Pn Values Research Articles

Commissioning of the BRIKEN beta-delayed neutron detector for the study of exotic neutron-rich nuclei

Beta-delayed neutron emission (Beta-n) is a form of radioactive decay in which an electron, an anti-neutrino and one or more neutrons are emitted. This process arises if the energy window of the decay Q_Beta is greater than the neutron separation energy S n of the daughter. The probability in each decay of emitting neutrons is called the Pn value. This form of decay plays a key role in the synthesis of chemical elements in the Universe via the rapid neutron capture process, or r-process. The r-process proceeds far from the valley of nuclear stability, and leads to very neutron-rich nuclei that then decay to the line of stability. Most of these nuclei are sn emitters. The initial abundance distribution is shaped by the decay half-life T1/2, but the neutron emission affects the final abundances in two ways: on the one hand it shifts the decay path to lower masses and on the other hand it provides a source of neutrons for late captures that will shift it in the opposite way. Thus, a good knowledge of Pn and T1/2 values of the nuclei between the line of stability and the r-process path is needed for a correct understanding of the observed abundances. Besides the astrophysical interest, the measurement of new Pn values and half-lives is also useful for refining nuclear structure models, constraining parameters of the models and testing s-strength functions [3]. Our current understanding of the process of s-delayed multiple neutron emission, as well as the competition between different open channels (gamma, one-neutron, two-neutron, etc), is incomplete because of the scarcity of experimental data. With these ideas in mind, the BRIKEN (Beta-delayed-neutron-measurements at RIKEN) collaboration was established, with the aim of greatly improving the quantity and quality of data the decays of very neutron-rich nuclei close to the r-process path.

蒲公英水浸液对辣椒幼苗生长的影响

本文以蒲公英地上和地下部分为试材，研究其不同浓度的水浸液对辣椒幼苗生长以及相关生理指标的影响。结果表明：辣椒幼苗生长的形态指标和叶片光合特性与水浸液浓度间存在正相关关系，A0.06、B0.04处理的PN、EVAP和GS有所下降但下降幅度不大。幼苗POD活性、MDA含量随水浸液浓度的增加而增加，而膜脂过氧化作用降低。地上和地下部分的水浸液对其影响趋势一致。 The above- and below-ground parts of Taraxacum mongolicum were taken as experimental materials. The effects of its aqueous extracts with different concentration on seed germination and seedling growth of hot pepper were investigated. The results showed that the morphological and photosynthetic characteristics of hot pepper seedlings growth were significantly positive with the aqueous extracts concentration. The PN, EVAP and GS values of A0.06, B0.04 treatment were not significant decrease. POD activity and MDA content were increased with the increasing concentration, and the MDA content was decreased. The membrane lipid peroxidation is also reduced. The effect trends of aqueous extracts of above- and below-ground parts were consistent.

Influence of high levels of Na+ and Cl− on ion concentration, growth, and photosynthetic performance of three salt-tolerant plants

This study aimed to measure the effects of elevated levels of Na+ and Cl− on ion concentration, growth, and photosynthetic performance of Melilotus siculus, Tecticornia pergranulata, and Thinopyrum ponticum in pot trials under controlled glasshouse conditions. Experiments were conducted using Na+ and Cl− dominant saline soil treated with constituted saline solutions (0, 2.0 and 4.0dSm−1 Na+ or Cl−). Maximum Na+ and Cl− concentration was in T. pergranulata shoots; maximum Na+ concentration was in T. pergranulata roots, whereas maximum Cl− in T. ponticum roots. Maximum quantum yield of PSII [Fv/Fm] values did not change significantly. Net-photosynthetic rate [Pn] and stomatal conductance [gs] values increased and non-photochemical quenching [NPQ] value decreased significantly in T. pergranulata with increasing Na+ dominant treatments and the reverse occurred in Cl− dominant treatments. Pn, gs, and NPQ values did not significantly change in T. ponticum with increasing Na+ and Cl− dominant treatments. The shoot and root biomasses of T. pergranulata were the maximum at 4.0dSm−1 Na+ dominant treatment. In T. ponticum, the maximum shoot and root fresh masses and shoot dry mass occurred in the control treatment and the maximum root dry mass occurred in the 2.0dSm−1 Cl− dominant treatment. In T. pergranulata, strong positive correlations occurred between Na+ concentration in shoots and salt tolerance (shoot mass over control) and moderately positive correlation occurred between Cl− concentration in shoots and salt tolerance. However, strong negative correlations were observed between Na+ and Cl− concentration in shoots and salt tolerance in T. ponticum as well as between Cl− concentration in shoots and salt tolerance in M. siculus. Our glasshouse experiments indicate that 4.0dSm−1 Cl− solutions in the soil was more intensely damaging than that of Na+. The greatest concentration of both Na+ and Cl− was in T. pergranulata under the tested circumstances indicating it to be the candidate of choice for restoring saline soils, followed in capacity by M. siculus and T. ponticum.

