Relative Yield Research Articles

Ayçiçeğinde Yabancı Ot Kontrolünde Kritik Periyot ve Uygulamaların Yabancı Ot Türleri ve Çeşitliliğine Etkileri

This study was carried out under field conditions in Adana, Turkey in 2018 and 2019 to determine the critical period for weed control in sunflower depending on the daily growth temperature (GDD) and weed species. A log-logistic model with four parameters was used to determine the relationship between relative crop yield and both increased weed intervention time and length of weed-free periods. In addition, dominant weeds and weed densities were determined in the experimental area. Data obtained from different periods of weed intervention were compared with data obtained from seasonal weed-free plots. During the sunflower growing season, 37.4% – 41.04% yield loss was determined in sunflower due to weed competition. For 5% acceptable yield loss in the first year, the critical period in weed control was determined as 243-1181 GDD; this is 24-86 days after the crop emergence (DAE) . It was found between 269 and 1409 GDD (16-72 DAE) in the second year. In sunflower, it was determined that the removal of weeds from the plot in the weed-free period started within 2-3 weeks from the emergence and continued for 10-12 weeks. These findings may help sunflower growers to plan and implement cost-effective and appropriate weed control programs.

Lanthanide(III)-Cu4 I4 Organic Framework Scintillators Sensitized by Cluster-Based Antenna for High-Resolution X-ray Imaging.

Scintillator-based X-ray imaging has attracted great attention from industrial quality inspection and security to medical diagnostics. Herein, a series of lanthanide(III)-Cu4 I4 heterometallic organic frameworks (Ln-Cu4 I4 MOFs)-based X-ray scintillators are developed by rationally assembling X-ray absorption centers ([Cu4 I4 ] clusters) and luminescent chromophores (Ln(III) ions) in a specific manner. Under X-ray irradiation, the heavy inorganic units ([Cu4 I4 ] clusters) absorb the X-ray energy to populate triplet excitons via halide-to-ligand charge transfer (XLCT) combined with the metal-to-ligand charge-transfer (MLCT) state (defined as the X/MLCT state), and then the 3 X/MLCT excited state sensitizes Tb3+ for intense X-ray-excited luminescence via excitation energy transfer. The obtained Tb-Cu4 I4 MOF scintillators exhibit high resistance to humidity and radiation, excellent linear response to X-ray dose rate, and high X-ray relative light yield of 29 379±3000 photons MeV-1 . The relative light yield of Tb-Cu4 I4 MOFs is ≈3 times higher than that of the control Tb(III) complex. X-ray imaging tests show that the Tb-Cu4 I4 MOFs-based flexible scintillator film exhibits a high spatial resolution of 12.6lpmm-1 . These findings not only provide a promising design strategy to develop lanthanide-MOF-based scintillators with excellent scintillation performance, but also exhibit high-resolution X-ray imaging for biological specimens and electronic chips.

Sahelian smallholders’ varietal mixtures reconcile yield and agrobiodiversity conservation

In the current setting, marked by the major challenges of growing food demand and climate change impacts, the ability of sub-Saharan agriculture to meet population needs depends on the resilience and adaptation capacity of this system. Using agrobiodiversity to promote agricultural sustainability is a strategy that has garnered much attention lately. Research suggests that mixing species or varieties within crop fields could increase the yield and/or stability. This mixing is also geared towards the conservation of crop diversity while ensuring that the various associated products and services will be available at the farm level.Few recent research studies have highlighted the benefits of varietal mixtures for Africa. This lack of research is a concern, given that this continent is considered to be highly vulnerable to climate change. This study was carried out to test whether plots with varietal mixtures would outperform monovarietal plots in terms of yield and pathogen regulation under smallholder farming conditions in Senegal. Together with farmers, we conducted 30 experiments in which mixtures of early- and late-flowering pearl millet landraces were grown in these farmers’ fields, while monitoring their low input management. We noted a significant positive effect of varietal mixtures on grain yield (mean gain of 63 ± 31.5 kg ha−1 for mixture plots, p = 0.046) with a relative yield total (RYT) averaging 1.87 ± 0.94. Both early- and late-flowering landraces benefited from mixtures, with a greater impact on late-flowering landraces. Higher fertility in terms of the seed number, percentage of fertile tillers and number of panicles per tiller, was documented in mixture plots. We did not find a significant effect of mixture on fodder, striga or weed infestation.In water and nutrient resource limiting conditions, such as in Sahelian agroecosystems, growing mixtures of early- and late-flowering landraces appeared to be an efficient way to increase productivity while ensuring agrobiodiversity conservation. Perhaps even more importantly, mixtures allowed farmers to harvest multiple products with different uses in an agrosocioecosystem context with constantly increasing land pressure.

