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AbstractThe Fram Strait is the only deep gateway between the Arctic Ocean and the Nordic Seas and thus is a key area to study past changes in ocean circulation and the marine carbon cycle. Here, we study deep ocean temperature, δ18O, carbonate chemistry (i.e., carbonate ion concentration [CO32−]), and nutrient content in the Fram Strait during the late glacial (35,000–19,000 years BP) and the Holocene based on benthic foraminiferal geochemistry and carbon cycle modeling. Our results indicate a thickening of Atlantic water penetrating into the northern Nordic Seas, forming a subsurface Atlantic intermediate water layer reaching to at least ∼2,600 m water depth during most of the late glacial period. The recirculating Atlantic layer was characterized by relatively high [CO32−] and low δ13C during the late glacial, and provides evidence for a Nordic Seas source to the glacial North Atlantic intermediate water flowing at 2,000–3,000 m water depth, most likely via the Denmark Strait. In addition, we discuss evidence for enhanced terrestrial carbon input to the Nordic Seas at ∼23.5 ka. Comparing our δ13C and qualitative [CO32−] records with results of carbon cycle box modeling suggests that the total terrestrial CO2 release during this carbon input event was low, slow, or directly to the atmosphere.

Endophytes and rhizospheric microorganisms support invasive species’ adaptation to environmental stresses. Here, we review the impacts of endophytes, rhizospheric microbes (particularly symbiotic nitrogen-fixers), mycorrhiza and pathogens on plant invasion in arid and semi-arid areas. Endophytes and soil microorganisms either enhance nutrient acquisition for enhancing the invasive plant immune system and/or negatively affect native plants. In addition, the positive feedback between mycorrhizal fungi and invasive plants enhances the competitive ability of the aliens, providing them more opportunities for success, establishment, and dominance. The microbes and their secondary metabolites promote invasive plant species by changing soil microbial community structure and carbon biomass as well as enzyme activity, which improves soil properties and processes. The negative impact of invasive exotic plants on the associated biota and the role of allelochemicals are also discussed. It could be concluded that endophytes interact with rhizosphere microbes to promote invasive plant species in arid and semi-arid areas in a way similar to what happens in other ecosystems; the differences are in the pathways and reactions, which depend upon the prevailing abiotic factors. More interdisciplinary field experiments integrating microbial, biotechnological, and molecular approaches are needed to understand the role of symbiotic microbes in invasion biology.

Plant growth regulators are naturally biosynthesized chemicals in plants that influence physiological processes. Their synthetic analogous trigger numerous biochemical and physiological processes involved in the growth and development of plants. Nowadays, due to changing climatic scenario, numerous biotic and abiotic stresses hamper seed germination, seedling growth, and plant development leading to a decline in biological and economic yields. However, plant growth regulators (PGRs) can potentially play a fundamental role in regulating plant responses to various abiotic stresses and hence, contribute to plant adaptation under adverse environments. The major effects of abiotic stresses are growth and yield disturbance, and both these effects are directly overseen by the PGRs. Different types of PGRs such as abscisic acid (ABA), salicylic acid (SA), ethylene (ET), and jasmonates (JAs) are connected to boosting the response of plants to multiple stresses. In contrast, PGRs including cytokinins (CKs), gibberellins (GAs), auxin, and relatively novel PGRs such as strigolactones (SLs), and brassinosteroids (BRs) are involved in plant growth and development under normal and stressful environmental conditions. Besides, polyamines and nitric oxide (NO), although not considered as phytohormones, have been included in the current review due to their involvement in the regulation of several plant processes and stress responses. These PGRs are crucial for regulating stress adaptation through the modulates physiological, biochemical, and molecular processes and activation of the defense system, upregulating of transcript levels, transcription factors, metabolism genes, and stress proteins at cellular levels. The current review presents an acumen of the recent progress made on different PGRs to improve plant tolerance to abiotic stress such as heat, drought, salinity, and flood. Moreover, it highlights the research gaps on underlying mechanisms of PGRs biosynthesis under stressed conditions and their potential roles in imparting tolerance against adverse effects of suboptimal growth conditions.

