Mol H2O Research Articles

Effects of Three Irrigation Strategies on Gas Exchange Relationships, Plant Water Status, Yield Components and Water Productivity on Grafted Carménère Grapevines.

In the Chilean viticultural industry, Carménère is considered an emblematic cultivar that is cultivated mainly in arid and semi-arid zones. For this reason, it is necessary to use precise irrigation scheduling for improving water use efficiency (WUE), water productivity (WP), yield and wine quality. This study evaluated the effects of three deficit irrigation strategies on gas exchange variables, WUE, WP and yield components in a drip-irrigated Carménère vineyard growing under semi-arid climatic conditions during two consecutive seasons (2011/12 and 2012/13). The irrigation strategies were applied in completely randomized design from fruit set (S) to harvest (H). The first irrigation strategy (T1) involved continuous irrigation at 100% of actual evapotranspiration (ETa) from S to the veraison (V) period and at 80% of ETa from V to H. The second irrigation strategy (T2) involved irrigation at 50% of ETa from S to H and the third one (T3) involved no-irrigation from S to V and at 30% of ETa from V to H. The results indicated that there was a significant non-linear correlation between net CO2 assimilation (AN) and stomatal conductance (gs), which resulted in three zones of water stress (zone I = gs > 0.30 mol H2O m-2s-1; zone II = between 0.06 and 0.30 mol H2O m-2s-1; and zone III = gs < 0.06 mol H2O m-2s-1). The use of less water by T2 and T3 had a significant effect on yield components, with a reduction in the weight and diameter of grapes. A significant increase in WP (7.3 kg m-3) occurred in T3, which resulted in values of WUE that were significantly higher than those from T1 and T2. Also, a significant non-linear relationship between the integral water stress (SIΨ) and WP (R2 = 0.74) was established. The results show that grafted Carménère vines were tolerant to water stress although differences between cultivars/genotypes still need to be evaluated.

Cost-effective and dynamic carbon dioxide conversion into methane using a CaTiO3@Ni-Pt catalyst in a photo-thermal hybrid system

This research focuses on the synergy of converting carbon dioxide (CO2) into methane (CH4) by simultaneously introducing light and heat as dynamic sources to activate the catalyst. A CaTiO3@Ni-Pt catalyst, loaded with 30.0 wt.% Ni and 1.0 wt.% Pt on a perovskite CaTiO3 support was introduced. The photo-thermal catalytic hybrid system has two features that distinguish it from other photo- or thermal-catalytic systems. First, unlike the CO2 thermal-methanation reaction where CO2 and H2 react at a molar ratio of 1:4, 2.0 mol of H2 was replaced with 2.0 mol H2O in the photo-thermal catalytic hybrid system compared to the thermal-methanation reaction requiring 4.0 mol of H2. Second, by loading Ni and Pt, which are catalytic active species with excellent CO2 and H2 adsorption abilities, the CO2 reduction (46.48%) was promoted and the CH4 selectivity (99.46%) in the product was increased compared to the photo-methanation reaction. The CaTiO3@Ni-Pt not only inhibited the recombination of the photo-generated charges, but also facilitated the adsorption of the reactants in the photo-thermal hybrid system. The quantum efficiency of the CaTiO3@Ni-Pt catalyst measured for the photo-thermal hybrid system steadily increased to 180 °C. Nevertheless, this study implies that a photo-thermal hybrid system can be useful to photo-reducing CO2 by adding a small amount of heat. From a thermal reaction standpoint, a photo-thermal hybrid system can be used to reduce the reaction temperature during CO2 thermal-methanation and to reduce the consumption of H2 in half.