Cs-Symmetric, Peripherally Fluorinated Boron Subphthalocyanine–Subnaphthalocyanine Hybrids: Shedding New Light on Their Fundamental Photophysical Properties and Their Functionality as Optoelectronic Materials

Hybridization of boron subphthalocyanine (BsubPc) and boron subnaphthalocyanine (BsubNc) has been modestly explored in the past, and was therefore carried out herein to access a subclass of these chromophores denoted as Ra-FxBsub(Pc3–p-Ncp) hybrids, where Ra is the axial halide substituent (axial chloride, Cl-, or axial fluoride, F-), x = 8, and p = 1. These chromophores were targeted as new candidate materials for organic electronic applications due to their Cs symmetry, in-plane dipole moment, and unique photophysical properties. Cl-/F- F8Bsub(Pc2-Nc1) hybrids were compared to Cl-/F- F8BsubPc hybrids, which are analogous compounds with an identical number of peripheral fluorine atoms but lower degree of π-conjugation. Upon photoexcitation of dilute toluene solutions and doped thin films with polystyrene as a nonemissive host, F8Bsub(Pc2-Nc1) hybrids exhibited distinctively broad absorption spectra and narrow emission profiles with red-shifted peak photoluminescence wavelengths in the 618–623 nm region compared to F8BsubPc hybrids (581–584 nm). Electroluminescence properties were probed in simple solution-cast organic light-emitting diodes (OLEDs) in which all four hybrids were diluted within an F8BT emissive polymer host. Upon electronic excitation, electroluminescence (EL) of Cs-symmetric hybrids followed the same trends as photoluminescence (PL), with OLED devices displaying narrow EL in the orange region (588–592 nm) for F8BsubPc hybrids and in the near-red region for F8Bsub(Pc2-Nc1) hybrids (627–632 nm). The photophysical processes important to OLEDs moderately improved with less π-conjugation in the periphery of the Cs-symmetric hybrids [F8Bsub(Pc2-Nc1) vs F8BsubPc; EQEMax: 0.099% vs 0.129%; luminance: 500 cd/m2 vs 1000 cd/m2 at maximum current density; relative PL quantum yields (QYs) ≈ 17–22% vs ≈ 35–44%]. Electrochemical data showed that Cs symmetry introduces reversibility or quasi-reversibility in the oxidation regime at potentials >1 V, and peripheral fluorination enables reversibility in the reduction process. Overall, F8Bsub(Pc2-Nc1) hybrids embody several unique physical characteristics into one: broad absorption spectra (full width at half-maximum height, FWHMsolabs = 53–55 nm, FWHMfilmabs = 71 nm), narrow near-red electroluminescence (FWHMOLEDEL = 33 nm), and photoluminescence (FWHMsolPL = 25–26 nm, FWHMfilmPL = 32 nm) emission, small energy band gaps (1.95–1.96 eV), high extinction coefficients (ε ≈ (5.65–6.16) × 104 M–1 cm–1), and dual electrochemical versatility. These results provide new physical insights into the material properties of Cs-symmetric macrocycles and advance the consideration of F8Bsub(Pc2-Nc1) and F8BsubPc hybrids for optoelectronic applications.

