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This paper looked at the leaf architecture characteristics of Vachellia tortilis to determine if either there is or not an effect of the tropic line on plants. Vachellia tortilis leaves were sampled along a national road (N1) in Limpopo province. Sampling points were set 10 km apart away from the Tropic of Capricon in opposite directions. Leaf morphology revealed that leaves of V. tortilis are bipinnately compound with alternate arrangement. The venation pattern of the pinnules was eucamptodromus and brochidodromous with imperfect reticulation. Areoles were imperfect and pentagonal or irregular in shape. 相似文献
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Satish P. RamachandraRao Michael A. Matthias Chanthel Kokoy-Mondrogon Eamon Aghania Cathleen Park Casey Kong Michelle Ishaya Assael Madrigal Jennifer Horng Roni Khoshaba Anousone Bounkhoun Fabrizio Basilico Antonella De Palma Anna Maria Agresta Linda Awdishu Robert K. Naviaux Joseph M. Vinetz Pierluigi Mauri 《PLoS neglected tropical diseases》2015,9(4)
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Marcel GA van der Heijden Susanne de Bruin Ludo Luckerhoff Richard SP van Logtestijn Klaus Schlaeppi 《The ISME journal》2016,10(2):389-399
Highly diverse microbial assemblages colonize plant roots. It is still poorly understood whether different members of this root microbiome act synergistically by supplying different services (for example, different limiting nutrients) to plants and plant communities. In order to test this, we manipulated the presence of two widespread plant root symbionts, arbuscular mycorrhizal fungi and nitrogen-fixing rhizobia bacteria in model grassland communities established in axenic microcosms. Here, we demonstrate that both symbionts complement each other resulting in increased plant diversity, enhanced seedling recruitment and improved nutrient acquisition compared with a single symbiont situation. Legume seedlings obtained up to 15-fold higher productivity if they formed an association with both symbionts, opposed to productivity they reached with only one symbiont. Our results reveal the importance of functional diversity of symbionts and demonstrate that different members of the root microbiome can complement each other in acquiring different limiting nutrients and in driving important ecosystem functions. 相似文献
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DOMINIK LERMEN BRUNHILDE BLÖMEKE ROBERT BROWNE ANN CLARKE PAUL W. DYCE THOMAS FIXEMER GÜNTER R. FUHR WILLIAM V. HOLT KATARINA JEWGENOW RHIANNON E. LLOYD STEFAN LÖTTERS MARTIN PAULUS GORDON MCGREGOR REID DANIEL H. RAPOPORT DAVID RAWSON JENNIFER RINGLEB OLIVER A. RYDER GABRIELE SPÖRL THOMAS SCHMITT MICHAEL VEITH PAUL MÜLLER 《Molecular ecology》2009,18(6):1030-1033
Cryobanking, the freezing of biological specimens to maintain their integrity for a variety of anticipated and unanticipated uses, offers unique opportunities to advance the basic knowledge of biological systems and their evolution. Notably, cryobanking provides a crucial opportunity to support conservation efforts for endangered species. Historically, cryobanking has been developed mostly in response to human economic and medical needs — these needs must now be extended to biodiversity conservation. Reproduction technologies utilizing cryobanked gametes, embryos and somatic cells are already vital components of endangered species recovery efforts. Advances in modern biological research (e.g. stem cell research, genomics and proteomics) are already drawing heavily on cryobanked specimens, and future needs are anticipated to be immense. The challenges of developing and applying cryobanking for a broader diversity of species were addressed at an international conference held at Trier University (Germany) in June 2008. However, the magnitude of the potential benefits of cryobanking stood in stark contrast to the lack of substantial resources available for this area of strategic interest for biological science — and society at large. The meeting at Trier established a foundation for a strong global incentive to cryobank threatened species. The establishment of an Amphibian Ark cryobanking programme offers the first opportunity for global cooperation to achieve the cryobanking of the threatened species from an entire vertebrate class. 相似文献
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Sodium balance determines the extracellular fluid volume and sets arterial blood pressure (BP). Chronically raised BP (hypertension)
represents a major health risk in Western societies. The relationship between BP and renal sodium excretion (the pressure/natriuresis
relationship) represents the key element in defining the BP homeostatic set point. The renin–angiotensin–aldosterone system
(RAAS) makes major adjustments to the rates of renal sodium secretion, but this system works slowly over a period of hours
to days. More rapid adjustments can be made by the sympathetic nervous system, although the kidney can function well without
sympathetic nerves. Attention has now focussed on regulatory mechanisms within the kidney, including extracellular nucleotides
and the P2 receptor system. Here, we discuss how extracellular ATP can control renal sodium excretion by altering the activity
of epithelial sodium channels (ENaC) present in the apical membrane of principal cells. There remains considerable controversy
over the molecular targets for released ATP, although the P2Y2 receptor has received much attention. We review the available data and reflect on our own findings in which ATP-activated
P2Y and P2X receptors make adjustments to ENaC activity and therefore sodium excretion. 相似文献
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