Canopy characteristics and light distribution in Sapindus mukorossi Gaertn. are influenced by crown architecture manipulation in the hilly terrain of Southeast China

Abstract Sapindus mukorossi Gaertn. (soapberry) is currently one of the most widely used biodiesel feedstocks in China. The canopy architecture of plants has significant impacts on microclimate, transpiration, and carbon acquisition and allocation, which can lead to plant disease and low yield. To solve low yield problems in soapberry and evaluate the relationship between light distribution and the canopy, crown architecture manipulation was carried out in this study to provide an ideotype to decrease leaf and fruit abscission. Canopy characteristics (LAI and CGfr), light characteristics (light ratio and PPFD) and photosynthetic characteristics (Pn, Tr, Gs and Ci) in different soapberry tree architectures were measured for 2 years to analyze light distribution, light interception and photosynthetic ability. This study also evaluated a two-factor interaction between scaffold branch angle (A30°, A45°, A60°, and A90°) and scaffold branch number (N3, N4, N5, and SC). Controlling the scaffold branch angle influenced light distribution, and branch angles of 60° and 90° increased light absorbance by 2–3 times in the vertical layers and decreased the disparity between inner and outer light ratios in the horizontal layers. Light interception ability was positively correlated (R2 = 0.785) with LAI from May to October, and the A90°N3 canopy architecture, which had 16% higher light interception ability than the other treatments and maintained the highest cumulative LAI (19.57) during the growing season, was the most suitable for preserving leaves in August and October. Light interception ability had no correlation with LAI in April (the month before blooming) but was positively correlated (R2 = 0.485) with the number of inflorescences, which indicated that higher light interception in April increased the number of inflorescences. Controlling the scaffold branch number significantly influenced Pn, Tr and Gs, and in particular, architectures with 3 scaffold branches provided 1–2 times higher photosynthetic ability than did the other architectures, with A60°N3 increasing Pn to 30 μmol CO2·m−2·s−1 and Gs to 0.26 mol H2O·m−2·s−1. The number of inflorescences was not directly correlated with yield, but yield in November was positively correlated (R2 = 0.5) with the photosynthetic rate*LAI in August. The highest yield, 0.3 kg·m−2 (projection area of crown), occurred in A60°N3 and A90°N3; the former was positively correlated with the photosynthetic rate in August, and the latter was influenced by high LAI and high light interception. Overall, high light interception ability could solve the problem of leaf abscission, and high photosynthetic ability could decrease fruit abscission in soapberry trees. A60°N3 and A90°N3 are the current ideotypes. These findings reveal the major factors influenced by canopy architecture and lay a foundation for further study of photosynthetic product distribution in different light environments. The selection of ideal architectural types will provide a mode and direction for further creative research into 3-dimensional visual structures, which will lead to additional theoretical and technical support for tree architecture planning.

Effects of preparation conditions on the performance of simultaneous desulfurization and denitrification over SiO 2 -MnO x composites

Abstract SiO2-MnOx composites were prepared by sol-gel method and used to simultaneously desulfurization and denitrification. The effects of TEOS (tetraethoxysilane) concentration, H2O concentration and ammonia concentration on the performance of simultaneous desulfurization and denitrification over the SiO2-MnOx composites were investigated. The experiment results showed that all of the SiO2-MnOx composites with a desulfurization efficiency of up to 100% in the experiment, while the denitrification efficiency was decreased from nearly 100% with the increasing of time. The SiO2-MnOx composite which was synthesized with 0.054 mol TEOS, 1.111 mol H2O, and 0.208 mol ammonia (TEOS: ammonia: H2O = 1.0: 3.9: 20.6) exhibited the best adsorption capacities of SO2 and NO, and the adsorption capacities of SO2 and NO were 0.0680 mmol/g and 0.1010mmoxl/g, respectively. The structure of the SiO2-MnOx composites, SiO2 distributed uniformly on the surface of MnOx, could reduce the adsorption inhibition of SO2 on NO, which was due to most of the SO2 could be adsorbed by the outer material (SiO2), while most of the NO molecules and the remaining SO2 enter into the inner layer and be adsorbed by MnOx. The urea treatment can increase the pore structure of the material by decomposing to produce NH3 and CO2, which made it easier for the gas to enter the material inside and improved the adsorption capacity of SO2 and NO. Based on the analysis of the TPD and FTIR spectra, it was apparent that the product of chemisorption was manganese nitrate, sulfuric acid and manganese sulfate.

