Organic Sources Research Articles

Impact of organic and inorganic sources on productivity of groundnut (Arachis hypogaea L.): A review

Impact of organic and inorganic sources on productivity of groundnut (Arachis hypogaea L.): A review

Controlled donation after circulatory death in post-cardiac arrest patients: Estimates from a large registry

BackgroundControlled donation after circulatory death (cDCD) in post-anoxic brain injury is a valuable source of organs that is still underused in some countries. We assessed the number of potential cDCD donors after out-of-hospital cardiac arrest (OHCA) in Paris and its suburbs and extrapolated the results to the French population. MethodsUsing the large regional registry of the Great Paris area, we prospectively included all consecutive adults with OHCA with a stable return of spontaneous circulation (ROSC) who ultimately died in the intensive care unit (ICU) after withdrawal of life-sustaining treatments (WLST) due to post anoxic brain injury. The primary endpoint was potential for organ donation by cDCD in this population. The number of potential cDCD donors was calculated and extrapolated to the entire French population. ResultsBetween 2011 and 2018, 4638 patients with stable ROSC were admitted to ICUs after OHCA, and 3170 died in ICU, of which 1034 died after WLST due to post-anoxic brain injury. When considering French criteria, 421/1034 patients (41%) would have been potential cDCD donors (55 patients per year in a 4.67 million population). After standardization for age and sex, the potential for cDCD was 515 (95% CI 471–560) patients per year in France corresponding to an annual incidence of 1.18 per 100 000 inhabitants per year. ConclusionsOrgan donation by cDCD after cardiac arrest could provide a large pool of donors in France.

63 Allogeneic Recellularized Lung Orthotopic (ARLO) Transplant Research

OBJECTIVES/GOALS: As of 2021, the lung transplantation waiting list has a mortality rate of 7.6 deaths per 100 patient-years. Bioengineered human organs is an emerging field of tissue engineering with a goal of developing suitable organs for transplantation. The focus of the project is to evaluate the efficacy of bioengineered lungs using a human-to-swine model. METHODS/STUDY POPULATION: This project will involve designing and assessing the bioengineered lung by establishing a human-to-pig xenotransplantation survival model. The project aims to evaluate how well the bioengineered lung functions within a living model. The bioengineered lung is constructed using swine connective tissue scaffolding, which has been recellularized with human cells. Anatomically, the lung will resemble a swine lung but will possess the immunological and cellular markers of human tissue. The proposed model will initially assess the immunological response of swine to human lung tissue. Lung function will be assessed during surgery using pulmonary vein gas samples and tissue sampling. Following the end of the study, additional tissues samples will be taken to evaluate the immunological response to the tissue. RESULTS/ANTICIPATED RESULTS: Xenotransplantation and bioengineered organs are two new emerging fields of research that have just begun to enter the large animal testing phase. This model will provide a novel human-to-pig xenotransplant survival model that will be used to test the efficacy of bioengineered lungs function in a dynamic living organism. The design has taken the principles of immunology learned from the current clinical and xenotransplant research and has incorporated this knowledge into the known pig-to-pig transplant models. We anticipate that this model design will be easily reproducible and can be expanded to other bioengineered organs as an effective means to test functionality. DISCUSSION/SIGNIFICANCE: The COVID-19 pandemic’s aftermath may lead to an increased demand for lung transplants. Bioengineered lungs could provide an additional source of organs to supplement current availability. This novel approach has the potential to offer a means to test several different types of bioengineered organs in the future.

Application of tetracyclic polyprenoid biomarkers in Yola Basin of the Northern Benue Trough, northeast Nigeria: Implications for source origin and paleoenvironment

Tetracyclic polyprenoids biomarkers (TPP) were investigated on the Cretaceous sediments of Yola Sub-basin based on gas chromatography-doublet mass spectrometry. This is with an objective to re-examine the organic source input and paleodepositional environment of the sediments. The study revealed that the Bima shales were deposited in the lacustrine environment under suboxic to relatively anoxic depositional condition while the analysed Yolde, Dukul, Jessu, Sekuliye and Numanha shale sediments were deposited within the marine environment under suboxic depositional condition. More so, the analysed Lamja coal and shale samples were deposited in a delta environment under oxic to suboxic depositional condition. The study therefore, suggest that the paleodepositional environments of the studied shale sediments within the Yola Sub-basin remain as continental (lacustrine), transitional (marine and delta) and could have the potential to generate appreciable quantity of oil and gas.