The impact of climate change on biodiversity has been the subject of numerous research in recent years. The multiple elements of climate change are expected to affect all levels of biodiversity, including microorganisms. The common worldwide fungus Fusarium oxysporum colonizes plant roots as well as soil and several other substrates. It causes predominant vascular wilt disease in different strategic crops such as banana, tomato, palm, and even cotton, thereby leading to severe losses. So, a robust maximum entropy algorithm was implemented in the well-known modeling program Maxent to forecast the current and future global distribution of F. oxysporum under two representative concentration pathways (RCPs 2.6 and 8.5) for 2050 and 2070. The Maxent model was calibrated using 1885 occurrence points. The resulting models were fit with AUC and TSS values equal to 0.9 (±0.001) and 0.7, respectively. Increasing temperatures due to global warming caused differences in habitat suitability between the current and future distributions of F. oxysporum, especially in Europe. The most effective parameter of this fungus distribution was the annual mean temperature (Bio 1); the two-dimensional niche analysis indicated that the fungus has a wide precipitation range because it can live in both dry and rainy habitats as well as a range of temperatures in which it can live to certain limits. The predicted shifts should act as an alarm sign for decision makers, particularly in countries that depend on such staple crops harmed by the fungus.

Jatropha curcas L. (Jatropha), une espèce arbustive de la famille des Euphorbiaceae, a été reconnue comme une usine de biocarburants prometteuse pour réduire les émissions de gaz à effet de serre. Cependant, les récentes tentatives de culture commerciale en Afrique et en Asie ont échoué en raison de la faible productivité. Il est important d'élucider la diversité génétique et la relation dans les ressources génétiques mondiales de Jatropha pour la sélection de meilleurs cultivars commerciaux. Ici, la diversité génétique a été analysée en utilisant 246 accessions de la Méso-Amérique, de l'Afrique et de l'Asie, sur la base de 59 marqueurs de répétition de séquence simple et de huit marqueurs de polymorphisme d'insertion à base de rétrotransposons. Nous avons constaté que le Chiapas central du Mexique possède les ressources génétiques les plus diverses, et la dépression centrale du Chiapas pourrait être le centre d'origine. Nous avons identifié trois groupes génétiques en Méso-Amérique, dont la répartition a révélé un cline géographique distinct. L'un d'eux consiste principalement en des adhésions du centre du Chiapas. Cela suggère qu'il représente le groupe génétique d'origine. Nous avons trouvé deux accessions Veracruz dans un autre groupe, dont les ancêtres pourraient être expédiés du port de Veracruz vers l'Ancien Monde, pour être la source de tous les Jatropha africains et asiatiques. Nos résultats suggèrent la sélection humaine qui a causé une faible productivité en Afrique et en Asie, ainsi que des stratégies de sélection pour améliorer le jatropha africain et asiatique. Les cultivars améliorés dans la productivité contribueront à développer la culture commerciale de masse du Jatropha en Afrique et en Asie pour augmenter la production de biocarburants, et enfin soutiendront la lutte contre le changement climatique. Jatropha curcas L. (Jatropha), una especie de arbusto de la familia Euphorbiaceae, ha sido reconocida como una planta de biocombustible prometedora para reducir las emisiones de gases de efecto invernadero. Sin embargo, los recientes intentos de cultivo comercial en África y Asia han fracasado debido a la baja productividad. Es importante dilucidar la diversidad genética y la relación en los recursos genéticos mundiales de Jatropha para la reproducción de mejores cultivares comerciales. Aquí, se analizó la diversidad genética mediante el uso de 246 accesiones de Mesoamérica, África y Asia, basadas en 59 marcadores de repetición de secuencia simple y ocho marcadores de polimorfismo de inserción basados en retrotransposones. Encontramos que el centro de Chiapas de México posee los recursos genéticos más diversos, y la Depresión Central de Chiapas podría ser el centro de origen. Identificamos tres grupos genéticos en Mesoamérica, cuya distribución reveló un clino geográfico distinto. Uno de ellos consiste principalmente en accesiones desde el centro de Chiapas. Esto sugiere que representa el grupo genético original. Encontramos dos accesiones de Veracruz en otro grupo, cuyos antepasados podrían ser enviados desde el Puerto de Veracruz al Viejo Mundo, para ser la fuente de toda la jatrofa africana y asiática. Nuestros resultados sugieren la selección humana que causó la baja productividad en África y Asia, y también estrategias de cría para mejorar la jatrofa africana y asiática. Los cultivos mejorados en la productividad contribuirán a expandir el cultivo comercial masivo de Jatropha en África y Asia para aumentar la producción de biocombustibles, y finalmente apoyarán en la batalla contra el cambio climático. Jatropha curcas L. (Jatropha), a shrub species of the family Euphorbiaceae, has been recognized as a promising biofuel plant for reducing greenhouse gas emissions. However, recent attempts at commercial cultivation in Africa and Asia have failed because of low productivity. It is important to elucidate genetic diversity and relationship in worldwide Jatropha genetic resources for breeding of better commercial cultivars. Here, genetic diversity was analyzed by using 246 accessions from Mesoamerica, Africa and Asia, based on 59 simple sequence repeat markers and eight retrotransposon-based insertion polymorphism markers. We found that central Chiapas of Mexico possesses the most diverse genetic resources, and the Chiapas Central Depression could be the center of origin. We identified three genetic groups in Mesoamerica, whose distribution revealed a distinct geographic cline. One of them consists mainly of accessions from central Chiapas. This suggests that it represents the original genetic group. We found two Veracruz accessions in another group, whose ancestors might be shipped from Port of Veracruz to the Old World, to be the source of all African and Asian Jatropha. Our results suggest the human selection that caused low productivity in Africa and Asia, and also breeding strategies to improve African and Asian Jatropha. Cultivars improved in the productivity will contribute to expand mass commercial cultivation of Jatropha in Africa and Asia to increase biofuel production, and finally will support in the battle against the climate change. Jatropha curcas L. (Jatropha)، وهو نوع من الشجيرات من عائلة Euphorbiaceae، تم الاعتراف به كمصنع واعد للوقود الحيوي لتقليل انبعاثات غازات الدفيئة. ومع ذلك، فشلت المحاولات الأخيرة للزراعة التجارية في أفريقيا وآسيا بسبب انخفاض الإنتاجية. من المهم توضيح التنوع الوراثي والعلاقة في الموارد الوراثية للجاتروفا في جميع أنحاء العالم لتربية أصناف تجارية أفضل. هنا، تم تحليل التنوع الجيني باستخدام 246 ملحقًا من أمريكا الوسطى وأفريقيا وآسيا، استنادًا إلى 59 علامة تكرار تسلسل بسيطة وثمانية علامات تعدد أشكال الإدراج القائمة على الترانسبروسون. وجدنا أن وسط تشياباس في المكسيك يمتلك الموارد الجينية الأكثر تنوعًا، ويمكن أن يكون الكساد المركزي في تشياباس هو مركز المنشأ. حددنا ثلاث مجموعات وراثية في أمريكا الوسطى، والتي كشف توزيعها عن سلالة جغرافية متميزة. يتكون أحدها بشكل أساسي من المنضمين من وسط تشياباس. هذا يشير إلى أنه يمثل المجموعة الوراثية الأصلية. وجدنا انضمامين لفيراكروز في مجموعة أخرى، قد يتم شحن أسلافهم من ميناء فيراكروز إلى العالم القديم، ليكونوا مصدر كل الجاتروفا الأفريقية والآسيوية. تشير نتائجنا إلى الانتقاء البشري الذي تسبب في انخفاض الإنتاجية في أفريقيا وآسيا، وكذلك استراتيجيات التكاثر لتحسين الجاتروفا الأفريقية والآسيوية. ستساهم الأصناف المحسنة في الإنتاجية في توسيع الزراعة التجارية الجماعية للجاتروفا في إفريقيا وآسيا لزيادة إنتاج الوقود الحيوي، وأخيرًا ستدعم المعركة ضد تغير المناخ.