Adsorption-based Process Modelling for Post-combustion CO2 Capture

The EU FP7-funded HiPerCap project aims to develop novel post-combustion CO2 capture technologies and processes which are environmentally benign and have high potential to lead to breakthroughs in energy consumption and overall cost. Three different separation technologies are being evaluated on a fair basis: absorption, membranes and adsorption. In this work, some of the results related to the development of adsorption-based fixed bed systems are presented. The design and optimization of a multibed adsorption-based separation process requires the use of powerful simulators that can describe the non-steady state process. However, prior to use a mathematical model for process design this should be validated against experimental data. A VTSA experiment has been carried out in order to provide information on the cyclic performance of a microporous biochar. The working capacity of the adsorbent is reduced due to incomplete regeneration during cyclic operation, although it stabilizes at 0.5 mol CO2 kg-1 and 0.4 mol H2O kg-1 once cyclic steady state is reached. A non-isothermal non-adiabatic dynamic model of the VTSA cycle was built in Aspen Adsorption, which makes use of the Ideal Adsorbed Solution theory to account for competitive adsorption between N2, CO2 and H2O. The model satisfactorily describes the history of the temperature of the adsorbent, the pressure, the total mass flow rate of the effluent, and the working capacity at cyclic steady state of the VTSA experiment. The validated model will be used as a starting point for process development.

Acclimation to light and avoidance of photoinhibition in Typha latifolia is associated with high photosynthetic capacity and xanthophyll pigment content.

Tall monocots with long, linear leaves have lower canopy light attenuation than plants with horizontal leaves, yet little is known about their light acclimation and sun-shade responses. The genus Typha, common in nutrient-rich wetlands, is highly productive with dense canopies of such leaves. The objective of this study was therefore to investigate photosynthetic acclimation and pigment content in linear leaves of Typha latifolia L. in response to light availability. This was done in a growth experiment with two light intensities and in the field. In the laboratory, T. latifolia exhibited typical morphological, anatomical and gas exchange sun-shade responses. Net photosynthesis rates in high light were very high for a C3 plant (>40µmol CO2 m-2s-1) in both laboratory and field studies, and this was associated with stomatal conductances that were correspondingly high (maximum values >1.0mol H2O m-2s-1). The size of the xanthophyll (violaxanthin, antheraxanthin and zeaxanthin; VAZ) pool was also among the top 0.5% of all species. In the field, T. latifolia was able to maintain high net photosynthetic rates (26-41µmol CO2 m-2s-1) throughout its canopy and could avoid photoinhibition through high investment in the VAZ pool (0.7-1.3µmolg-1 DW total VAZ pigments). This pattern of acclimation is likely to be adaptive, explaining why this species is so successful and dominant in high-light, high-nutrient wetland environments.

Defining biological thresholds associated to plant water status for monitoring water restriction effects: Stomatal conductance and photosynthesis recovery as key indicators in potato

The definition of irrigation schedules depends on the understanding of the response of key plant traits to different water restriction characteristics with the aim to avoid physiological impairment. In this study, different timings (at tuber initiation and bulking) and intensities (four soil moisture levels) of water restriction were tested in the potato crop. The temporal patterns of mid-morning or maximum, light saturated stomatal conductance (gs_max), recovery of net photosynthesis (Arecovery), stem water potential (Ψstem), carbon isotope discrimination in tubers (Δtuber), plant water concentration (PWC), photochemical reflectance index (PRI) and crop water stress index (CWSI) were analyzed. Early-severe water restriction caused a drastic yield reduction, with low recovery of physiological responses (gs_max, Δtuber, Ψstem, CWSI, Arecovery) after 15days of post-restriction irrigation and even a continued reduction of some of them (PWC, PRI). It also caused a prolonged gs_max reduction below 0.05mol H2O m−2s−1 (≈5μmol CO2 m−2s−1 of net photosynthesis) suggesting that this value defines a physiological severity threshold in potato, under which a metabolic impairment occurs. CWSI and PRI showed a close linear (R2=0.76) and no linear (natural logarithm function, R2=0.67) relationship with gs_max respectively. In cloudless dry environments, irrigation schedules in potato should aim to avoiding CWSI values higher than 0.4, especially until before of maximum canopy cover establishment. A close relationship between Arecovery at maximum stress moment and yield reduction was found. The strong relationship between the measured traits (except PWC and Ψstem) and final yield at maximum stress moment found in the present study warrants further research on drought phenotyping immediately before post-restriction irrigation or when the defined severity threshold in potato is reached.