A Study Exploring the Effects of Cell Disruption Techniques on Lipid Recovery in Co-cultivated Microalgae and Oleaginous Yeast

Co-cultivation and effective downstream processing of microalgae and oleaginous yeast are potential strategies to enhance lipid yield. The findings of this work suggest that each cultivable partner should be screened and optimized for the best mutualistic co-cultures. In this case, T. pullulans was found to be the most effective yeast culture with microalgae S. obliquus, C. sorokiniana, and C. protothecoides along with additional cell disruption techniques. Co-cultures of C.protothecoides and T.pullulans had the highest relative lipid yield (RLY) of 68.71%, 59.32%, 55.33%, 53.19%, and 47.3% with sonication, microwave, osmotic shock, freeze-drying, and autoclave, respectively. Sonication was concluded as the best disruption technique with five out of nine co-cultures showing significant lipid enhancement. Even though T. pullulans was the best yeast partner with disruption techniques, co-culture of Y. lipolytica and S.obliquus (RLY 37.11%) produced lipids which was significantly higher than that of their respective monocultures (S. obliquus RLY 23.96%, Y. lipolytica RLY 4.96%) without any disruption process. R. glutinis and Y. lipolytica produced significantly enhanced lipid yield with C.sorokiniana and S. obliquus with sonication (RLY 51.44%) and osmotic shock (RLY 57.70%), respectively. FAME analysis reported that the co-cultures produced higher percentage of total FAME nearly 100% in the case of C. sorokiniana and R. glutinis with high content of saturated fatty acids (SFAs). The presence of biofuel precursors like palmitic acid, linoleic acid, oleic acid, and heptadecanoic acid, confirms their suitability for biofuel production.Graphical Abstract

Assessment of data‐limited fisheries: A case study of three finfish species in Chilika lagoon, India

AbstractInland capture fisheries in many parts of the world, especially in developing nations, receive relatively low governance priority, thereby raising concerns about their sustainability. Consequently, most inland capture fisheries are data‐limited, which renders conventional capture fisheries assessment methods inapplicable for making science‐based monitoring and management decisions. Three recent data‐limited approaches for marine fish stock assessments using length frequency and catch data (Length‐Based Indicators [LBI], Growth‐Type Groups Length‐Based Spawning Potential Ratio [GTG‐LBSPR] and Catch Maximum Sustainable Yield [CMSY]), were explored for applicability to assess stock status of three commercially exploited finfish species, Daysciaena albida, Eleutheronema tetradactylum and Mugil cephalus, in Chilika lagoon, an inland water body along the east coast of India. The LBI and GTG‐LBSPR approaches are based on catch length‐frequency data, while the CMSY is based on catch‐only data. The LBI provided insight into current exploitation status of the three species in relation to sustainable fishing, the GTG‐LBSPR provided reference points (RP) for the unfished portion of spawning biomass and relative yield in relation to selectivity, and the CMSY provided RPs for MSY, biomass and fishing pressure that yield MSY, to assess stock status and fishery management decisions. All three approaches suggested that the three species were overfished in terms of catch length and quantity, which agreed with expert knowledge of the fishery in the lagoon. All three approaches can support management and policy decisions in inland fisheries and fishery management recommendations. Future research should explore and standardise such approaches to overcome data limitations in assessing and managing inland capture fisheries.

White light-emitting, biocompatible, water-soluble metallic magnesium nanoclusters for bioimaging applications

Ultra-small (1.6 nm), water-soluble, white light-emitting (WLE), highly stable (∼8 months) BSA templated metallic (Mg0) nanoclusters (fluorescent magnesium nanoclusters = FMNCs) is developed using the green and facile route. Synthesis was facilitated by the reduction of magnesium salt, where template bovine serum albumin is utilized as a reducing agent and ascorbic acid act as a capping agent to impart stability in water, thereby obtaining stabilized Mg0 nanoclusters In solution, stabilized Mg0 nanoclusters produce white light (450–620 nm with FWHM ∼120 nm) upon 366 nm light excitation. This white light emission was found to have a CIE coordinate of 0.30, 0.33 [pure white light CIE (0.33, 0.33)]. Taking advantage of WLE and ultrasmall size, FMNCs were used for in vitro fluorescence imaging of HaCaT cell lines, yielding blue (τ = 2.94 ns, with a relative of QY = 1.2 % w.r.t QS), green (τ = 3.07 ns; relative quantum yield of 4.6% w.r.t R6G) and red (τ = 0.3 ns) images. Further, incubation of FMNCs with HEK293 (Human embryonic kidney cell) and cancerous MDA-MB-231 (Breast cancer cell line) human cell lines yielded 100 % cell viability. Current work is envisioned to contribute significantly in the area of science, engineering, and nanomedicine.

