morphological and physiological parameters of licorice, and was considered to be the most suitable water regime for licorice cultivation. Plant growth under the 50–60% WC treatment was slightly higher as compared to 70–80% WC treatment, exhibiting weak water deficit promotes licorice growth, root yield and secondary metabolite production. In particular, secondary metabolites i.e., ash, glycyrrhizic acid, extractive compounds and flavonoids, tended to increase under moderate water deficit, however further drought intensification brought a sharp decline of these values. These results contribute to the development of licorice cultivation technologies in arid regions and the most important consideration is the restoration of ecological and economical functions of the dryland agricultural system.

Allocation of photoassimilated carbon of radiata pine (Pinus radiata) seedlings as affected by soil water stress

ABSTRACT This study was carried out to determine the carbon (C) allocation of tree components following water stress in radiata pine (Pinus radiata) seedlings. The seedlings were exposed to various water contents (low, moderate and high soil water content) for 30 days and labelled with 14CO2 gas for six hours on the 31st day. Biomass in all seedling components (foliage, stems and roots) was significantly higher in the moderate soil water content treatment than in the low soil water content treatment, while seedling biomass did not significantly differ between the moderate soil water and high soil water content treatments. The shoot/root ratio of seedlings decreased when soil water content decreased. The C concentrations of radiata pine seedlings were not affected by the soil water content, whereas the soil water stress-induced difference in the C allocation of seedlings was attributed to differences in seedling biomass. The translocation of pulse-labelled 14C from the foliage to the roots was enhanced by low soil water content. The distribution of 14C was highest in foliage, followed by roots, stems and soil. The results indicate that soil water content was one of the primary factors influencing biomass allocation in the early growth of radiata pine seedlings.