Estimation of gas exchange parameters in backcross introgressed lines of rice (Oryza sativaL.) with different combinations of drought qtls

The present investigation was carried out to study the gas exchange parameters in backcross inbred lines of ‘Improved White Ponni’ (IWP) introgressed with different drought yield QTLs and their parents raised under control and stress conditions. Various gas exchange parameters and single plant yield were observed using portable photosynthetic system (infra red gas analyser -IRGA). Among the genotypes, three combination of QTL line IWP-4-2 recorded significantly higher photosynthetic rate (22.97 μ mol CO2 m−2 s−1), stomatal conductance (0.36 mol H2O m−2 s−1), transpiration rate (6.25 mmol H2O m−2 s−1), internal CO2 concentration (240.82) ratio between internal and atmospheric CO2 concentration (0.25) and single plant yield (15.11) which was on par with the tolerant parent Apo (an high yielding indica cultivar moderately tolerant to drought stress) under severe moisture stress regime. Overall study clearly revealed that, the performance of introgressed line with three drought QTLs (IWP-4-2) was better than two drought QTL introgressed lines of IWP-1-52 and IWP-1-57. Results from graphical genotyping using three foreground and 36 polymorphic background markers revealed that, the three QTL introgressed line IWP-4-2 had 72.20% genome recovery from Improved White Ponni, 13.89% from APO and 13.89% heterozygous region.

The effects of plastic greenhouse covering on cucumber (Cucumis sativus L.) growth

Cucumber (Cucumis sativus L.) is an important vegetable crop belonging to the cucurbit family. Cucumbers are grown under protected cultivation worldwide. The influence of greenhouse covering materials on cucumber physiological processes and yield were evaluated. Three greenhouses, each with 48 m2, North–South direction and with wet-pad and fan cooling system were covered by either one of the 200μm thickness plastic films; newly developed NIR-reflective film (C1) and two commercial films (C2 and C3). The predicted equations of the photosynthetic rate (μmol CO2 m−2 s−1), transpiration (m mol H2O m−2 s−1), intercellular CO2 concentration (μmol CO2 mol−1), stomatal conductance (mol H2O m−2 s−1) and leaf temperature were obtained by multiple regression analysis of the measured data. The average temperatures were 22.27 ± 2.06°C, 23.80±2.26°C, 25.42±2.41°C and 31.12±4.30°C for films C1, C2, C3 and outside respectively. The results revealed that vapour pressure deficit (VPD) under (C1) was lower than that under C2 and C3 during the production period. The average of photosynthetic rate values were 16.61±5.49, 15.51±5.18 and 14.91±4.78μmol CO2 m−2 s−1 for films C1, C2 and C3, respectively. While, the transpiration rate and the intercellular CO2 concentration under (C1) were higher than those under C2 and C3 during the production period. Therefore, fruit and yield traits increased under C1 followed by C2 and then by C3 of greenhouses covers. It can be concluded that the greenhouses plastic covering material has a great influence on the internal environmental conditions, physiological processes and productivity of cucumber plants.

Ear Leaf Photosynthesis and Related Parameters of Transgenic and Non-GMO Maize Hybrids

Hybrid maize (Zea maysL.) through transgenics now includesδ-endotoxins for insect control and tolerance to the herbicides glyphosate and glufosinate. Some hybrids have multiple transgenic traits as part of their genotype (stacked gene). Limited information is available on how these traits alone affectA(net assimilation rate;µmol CO2m−2s−1) and related physiological parameters. A two-year, two-location, irrigated experiment comparing four stacked gene, four glyphosate tolerant, and two non-GMO hybrids for ear leafA,gs(stomatal conductance; mol H2O m−2s−1),Em(transpiration; mol H2O m−2s−1), IWUE (intrinsic water use efficiency;(A/(gs*100))), and Ci(intercellular [CO2]µmol CO2mol air−1) was completed at Stoneville, MS, in 2012. Data were collected at growth stages R1 (anthesis) and R2 (early kernel filling) using a Li-Cor LI-6400XT set at 355 μmol mol−1CO2with a flow rate of 500 μmol s−1and a 6400-02 light source set at 87.5% full sunlight. Measurements were made between 08:30 h and 11:30 h CST, within 48 h of 25 ha mm irrigation and ≥33.0% cloud cover. Transgenic traits did not influence the physiological parameters ofA,gs,Em, IWUE, or Ciduring the critical growth stages of R1 or R2.