Cuticular Wax Accumulation Is Associated with Drought Tolerance in Wheat Near-Isogenic Lines.

Previous studies have shown that wheat grain yield is seriously affected by drought stress, and leaf cuticular wax is reportedly associated with drought tolerance. However, most studies have focused on cuticular wax biosynthesis and model species. The effects of cuticular wax on wheat drought tolerance have rarely been studied. The aims of the current study were to study the effects of leaf cuticular wax on wheat grain yield under drought stress using the above-mentioned wheat NILs and to discuss the possible physiological mechanism of cuticular wax on high grain yield under drought stress. Compared to water-irrigated (WI) conditions, the cuticular wax content (CWC) in glaucous and non-glaucous NILs under drought-stress (DS) conditions both increased; mean increase values were 151.1 and 114.4%, respectively, which was corroborated by scanning electronic microscopy images of large wax particles loaded on the surfaces of flag leaves. The average yield of glaucous NILs was higher than that of non-glaucous NILs under DS conditions in 2014 and 2015; mean values were 7368.37 kg·ha−1 and 7103.51 kg·ha−1. This suggested that glaucous NILs were more drought-tolerant than non-glaucous NILs (P = 0.05), which was supported by the findings of drought tolerance indices TOL and SSI in both years, the relatively high water potential and relative water content, and the low ELWL. Furthermore, the photosynthesis rate (Pn) of glaucous and non-glaucous wheat NILs under DS conditions decreased by 7.5 and 9.8%, respectively; however, glaucous NILs still had higher mean values of Pn than those of non-glaucous NILs, which perhaps resulted in the higher yield of glaucous NILs. This could be explained by the fact that glaucous NILs had a smaller Fv/Fm reduction, a smaller PI reduction and a greater ABS/RC increase than non-glaucous NILs under DS conditions. This is the first report to show that wheat cuticular wax accumulation is associated with drought tolerance. Moreover, the leaf CWC can be an effective selection criterion in the development of drought-tolerant wheat cultivars.

Effects of truncation intensity on the biomass allocation and physiological characteristics of Dendrocalamus latiflorus

The effects of three different truncation treatments, i.e., light, medium and heavy truncation treatments on biomass allocation, current-year twig indexes, and quantity of commodity lea-ves, net photosynthetic rate (Pn), transpiration rate (Tr), water use efficiency (WUE), and leaf water potential (LWP) values of Dendrocalamus latiflorus were studied, and the adaptation mechanisms and survival strategy of D. latiflorus under these silvicultural truncation treatments were discussed. Results showed that the biomass of D. latiflorus and its allocation rates were significantly affected by truncation treatments, compared with the untruncated control. Leaf to branch, leaf to stem, and branch to stem biomass ratios under all truncation treatments were significantly higher than under the untruncated control. The diameter, number, and length of current-year twigs, and the quantity of commodity leaves in light truncation and medium truncation treatments were markedly higher than in the control, and were increased by 43.0%, 53.3%, 29.8% and 39.5%, respectively, in medium truncation treatment compared with the control. After truncation treatments, the overall trend of the physiological characteristics of D. latiflorus, including Pn, Tr, WUE, LWP values, were displayed in the order of the peak stage > the telophase stage > the initial stage. The Pn, Tr and WUE values of D. latiflorus were significantly improved in the truncation treatments. The Pn va-lues were greatest in the medium truncation treatment followed by the light truncation treatment, heavy truncation treatment, and were the lowest in the control at the peak and telophase stages. At the peak and telophase stage the Pn values in the medium truncation treatment were 1.4 and 1.3 times as much as the control. The Tr values at the initial, peak and telophase stages were the greatest in the heavy truncation treatment, followed by the middle truncation treatment and the light truncation treatment, and were the lowest in the control. In this study, the medium truncation treatment showed a significant advantage in improving plant biomass allocation, quantity of commodity leaves, and other physiological indices, and could effectively improve the ability of moisture acquisition for D. latiflorus.

