High Water Extraction Research Articles

Dynamic changes in chemical components, volatile profile and antioxidant properties of Xanthoceras sorbifolium leaf tea during manufacturing process.

In order to elucidate the dynamic changes of quality characteristics in Xanthoceras sorbifolium leaf tea (XLT), this work investigated the chemical components, volatile profile, and antioxidant properties at key stages of fixation, shaping, and drying. The process of fixation and drying emerged as critical stages that affected the chemical components and taste of XLT. Total polyphenols, reducing sugars and chlorophyll were the differential compounds, which decreased by 29.1%, 63.3% and 69.5% during processing, respectively. Threonine, glycine, arginine, reducing sugar, caffeine, catechin (C), and epicatechin gallate (ECG) were primary taste characteristic compounds. A total of 95 volatile organic components (VOCs) and 24 key odorants with relative odor activity value (ROAV)>1.0 were identified in XLT, ethyl 2-methylbutanoate-D, dimethyl disulfide, and ethyl isobutyrate (ROAV=100) were the central contributors to volatiles profile. Moreover, tea manufacturing enhanced the antioxidant potency composite (APC) by 1.1%, primarily due to its high water extract content.

Assessing the isotopic biases of soil water from cryogenic water extraction in different soil types in China

AbstractThe utilization of deuterium (δ2H) and oxygen (δ18O) isotope ratios in cryogenically extracted water from soil samples is a widely employed method in hydrological and ecological research. Nevertheless, an increasing body of research indicates that cryogenic water extraction (CWE) leads to δ2H depletion in soil water. To investigate the widespread existence of this phenomenon, samples from eight physicochemically distinct soils in China underwent rehydration with a reference water at five different water contents and were subsequently extracted using CWE. In comparison to the reference water, significant and inconsistent δ2H depletion was observed in all eight soil samples. The δ18O bias also exhibited variation, ranging from enrichment to depletion. Generally, Z score assessments indicated unacceptable results for all soils. Water content emerged as the most influential variable affecting both δ2H and δ18O biases, while soil properties had different impacts on these biases. Source water, as calculated by a linear regression model, revealed that the isotopic composition of extracted soil water differed from that of the reference water. The cryogenic extraction error in soil water could not solely attributed to fractionation processes during the extraction but resulted from the release of tightly bound soil water into the reference water. Using the influencing factors, correction models for δ2H and δ18O biases by CWE were developed. By these models, the δ2H and δ18O biases were mostly successful corrected. High soil water extraction efficiency (e.g., 99%) was recommended to minimize isotopic biases. These efforts necessitate further testing, particularly in ecohydrological studies involving isotope measurements of soil water through CWE.

Performance improvement of tubular solar still with pistachios shell materials: Energy, exergy, economic, and sustainability analysis

This study is based on the effects of using a tubular solar still (TSS) with pistachio shells of macro size as an energy storage material for generating high water extraction from the solar still. Two different solar stills are used for performing the distillation process, in which one still is accommodated with pistachio shells for storing solar energy to escalate water productivity. Energy and exergy analysis were performed along with the calculation of the freshwater production for both modified tubular solar stills (MTSS) and conventional tubular solar stills (CTSS) without a heat storage facility. The results indicate that the modified distillation apparatus yielded more fresh water, collecting about 2.41 kg from the saline water, whereas the non-modified still obtained 1.91 kg. This represents a 27.3 % enhancement in the performance of the modified still. The thermal efficiency of both systems is also evaluated with MTSS achieving a maximum efficiency of 39.15 % whereas CTSS achieved 26.15 %. Furthermore, the exergy efficiency of the systems is evaluated, where the maximum exergy efficiency is attained as 3.82 % and 2.22 % for MTSS and CTSS, respectively. In economic analysis CPL and payback time of the study are also evaluated, and it is found that the CPL of MTSS and CTSS is obtained as 0.027 $/l and 0.031 $/l, and 0.443 years and 0.515 years, respectively.

Impact of high pressure pre-treatment and hot water extraction on chemical properties of crude polysaccharide extract obtained from mushroom (Volvariella volvacea).