Energetics of sodium-calcium exchanged zeolite A.

A series of calcium-exchanged zeolite A samples with different degrees of exchange were prepared. They were characterized by powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC). High temperature oxide melt drop solution calorimetry measured the formation enthalpies of hydrated zeolites CaNa-A from constituent oxides. The water content is a linear function of the degree of exchange, ranging from 20.54% for Na-A to 23.77% for 97.9% CaNa-A. The enthalpies of formation (from oxides) at 25 °C are -74.50 ± 1.21 kJ mol(-1) TO2 for hydrated zeolite Na-A and -30.79 ± 1.64 kJ mol(-1) TO2 for hydrated zeolite 97.9% CaNa-A. Dehydration enthalpies obtained from differential scanning calorimetry are 32.0 kJ mol(-1) H2O for hydrated zeolite Na-A and 20.5 kJ mol(-1) H2O for hydrated zeolite 97.9% CaNa-A. Enthalpies of formation of Ca-exchanged zeolites A are less exothermic than for zeolite Na-A. A linear relationship between the formation enthalpy and the extent of calcium substitution was observed. The energetic effect of Ca-exchange on zeolite A is discussed with an emphasis on the complex interactions between the zeolite framework, cations, and water.

Natural sepiolite: Enthalpies of dehydration, dehydroxylation, and formation derived from thermochemical studies

Sepiolite is widely used in various fields due to its unique colloidal-rheological and physicochemical properties. The first experimental thermochemical study of natural sepiolite Mg8Si12O30(OH)4(H2O)4·nH2O from Akkermanovskoe field (Southern Ural, Russia) was performed utilizing the high-temperature heat-flux Tian-Calvet microcalorimeter. X-ray powder diffraction, thermal analysis, and FTIR spectroscopy methods were used to characterize sepiolite. Processes of dehydration, dehydroxylation, and various water types’ removal enthalpies were studied using thermochemical methods. The values of Ddehydr.H0(298.15 K) of adsorbed, zeolitic, and bound water calculated per 1 mol of released H2O, were as follows: 15 ± 4, 28 ± 8, and 39 ± 15 kJ/mol, respectively. The enthalpy of dehydroxylation of sepiolite was found as 145 ± 14 kJ/(mol H2O). Obtained data point at different binding strengths of water in the structure of sepiolite. The enthalpies of formation from the elements ΔH0f (298.15 K) were derived by melt solution calorimetry for sepiolite with various content of different water types: -18 773 ± 28 kJ/mol for Mg8Si12O30(OH)4(H2O)4·4H2O and -16 426 ± 21 kJ/mol for Mg8Si12O30(OH)4(H2O)4

Gasification Coupled Chemical Looping Combustion of Coal: A Thermodynamic Process Design Study

A thermodynamic investigation of gasification coupled chemical looping combustion (CLC) of carbon (coal) is presented in this paper. Both steam and CO2 are used for gasification within the temperature range of 500–1200°C. Chemical equilibrium model was considered for the gasifier and CLC fuel reactor. The trends in product compositions and energy requirements of the gasifier, fuel reactor, and air reactor were determined. Coal (carbon) gasification using 1.5 mol H2O and 1.5 mol CO2 per mole carbon at 1 bar pressure and 650°C delivered maximum energy (−390.157 kJ) from the process. Such detailed thermodynamic studies can be useful to design chemical looping combustion processes using different fuels.