Viability of organic sources as a sustainable highlighter pen ink

Highlighter pens have been essential tools for students, instructors, and office employees for many years. They are used to emphasize specific information in written texts, making it easier to recognize, remember, and retrieve later. This study proposed the use of organic sources to create solvent-based highlighter pen ink. Specifically, it aimed to determine the viability of using organic sources such as Annatto seeds and blue butterfly pea as sustainable highlighter pen ink and to assess if there was a significant difference between the physical properties of commercial and organic highlighters. An experimental research design was applied, wherein the researchers produced two concentrations of ink and observed which concentration was suitable as highlighter pen ink. The study involved forty (40) students from the College of Education at Laguna University who tested the organic highlighters in one day and answered a validated questionnaire. The results revealed that Annatto seed highlighter pen ink exhibited a more intense color, while blue butterfly pea highlighter pen ink had a mild odor. As a result, respondents strongly agreed on the physical properties of the two organic sources as highlighter pen ink. However, both organic sources resulted in show-through, meaning that the ink could be seen through to the other side, usually due to thin paper or bold ink. Additionally, the study showed that both Annatto seed and blue butterfly pea highlighters were acceptable. However, Annatto seed highlighter was preferred due to its better ink qualities. The research also indicated that there was no significant difference between the physical properties of commercial and organic highlighters, suggesting that highlighter pens made from organic sources can be used as sustainable alternatives. The researchers encouraged further investigation into the advantages of using natural inks derived from organic sources in ecologically friendly and sustainable production methods. This study opens possibilities for utilizing organic materials as alternatives to traditional highlighter pen inks, contributing to environmentally conscious practices in the stationery industry.

Effect of organic carbon sources on growth, lipid production and fatty acid profile in mixotrophic culture of Scenedesmus dimorphus (Turpin) Kützing

Due to non-renewability of fossil fuels and various environmental problems associated with their use, there is a growing interest in producing biodiesel from microalgae. Finding novel microalgal strains with desired characteristics such as rapid growth rates, high lipid productivity, and suitable fatty acid compositions is important for the production of biodiesel. Comparatively, photoautotrophic cultivation of microalgae results in low biomass yields and lipid productivities. Mixotrophic and heterotrophic cultures, in contrast, lead to higher biomass and lipid productivities but their productivities are species specific and depend a lot on the organic carbon source and culture conditions. In the present study, the potential of Scenedesmus dimorphus for biodiesel oil production under mixotrophic culture was investigated. The effects of organic carbon sources (glucose, ethanol and glycerol) on growth, biomass yields, lipid contents, lipid productivities and fatty acids compositions of Scenedesmus dimorphus in mixotrophic cultures were investigated. In comparison to photoautotrophic cultures, mixotrophic cultures produced significantly higher biomass concentration, lipid content, and lipid productivities (P≤0.05) under all the cultivation conditions investigated. The maximum biomass and lipid productivities achieved by mixotrophic culture were 83.88±0.05 and 17.11±0.04 mg L−1 day−1 respectively which are more than 2.6 and 3.1 folds higher than those obtained under photoautotrophic condition. Using glucose as the organic carbon source was better than ethanol and glycerol in terms of biomass and lipid productivities (glucose > ethanol > glycerol). The majority of the produced fatty acids were composed of C16 and C18 fatty acids. The two most abundant fatty acids in all the cultures were linolenic and palmitic acids. The values of biodiesel properties of oil obtained from S. dimorphus are within the American (ASTM D6751) and European (EN 14214) biodiesel specifications. The results show that S. dimorphus has good potentials for biodiesel oil production and that the productivity can be enhanced by mixotrophic cultivation.