An examination of the process of extracting crude polysaccharides from Volvariella volvacea solely through hot water treatment (HWE) at 60, 80, and 100°C and through an approach involving high pressure processing (HPP) at 200, 400, and 600MPa followed by HWE. The physiological properties of the polysaccharides could be explained by the structural analysis performed via FT-IR spectroscopy and NMR spectroscopy, which revealed the extract composition of the protein-bound polysaccharides connected by β-glycosidic bonds. Under the extraction conditions investigated in this current study, the recommended extraction condition was a combination of HPP (600MPa, 10min) and HWE (60°C, 2h). This condition gave high crude polysaccharide yields (with a 2-12% increase), and β-glucan content (with a 15-20% increase) without disrupting the β-glycosidic bond, as compared to using HWE alone. High pressure extraction could be an alternative technique for reduced extraction temperatures of active compounds from mushrooms.

بررسی تأثیر نسبت های مختلف کلسیم به منیزیم آب آبیاری بر خصوصیات رشدی و عملکرد کینوا (.Chenopodium quinoa Willd)

Introduction Quinoa (Chenopodium quinoa Willd.) is a facultative halophyte with very high adaptability to varied climatic conditions and high nutritional value. Different quinoa cultivars can have economical and stable yield in saline soil and water conditions. In addition to salinity, the chemical composition of irrigation water and thus soil solution affect the uptake and transfer of water and nutrients, and so plant yield. The intensity of this effect depends on various factors such as plant species. Calcium to magnesium ratio (Ca/Mg) is one of the quality indicators of irrigation water that can affect soil physical conditions and nutrient uptake independent of salinity level. A Ca/Mg < 1 and exchangeable magnesium percentage more than 25% in irrigation water are considered high enough to reduce soil quality and crop yields. Currently, frequent droughts and high water extraction have caused a sharp drop in water levels, increase in salinity, and in some cases a decrease in the Ca/Mg in the groundwater of most arid regions of the country. Since the effect of Ca/Mg in irrigation water on growth and yield of quinoa has not been studied so far, so the aim of this study was to investigate the effect of different Ca/Mg in irrigation water on growth parameters and quinoa grain yield in saline conditions. Materials and methods To study the effect of different Ca/Mg of irrigation water on quinoa growth and yield, three separate experiments in a randomized complete block design with four replications were conducted at the Research Greenhouse of Soil and Water Research Institute in 2018. Experimental treatments included three different Ca/Mg in irrigation water consisting of 0.25, 0.5 and 1, which were made by sodium chloride, magnesium and calcium as nutrient solutions fit to the salinity tolerance threshold of quinoa at different growth stages. In the previous research, yield reduction thresholds for Titicaca cultivar at different growth stages in a soilless culture (perlite) were a: 8 dS m-1 for emergence, b: 15 dS m-1 for flowering and c: 20 dS m-1 for grain filling. To conduct this research, 100 quinoa seeds were planted in pots, and the pots were irrigated with 8 dS m-1 water along with the desired Ca/Mg treatments. After establishing the quinoa seedlings and thinning to six plants per pot, pot irrigation was done with 15 dS m-1 salinity along with the desired treatments. After ensuring the end of the flowering stage, the remaining pots were irrigated with 20 dS m-1 salinity with the desired treatments until physiological ripening. Finally, the analysis of variance of the data was performed using SAS software and the means were compared with the protected LSD at 5% probability level. Results and discussion The results showed that the emergence percentage and non-uniformity of quinoa were not affected by Ca/Mg of irrigation water, however, increasing the magnesium amount significantly improved the emergence rate of quinoa seeds. Although the results showed that the fresh and dry weight at the flowering stage was significantly affected by Ca/Mg of irrigation water, the yield and yield components were not significantly affected. Therefore, the quinoa growth and yield are not affected by the ionic composition of irrigation water in terms of low Ca/Mg, however, the composition of absorbed and accumulated ions in plant tissues are significantly changed. So, compared to other conventional crops, quinoa has the potential to produce economic yield in saline conditions and is not affected by the Ca/Mg of water sources. Conclusion The results of this study showed that different Ca/Mg in irrigation water do not reduce the growth and yield of quinoa. Therefore, if the salinity tolerance threshold of the plant is considered, low water quality in terms of high magnesium concentration does not damage the plant and so can be cultivated with saline water sources such as diluted seawater.