Bubble nucleation in a Lennard-Jones binary liquid mixture

We report a molecular dynamics (MD) study of homogeneous bubble nucleation in a stretched Lennard-Jones binary mixture at a temperature close to the solvent triple point. The pressure of the limiting stretching pn corresponding to a fixed value of the nucleation rate has been determined. The values of pn achieved in MD simulation are lower than those calculated from classical nucleation theory (CNT). The discrepancy between the data of MD simulation and CNT may be connected with the neglect in the latter of the size dependence of the surface tension of critical bubbles.

Novel assessment method of heavy metal pollution in surface water: A case study of Yangping River in Lingbao City, China

The primary purpose of this research is to understand those elements that define heavy metals contamination and to propose a novel assessment method based on principal component analysis (PCA) in the Yangping River region of Lingbao City, China. This paper makes detailed calculations regarding such factors the single-factor assessment (Pi) and Nemerow’s multi-factor index (PN) of heavy metals found in the surface water of the Yangping River. The maximum values of Pi (Cd) and Pi (Pb) were determined to be 892.000 and 113.800 respectively. The maximum value of PN was calculated to be 639.836. The results of Pearson’s correlation analysis, hierarchical cluster analysis, and PCA indicated heavy metal groupings as follows: Cu, Pb, Zn and As, Hg, Cd. The PCA-based pollution index (Pαn) of samplings was subsequently calculated. The relative coefficient square was valued at 0.996 between Pαn and PN, which indicated that Pαn is able to serve as a new heavy metal pollution index; not only this index able to eliminate the influence of the maximum value of Pi, but further, this index contains the principal component elements needed to evaluate heavy metal pollution levels. Keywords: Heavy metals contamination, Hierarchical cluster analysis (HCA), Pollution evaluation, Principal component analysis (PCA), Yangping River

Spatial heterogeneity of canopy photosynthesis for Larix olgensis.

Based on a 14-year-old planted Larix olgensis in the Maoershan Forest Farm, Heilongjiang Province in 2014, the spatial heterogeneity of photosynthetic indicators, environmental factors and photosynthetic physiological parameters were analyzed, meanwhile the relationship between net photosynthetic rate (Pn) and other indicators were studied. Results showed that in the vertical direction, Pn, stomatal conductance (gs) and transpiration rate (Tr) were higher in upper than middle and lower canopy significantly, intercellular CO2 concentration (Ci) increased in the sequence of upper < middle < lower canopy. Photosynthetic active radiation (PAR) decreased from outside of upper to inside of lower canopy significantly, vapor pressure deficit (VPD) and needle leaf temperature (Tl) in upper canopy were respectively higher than in middle and lower canopy significantly, while relative humidity (RH) showed no significant difference with spatial location. The mean value of maximum Pn(Pn max), dark respiration rate (Rd), light compensation point (LCP) and light sa-turation point (LSP) followed the pattern of upper > middle > lower canopy and decreased by 32.7%, 55.8%, 80.2% and 51.6% from upper to lower canopy respectively. Apparent quantum yield (AQY) in lower canopy was 1.2 and 1.3 times as much as that of middle and upper canopy, respectively. In the horizontal direction, Pn, gs, Tr, PAR and VPD were significantly higher from outside to inside in the upper crown, but Ci and RH showed no significant diffe-rence. The mean value of Pn max, Rd, LCP and LSP declined by 0.4%, 37.7%, 42.0% and 16.4% from outside to inside, on the contrary, AQY was 0.7% higher from inside to outside. Ci was the main physiological impact factor for Pn, and PAR was an important environmental factor that had the most obvious influence on Pn, especially in weak light region. Therefore, spatial heterogeneity should be considered necessarily when simulating and/or predicting the tree canopy photosynthesis.

The Expression of TaRca2-α Gene Associated with Net Photosynthesis Rate, Biomass and Grain Yield in Bread Wheat (Triticum aestivum L.) under Field Conditions.