Analyzing the impact of extreme heat events and drought on wheat yield and protein concentration, and adaptation strategies using long-term cultivar trials under semi-arid conditions

Extreme weather events, lower precipitation and higher temperatures play a relevant role in the assessment of wheat yield and protein concentration under future weather conditions in Mediterranean environments. To explore this topic, a dataset of long-term wheat cultivar trials carried out in 17 locations in Andalusia, southern Spain, between 1990 and 2017, and covering a wide range of weather conditions, has been analyzed.The occurrence of maximum temperatures surpassing 32.5°C during heading showed significant correlations with yield, and generated reductions of up to 30% of the maximum observed yield. Similarly, water stress up to 20 days after heading or numerous days with both high temperatures and water stress up to 45 days after heading, also showed significant correlations with yield, and generated reductions of up to 23% and 41%, respectively. Moreover, irrigation showed a very relevant role, with the minimum relative yield increasing from 9% under rainfed conditions to 56% with irrigation supply higher than 150mm. For protein concentration, frequent joint events combining mild temperatures and severe water stresses around heading showed increases of 3 %-units. The future weather conditions projected for southern Spain will enhance risk of yield reduction and protein concentration increases, with a high spatial variability.Earlier sowing dates reduce the coincidence of extreme weather events with critical crop development stages, and thus the effects on yield and protein concentration, even identifying conditions that the impact was fully reversed. Similarly, irrigation during heading mitigated the negative effects of water stress on yield and the positive effects on protein concentration.The combination of long-term cultivar trials under semi-arid weather conditions, modeling and future climate projections constitutes an excellent tool for the assessment of vulnerable/suitable areas, and for the identification of site-specific adaptation measures to ensure the sustainability of wheat-growing areas in southern Europe.

Characterization of Azospirillum brasilense Lipopolysaccharides

Azospirillum brasilense is a gram-negative, nitrogen-fixing bacterium that colonizes the rhizosphere of various types of grasses and cereals. Lipopolysaccharides (LPS) are a class of complex glycolipids present in the cell membrane of gramnegative bacteria and mediate plant-bacteria interactions. Although the effects of LPS of pathogenic plant bacteria on the induction of plant defense mechanisms have been characterized, the role of LPS of beneficial rhizobacteria on plant growth is less clear. Therefore, a very important point is the study of the chemical, biological, and functional activities of A. brasilense LPS, which was the aim of this work. Methods. A. brasilense LPSs were isolated from dry bacterial mass by the phenol-water method. The carbohydrates were analyzed by the Dubois method, nucleic acids — by Spirin, protein content — by Lowry and 2-keto-3-deoxyoctonic acid (KDO) — by Osborn. Pyrogenicity of LPS was tested observing the rules of bioethics in rabbits. Serological studies were performed by the Ouchterlony method. The identification of monosaccharides and fatty acids in LPS preparations was carried out on an Agilent 6890N/5973 inert chromatomass spectrometry system. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAAG electrophoresis) was performed according to Laemmli. Results. LPS of 3 strains of A. brasilense were isolated from dry bacterial mass and purifi ed from nucleic acids by ultracentrifugation. The purified LPSs were characterized by different relative yields from 2.44% to 4.75%, which is slightly higher than other strains of the A. brasilense (1—3%). The studied preparations were characterized by a rather high content of carbohydrates from 50.1% to 72.1%. All LPS contained up to 0.17% KDO, which is a specific component of the LPS of gram-negative bacteria. Analysis of the monosaccharide composition indicates that the LPSs of the studied A. brasilense strains turned out to be heterogeneous. At the same time, such monosaccharides as mannose, galactose, glucose, and heptose were recorded in the LPS of all tested strains. The study of the fatty acid composition of LPS showed the presence of fatty acids containing from 14 to 18 carbon atoms. Нydroxylated, saturated, and monounsaturated acids and their cis isomers were found. In the investigated LPS, the dominant fatty acids were 16:0, 18:1, 14:0(3-OH), and 16:0(3-OH), which coincides with the literature data. The research of the pyrogenic effect of LPS of A. brasilense studied strains showed that LPS solutions are apyrogenic. The double immunodiffusion reaction in Ouchterlon agar showed that all tested LPS in homologous systems exhibited ancultitigenic activity. Serological cross-reactions can be used as an approach in classifying different bacteria. Thus, we found that antisera to A. brasilense 18-2 and 61 react with all LPSs of the studied strains, which may indicate the presence of common antigenic determinants in them and that these strains belong to the same serogroup. The electrophoretic distribution data indicate that A. brasilense produces S-forms of LPS which differ in the length of O-specifi c polysaccharide chains. Conclusions. For the first time, LPS were isolated from cells of A. brasilense 10/1, 18-2 and 61. A characteristic feature of these LPS is their heterogeneity in monosaccharide and fatty acid composition, all of them were apyrogenic. The results obtained during biological-functional studies of three strains of A. brasilense LPS contribute to the biological characteristics of this species.