Repeated exposure to fine particulate matter constituents lead to liver inflammation and proliferative response in mice

BackgroundFine particulate matter (particulate matter with aerodynamic diameter of ≦2.5 µm, PM2.5) exposure cause adverse health effects, including lung inflammation. Through intra-tracheal instillation of PM2.5 components, the study aimed to evaluate the inflammatory and proliferative effects on mice liver. PM2.5 samples were collected near an industrial complex at southern Taiwan. Mice were exposed to water extracts or insoluble particles by intra-tracheal instillation. Male C57BL/6 mice were divided into five groups: control, low dose insoluble particle exposure (LP), high dose insoluble particle exposure (HP), low dose water extract exposure (LW), and high dose water extract exposure (HW). Biochemical analysis, western blotting, histological examination, and immunohistochemistry were employed to evaluate the results. ResultEnrichment factor (EF) of metallic elements showed that the EFs of trace elements (Ti, V, Ni, Zn, Pb, Cr, and Cu) in PM2.5 were above 10. Hematoxylin and Eosin (H&E) staining of the liver tissue showed inflammatory infiltration in particle exposure group; hepatocyte ballooning degeneration and karyomegaly were seen in the water extract exposure group. Upregulation of inflammatory signaling, p65 and p50, and caspase-3 (an important effector involved in apoptosis) positive hepatocytes was significantly increased in the HP group, followed by an elevation in protein levels of growth arrest and DNA damage-inducible protein 153 (GADD153). Increased protein expression of proliferating cell nuclear antigen (PCNA) was noted in the LW and HW groups. An increase in phosphorylation of regulators of cell proliferation, Akt and extracellular signal-regulated kinase (ERK) 1/2, were detected in the LW and HW groups. ConclusionThe present study shows that the insoluble particle composition of PM2.5 induced inflammatory signaling and cytokines upregulation in the liver, accompanied with inflammatory cell and macrophage infiltration and an abnormal liver function. Exposure of water extract to PM2.5 induced signals of upregulated cellular proliferation, elevated markers of cell proliferation in liver, hepatocyte ballooning degeneration and karyomegaly.

Management of trickle irrigation for banana: Hydrodynamic processes and sensor placement at the root zone

ABSTRACT Information on soil hydrodynamic processes assists in explaining the soil-water-plant relationship and has practical applications to irrigation management, such as the definition of soil water sensor placement. The objective of this study was to detail the hydrodynamic process in the soil root zone and to define the location for placement of soil water sensor under different configurations of trickle irrigation in banana crops. Three micro-sprinkler emitters with flow rates of 70 (T1), 53 (T2), 35 L h-1 (T3), and two drip system, one with one drip line per row of plants (T4), and another with two drip lines per row of plants (T5) were evaluated. The experiment was conducted in a randomized block design with five repetitions. Higher water extraction was found for irrigation systems with higher flow rates for all configurations of trickle irrigation systems. Soil moisture sensors in drip systems should be placed at distances of 0.75 to 0.81 m from the pseudo stem and at depths of 0.33 to 0.44 m. Under micro-sprinkler systems, soil water sensors should be placed at 0.75, 0.77 and 0.83 m from the pseudo stem towards to the emitter and at depths of 0.33, 0.48 and 0.55 m for emitter flow rates of 35, 53 and 70 L h-1, respectively.