Improvement in activation of Rubisco by Rubisco activase can potentially enhance CO2 assimilation and photosynthetic efficiency in plants. The three homoeologous copies of TaRca2-α were identified on chromosomes 4AL, 4BS and 4DS (TaRca2-α-4AL, TaRca2-α-4BS, and TaRca2-α-4DS) in bread wheat. Expression patterns of the three copies at heading (Z55), anthesis (Z67) and grain-filling (Z73) stages were investigated through qRT-PCR analyses in a panel of 59 bread wheat genotypes and their effects on net photosynthesis rate (Pn), biomass plant-1 (BMPP) and grain yield plant-1 (GYPP) were further explored. Different but similar expression patterns were observed for the three copies of TaRca2-α at the three growth stages with highest expression at grain-filling stage. TaRca2-α-4BS expressed higher at the three stages than TaRca2-α-4AL and TaRca2-α-4DS. The 59 genotypes could be clustered into three groups as high (7 genotypes), intermediate (41 genotypes) and low (11 genotypes) expression based on the expression of the three copies of TaRca2-α at three growth stages. Significant variations (P<0.01) were observed among the three groups of bread wheat genotypes for Pn, BMPP and GYPP. Generally, the genotypes with higher TaRca2-α expression also showed higher values for Pn, BMPP and GYPP. The expressions of the three copies of TaRca2-α at heading, anthesis and grain-filling stages were positively correlated with Pn, BMPP and GYPP (P<0.01) with stronger association for TaRca2-α-4BS at grain-filling stage. These results revealed that the expression of TaRca2-α contribute substantially to Pn, BMPP and GYPP, and suggested that manipulating TaRca-α expression may efficiently improve Pn, BMPP and GYPP in bread wheat and detecting TaRca-α expression levels with emphasis on TaRca2-α-4BS may be a positive strategy for selection in improving photosynthetic efficiency and grain yield of bread wheat.

Photosynthetic Physiological Characteristics of Gazania rigens L. Under Drought Stress

To investigate the responses of photosynthetic physiological characteristics of Gazania rigens L. to drought stress, the changes of three cultivars (‘Xingbai’, ‘XH’ and ‘Hongwen’) photosynthetic values under drought stress were determined via LI-6400 portable photosynthesis analyzer (LI-COR, USA), and the relationships between photosynthesis and drought resistance of each cultivar were analyzed. The results showed that, three cultivars net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and light use efficiency (LUE) value indicated the trend of decreasing gradually and there existed significant reduction in Pn and Gs values. There were extremely negative significant correlations between drought stress treatment days and Pn, Gs, Tr, water use efficiency (WUE) and LUE values. A small amount of leaves began to turn soft and yellow after drought stress treatment for 10 days, but they could recover to grow quickly after rehydration. The Pn values of ‘Hongwen’ decreased quickly and changed in a large range, so it had a poor resistance; the Pn values of ‘Xingbai’ decreased slowly and changed in a small range, so it had a strong resistance; while the changes of their hybrids -‘XH’ were between its parents. This research would provide a theoretical basis for gazania resistance cultivar breeding and application in landscape.

Effects of water and fertilizer coupling on photosynthetic characteristics of maize leaves in ear position at filling stage in an apple-maize intercropping system in Losses Plateau of west Shanxi Province, China.

Taking a typical apple×maize intercropping system in the loess region of Shanxi Pro-vince, China as test object, the current study analyzed the photosynthetic characteristics of maize leaves of ear position at filling stage under different irrigation and fertilization regimes. There were three irrigation levels [low (W1), 50% field capacity (Fc); medium (W2), 65% Fc; and high (W3), 85% Fc], three fertilizer levels {F1 [N (289 kg·hm-2) + P2O5 (118 kg·hm-2) + K2O (118 kg·hm-2)]; F2 [N (412.4 kg·hm-2) + P2O5 (168.8 kg·hm-2) + K2O (168.8 kg·hm-2)], F3 [N (537 kg·hm-2) + P2O5 (219 kg·hm-2) + K2O (219 kg·hm-2)]}, and a control (CK, no irrigation and fertilization throughout the growing season). The nine irrigation and fertilization treatment combinations were W1F1, W2F1, W3F1, W1F2, W2F2, W3F2, W1F3, W2F3, and W3F3, respectively. The results indicated that different water and fertilizer regimes had no significant effect on the variation in diurnal photosynthetic indexes. However, the application of water and fertilizers considerably increased the peak value of net photosynthetic rate (Pn), exten-ded the stomatal opening period, influenced the lowest value of intercellular CO2 concentration (Ci), and reduced the maximum value of water use efficiency (WUE) during the day. The limiting factors affecting photosynthesis were nonstomatal factors. Stomatal conductance (gs) and transpiration rate (Tr) were both significantly negatively correlated with the distance from tree line (P<0.01). WUE were significantly positively correlated with the distance from the tree line (P<0.05). gs decreased by 0.028-0.093 mol·m-2·s-1, Tr decreased by 0.56-1.41 mmol·m-2·s-1, WUE increased by 0.08-1.00 μmol·mmol-1, as the average distance from the tree line increased by 1 m. Thus, irrigation and fertilizers significantly increased the mean value of Pn, Tr, and gs, but decreased the mean value of WUE during the day. The W3F1 treatment had the highest mean values of Pn(10.64 μmol·m-2·s-1), gs(0.295 mol·m-2·s-1), WUE (3.05 μmol·mmol-1), but a lower mean value of Tr(4.32 mmol·m-2·s-1) compared with the other treatment combinations during the day. When the total irrigation rate was 1300 m3·hm-2, the total fertilization rate was 525 kg·hm-2, Pn was at its maximum, and the theoretical maximum value was 10.32 μmol·m-2·s-1. Therefore, the W3F1 treatment was the irrigation and fertilizer regime that was most likely to improve the photosynthetic efficiency of the apple-maize intercropping system.