Combining Dissolved Air Flotation (DAF) and Modified Moving Bed Biofilm Reactors (MMBBR) for Synthetic Oily Wastewater Treatment

<p>Numerous industrial processes, including petroleum refining, food production, car washes, leather manufacturing, and slaughter houses, generate significant volumes of wastewater due to their substantial water consumption during processing. The presence of oily wastewater has detrimental effects on surface and ground water resources, Human health and aquatic ecosystems. This study aims to integrate dissolved air flotation (DAF) and moving bed biofilm reactors (MBBR) for the treatment of oily wastewater. For this reason, a synthetic oily wastewater was prepared by utilizing commercially available powdered starch as an organic source, along with diesel oil and a finely ground soil. In addition, the experiments were designed and analyzed using Response Surface Methodology (RSM). DAF reactor factors were flotation time and air flow rate. While the MBBR reactor variables were mixing time and hydraulic retention time (HRT). The responses were chemical oxygen demand (COD), oil and grease(O&G), ammonia (NH3-N) and total suspended solids (TSS). Optimum results obtained by RSM for the DAF were 10 min for the flotation time and air flow rate of 72 L/min. in addition, HRT for both MBBRs was 23.5 hr and mixing time of 13 min and 23 min for MBBR1 and MBBR2 respectively.</p>

Effects of erosion on macroaggregation, aggregate associated organic carbon sources and compositions in a Mollisol agricultural landscape

Macroaggregation is widely recognized as an important soil carbon (C) stabilization mechanism. However, in eroding landscapes, the relationships among soil aggregation, organic carbon (OC) sources, and chemical composition are poorly understood. In this study, we aimed to explore the effects of erosion and deposition on macroaggregation, OC sources, and chemical compositions in topsoil (0–20 cm) versus subsoil (80–100 cm) in a Mollisol agricultural landscape. The bulk soil was fractionated into macroaggregates (0.25–2 mm), microaggregates (0.053–0.25 mm), and clay and silt (<0.053 mm) using a wet sieving procedure. The plant sources of soil OC were quantified based on the stable isotope 13C (δ13C), and the chemical composition of macroaggregate associated OC (MaOC) was determined by solid-state nuclear magnetic resonance techniques. The results indicated that macroaggregates and MaOC comprised 45–72% of soil mass and 50–66% of soil OC, respectively. There was a reduction in macroaggregate-associated C3-derived C (C3-C) in the eroding position compared to that in the non-eroding position. However, similar amounts of C4-derived C (C4-C) were detected among three topographical areas, indicating the re-macroaggregation of eroded materials in the depositional position and preferential protection of C3-C. In the up-slope positions, topsoil MaOC was composed primarily of O-alkyl C (52%). Compared with the up-slope position, there was a considerable increase in the amount of aromatic C in the erosional macroaggregate fraction. However, at the eroding position, there was a marked increase in the proportion of substituted alkyl-C in the topsoil material, and deposition resulted in an increase in aromatic C in the subsoil. Overall, erosion and deposition change soil aggregation, and sources and composition of OC in different functional pools have important implications for the stabilization of organic matter along an eroding Mollisol hillslope.

Investigation on the thermal maturity, organic matter sources and depositional environment of lacustrine source rocks in the Dongying Formation of the Bozhong Sag, Bohai Bay Basin, China