Beneficial Effects on Cosmetic Activity by Optimizing the Calamondin Orange Extraction Process

This study expands the usage of Citrus madurensis ( Citrofortunella microcarpa), which is a good source of skin whitening and antioxidants activation in cosmetics. The goal of this study is to provide cosmeceutical activity data about the extraction yield and total polyphenol of calamondin orange by optimizing the focused high ultrasound (INEFU), ultrasound extraction (UE), and water extraction (WE) conditions. Under optimal extraction conditions, which consisted of 1800 W for 45 minutes (INEFU) and 500 W for 45 minutes (UE), 21.55% (w/w) and 13.27% (w/w) of the highest extractions yield and total polyphenol content was obtained. For the skin whitening activity, tyrosinase inhibitory activity was observed at 69.28% in the INEFU extracts, which was 69.24% higher than that of the UE extracts (58.82%). To reduce melanin production in Clone M-3 cells, 86.9% melanin production was observed following the addition of control, WE relative to the control without a sample, and 81.2% and 78.9% were found in the UE and INEFU conditions, respectively. The highest total phenol secretion was conclusively obtained under the optimal conditions and resulted in a significant improvement of the cosmetic activities of C. madurensis ( C. microcarpa)-based cosmeceutical ingredient.

Response of Maize ( Zea mays L.) Hybrids to Diurnal Variation of Vapor Pressure Deficit (VPD) and Progressive Soil Moisture Depletion

This study investigated the transpiration (TR) response to (i) diurnal changes of vapor pressure deficit (VPD) and (ii) soil dry down in four maize hybrids contrasting for yield performance under drought stress in the field. These four hybrids included a popular local variety P3K and a commercial check SC303 that were found to be drought susceptible. The experiment was carried out in pots at early vegetative stage (8-leaf stage). Results showed an increase of TR with increasing VPD but with significant variations between the hybrids tested. The two susceptible hybrids P3K and SC303 had higher TR over nearly the whole range of VPD values than the two other hybrids, with the largest variation recorded at VPD values above 6 kPa. Regarding the TR response to soil moisture depletion, normalized TR (NTR) of all genotypes reduced with soil moisture depletion for all treatments. In addition, NTR showed a significant reduction for plants that were irrigated at 3 days intervals before the experiment as compared to those irrigated daily. There was a trend of higher water extraction, as evaluated with the fraction of transpirable soil water (FTSW) threshold, in the tolerant hybrids relative to the susceptible ones for the two irrigation treatments. In addition, prior exposure to water deficit tends to lower the FTSW threshold which leads to increased water extraction capacity at lower soil moisture level. These results demonstrate that control of TR under high VPD conditions coupled with high water extraction capacity from progressively drying soil can contribute to drought tolerance in maize hybrids.

Influence of microalgae wastewater treatment culturing conditions on forward osmosis concentration process.

Forward osmosis is envisioned as a technology for microalgae concentration but fouling propensity during dewatering is currently a limiting factor that requires better understanding. The purpose of this study is to define the impact of microalgae culturing conditions on the downstream forward osmosis (FO) separation process-water recovery and microalgae harvesting. Chlorella vulgaris was cultivated in an outdoor lab-scale reactor fed with synthetic wastewater mimicking primary settled municipal influent under changing environmental conditions (temperature, solar radiation, nutrient balance) with varying hydraulic retention time. High efficiency of nutrient removal was achieved under all tested conditions but microalgae autoflocculation and lower rate of pollutant removal were observed with batches where culturing temperature (6.5-21°C), solar irradiation rate (181W/m2), and nitrogen/phosphorous ratio (2.9) were below the optimal range. Regarding FO concentration, high initial water fluxes (in the range of 18.2 to 19.5L·m2·h-1) and water extraction rate (60.1-83.9%) were observed in all subsequent FO concentration tests. Significant membrane fouling (microalgae deposition on surface) associated with poor biomass recovery from the FO cell was found to be dependent on exopolymeric substance accumulation, which was a response to non-optimal environmental culturing conditions.

QTL mapping reveals genetic architectures of malting quality between Australian and Canadian malting barley (Hordeum vulgare L.)