DC slice ion imaging of the ultraviolet photodissociation of 2-bromohexane

The ultraviolet photodissociation dynamics of 2‑bromohexane around 234 nm has been investigated using the DC slice velocity map imaging technique. Relative quantum yield of the ground state bromine atom is measured to be 0.961. By analyzing the slice images, we can obtain the speed and angular distributions of the ground state and excited state bromine atoms. The speed distribution contains two Gaussian components, which are attributed to two dissociation channels. The high translational energy component is formed via the direct dissociation along the C–Br bond. Nevertheless, the low translational energy component is formed via the multidimensional dissociation along the C–Br bond coupling with the bending modes. The alkyl radical branching promotes the multidimensional dissociation. What’s more, the contribution of the electric-dipole allowed3Q1, 3Q0 and 1Q1 states to the product formation is also discussed. The nonadiabatic 1Q1←3Q0 transition plays a significant role in the dissociation process.

Methodology for assessing the agroecological adaptability of genotypes under global climate warming

Background. The relevance of the research is due to the fact that, despite the breeding achievements in releasing cultivars with high potential yield and resistance to the most common stressors in the regions, it is almost impossible to foresee and accurately predict the reaction of cultivars under production conditions. Besides, extreme weather events, including heat waves, droughts and downpours, will increasingly manifest themselves under global climate warming. To reduce the risk of a significant decrease in gross grain harvests in dry years and achieve high results under favorable conditions, the goal was to develop a comprehensive indicator for assessing the agroecological adaptability of genotypes to some consequences of global climate warming.Materials and methods. The results of a competitive test of 5 cultivars and 9 promising lines of spring wheat for their yield across six years contrasting in moisture availability by calculating the indicators of responsiveness to favorable conditions, grain yield depression under unfavorable conditions and the relative yield index were used to develop a complex indicator proposed to assess the agroecological adaptability of a genotype to contrasting environmental conditions.Results. The proposed method makes it possible to perform a comprehensive assessment that takes into account the responsiveness of an accession to improved agroclimatic conditions and the degree of its reaction to adverse environmental factors, taking into account the yield index in the studied set. The method is recommended for evaluating the source material and identifying the diversity of its responses to changes in agroclimatic conditions as well as for the stage of competitive variety testing in plant breeding for adaptability.