The unclear understanding of the source rock characteristics for the Paleogene Dongying Formation in the Bozhong Sag leads to the lack of cognition in oil and gas exploration. This research systematically evaluated the discrepancy in geochemical characteristics of source rock intervals in the Dongying Formation based on detailed analysis using Rock‐Eval pyrolysis, total organic carbon (TOC), vitrinite reflectance (Ro), maceral components, stable carbon isotopes and biomarker parameters. It discusses the organic matter sources, depositional environment, thermal maturity and hydrocarbon generation potential in the source rock intervals of the Dongying Formation. The organic matter abundance in the third member (E3d3) and lower sub‐member of the second member (E3d2L) of the Dongying Formation is higher, with an average TOC of 2.08% and 1.03%, respectively, indicating that these source rock intervals could have good and excellent quality. The source rocks of the Dongying Formation predominately contain exinite maceral group and type II1 and II2 kerogen. The thermal evolution is mainly in the low‐mature and mature stages. The organic matter sources in the Dongying Formation are mainly dominated by mixed origin (the carbon isotope reversal of aromatics also provides a potential explanation). However, the values of 1,2,5−/1,3,6‐trimethylnaphthalene, (1,2,5,6 + 1,2,3,5)‐tetramethylnaphthalene/tetramethylnaphthalenes, methyldibenzofuran/methylphenanthrene (MDBF/MP) and dibenzofuran/phenanthrene (DBF/PHEN) parameters in the E3d3 and some samples in E3d2L decipher relatively smaller values than other source rock intervals, proving the enhancement of the contribution of lower organisms. Moreover, the terrestrial input in the bottom‐up deposition process of the Dongying Formation gradually increases. The depositional environment reveals the Dongying Formation source rocks mainly developed freshwater sulphur‐poor lacustrine facies and shallow lake‐fluvial delta facies in an open clay‐rich sedimentary environment with poor water column stratification, belonging to the typical weak oxidation–reduction depositional conditions. The comprehensive geochemical evaluation concludes that the favourable supply of lower organisms and stable clay‐rich depositional environment in the E3d3 interval of the Dongying Formation are potential explanations for the formation of lacustrine source rocks with high organic matter abundance, intermediate thermal evolution and excellent hydrocarbon generation potential, providing a good foundation for the exploration and development prospects of hydrocarbons.

The future of liver transplantation.

Over the last 50 years, liver transplantation has evolved into a procedure routinely performed in many countries worldwide. Those able to access this therapy frequently experience a miraculous risk-benefit ratio, particularly if they face the imminently life-threatening disease. Over the decades, the success of liver transplantation, with dramatic improvements in early posttransplant survival, has aggressively driven demand. However, despite the emergence of living donors to augment deceased donors as a source of organs, supply has lagged far behind demand. As a result, rationing has been an unfortunate focus in recent decades. Recent shifts in the epidemiology of liver disease combined with transformative innovations in liver preservation suggest that the underlying premise of organ shortage may erode in the foreseeable future. The focus will sharpen on improving equitable access while mitigating constraints related to workforce training, infrastructure for organ recovery and rehabilitation, and their associated costs. Research efforts in liver preservation will undoubtedly blossom with the aim of optimizing both the timing and conditions of transplantation. Coupled with advances in genetic engineering, regenerative biology, and cellular therapies, the portfolio of innovation, both broad and deep, offers the promise that, in the future, liver transplantation will not only be broadly available to those in need but also represent a highly durable life-saving therapy.

Organic Petrologic Characterization and Paleoenvironmental Analysis of Permian Shale in Northeast Sichuan Province, China

The Permian shale in Northeast Sichuan is an important shale oil and gas resource potential area, and the study of its organic matter characteristics and paleoenvironmental analysis is of great significance for revealing the shale oil and gas formation mechanism and resource evaluation. In this study, the organic matter of Permian shales in northeast Sichuan was carefully studied based on various analytical tools, such as petrology, laser Raman, microscopy, and principal trace elements, and the paleoenvironmental parameters of the shales were comprehensively analysed. A detailed study of the organic matter characteristics of Permian shales in northeast Sichuan reveals important features such as organic matter fractions, structural characteristics, maturity and sources. The results show that the organic matter of the shale consists mainly of solid bitumen, putrescine group, specular group and multicellular planktonic algae. Petrological observations and laser Raman analyses indicate a high maturity of the organic matter and a high content of organic carbon (TOC), showing good hydrocarbon potential. In this study, we reconstructed the palaeoenvironmental parameters and inferred the palaeoenvironmental evolution through palaeoenvironmental analyses of Permian shales in northeast Sichuan. The results of the comprehensive multi-indicator study show that the type of palaeoenvironment at the time of shale deposition was mainly an anoxic-reducing environment, and the depositional conditions were favourable to the enrichment and preservation of organic matter. In summary, the organic matter characteristics and paleoenvironmental analyses of the Permian shales in Northeast Sichuan provide important geological background information for an in-depth understanding of the formation mechanism, exploration potential and development prospect of shale hydrocarbons in this area. The results of this study can provide a scientific basis for the evaluation and development of shale oil and gas resources in this area, which is of great significance to geologists and the energy industry.

