Nutrient solution

Nahr-vorrat, m. reserve food, -wasser, n. nutrient solution, -wert, m. nutritive value, food value. 

After two days of culturing at 25°C under stirring (220 revolutions per minute) and ventilating (1.65 m /hr), 18 liters of the obtained culture are removed under sterile conditions and introduced into a fermenter of the same size charged with 28.2 liters of a nutrient solution containing ... 

For this purpose a fermenter made of stainless steel having a 50 liter capacity is charged with 30 liters of a nutrient solution of 0.1% yeast extract, 0.5% cornsteep and 0.2% glucose, heated for one-half hour at 120°C for sterilization purposes, and after cooling, inoculated with a bacterial suspension of Bacillus lentus MS 2B4. 

As described in U.S. Patent 2,929,763, methandrostenolone may be made by a fermentation route. 2 g of sodium nitrate, 1 g of primary potassium orthophosphate, 0.5 g of magnesium sulfate heptahydrate, 0.5 g of potassium chloride, 50 g of glucose and 1 g of Difco yeast extract are dissolved in one liter of tap water, brought to pH 5 by addition of a sodium hydroxide solution and sterilized. The resulting nutrient solution is inoculated with 50 cc of a 4-day-old shaking culture of Didyniel/a lycopersici and shaken for 48 hours at 27 C, whereby the culture becomes well developed. 

Nutrient solutions used in intravenous feeding must be isotonic with blood that is, they must have the same osmotic pressure as blood. If the solution is too dilute, its osmotic pressure will be less than that of the fluids inside blood cells in that case, water will flow into the cell until it bursts. Conversely, if the nutrient solution has too high a concentration of solutes, water will flow out of the cell until it shrivels and dies. 

Although it is possible to obtain cells from whole animals or plants and to cultivate them in suitable nutrient solutions, in general they are not as easy to handle as microbes. Nevertheless, plant and animal cells are a valuable genetic resource for biotechnology and many newly developed bioprocesses rely on transfer of their genes to micro-organisms. 

The simplest devices have rakes mounted on the stirrer shaft located on the surface of the liquid. A more sophisticated device is the Funda-foam system , in which the foam is destroyed by centrifugal forces. The nutrient solution held in the foam flows back into the bioreactor, and the air released from the foam leaves the vessel. 

Take a loop full of the creamy culture off the agar plate. Dip the loop into a 250 ml flask containing 100ml of 5.0g-l 1 glucose and 1 g-1 1 yeast extract. Swirl the loop in the nutrient solution to dislodge the selected culture from the loop. 

The technology is based on the addition of low concentrations of a water-soluble nutrient solution that selectively stimulates the growth of an indigenous microbial population, thereby inhibiting the detrimental sulfate-reducing bacteria population that causes the generation of H2S. This deliberate and controlled modification of the microflora and reservoir ecology has been termed biocompetitive exclusion [835,1548]. 

B. licheniformis JF-2 and Clostridium acetogutylicum were investigated under simulated reservoir conditions. Sandstone cores were equilibrated to the desired simulated reservoir conditions, saturated with oil and brine, and flooded to residual oil saturation. The waterflood brine was displaced with a nutrient solution. The MEOR efficiency was directly related to the dissolved gas/oil ratio. The principal MEOR mechanism observed in this work was solution gas drive [505]. 

Table 4 Release of Reducing Root Exudates (e.g., Phenolics) by Peanut Plants as Affected by Fe Nutritional Status and Short-Term (10 h) Supply of a mMl-containing nutrient solution...

N form in nutrient solution pH of the nutrient solution after 10 h Reducing substances in the nutrient solution (nmol caffeic acid equivalents 10 h g root fresh weight] ... 

R. Schonwitz and H. Ziegler, Exudation of water soluble vitamins and some carbohydrates by intact roots of maize seedlings Zea mays L.) into a mineral nutrient solution. Z. Planzenphysiol. 107 1 (1982). 

P. Imas, B. Bar-Yosef, U. Kakafi, and R. Ganmore-Neumann, Carboxylic anions and proton secretion by tomato roots in response to ammonium/nitrate ratio and pH in nutrient. solution. Plant Soil 191 (1997). 

Z. Rengel and D. Graham, Uptake of zinc from chelate-buffered nutrient solutions by wheat genotypes differing in zinc efficiency. J. E.xp. Bat. 47 217 (1996). 

G. Cieslinski, K. C. J. Van Rees, and P. M. Huang. Low molecular weight organic-acids released from roots of durum wheat and flax into sterile nutrient solutions. Journal of Plant Nutrition 20 753 (1997). 

S. Prat and R. Retovsky, Root excretion in nutrient solution, Vestnik Krai. Ces spol. Nauk. 1-19(1944). 

J. C. Lobartini and G. A. Orioli, Adsorption of iron Fe-humate in nutrient. solution by plants. Plant Soil 706 153 (1988). 

Table 2 Changes in Plant Growth Parameter in Response to Iron Stress for Barley Plants Grown in Chelator Buffered Hydroponic Nutrient Solutions...

Experiments to examine rhizodeposition can vary markedly in scale and complexity depending on the information required, the equipment available, and the plants concerned. In general, experiments to study exudates and other material lost from young roots are the simplest and are carried out in the laboratory under controlled conditions. Plants are grown in nutrient solution culture, sometimes with sand or other solid support systems, and compounds released into the culture solution are collected and analyzed chemically. The experiments are mainly short-term and the roots can be kept sterile if required. Techniques are also available to label plants growing in these systems with C and to monitor the presence of the isotopes in the rhizodeposits. 

Seeds can be placed in water, and as imbibition occurs, the materials lost from seeds can be collected and analyzed qualitatively and quantitatively (10). Once germinated, seeds are commonly placed on some form of grid or support above the nutrient solution and, as the roots grow in the nutrient solution, it can be collected at intervals and the rhizodeposits analyzed. Seeds are often surface-sterilized to prevent utilization or alteration of the materials derived from the seed by contaminating microorganisms (e.g.. Ref. 11). 

The ability to change and control the composition of the nutrient solution and the relatively small size of the microcosms used enables manipulation of environmental variables and time-course studies of rhizodeposition to be made relatively easily. The influence of nutrient availability, mechanical impedance, pH, water availability, temperature, anoxia, light intensity, CO2 concentration, and microorganisms have all been examined within a range of plant species (9). A few examples to illustrate the continued interest in examining the effect of such variables on rhizodeposition in nutrient culture are given in Table 1. 

Rather than measuring rhizodeposition in nutrient. solutions chemically, another approach has been to expose shoots to COi for a short period of time and to follow the spread of the through the plant, into the roots, and then into the nutrient solution. Kinetics of carbon flow and quantification of rhizodeposition can then be obtained (e.g.. Ref. 24). Advantages and limitations of this approach are discussed more fully in Sec. II.C. 

Rhizodeposition in nutrient solution culture is relatively easy to measure and readily altered. It may not reflect what happens in vivo due to the absence of a solid substratum for root growth. Simply including glass beads in nutrient solution can significantly increase rhizodeposition in maize (16), and such an effect must be considered when estimating rhizodeposition in relation to the natural environment. Consequently, a range of systems using various solid supports have been developed. Rhizodeposition in soil is considered in Sect. II.C. 

Various bioassay methods have been used to detect the "natural" release of allelopathic agents. Sane authors preferred, after partial purification, to assay the extracts by petri dish methods for gemination, growth of roots or shoots and other symptoms of seedlings. The bioassays also included tests in soil or sand and also in nutrient solution (Table 3). 

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