Effects of flooding on photosynthesis and root respiration in saltcedar (Tamarix ramosissima), an invasive riparian shrub

The introduced shrub Tamarix ramosissima invades riparian zones, but loses competitiveness under flooding. Metabolic effects of flooding could be important for T. ramosissima, but have not been previously investigated. Photosynthesis rates, stomatal conductance, internal (intercellular) CO2, transpiration, and root alcohol dehydrogenase (ADH) activity were compared in T. ramosissima across soil types and under drained and flooded conditions in a greenhouse. Photosynthesis at 1500μmolquantam−2s−1 (A1500) in flooded plants ranged from 2.3 to 6.2μmolCO2m−2s−1 during the first week, but A1500 increased to 6.4–12.7μmolCO2m−2s−1 by the third week of flooding. Stomatal conductance (gs) at 1500μmolquantam−2s−1 also decreased initially during flooding, where gs was 0.018 to 0.099mol H2O m−2 s−1 during the first week, but gs increased to 0.113–0.248molH2Om−2s−1 by the third week of flooding. However, photosynthesis in flooded plants was reduced by non-stomatal limitations, and subsequent increases indicate metabolic acclimation to flooding. Root ADH activities were higher in flooded plants compared to drained plants, indicating oxygen stress. Lower photosynthesis and greater oxygen stress could account for the susceptibility of T. ramosissima at the onset of flooding. Soil type had no effect on photosynthesis or on root ADH activity. In the field, stomatal conductance, leaf water potential, transpiration, and leaf δ13C were compared between T. ramosissima and other flooded species. T. ramosissima had lower stomatal conductance and water potential compared to Populus deltoides and Phragmites australis. Differences in physiological responses for T. ramosissima could become important for ecological concerns.

Photosynthetic Characteristics of Resistance and Susceptible Lines to High Temperature Injury in Panax ginseng Meyer

In this study, photosynthetic parameters such as the net photosynthesis rate, stomatal conductance, intercellular CO2 concentration, and transpiration rate were examined in selected ginseng varieties and/or lines that are resistant (Yunpoong, HTIR 1, HTIR 2, and HTIR 3) and susceptible (Chunpoong) to high temperature injury (HTI). The net photosynthesis rate increased with the increase in the light intensity in all the HTI-resistant and -susceptible ginseng lines with a light saturation point of 200 μmol m-2s-1, except for Yunpoong that had a light saturation point of 400 μmol m-2s-1. At the light saturation point, the net photosynthesis rate in July was highest in HTIR 3, at 4.2 μmol CO2 m-2s-1, and was lowest in Yunpoong, HTIR 1, Chunpoong, and HTIR 2, in that order, at 1.9 to 3.7 μmol CO2 m-2s-1. The net photosynthesis rate in August was highest in Yunpoong at 5.9 μmol CO2 m-2s-1, and lowest in HTIR 1 and HTIR 3 (4.5 μmol CO2 m-2s-1) and in other lines, in that order, at 2.8 to 2.9 μmol CO2 m-2s-1. The stomatal conductance in July was highest in HTIR 3 (0.055 mol H2O m-2s-1) and Yunpoong, Chunpoong, HTIR 1, and HTIR 2 were 0.038, 0.037, 0.031, and 0.017 in that orders. In August, meanwhile, HTIR 1 showed the highest as 0.075, and followed by HTIR 3, Chungpoong, and HTIR 2 with 0.070, 0.047, and 0.023, respectively. The intercellular CO2 concentration at the light saturation point in July and August was much lower in HTIR 2 at 139 and 185 μmol mol-1 than in the other ginseng lines at 217 to 257 and 274 to 287 μmol mol-1, respectively. The transpiration rate in July and August was higher in the HTI-resistant lines of Yunpoong, HTIR 1, and/or HTIR 3 at 0.83 to 1.03 and 1.67 to 2.10 mol H2O m-2s-1 than in the other ginseng lines at 0.27 to 0.79 mol H2O m-2s- 1 and 0.51-1.65 mol H2O m-2s-1, respectively. Conclusively, all the photosynthetic parameters that were examined in this study were generally higher in the HTI-resistant ginseng lines than in the HTI-susceptible lines, except for HTIR 2, and were much higher in August than in July, especially in the resistant ginseng lines. All these results can be used to provide basic information for the selection of HTI-resistant ginseng lines and the application of cultural practices that are efficient for ginseng growth, based on the photosynthetic characteristics of the lines.