Alternation between terrestrial and aquatic plants dominated organic matter sources in the Tiaoshu wetland (south China) and its response to late Pleistocene environmental changes

Widely distributed wetlands in China play an important role in the global carbon cycle. However, the long-term response of wetland evolution and carbon storage in tropical southern China to climate change remains unclear. Here, we present a sediment core record from the Tiaoshu Wetland in the northern Leizhou Peninsula and multiple proxy indicators are investigated, with the aim of better understanding past vegetation and environmental changes. The following conclusions were drawn: (i) The organic matter deposited in the Tiaoshu Wetland was mainly derived from terrestrial C3 plants and aquatic plants growing in and/or around the catchment. The temporal variability in the relative proportions of organic matter contributed by various sources revealed paleoenvironmental changes in the study area, generally consistent with regional and global climate records. (ii) The peat formation pattern in the Tiaoshu Wetland is in contrast to some individual sites reported in subtropical China, suggesting that there may be different peat formation patterns in the tropical and subtropical regions of China, which may be closely related to specific hydrothermal conditions in different regions. In addition, by comparison with atmospheric CH4 concentrations, our results suggest potential relationships between the evolution of wetlands in tropical China and global atmospheric CH4 cycles.

Organic Carbon Sources in Surface Sediments on the Northern South China Sea

AbstractThe burial of organic carbon (OC) in marine sediments regulates CO2 content in the atmosphere. However, the OC sources and their effect on the OC preservation in sediments of the continental marginal sea remain elusive. Here, we survey the abundance, stable carbon and radiocarbon isotopes of OC, as well as mineral surface area and grain size in surface sediments from the shelf to the abyssal plain of the South China Sea. We found that the marine OC comprises the 63 ± 9% and 78 ± 14% of sedimentary OC off South China and Luzon, respectively. The petrogenic OC contributing to sedimentary OC in these sites is generally higher than that of soil OC (22 ± 10% vs. 12 ± 6%). The sedimentary OC off Taiwan is predominantly derived from petrogenic OC, accounting for 57 ± 10%, with remaining consisting of marine OC (36 ± 10%) and soil OC (6 ± 1%). High soil OC contents are found in fine sediments on the inner shelf off South China, and high petrogenic OC contents occur in fine sediments off Taiwan. Marine OC contents are high in fine sediments on the middle shelf and upper slope off South China, but low in coarse sediments on the outer shelf and upper slope, and fine sediments on the lower slope and abyssal plain. The OC sources, mineral surface area, and oxygen exposure time of OC together control the preservation of OC in sediments with their relative importance differing on varying depositional settings of this sea.

Effect of Different Integrated Nutrient Management Approaches on Growth, Yield Attributes and Yield of Wheat (Triticum aestivum L.) Crop: A Review

The adequate and balanced supply of plant nutrients is of critical importance in improving the productivity of wheat crop. Due to prohibitive cost of chemical fertilizers, Indian farmers, mostly marginal and small, do not supply the recommended doses of nutrients to these energy rich crops, indigenously available organic sources of nutrients have been recorded to enhance the efficiency and reduce the requirement of chemical fertilizers. The nutrients (N, P, K and Zn) can be supplied through fertilizers, organic manures, biofertilizers, bio-stimulants and their combined applications under integrated nutrient management. Wheat varieties differ in their phenology, requirement of thermal and photoperiod units and growth habits which cumulatively determine the varietal adaptation at different locations and sowing times. Therefore, comparative evaluation of varieties suitable for early, normal and late sown conditions is warranted to identify the growth patterns, physiological traits and yield attributes that will favorably influence the grain yield and biomass in wheat under normal and late sown conditions. This review examines response of wheat varieties to integrated nutrient management practices in wheat crop sown under normal and late planting conditions.

