نتایج جستجو برای: nitrate nitrogen content

تعداد نتایج: 546641  

2016
Peter Stief Anja Kamp Bo Thamdrup Ronnie N. Glud

In the world's oceans, even relatively low oxygen levels inhibit anaerobic nitrogen cycling by free-living microbes. Sinking organic aggregates, however, might provide oxygen-depleted microbial hotspots in otherwise oxygenated surface waters. Here, we show that sinking diatom aggregates can host anaerobic nitrogen cycling at ambient oxygen levels well above the hypoxic threshold. Aggregates wer...

Journal: :Tree physiology 1996
Matthew H. Turnbull Susanne Schmidt Peter D. Erskine Suanne Richards George R. Stewart

The capacity for nitrate reduction, as measured by nitrate reductase activity (NRA), was generally low for a range of plant communities in Australia (coastal heathland, rainforest, savanna woodland, monsoon forest, mangrove, open Eucalyptus forest, coral cay open forest) and only a loose relationship existed between NRA and leaf nitrogen concentration. This suggests that nitrate ions are not th...

ژورنال: علوم آب و خاک 2013
سید مجید میرلطیفی, , ملیحه ربیع, , مهدی قیصری, ,

Nitrate leaching from agricultural lands can pollute groundwater, and the degree of pollution caused significantly depends on agricultural practices implemented on farms. Field studies required to evaluate the effects of various agricultural management strategies on nitrate leaching are expensive and time consuming. As a result, it is suggested to use crop models to simulate the effects of mana...

Increasing nitrogen absorption efficiency reduces use of excessive application of N. The effect of rootzone temperature on nitrogen absorption needs clarification. The experiment was conducted to investigate low (15°C, RTZ1), high (35°C, RTZ2) and optimum (25°C, RTZ3) root zone temperatures and nitrogen 52.5 (ND1), 78.75 (ND2) and 105 (ND0) mg∙L-1 levels on cucumber (Cucumis sativus L.), cv. Su...

Journal: :Plant physiology 1983
K Mengel P Robin L Salsac

The effect of nitrogen form (NH(4)-N, NH(4)-N + NO(3) (-), NO(3) (-)) on nitrate reductase activity in roots and shoots of maize (Zea mays L. cv INRA 508) seedlings was studied. Nitrate reductase activity in leaves was consistent with the well known fact that NO(3) (-) increases, and NH(4) (+) and amide-N decrease, nitrate reductase activity. Nitrate reductase activity in the roots, however, co...

Journal: :Biochemical Society transactions 2011
Víctor M Luque-Almagro Andrew J Gates Conrado Moreno-Vivián Stuart J Ferguson David J Richardson M Dolores Roldán

In the context of the global nitrogen cycle, the importance of inorganic nitrate for the nutrition and growth of marine and freshwater autotrophic phytoplankton has long been recognized. In contrast, the utilization of nitrate by heterotrophic bacteria has historically received less attention because the primary role of these organisms has classically been considered to be the decomposition and...

Journal: :iranian journal of environmental technology 0
badri fazeli m.sc. of microbiology, university of isfahan, iran giti emtiazi professor of microbiology, university of isfahan, iran

denitrification is a reduction of nitrate by heterotrophic and autotrophic bacteria that may ultimately produce molecular nitrogen (n2) through a series of intermediate nitrogen compounds.vermiculite is a hydrous phyllosilicate mineral (mg, fe+2,fe+3)3[(al,si)4o10](oh)2·4h2o with several layers for bacterial immobilization. the goal of this study was removal of nitrate from water with vermiculi...

2013
Chrystalla Antoniou Panagiota Filippou Photini Mylona Dionysia Fasoula Ioannis Ioannides Alexios Polidoros Vasileios Fotopoulos

Nitric oxide (NO) is a bioactive molecule involved in numerous biological events that has been reported to display both pro-oxidant and antioxidant properties in plants. Several reports exist which demonstrate the protective action of sodium nitroprusside (SNP), a widely used NO donor, which acts as a signal molecule in plants responsible for the expression regulation of many antioxidant enzyme...

Journal: :Plant physiology 1980
J R Manhart P P Wong

The effect of nitrate on symbiotic nitrogen fixation by root nodules of cowpea (Vigna unguiculata L., Walp., cv. California Blackeye) and lupine (Lupinus augustifolius L., cv. Frost) plants inoculated with nitrate reductase-expressing and nitrate reductase-nonexpressing Rhizobium strains were examined. Nitrate reductase of Rhizobium bacteroids in the nodules of cowpea and lupine reduced nitrate...

Journal: :Plant physiology 2015
Eleodoro Riveras José M Alvarez Elena A Vidal Carolina Oses Andrea Vega Rodrigo A Gutiérrez

Understanding how plants sense and respond to changes in nitrogen availability is the first step toward developing strategies for biotechnological applications, such as improvement of nitrogen use efficiency. However, components involved in nitrogen signaling pathways remain poorly characterized. Calcium is a second messenger in signal transduction pathways in plants, and it has been indirectly...

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