Geochemical characteristics of heavy metal contamination induced by a sudden wastewater discharge from a smelter

Metal contaminations from smelting have been widely reported, however, the study on metal mobility or transfer characteristics in soil profiles after a sudden wastewater overflow is far limited. This study was undertaken to investigate distribution and potential mobility of heavy metals in soils flooded by smelting wastewater in Hechi, China. Total heavy metal/metalloid levels were measured in topsoil, profile and profile pore-water taken in-situ. Enrichment factor (EF) and nemero synthesis index (PN) were used to detect the contribution of anthropogenic emissions to trace element fluxes and pollution levels, respectively. Soil-water partition coefficient (Kd) was used to reflect the fate and the mobility of elements. Results showed topsoil were seriously contaminated with Sb (289–3100mgkg−1), Pb (444–6388mgkg−1), Zn (294–923mgkg−1), Cu (59–192mgkg−1), Cd (12–34mgkg−1), and As (32–405kg−1), and PN values indicated this area was in severe or strongly pollution level. Higher EF values of Sb, Zn, Cd and As were found in the flooded soils, and PN in flooded area was 5 times of that in the unflooded sites, indicating wastewater flooding aggregated pollution in the low-lying area. The Sb, Pb, and Cd concentrations declined drastically with profile but dropped to constant levels below a depth of about 20cm. In contrast, Zn and Cu in flooding soils declined first and then increased to another extreme value even at depth of 50cm. Pore-water profiles exhibited the similar declining trends of vertical metal/metalloid distribution pattern. The Kd values ranged from 102–106Lkg−1, and the mobility and bioavailability of the six elements in the profiles declined in the following order: Sb>Zn>Cu>Cd>As>Pb. The relatively low Kd values for some depth intervals may reflect adsorption decrease or migration increase of metal/metalloid. However, it is worth to further study and assess their potential risk to environment in longer period.

A molecular dynamics study of local pressures and interfacial tensions of SDS micelles and dodecane droplets in water.

To obtain the radial (normal) and lateral (transverse) components of the local pressure tensor, PN(R) and PT(R), respectively, and the interfacial tension of micelles, molecular dynamics (MD) calculations were performed for spherical sodium dodecyl sulfate (SDS) micelles. The local pressure tensor was calculated as a function of radial distance R using the Irving-Kirkwood formula. Similar MD calculations were also carried out for an n-dodecane droplet in water to compare the differences in the local pressure and interfacial tension values with those of the micelles. The calculated interfacial tensions were 20 ± 5 and 44 ± 10 mN/m for the SDS micelles and dodecane droplets, respectively. The excess free energies due to the interfacial tension were 340 and 1331 kJ/mol for the SDS micelle and dodecane droplet, respectively. The micelles are stabilized by 991 kJ/mol by covering their hydrophobic cores with hydrophilic groups. The dodecane droplet has a large interfacial tension caused by the zero or positive values of PN(R) - PT(R) at all values of R. In contrast, the small interfacial tension in the SDS micelles comes from the negative PN(R) - PT(R) values over a wide range of R. The pressure difference between the inside and outside of the oil droplet and its interfacial tension well satisfies the Laplace equation. However, the hydrophobic core of the SDS micelle is quite different from the liquid alkane, and the SDS micelles do not follow Laplace's picture. Decomposing the interfacial tension into contributions from various interactions, it is found that those between charged and polar groups dominate the interfacial tension of the SDS micelles. The positive electrostatic potential (1.3 V) on the micelle surface and the negative potential (-0.15 V) on the oil droplet contribute to the interfacial tensions by 19 and 0.5 mN/m, respectively. Thus, the interfacial tension of the SDS micelles is produced by electrostatic interactions, in contrast to the dodecane droplet.