Enhancing fucoxanthin production in Chaetoceros calcitrans under mixotrophic condition and LED wavelength shift strategy

This study addresses the challenge of achieving high fucoxanthin (Fx) productivity in Chaetoceros calcitrans under mixotrophic cultivation which often struggle to simultaneously increase biomass and Fx content. To overcome this, we investigated the potential of C. calcitrans for Fx production under mixotrophic conditions by investigating the interaction of organic carbon, light intensity, and light emitting diode (LED) color shifts during cultivation to optimize Fx production. Results revealed significant influences of various organic carbon sources on Fx productivity, with glycerol and glucose showing promising outcomes. Furthermore, the addition of external urea enhanced Fx content in mixotrophic cultivation. Response Surface Methodology (RSM) analysis highlighted the synergistic effect of light intensity and glycerol addition on Fx productivity. Most notably, shifting from white to blue LED during mixotrophic cultivation at the end of the exponential phase significantly increased Fx productivity in C. calcitrans to 3.2 mg L−1 d−1, representing a 1.3-fold enhancement compared to white LED sources. These findings underscore the potential of mixotrophic cultivation and LED color shifts as effective strategies for improving Fx productivity in diatoms.

The Multiphasic Teeth of Chiton Articulatus, an Abrasion‐Resistant and Self‐Sharpening Tool for Hard Algae Collection

AbstractChiton articulatus is a species of mollusk living in the tropical Pacific intertidal rocky shores of Mexico. This species feeds on solid waste organic sources, including hard crustose algae that grow on rocky substrates, by grazing on them with its radula, a flexible chitinous membrane lined with mineralized major lateral teeth. In this study, the composition, morphology, and resulting mechanics of the mature teeth of this species, which have yet to be examined, are revealed. The results show the presence of multiphasic mature teeth, each consisting of aligned hard magnetite nanoparticles on the leading edge of the tooth underneath which are magnetite lamellae, followed by goethite, lepidocrocite, and eventually hydroxyapatite near the trailing edge. This multiregional structure demonstrates a gradation in hardness as well as different microstructural features integrated with tough interfaces. The combination of these microstructural and phase arrangements results in an abrasion‐resistant tough structure with a self‐sharpening ability. The results of this work will help contribute to developing new bioinspired designs while also helping to understand the evolution and feeding habits of these intriguing invertebrates.

Evaluating the response of Different Chemical and Organic Fertilizers on Carrot Vegetative and Reproductive Characteristics in Gothgaun, Nepal

This research aimed to assess the influence of various chemical and organic fertilizers on the vegetative and reproductive characteristics of the New Kuroda variety of carrots (Dacus Carota). The study included the recommended NPK dose (80:60:60 kg/ha), individual components of N (80 kg/ha), P (60 kg/ha), K (60 kg/ha), as well as organic sources such as goat manure (15 t/ha), FYM (20 t/ha), and a control group without any fertilizer. Measurements of growth and reproductive traits were taken at 45, 55, 65, 75, and 85 days post-sowing. Results indicated that the recommended NPK dose consistently outperformed other fertilizer sources in enhancing both vegetative and reproductive parameters. The highest yield of 10.94 tons/ha was achieved with NPK fertilizer, while organic sources like goat manure demonstrated the second-highest growth and development traits. The control group exhibited the lowest growth and development parameters. These results show that these fertiliser sources have a considerable favourable influence on the vegetative and reproductive development of the New Kuroda carrot variety. The outcomes indicate how various fertiliser sources may significantly improve the vegetative and reproductive development of the New Kuroda carrot; the recommended dosage of NPK in conjunction with the supply of goat manure fertilizer stands out as very appropriate techniques for producing carrots. This illustrates how applying a balanced dosage of these fertilisers may lead to increased carrot yield.

Granulated fertilizers are more efficient in reducing potassium leaching losses than combining biosolids with inorganic sources

ABSTRACT Widespread use of soluble mineral fertilizers derived from non-renewable sources has raised concerns about environmental impacts, energy expenditures, and sustainability. Combining biosolid and mineral sources of phosphorus and potassium to produce organomineral fertilizers (OMF) can be used as an alternative nutrient source while reducing the environmental impact of sewage residues. As this approach simultaneously provides nutrients and incorporates organic matter, we hypothesized the presence of an organic source (biosolid) granulated with mineral sources of potassium (K) and phosphorus (P) would reduce leaching due to the benefits of the organic source and the slower release caused by granulation. Our goal was to evaluate the effect of different OMFs on the leaching losses of nutrients. Two forms of isolated N, P, and K sources (granulated and non-granulated), five OMFs with different NPK proportions (1-2-0, 1-4-0, 1-0-2, 1-2-2, 1-2-4), and a control (unfertilized) were evaluated over ten weeks in a leaching column experiment. Non-granulated potassium sulfate exhibited the highest K leaching and did not differ from OMFs with K in their formulation (granulated PS, 1-0-2, 1-2-2, and 1-4-2). Planned contrasts showed that granulation was particularly effective at reducing K leaching, resulting in a 70 % reduction compared to non-granulated PS. While formulation and granulation showed a trend of potential benefits in reducing N-(NO 3 - + NO 2 - ) leaching, the effect was not statistically significant. Interaction between fertilizer treatments and leaching events was marginally significant for NH 4 + leaching, indicating temporal variations of OMFs in nutrient dynamics may be influenced by mineralization. As granulation modulated how OMFs affected nutrient leaching dynamics, this highlights the importance of the physical characteristics of fertilizers for effective nutrient management.