Growth and Yield Responses of Leafy Vegetables Grown in Organic and Conventional Agriculture Systems

Several scientific reports indicate lower as well as higher relative yield stability in organic and conventional (chemical) agriculture systems. This study present results of on-farm trials conducted on leafy vegetables grown in in organic and conventional management systems. Four leafy vegetables collard green (Brassica oleracea cv. acephala), kale (Brassica oleracea cv. sabellica), lettuce (Lactuca sativa) and swiss chard (Beta vulgaris L. cv. cicla) were grown in organic and conventionally managed plots in the spring 2018 and 2020. United States Department of Agriculture (USDA), National Organic Program (NOP) standards were followed for cultural and management practices in organically managed experimental field plots. Synthetic chemical inputs (seeds and fertilizer) were applied in the experimental field plots managed in conventional production system. Data on plant height, leaf number and total fresh weight of leafy vegetables were measured at the end of the experiment. Results showed that maximum fresh weight per plant was obtained from conventionally grown kale and the lowest was recorded in conventionally grown lettuce. The fresh weight of collard (344.1 g/plant) and kale (475.6 g/plant) was significantly higher in conventional system relative to the organic management system in collar (184.9 g/plant) and kale (242.3 g/plant). In contrast, for lettuce, significantly greater fresh weight was obtained in the organic (266.5 g/plant) compared to conventional (189.3 g/plant). No difference recorded in fresh weight of swiss chard grown in organic (222.0 g/plant) and conventional (263.7 g/plant) production systems. No difference observed in plant height and number of leaf count between the two production systems. Findings suggest that growth and yield responses in organic and conventional production systems can vary with the individual crop species. Results presented could be helpful to growers in planning for the organic production of leafy greens vegetables.

Thermally Activated Delayed Fluorescent Scintillators Based on Mononuclear Copper(I) Halide Complexes for High‐Resolution X‐Ray Imaging

AbstractScintillators have attracted tremendous attention due to their great potential in radiation detection, industrial non‐destructive testing, and medical theranostic applications. Thermally activated delayed fluorescence (TADF) based scintillators can simultaneously harvest radiation‐induced singlet and triplet excitons for high‐efficient X‐ray excited luminescence. However, pure organic TADF materials composed of light elements exhibit low X‐ray absorption coefficients, resulting in relatively weak X‐ray excited luminescence. Herein, a series of novel high‐performance X‐ray scintillators based on TADF mononuclear Cu(I)‐halide complexes are successfully developed. Together with high X‐ray absorption coefficient of heavy halogen elements and halide‐to‐ligand charge transfer characteristics, these TADF scintillators display excellent performance with high X‐ray relative light yields (as high as 28385 ± 1335 photons MeV−1), good linear response to X‐ray dose rate and high resistance to humidity and radiation. X‐ray imaging tests show that a relatively high spatial resolution of 9.8 lp/mm is realized based on their flexible scintillator films. These features suggest that it is a promising strategy to realize strong X‐ray excited luminescence by incorporating heavy halogen elements in TADF materials, providing more possibilities for exploring new low‐cost and high‐performance scintillators.

The longevity of cultivation in decreasing the potential for phosphorus loss in runoff

Phosphorus (P) loss from highly fertilised grazed pastures can impair surface water quality. High P concentrations in grazed pastures are maintained to boost legume production, but systems that use monocultures of grass and clover can be more profitable and decrease P losses by lowering soil P in grassed areas. In contrast with using a direct drill to establish new pastures, conventional cultivation can lower topsoil P quickly and can be used as part of a farm re-grassing programme every six years. We tested if the potential for low P losses (measured by water extractable P; WEP) could be maintained over six years in pastures (ryegrass and white clover monocultures and a ryegrass and clover mixed sward) despite being fertilised (10, 35 and 100 kg P ha-1) and grazed. Cultivation (0–20 cm) decreased WEP and Olsen P in all three pastures and P rates by 30–50 % compared to direct drill and maintained this decrease for six years. A threshold in Olsen P (22 mg L-1) was noted where WEP concentrations increased at a greater rate relative to Olsen P than below. This threshold was like the critical point in Olsen P for 97 % relative yield in the pastures (22–28 mg L-1) and could be used to advise on cultivation and P fertiliser strategies to help avoid the potential for P loss without significantly compromising yield. The data indicated that cultivation could be used to quickly establish and maintain lower soil P concentrations as part of a strategy to decrease P losses and improve profit by using a split grass-clover system.