Improved water use efficiency and fruit quality of greenhouse crops under regulated deficit irrigation in northwest China

Water limit is the major bottleneck that restrains sustainable development of agriculture in northwest China. In order to obtain higher water use efficiency (WUE) and improve fruit quality of greenhouse crops with less water, experiments with regulated deficit irrigation (RDI) on watermelon (Citrullus vulgaris; 2008–2010), hot pepper (Capsicum annum L.; 2011–2012) and tomato (Solanumlycopersicum L.; 2008–2013) in solar greenhouse were conducted in Shiyang River Basin of arid northwest China. Results showed that the feasible growth season of watermelon for high WUE and better fruit quality was in the winter-spring season with total irrigation amount of 114mm. The specific irrigation water were 25, 12, 62 and 15mm, respectively at seeding stage, plant-stem elongation stage, fruit bearing-expanding stage and fruit mature stage. It also showed that the positive relationship between hot pepper yield and seasonal evapotranspiration (ET) was fitted by linear model under drip irrigation, but exhibited an exponential relationship under furrow irrigation. The better RDI strategy for pepper to improve both WUE and fruit quality was maintaining soil water content at 70% of field capacity (θf) throughout the growth season except at the late fruit bearing and harvesting stage. At this stage, sufficient water (90% θf) should be applied. Results of tomato also suggested that the ventilation of greenhouse should be good around 1–3 pm in the local arid condition in northwest China. Mean values of Pn and Tr were decreased by 27.6% and 27.0% under irrigation quota of 214.2mm, but leaf water use efficiency (WUE) significantly increased with comparison to quota of 260.8mm. Moreover, the maximum values of yield and total water use efficiency (WUEET) of tomato were obtained at 89.5% and 77.0% of maximum ET, respectively. There are linear regression relationships between relative fruit quality parameters and relative ET, which provided a scientific basis for water-saving crop production in greenhouse. Application of such RDI strategy on greenhouse crops has great potential in saving water, maintaining economic yield and improving WUE and fruit quality.

Response of the leaf photosynthetic rate to available nitrogen in erect panicle-type rice (Oryza sativa L.) cultivar, Shennong265

Increasing the yield of rice per unit area is important because of the demand from the growing human population in Asia. A group of varieties called erect panicle-type rice (EP) achieves very high yields under conditions of high nitrogen availability. Little is known, however, regarding the leaf photosynthetic capacity of EP, which may be one of the physiological causes of high yield. We analyzed the factors contributing to leaf photosynthetic rate (Pn) and leaf mesophyll anatomy of Nipponbare, Takanari, and Shennong265 (a EP type rice cultivar) varieties subjected to different nitrogen treatments. In the field experiment, Pn of Shennong265 was 33.8 μmol m−2 s−1 in the high-N treatment, and was higher than that of the other two cultivars because of its high leaf nitrogen content (LNC) and a large number of mesophyll cells between the small vascular bundles per unit length. In Takanari, the relatively high value of Pn (31.5 μmol m−2 s−1) was caused by the high stomatal conductance (gs; .72 mol m−2 s−1) in the high-N treatment. In the pot experiment, the ratio of Pn/Ci to LNC, which may reflect mesophyll conductance (gm), was 20–30% higher in Nipponbare than in Takanari or Shennong265 in the high N availability treatment. The photosynthetic performance of Shennong265 might be improved by introducing the greater ratio of Pn/Ci to LNC found in Nipponbare and greater stomatal conductance found in Takanari.

Effects of reduced nitrogen application and supplemental irrigation on photosynthetic characteristics and grain yield in high-yield populations of winter wheat.

A field experiment was conducted to study the effects of reduced nitrogen application and supplemental irrigation on the light environment, photosynthetic characteristics and yield components in high-yield wheat population. The treatments included three irrigation schedules [no irrigation (W1), medium irrigation (W2, the soil relative water content of 70%±5% after jointing stage), well-irrigation (W3, the soil relative water content of 85%±5% after jointing stage)] and three nitrogen application levels [no nitrogen (N1), reduced nitrogen (N2,195 kg N·hm-2), high nitrogen (N3, 270 kg N·hm-2)]. The results indicated that the N2W2 treatment significantly improved the light environment of high-yield wheat populations, the photosynthetically active radiation (PAR) and the light transmission rate at the region of 20-30 cm canopy increased by 34.5% and 10.8%, respectively, when compared with the high nitrogen-supplementary water treatments (N3W2, N3W3). The leaf area index (LAI) of N2W2 was the highest among all treatments tested, which decreased slowly at grain filling stage, and the period with higher LAI value (>7.6) was 3-4 days longer than that of high-nitrogen and non-nitrogen treatments, as well as, the leaf photosynthetic potential was increased by 9.7% on average. Under the treatments of N2W2 and N2W3, the photosynthetic rate (Pn) was relatively higher at grain-filling stage, while the difference was not significant compared with the treatment of N3W2. The apparent quantum yield in flag leaves of N2W2 reached 0.1 μmol CO2·m-2·s-1, Pn value kept on the level of 27.692 μmol CO2·m-2·s-1 and the light compensation point (LCP) was relatively lower, which demonstrated a stronger photosynthetic productivity. The grain yield of N2W2 was the highest among all treatments.