Stochastic modelling of development and biomass allocation: Computation applied to architecture of young mahogany trees (Khaya senegalensis Desr. A. Juss), a native African savannah emblematic agroforestry species

The architectural plasticity forms observed in trees is a result of meristem functioning, which generates new organs and branches, and adjusts growth processes in response to heterogeneous climatic adaptations that affect biomass allocation. Analyzing this plasticity should enable the selection of adapted individuals for optimizing successful cropping systems. Mahogany tree (Khaya senegalensis) is a rhythmically growing indigenous agroforestry tree that is heavily exploited for its multiple uses. Understanding its growth characteristics, as well as the complexity of its structure (randomness, rhythmicity, etc. of Mahogany tree), could facilitate its conservation and sustainable management. This study aims to model the architecture and physiology of young mahogany trees based on field data using an organ-level structural–functional model called 'GreenLab', which is founded on source-sink relationships. Ninety trees aged 6, 12, and 24 months were measured in the field. Development was calculated using a dual-scale automaton based on the Monte Carlo process, while biomass production and its distribution to different plant organs (source and sink) were calibrated using Pressler's law using Markov chains. Meristematic activity laws, combined with organ sinks (D: Demand), photosynthesis (Q: Supply), and organic series (Q/D: Trophic pressure), were employed to simulate individual architecture. The results demonstrate that the model realistically and flexibly describes topological development and replicates biomass production and allocation processes for rhythmically growing trees. This model will enable the identification of mahogany ideotypes suited for enhancing agroforestry cropping systems based on this species and several other threatened species. These findings introduce and thus lay the groundwork for a computational plant model tailored to the needs of agroforestry from a novel perspective, offering new avenues for agronomic and forestry applications in West Africa and Côte d'Ivoire.

Organic carbon utilisation by the filamentous alga Tribonema

Filamentous algae have potential application to wastewater treatment, in particular for efficient recovery of nutrients into biomass. However, supplying inorganic carbon is a major limiting factor. The utilisation of organic carbon present in wastewater may reduce the constraints in carbon supply, however there is little knowledge of mixotrophic growth amongst filamentous algae. This study investigated the utilisation of organic carbon sources relevant to wastewater by the filamentous xanthophyte alga Tribonema. Algae growth was compared in the absence of organic carbon (autotrophic) and in presence of 0.2 g-C L-1 glucose, ethanol or acetate under mixotrophic (presence of organic carbon and light) or heterotrophic (presence of organic carbon and absence of light) conditions. To investigate direct utilisation of organic carbon and indirect utilisation via bacterial CO2-genesis, cultivation was performed under both axenic and non-axenic conditions. Tribonema was found to directly utilise glucose, which increased mixotrophic productivity and maintained growth under heterotrophic conditions. In contrast, acetate was only indirectly utilised mixotrophically in the presence of bacteria, whereas ethanol was not utilised under any conditions. The underlying mechanisms of glucose utilisation by Tribonema were also investigated by analysing its photosynthetic rate and respiration rate under glucose concentrations ranging from 0 – 100 g L-1. Based on the results, enhancements to metabolic pathways and reduced CO2 requirements provided by glucose utilisation were proposed. Despite the positive results with respect to glucose utilisation, out competition for this resource by bacteria suggest that Tribonema is more suitable for treatment of wastewater with low organic carbon concentrations, such as secondary-treated wastewater effluent.