Hydrogen and synthesis gas production from activated carbon and steam via reusing carbon dioxide

A method of producing hydrogen and syngas from the interaction of activated carbon, steam and carbon dioxide is conducted in the present study, where the interaction combines the solution loss reaction and steam gasification reaction. Two important parameters of reaction temperature and steam/CO2 molar ratio (i.e. S/C ratio) in the ranges of 850–950°C and 0–1 are taken into account. The experiments indicate that the CO2 conversion from the reaction in the absence of steam is around 50% at 950°C. Increasing S/C ratio increases the H2 yield, but the CO2 conversion decreases, revealing the competing roles played by steam and CO2 with the reaction of activated carbon. With the conditions of S/C=0.5 and 950°C, the CO2 conversion drops to around 30% and the H2 yield is around 0.45mol (mol H2O)−1. Furthermore, from the analyses of SEM and BET, the results indicate that an increase in S/C ratio intensifies the number of pores on the surface of the activated carbon, and its surface area is increased from 833.13m2g−1 in the raw material to 1100–1450m2g−1 in the reacted activated carbon. It follows that the porous structure of the activated carbon has a significant influence on syngas formation. In summary, the novel method simultaneously possesses the merits of low cost of raw material, reusing CO2 and generating hydrogen and syngas.

Synthesis, structure, and electric properties of oxygen-deficient perovskites Ba3In2ZrO8 and Ba4In2Zr2O11

Perovskite phases Ba3In2ZrO8 and Ba4In2Zr2O11 with the nominal concentration of structural oxygen vacancies 1/9 and 1/12, respectively, were synthesized by solid-phase and solution methods. X-ray diffraction showed cubic symmetry of both phases with the unit cell parameter a = 0.4193(2) and 0.4204(3) nm, respectively. The absence of superstructural lines resulted in the conclusion on statistical arrangement of oxygen vacancies. Thermogravimetry and mass spectrometry proved that both phases can reversibly absorb water from gas phase (pH2O = 2 × 10−2 atm) with observed correlation between the concentration of oxygen vacancies and amount of absorbed water. The total water amount was up to 0.9 mol per formula unit or, if recalculated for perovskite unit ABO3, 0.3 and 0.23 mol H2O, respectively. The temperature curves of coductivity in the atmosphere with various partial water vapor pressures (pH2O = 3 × 10−5 and 2 × 10−2 atm) showed significantly higher conductivity and lower activation energy (0.52 eV) in humid atmosphere due to proton transfer. The proton conductivity is up to 5 × 10−4 Ohm−1 cm−1 at 300°C for Ba3In2ZrO8 specimen. IR spectrometry showed that protons in the structure exist primarily in OH-groups.