Australia and Canada are major exporters of malting barley (Hordeum vulgare L.), with Baudin from Australia and AC Metcalfe from Canada being the benchmark varieties for premium malting quality in the past 10 years. We used the barley doubled haploid population derived from a cross of Baudin and AC Metcalfe to map quantitative trait loci (QTLs) for malting quality. The results revealed different genetic architectures controlling malting quality for the two cultivars. Sixteen QTLs were identified and located on chromosomes 1H, 2H, 5H and 7H. The Australian barley Baudin mainly contributed to the malting quality QTL traits of high diastatic power and high β-glucanase on chromosome 1H, while Canadian barley AC Metcalfe mainly contributed to the QTL traits of high hot water extract, high free amino nitrogen, high α-amylase and low malt yield in chromosome 5HL telomere region. This study demonstrated the potential to breed new barley varieties with superior malting quality by integrating genes from Australian and Canadian malting barley varieties. This paper also provides methods to anchor traditional molecular markers without sequence information, such as amplified fragment length polymorphism markers, into the physical map of barley cv. ‘Morex’.

Environmentally Sound Desludging Concept for Hoan Kiem Lake in Hanoi Vietnam

Due to urbanization, more and more lakes are being swallowed up by the catchments of growing cities. The ecosystem of shallow, small to mid-sized lakes reacts very sensitively to changing environmental conditions. Water quality deteriorates as a result of sewage discharge, higher water extraction, and the growing inflow of urban suspended solids. Since water bodies and, in particular, lakes are very important for the microclimate, urban beautification and recreational purposes, they need to be protected. Therefore, many growing cities are developing management concepts for urban lakes. A Vietnamese–German research project developed and applied a sustainable concept to remediate urban shallow lakes in tropical regions. This paper provides an insight into the current situation of Hoan Kiem Lake in the center of Hanoi as well as other urban water bodies in Asia, and presents approaches for environmentally sound remediation and sustainable water management.

Modeling Groundwater Flow in Heterogeneous Porous Media with YAGMod

Modeling flow and transport in porous media requires the management of complexities related both to physical processes and to subsurface heterogeneity. A thorough approach needs a great number of spatially-distributed phenomenological parameters, which are seldom measured in the field. For instance, modeling a phreatic aquifer under high water extraction rates is very challenging, because it requires the simulation of variably-saturated flow. 3D steady groundwater flow is modeled with YAGMod (yet another groundwater flow model), a model based on a finite-difference conservative scheme and implemented in a computer code developed in Fortran90. YAGMod simulates also the presence of partially-saturated or dry cells. The proposed algorithm and other alternative methods developed to manage dry cells in the case of depleted aquifers are analyzed and compared to a simple test. Different approaches yield different solutions, among which, it is not possible to select the best one on the basis of physical arguments. A possible advantage of YAGMod is that no additional non-physical parameter is needed to overcome the numerical difficulties arising to handle drained cells. YAGMod also includes a module that allows one to identify the conductivity field for a phreatic aquifer by solving an inverse problem with the comparison model method.

Preface &amp;quot;Practice and strategies for managing water conflicts between human and ecosystems&amp;quot;

Water conflicts between humans and ecosystems are key issues for sustainable water resource management. In the past decades, human-oriented regulation of water resources and construction of many hydraulic projects for hydropower generation, agricultural irrigation, and flood control has significantly altered natural flows in many rivers, resulting in increasing variances in water availabilities and flow regimes. For example, every year, a large amount of water is being diverted for agricultural irrigation in major river basins worldwide. Annually, over 70 % of water is extracted from the rivers to meet agricultural water needs in many countries. Particularly, a number of rivers are subjected to extremely high water extraction rates and the water can hardly reach the sea. Incessant declination in water availabilities has caused a series of impacts on many valuable aquatic habitats, such as riparian floodplains, wetlands, and estuaries. Due to population growth and economic development, enhanced amounts of freshwater are expected to be extracted to support human activities, further worsening such situations. Conflicts over water resources are thus intensive for human beings and ecosystems across the world. Many concerns are rising, particularly in many developing countries. For example, in China, since the early 1970s, the frequency of drying or ephemeral stream flows has been increasing in the Yellow River, which is the sixth largest river in the world. Since the early 1990s, drying took place annually in this river. Averagely, the time length without water in the lower reach of the river was approximately 100 days every year. Such extreme alterations have caused a cascade of adverse impacts on hydrological diversity, species distribution, and indigenous ecosystems in the Yellow River basin. This may eventually lead to unrecoverable effects on biodiversities, services, and even core functions of the associated ecosystems. Similarly, the other major river of China, i.e., the Yangtze River, is also subject to great alterations due to the construction of many mega water-related projects, such as the Three Gorges Dam and the South–North Water Transfer Project. Considering the pressure of stimulating economic growth in many developing countries across the world, similar constructions and projects have been undertaken. However, due to complexities of the associated river systems, as well as the interactions between humans and ecosystems, no clear results could be obtained regarding what unrecoverable and/or recoverable effects would happen because of such profound alterations. Moreover, the alterations may be multiplied by climate change, further affecting water availability and thus intensifying water competition between humans and ecosystems. In order to achieve sustainable water resource management, fostering a socio-economically and ecologically healthy consensus over water demands by humans and ecosystems is of great importance. Environmental flow that can be used to quantify the amount of water needed by a given ecosystem has become a competitive component with human water demand in watershed management. Thus, the management of water conflicts between humans and ecosystems in river basins is desired.