Given crude oil prices and their environmental impacts, the use of sustainable renewable alternative energies such as biofuels is rapidly progressing in numerous countries. Among biofuels, bioethanol is a renewable and clean fuel that can be obtained from the fermentation of several raw agricultural materials, including date fruit. However, the low product yield, mainly due to the low-grade nutrient content, limits its use as a promising alternative biofuel. This current study investigated bioethanol production from date by-products in Saudi Arabia and examined the impact of calcium and nitrogen sources added at different concentrations (0 to 1 g/L) on the productivity and ethanol concentration using Saccharomyces cerevisiae. Yeast extracts and ammonium chloride (NH4Cl) were tested as nitrogen sources for bioethanol fermentation from date juice. Calcium chloride (CaCl2) and calcium carbonate (CaCO3) were evaluated as calcium sources for the same purpose mentioned above. The results showed that both calcium and nitrogen sources improved ethanol production efficiencies. The addition of calcium sources such as CaCl2 at 0.4 g/L resulted in maximum ethanol concentration (41.5 ± 0.85 g/L) and the highest productivity of 0.511 g/L/h. Thus, an increase of 31.3% compared to the control sample was acquired. Ammonium chloride was found to be the best nitrogen supplement among them. Indeed, supplementing the fermentation medium with 1 g/L NH4Cl gave an optimal ethanol concentration and productivity, reaching more than 65 g/L and 0.83 g/L/h, respectively. This is an increase of 106.6%. The functional group of ethanol (C2H5OH) for all the elaborated samples was confirmed by Fourier-transform infrared spectroscopy (FTIR) and NMR analyses. Moreover, the results confirmed the high quality and purity of the bioethanol products. Thus, the “Khodhari” date variety of low market value is a privileged substrate for industrial bioethanol production. For this reason, a proposed flow diagram of a designed plant for bioethanol industrialization is provided and detailed.