GAS EXCHANGE AND GROWTH OF TRITICALE SEEDLINGS UNDER DIFFERENT NITROGEN SUPPLY AND WATER STRESS

The effect of nitrogen (30 and 120 mg N per cuvette) on photosynthetic rate of four cultivars of triticale (‘Bolero’, ‘Grado’, ‘Largo’, and ‘Lasko’) grown 14 days in phytotron was strongly modified by water content (75, 45 and 35% of full water capacity). For plants grown under 35% of full water capacity, it was higher when they were grown under 30 than under 120 mg N/cuvette (9.88 and 8.76 μmol CO2 m−2 s−1, respectively) but for plants grown under 45 and 75% of full water capacity there were not significant differences. Transpiration, stomatal conductance, photosynthetic water use efficiency, and internal water use efficiency were not influenced by nitrogen doses independently of water content. Photosynthetic rate, transpiration, stomatal conductance, photosynthetic water use efficiency, and dry matter of studied cultivars of triticale grown under 45 and 35% of full water capacity and both nitrogen doses were lower than for plants grown under 75% of full water capacity. With lowering of water content stomatal conductance was decreasing similarly as photosynthetic rate e.g. for plants grown under 35% of full water capacity as compared with those grown under 75% of full water capacity average stomatal conductance decreased from 0.209 to 0.138 mol H2O m−2 s−1 and photosynthetic rate from 13.69 to 9.32 μmol CO2 m−2 s−1 and as a result there were not significant differences in internal water use efficiency for all studied combinations (67.09 μmol CO2 mol−1 H2O) which shows that stomatal factors were mainly responsible for changes of photosynthetic rate. With lowering of water content from 75 to 35% of full water capacity the decrease of photosynthetic rate and stomatal conductance was much higher than the decreases of transpiration (from 3.57 to 3.02 mmol H2O m−2 s−1) what shows not direct dependence of transpiration on stomatal conductance (water use efficiency decreased from 3.87 to 3.10 μmol CO2 mmol−1 H2O). The effect of nitrogen on dry matter production was strongly modified by water availability e.g. for plants grown under 35% of full water capacity, dry matter was similarly independent of nitrogen dose but for plants grown under 45 and 75% of full water capacity dry matter was significantly higher than when they were grown under 120 (79.05 and 86.75 mg, respectively) or with 30 mg N/cuvette (74.03 and 80.30 mg, respectively).

Comparison of leaf water use efficiency of oak and sycamore in the canopy over two growing seasons

The seasonal trends in water use efficiency of sun and shade leaves of mature oak (Quercus robur) and sycamore (Acer pseudoplatanus) trees were assessed in the upper canopy of an English woodland. Intrinsic water use efficiency (net CO2 assimilation rate/leaf conductance, A/g) was measured by gas exchange and inferred from C isotope discrimination (δ13C) methods. Shade leaves had consistently lower δ13C than sun leaves (by 1–2‰), the difference being larger in sycamore. Buds had distinct sun and shade isotopic signatures before bud break and received an influx of 13C-rich C before becoming net autotrophs. After leaf full expansion, δ13C declined by 1–2‰ gradually through the season, emphasising the importance of imported carbon in the interpretation of leaf δ13C values in perennial species. There was no significant difference between the two species in the value of intrinsic water use efficiency for either sun or shade leaves. For sun leaves, season-long A/g calculated from δ13C (72–78 μmol CO2 [mol H2O]−1) was 10–16% higher than that obtained from gas exchange and in situ estimates of leaf boundary layer conductance. For shade leaves, the gas exchange–derived values were low, only 10–18% of the δ13C-derived values. This is ascribed to difficulties in obtaining a comprehensive sample of gas exchange measurements in the rapidly changing light environment.

Stem growth habit affects leaf morphology and gas exchange traits in soybean

The stem growth habit, determinate or indeterminate, of soybean, Glycine max, varieties affects various plant morphological and developmental traits. The objective of this study is to identify the effect of stem growth habit in soybean on the stomatal conductance of single leaves in relation to their leaf morphology in order to better understand the ecological and agronomic significance of this plant trait. The stomatal conductance of leaves on the main stem was measured periodically under favourable field conditions to evaluate g(max), defined as the maximum stomatal conductance at full leaf expansion, for four varieties of soybean and their respective determinate or indeterminate near isogenic lines (NILs). Leaf morphological traits including stomatal density, guard cell length and vein density were also measured. The value of g(max) ranged from 0.383 to 0.754 mol H(2)O m(-2) s(-1) across all the genotypes for both years. For the four pairs of varieties, the indeterminate lines exhibited significantly greater g(max), stomatal density, numbers of epidermal cells per unit area and total vein length per unit area than their respective determinate NILs in both years. The guard cell length, leaf mass per area and single leaf size all tended to be greater in the determinate types. The variation of g(max) across genotypes and years was well explained by the product of stomatal density and guard cell length (r = 0.86, P < 0.01). The indeterminate stem growth habit resulted in a greater maximum stomatal conductance for soybean than the determinate habit, and this was attributed to the differences in leaf structure. This raises the further hypothesis that the difference in stem growth habit results in different water use characteristics of soybean plants in the field. Stomatal conductance under favourable conditions can be modified by leaf morphological traits.