Patterns of Water Use by Great Basin Plant Species Under Summer Watering

We analyzed temporal and spatial patterns of water use by a functionally-diverse group of Great Basin plant species and determined their water use rates at the whole-plant and individual-leaf scales under variable summer watering. Species studied were the desert grasses Distichlis spicata and Sporobolus airoides, the desert shrubs Artemisia tridentata, Ericameria nauseosa, and Atriplex confertifolia; the wetland/riparian plants Juncus arcticus, Leymus triticoides, and Salix exigua; and the annual exotic Salsola tragus. Plant species were individually grown in 5.8 m2 plots in a common garden in eastern California. Three irrigation treatments in the form of monthly pulses were applied during the summer: low (1.3 cm), medium (2.6 cm), and high (3.9 cm), in addition to a nonirrigated control. Whole-plant water uptake characteristics were determined by soil water depletion at different soil depths, while leaf transpiration was determined by gas exchange. Whole-plant water extraction and leaf transpiration varied similarly among species. Desert shrubs had low water extraction (35 to 395 g m−2 day−1) and were not affected by irrigation. The desert grasses and riparian/wetland species had higher water extraction, increasing with irrigation levels. L. triticoides and J. arcticus had the highest water extraction overall (>2,000 g m−2 day−1). Desert shrubs relied 10 times more on deeper water sources than herbaceous species. The average T/ET was 31%, but varied by species. Summer available water in environments such as the Great Basin favors desert grasses and riparian/wetland species, but not desert shrubs. The observed species differences provide alternatives for water and vegetation management.

An attenuated total reflectance mid infrared (ATR-MIR) spectroscopy study of gelatinization in barley

The aim of this study was to evaluate the use of attenuated total reflectance and mid infrared (ATR-MIR) spectroscopy and to understand the gelatinization and retro-gradation of flour barley samples and the relationship with malting quality. Samples were sourced from two commercial barley varieties exhibiting high hot water extract (HWE) namely Navigator (n=8), and Admiral (n=8). Samples were analysed using the Rapid Visco Analyser (RVA) and ATR-MIR analysis. These results showed that ATR-MIR spectroscopy is capable of characterising gel samples derived from barley flour samples having different malting characteristics. Infrared spectra can effectively represent a ‘fingerprint’ of the sample being analysed and can be used to simplify and reduce analytical times in the routine methods currently used.

System for High Throughput Water Extraction from Soil Material for Stable Isotope Analysis of Water

A major limitation in the use of stable isotope of water in ecological studies is the time that is required to extract water from soil and plant samples. Using vacuum distillation the extraction time can be less than one hour per sample. Therefore, assembling a distillation system that can process multiple samples simultaneously is advantageous and necessary for ecological or hydrological investigations. Presented here is a vacuum distillation apparatus, having six ports, that can process up to 30 samples per day. The distillation system coupled with the Los Gatos Research DLT-100 Liquid Water Isotope Analyzer is capable of analyzing all of the samples that are generated by vacuum distillation. These two systems allow larger sampling rates making investigations into water movement through an ecological system possible at higher temporal and spatial resolution.