Nitrogen Deficiency Tolerance and Responsiveness of Durum Wheat Genotypes in Ethiopia

Development of low-nitrogen (N) tolerant and N-responsive durum wheat genotypes is required since nitrogen efficiency has emerged as a highly desirable trait from economic and environmental perspectives. Two hundred durum wheat genotypes were evaluated at three locations under optimum (ON) and low (LN) nitrogen conditions to screen genotypes for low-nitrogen tolerance and responsiveness to an optimum N supply. The results showed significant variations among the durum wheat genotypes for low-N tolerance and responsiveness. The average reduction in grain yield under the LN condition was 48.03% across genotypes. Only 17% of the genotypes tested performed well (grain yield reduction <40%) under LN conditions. Based on the absolute grain yield, biomass yield, and normalized difference vegetative index value, on average, 32, 14, 17, and 37% of the tested genotypes were classified as efficient and responsive, efficient and nonresponsive, inefficient and responsive, and inefficient and nonresponsive, respectively. Considering the absolute and relative grain yield, biomass yield, normalized difference vegetative index values, and stress tolerance indices as selection criteria, 17 genotypes were chosen for subsequent breeding. Among the screening indices, geometric mean productivity, stress tolerance index, yield index, and stress susceptibility index exhibited positive and significant correlations with grain yield under both N conditions; hence, either of these traits can be used to select low-N-tolerant genotypes. The common genotypes identified as LN-tolerant and responsive to N application in this study could be used as parental donors for developing N-efficient and responsive durum wheat varieties.

Alleviating the adverse effects of plant pathogens, drought and salinity stress factors using plant growth promoting bacteria

Climate change is one of the most important threats to agricultural production, therefore, more attention must be paid to study the environmental stresses that affect plant production. Pathogen stress is one of the most important stresses that negatively affect growth and yield, also drought and salinity are very dangerous abiotic factors. Pathogens, drought and salinity stresses led to decrease morphological characters and yield production of plant. However, the application of plant growth promoting bacteria (PGPB) positively affect morphological, physiological, and yield characters such as number of leaves, stem height, chlorophyll concentration, relative water content, antioxidant enzymes and crop yield. PGPB can play a pivotal role in facilitating nutrient uptake, bioactive compounds and scavenging reactive oxygen species (ROS) to control various pathogens and increase plant tolerance to drought and salinity stresses. Finally, the latest studies of these beneficial bacteria have been presented comprehensively under stress conditions to highlight the recent trends with the aim to maximize the crop production.

Controls on the relative abundances and rates of nitrifying microorganisms in the ocean

Abstract. Nitrification controls the oxidation state of bioavailable nitrogen. Distinct clades of chemoautotrophic microorganisms – predominantly ammonia-oxidizing archaea (AOA) and nitrite-oxidizing bacteria (NOB) – regulate the two steps of nitrification in the ocean, but explanations for their observed relative abundances and nitrification rates remain incomplete and their contributions to the global marine carbon cycle via carbon fixation remain unresolved. Using a mechanistic microbial ecosystem model with nitrifying functional types, we derive simple expressions for the controls on AOA and NOB in the deep, oxygenated open ocean. The relative biomass yields, loss rates, and cell quotas of AOA and NOB control their relative abundances, though we do not need to invoke a difference in loss rates to explain the observed relative abundances. The supply of ammonium, not the traits of AOA or NOB, controls the relatively equal ammonia and nitrite oxidation rates at steady state. The relative yields of AOA and NOB alone set their relative bulk carbon fixation rates in the water column. The quantitative relationships are consistent with multiple in situ datasets. In a complex global ecosystem model, nitrification emerges dynamically across diverse ocean environments, and ammonia and nitrite oxidation and their associated carbon fixation rates are decoupled due to physical transport and complex ecological interactions in some environments. Nevertheless, the simple expressions capture global patterns to first order. The model provides a mechanistic upper estimate on global chemoautotrophic carbon fixation of 0.2–0.5 Pg C yr−1, which is on the low end of the wide range of previous estimates. Modeled carbon fixation by AOA (0.2–0.3 Pg C yr−1) exceeds that of NOB (about 0.1 Pg C yr−1) because of the higher biomass yield of AOA. The simple expressions derived here can be used to quantify the biogeochemical impacts of additional metabolic pathways (i.e., mixotrophy) of nitrifying clades and to identify alternative metabolisms fueling carbon fixation in the deep ocean.