Gas exchange and Triticum sp. with different ploidy in relation to irradiance

Different species of Triticum were grown during a greenhouse experiment, including T. monococcum L., T. dicoccum Schrank, T. durum Desf., T. spelta L. and T. aestivum cv. VĂĄnek. The goal was to establish the influence of irradiance on the parameters of photosynthetic performance in relation to their ploidy. Photosynthetic rate (Pn), transpiration (E) and stomatal conductance (gs) were measured at irradiance ranging from 217-1305 µmol/m2/s. In all monitored species, saturation irradiance for photosynthesis at the level of 609 µmol/m2/s was reached. The highest average Pn was measured in the diploid T. monococcum (32.5 µmol CO2/m2/s) while the lowest Pn occurred in the hexaploid T. spelta (22.0 µmol CO2/m2/s). The Pn in hexaploid T. aestivum (29.6 µmol CO2/m2/s) was comparable with the tetraploid T. durum. Similarly, E also decreased with the increase of ploidy. The highest gs was measured in T. durum (1.03 mol CO2/m2/s) and T. aestivum (0.99 mol CO2/m2/s). In all monitored species a close linear dependency was recorded between Pn and gs. Species with lower ploidy reach maximum values of Pn with lower gs. Hexaploid T. aestivum and tetraploid T. durum, require higher gs in order to achieve higher Pn and yet they do not reach the Pn values of species with lower ploidy.

Natriuretic peptides for the management of patients with heart failure: a bridge between primary care and cardiology?

The increasing prevalence of heart failure (HF) mandates the establishment of shared strategies between primary care physicians (PCP) and cardiologists to offer patients continuity of care. Easily available, low-cost biomarkers hold potential to facilitate this process. Data on the diffusion of natriuretic peptides (NP), a major novelty in the HF field in the last decade, in primary care are scarce. The Cardiovascular Area of the Italian General Practice Society led a web survey among its members to investigate knowledge, perceptions and use of NP for HF management among Italian PCP. Over 700 PCP took part in the survey, three out of four declared they never or only occasionally prescribed NP assays. Among participating PCP, 86% reported that PN values were not regularly mentioned in discharge summaries of their patients hospitalized for acute HF. Conversely, only 4% reported to receive regularly PN prescription by cardiologists for their outpatients with chronic HF. One of five respondents ignored whether the assay was reimbursed by the National Health Service. The high negative predictive value for HF of elevated NP levels, the strongest evidence-based indication of NP, was correctly pointed out only by 13% of PCP. In our PCP sample, we documented a marginal use of NP in the management of HF patients. This is likely, at least in part, linked to a perceived scarce indication of NP values in discharge summaries and limited prescription in HF outpatients by cardiologists. Overall, PCP knowledge of the evidence on NP assay use for diagnosis, risk stratification and guided therapy of HF was limited. Two expert cardiologists were asked to comment on these findings and on the controversial aspects of the current use of NP in HF patients to better define their role as a tool for shared care between cardiologists and PCP.

Salt effects on proline and glycine betaine levels and photosynthetic performance in Melilotus siculus, Tecticornia pergranulata and Thinopyrum ponticum measured in simulated saline conditions.