Water Quality Management Strategies for Various River Flows with QUAL2K Model

This study utilizes the river and stream water quality (QUAL2K) model as a tool to simulate and forecast the water quality and then to develop the management strategies for various flow rates above the Kaoping weir of Kaoping River in Taiwan. Model results based on the river assimilative capacity of four various flow rates including Q95, Q75, Q60, and Q25 were conducted to determine the corresponding amounts of pollution reduction. The average pollution reduction ratios of biochemical oxygen demand (BOD5) and ammonia nitrogen (NH3-N) should at least reach to 42.0% and 28.3% respectively to meet the restoration goals of Class A water quality standards regulated by Taiwan. The modeling results demonstrate that an increase of water extraction rates in the upstream reaches will have significant adverse effects on the water quality of the Kaoping River. Higher water extraction rates will lower the assimilative capacity that reduces the buffering capacity of river. It also induces that the water quality is susceptible to the impacts of the influent pollutant loads from the tributaries or drainages.

Soil water dynamics along a tree diversity gradient in a deciduous forest in Central Germany

AbstractThis study aimed to investigate whether soil water dynamics differ along a tree species diversity gradient. The 12 study plots in the Hainich National Park, Germany, were composed of up to 11 tree species. Fagus sylvatica formed the monospecific plots. Mixed forest plots consisted of a variable admixture of other broad‐leaved deciduous tree species such as Tilia spp., Fraxinus excelsior, Carpinus betulus, and Acer pseudoplatanus. Volumetric soil water content and soil water potential were measured for about two and a half years. Overall patterns of soil water dynamics were similar in all study plots. However, during a desiccation period in summer 2006, significant correlations between soil water in the upper soil and tree species diversity of the 12 study plots were observed. At the beginning of this period, soil water was extracted at higher rates in the species‐rich plots than in the beech‐dominated plots. However, later during the desiccation period, when atmospheric evaporative demand was higher, only the beech‐dominated stands were able to increase soil water extraction. In plots of high tree species diversity, soil water reserves were already low and soil water extraction reduced. Possible explanations for high water extraction rates in mixed species plots at the beginning of the desiccation period include species‐specific characteristics such as high maximum water use rate of some species, enhanced exploitation of soil water resources in mixed stands (complementarity effect), and additional water use of the herb layer, which increased along the tree species diversity gradient. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Assessment of transpiration efficiency in peanut (Arachis hypogaea L.) under drought using a lysimetric system

Transpiration efficiency (TE) is an important trait for drought tolerance in peanut (Arachis hypogaea L.). The variation in TE was assessed gravimetrically using a long time interval in nine peanut genotypes (Chico, ICGS 44, ICGV 00350, ICGV 86015, ICGV 86031, ICGV 91114, JL 24, TAG 24 and TMV 2) grown in lysimeters under well-watered or drought conditions. Transpiration was measured by regularly weighing the lysimeters, in which the soil surface was mulched with a 2-cm layer of polythene beads. TE in the nine genotypes used varied from 1.4 to 2.9 g kg(-1) under well-watered and 1.7 to 2.9 g kg(-1) under drought conditions, showing consistent variation in TE among genotypes. A higher TE was found in ICGV 86031 in both well-watered and drought conditions and lower TE was found in TAG-24 under both water regimes. Although total water extraction differed little across genotypes, the pattern of water extraction from the soil profile varied among genotypes. High water extraction within 24 days following stress imposition was negatively related to pod yield (r(2) = 0.36), and negatively related to water extraction during a subsequent period of 32 days (r(2) = 0.73). By contrast, the latter, i.e. water extraction during a period corresponding to grain filling (24 to 56 days after flowering) was positively related to pod yield (r(2) = 0.36). TE was positively correlated with pod weight (r(2) = 0.30) under drought condition. Our data show that under an intermittent drought regime, TE and water extraction from the soil profile during a period corresponding to pod filling were the most important components.