Divergent Synthesis of Alternant Bisanthenequinone and Nonalternant Heptalenodifluorenedione Ring Systems via a Concentration-Dependent Rearrangement.

The synthesis of a diol containing a nonalternant aromatic core was investigated to access a nonalternant isomer of bisanthene with functional groups suitable for two-dimensional polymerization. An alternant diol and its nonalternant isomer were prepared in a short synthetic route from the same bifluorenylidene starting material. The bifluorenylidene reactant undergoes a Stone-Wales rearrangement in neat triflic acid, which unexpectedly provided both an alternant and nonalternant dione. The rearrangement was characterized by spectroscopy and single crystal X-ray diffraction of Grignard addition products of both isomers. The relative yield of the rearranged, alternant product increased along with the initial concentration of its polycyclic aromatic hydrocarbon (PAH) precursor, implicating a bimolecular rearrangement mechanism and enabling the divergent synthesis of both the nonalternant and alternant products. These findings offer convenient access to functional derivatives of two PAH classes of interest for their optoelectronic properties and serve as yet another warning about the importance of characterizing these materials with care, especially when insoluble products must be carried forward in a multistep synthetic route.

Effects of Various Liming Materials on the Growth of Rice under Rainshelter Condition

A study was conducted to evaluate the effects of liming materials on the growth of rice under rainshelter conditions and MR 219 rice variety was used in this experiment. The treatments were: 1) T1, no application of lime, 2) T2, 4 t ha-1 of ground magnesium limestone (GML), 3) T3, 2 t ha-1 of hydrated lime, 4) T4, 20 L ha-1 of liquid lime. It was found that the application of 4 t ha-1 of GML had produced the highest rice yield of 8.2 t ha-1. The result showed that as panicle length increase, spikelet per panicle also increases. Relative rice yield is negatively correlated with the soil pH, and this indicates that as soil acidity increase (observed with pH between 2 to 3), the rice yield decrease and vice versa. At harvest, the soil pH exceeded 6 for all the treatment. It was also observed that as soil exchangeable Ca increase, soil pH also increases. Among the treatment, soil treated with 2 t ha-1 of hydrated lime gave the highest exchangeable Ca in the soil of 11.86 cmolc kg-1 soil with Ca concentration of 0.12% in the root. It was observed that liming increases soil pH and exchangeable cations in the soil. Therefore, liming is essential to ameliorate the acid sulfate soils for rice cultivation.

Isotopic yields and spontaneous fission half-lives of 279Ds and 281Ds superheavy isotopes

In this paper, Isotopic yield and half-lives of cold spontaneous fission for [Formula: see text] and [Formula: see text] superheavy isotopes are studied. The interacting potential between fragments includes mean field proximity and Coulomb potentials. Fission [Formula: see text]-value, driving potential, [Formula: see text] and partial penetration probability of each possible individual fragmentation are calculated using [Formula: see text] approximation. According to the tunneling effect, the most favored pair of fragments is produced for the highest [Formula: see text]-value or the lowest driving potential. A few fragmentation with higher [Formula: see text]-value are selected for each atomic number Z. It is found that for [Formula: see text] isotope, the highest relative yield belongs to the [Formula: see text]Te + [Formula: see text]Ce fragmentation while for [Formula: see text], the combination [Formula: see text]Te + [Formula: see text]Ce has lowest driving potential and highest yield due to presence of fragments with magic or near magic proton and neutron numbers ([Formula: see text] and [Formula: see text]). By calculating yield of each fragmentation, its partial fission decay constant and then by summing over all decay constants for possible fragmentation, the fission decay constant for each superheavy isotope is obtained. Furthermore, half-life of each superheavy isotope is also estimated. Finally, the calculated half-lives using this method are compared with the experimental data. Good agreement achieved between our calculated half-lives and the experimental data.