We measured proline and glycine betaine levels and photosynthetic performance (net-photosynthetic rate (Pn), stomatal conductance (gs), maximum quantum yield of PSII (Fv/Fm) and non-photochemical quenching (NPQ)) in relation to Na+ and Cl- accumulation in Melilotus siculus (Turra) B.D.Jacks. (Fabaceae), Tecticornia pergranulata (J.M.Black) K.A.Sheph. & Paul G.Wilson (Amaranthaceae: Salicornioideae) and Thinopyrum ponticum (Podp.) Z.-W.Liu & R.-C.Wang (Poaceae) grown under saline conditions in the greenhouse. These plants were selected in this study because of their known salt-tolerance capacity and value as forage plants. Moreover, the pasture legume M. siculus is considered to have particular potential for saline land remediation because of its salinity and waterlogging tolerance. Maximum Na+ and Cl- accumulation occurred in Te. pergranulata shoots. Minimum was in Th. ponticum shoots. Maximum Na+ accumulation occurred in the roots of Te. pergranulata, whereas that of Cl- occurred in the roots of Th. ponticum. Accumulation of both Na+ and Cl- was the least in M. siculus roots. Te. pergranulata metabolized high levels of glycine betaine (110µmolg-1 DW). M. siculus metabolized high levels of proline (6µmolg-1 DW). Th. ponticum accumulated intermediate levels of these organic osmolytes. No significant change occurred in Fv/Fm values. Pn value increased and NPQ value decreased in Te. pergranulata with increasing salinity and the reverse occurred in both M. siculus and Th. ponticum. A negative significant correlation occurred between Pn and glycine betaine in M. siculus and Th. ponticum. A positive significant correlation occurred between NPQ and glycine betaine in M. siculus. No correlation occurred between proline and Pn, proline and NPQ in the tested three plants. Te. pergranulata could maintain cell-osmotic balance by synthesising high levels of organic osmolytes especially glycine betaine and concurrently showing the most efficient photosynthetic performance. Compared with the levels of osmolytes in Te. pergranulata, the levels of osmolytes that occur in M. siculus and Th. ponticum were insufficient to maintain cell-osmotic balance and also that M. siculus and Th. ponticum showed a lower level of photosynthetic performance. We conclude that glycine betaine is potentially the vital organic osmolyte for Te. pergranulata and Th. ponticum enabling salinity stress tolerance. However, in M. siculus, proline appears to be the potential organic osmolyte in salinity stress tolerance. In terms of the potential of these species for stabilising saline soils in central-western New South Wales, Te. pergranulata would be the candidate of choice; however, for greater pasture value Th. ponticum would be the next.

Effects of silicon application on diurnal variations of physiological properties of rice leaves of plants at the heading stage under elevated UV-B radiation.

We investigated the effects of silicon (Si) application on diurnal variations of photosynthetic and transpiration physiological parameters in potted rice (Oryza sativa L. cv Nanjing 45) at the heading stage. The plants were subjected to two UV-B radiation levels, i.e., reference UV-B (A, ambient, 12.0 kJ m(-2) day(-1)) and elevated UV-B radiation (E, a 20% higher dose of UV-B than the reference, 14.4 kJ m(-2) day(-1)), and four Si application levels, i.e., Si0 (no silicon supplementation, 0 kg SiO2 ha(-1)), Si1 (sodium silicate, 100 kg SiO2 ha(-1)), Si2 (sodium silicate, 200 kg SiO2 ha(-1)), and Si3 (slag silicon fertilizer, 200 kg SiO2 ha(-1)). Compared with the reference, elevated UV-B radiation decreased the diurnal mean values of the net photosynthetic rate (Pn), intercellular carbon dioxide (CO2) concentration (Ci), transpiration rate (Tr), stomatal conductivity (Gs), and water use efficiency (WUE) by 11.3, 5.5, 10.4, 20.3, and 6.3%, respectively, in plants not supplemented with silicon (Si0), and decreased the above parameters by 3.8-5.5, 0.7-4.8, 4.0-8.7, 7.4-20.2, and 0.7-5.9%, respectively, in plants treated with silicon (Si1, Si2, and Si3), indicating that silicon application mitigates the negative effects of elevated UV-B radiation. Under elevated UV-B radiation, silicon application (Si1, Si2, and Si3) increased the diurnal mean values of Pn, Ci, Gs, and WUE by 16.9-28.0, 3.5-14.3, 16.8-38.7, and 29.0-51.2%, respectively, but decreased Tr by 1.9-10.8%, compared with plants not treated with silicon (E+Si0), indicating that silicon application mitigates the negative effects of elevated UV-B radiation by significantly increasing the P n, C i, G s, and WUE and decreasing the T r of rice. Evident differences existed in mitigating the depressive effects of elevated UV-B radiation on diurnal variations of physiological parameters among different silicon application treatments, exhibiting as Si3>Si2>Si1>Si0. In addition to recycling steel industrial wastes, the application of slag silicon fertilizer mitigates the negative effects of elevated UV-B radiation on photosynthesis and transpiration in rice.