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21.
Abstract. Maintenance of realistically low solution P concentrations under controlled conditions is a major difficulty in studies of P nutrition. In this report, we describe a relatively simple and economical sand culture system capable of sustaining plant growth to maturity under controlled yet realistic P regimes. The system uses Al2 O3 as a solid-phase P buffer, and modern process control technology to control irrigation and addition of other mineral nutrients. Aspects of the design, use and potential applications of automated solid-phase systems are discussed. The system was used to grow Phaseolus vulgaris to matarity at 0.4 mmol m3 , 1.0 mmol m3 and 27 mmol m3 P with and without mycorrhizal inoculation. At flowering, low solution P concentrations were associated with reduced leaf concentrations of P in nonmycorrhizal plants, and reduced leaf concentrations of Ca in both mycorrhizal and nonmycorrhizal plants. Mycorrhizal inoculation increased leaf P, K, Mg and Mn concentrations, but reduced leaf N concentration. Low P regimes reduced final seed yield by diminishing both the number of pods per plant and the number of seeds per pod. Mycorrhizal inoculation significantly enhanced seed yield under low P regimes by increasing seed weight, the number of pods per plant, and the number of seeds per pod. 相似文献
22.
We designed an Integrated Media Preparation System (IMPS) for continuous, on-line preparation of cell culture media and delivery to intermediate storage vessels or directly to a bioreactor. Key components of the IMPS include: a high precision, continuous fluid mixing device; formulation-specific liquid medium concentrates; validated process controls and membrane filtration; and automated dispensing into large volume flexible plastic containers. The IMPS system is designed to produce sterile, single-strength liquid medium from common raw materials at a delivery rate of 1000–3000 liters per hour and will manufacture homogenous batches from several thousand liters to over 60,000 liters. Fortified nutrient media prepared from multi-component 50X concentrates have been demonstrated to accelerate bioreactor seed chains, increase product yield, and reduce the overall manufacturing cost of nutrient medium. A productivity matrix will analyze the fully-loaded costs and contrast alternative methods for media preparation against projected biological yield.Abbreviations IMPS
Integrated Media Preparation System
- 50X
Nutrient fluid components formulated at fifty-fold final use concentration
- 1X
Nutrient fluid formulated at final, single-strength use concentration
- cGMP
Current Good Manufacturing Practices
- SCADA
Supervisory Control and Data Acquisition
- PLC
Process Logic Controller
- LTI
Life Technologies, Inc.
- WFI
Water for Injection
- CIP
Clean in place
- SIP
Sterilize in place
- HPLC
High performance liquid chromatography
- DMEM
Dulbecco's Modified Eagle's Medium 相似文献
23.
Morphological variability of geographically distinct populations of the estuarine copepod Acartia Tonsa 总被引:1,自引:1,他引:0
Garmew Tanya G. Hammond Susan Mercantini Amy Morgan Jessica Neunert Cindy Fornshell John A. 《Hydrobiologia》1994,(1):149-156
Variations in the number of spines on the left and right posterior dorsal and posterior margins of the prosome as well as the length of the prosome of Acartia tonsa from three estuaries, the upper western side of the Chesapeake Bay, Montauk Bay near the eastern end of Long Island Sound and the coast of Peru were determined. The length of the prosome and number of spines in each of the four locations were used as an indication of morphological similarity between the populations. 相似文献
24.
Amino acid release from roots of sterile and non-sterile, solution-grown, 7-, 21- and 60-days-old forage rape plants (Brassica napus L.), was measured over periods of up to 6 hours. With sterile plants, release of amino acids into a fixed volume of collection medium (6, 12, 70 mL) was concentration-limited, giving rise to similar convex accumulation profiles for individual acids. In contrast, amino acid accumulation in continuously circulating collection medium was not concentration limited, giving a linear accumulation pattern. The compositions of accumulating amino acids, which were similar to those measured in root extracts, did not change significantly. However, the proportions of ALA, GABA, GLU and ILE in both root extracts and root-derived amino acids increased as plants aged. Older plants released more amino acids per plant, while younger plants released more amino acids g-1 root DW. Using non-sterile plants, the patterns of change in amino acid concentration and composition in the collection medium were completely different from those determined with sterile plants. In general, with 7-days-old plants, and 60-days-old plants that had recently become non-sterile, an initial rise in the concentration of all acids was followed by a fall to low levels. The loss of amino acids was apparently due to microbial consumption. Individual amino acids attained maximum concentration at different times during the collection process. This is attributed mainly to concentration-dependent differential assimilation of amino acids, since those with the highest initial concentrations, the major components of the mixtures released from roots, declined the earliest. When calculated rates of amino acid release from roots (Rr) and microbial consumption of amino acids (Rc) were compared (for 7-days-old plants), the highest ratios of Rc/Rr were found for ASN, ARG, GLU, GLN, and LYS. This suggests a degree of selectivity for glutamate and nitrogen-rich acids on the part of the consuming micro-organisms. With 21-days old plants and 60-days old plants grown entirely under non-sterile conditions, fluctuations in amino acid concentration were similar for all acids. 相似文献
25.
Roots of ten-days-old seedlings obtained from a maize hybrid grown in complete or in sulphate-deprived medium were used to extract Poly(A)+RNA. The response to sulphate deprivation, which is known to increase the uptake capacity up to ten times, was manifested also by the expression of three mRNA species, as shown by the in vitro translation of the mRNA population. One hour after transfer to complete nutrient medium all three mRNAs were still present.Abbreviations BSA
Bovine Serum Albumine
- DTT
1,4-Dithio-DL-Threitol
- EDTA
Ethylenediaminetetraacetic-acid
- MES
2-(N-Morpholino) ethane sulfonic acid
- SDS
Sodium Dodecyl Sulfate
- TCA
Trichloracetic acid
- TRIS
Tris(hydroxy-methyl)-aminomethane 相似文献
26.
Role of proteinaceous amino acids released in root exudates in nutrient acquisition from the rhizosphere 总被引:1,自引:1,他引:0
The role of proteinaceous amino acids in rhizosphere nutrient mobilization was assessed both experimentally and theoretically. The degree of adsorption onto the soil's solid phase was dependent on both the amino acid species and on soil properties. On addition of amino acids to both soil and freshly precipitated Fe(OH)3, no detectable mobilization of nutrients (K, Na, Ca, Mg, Cu, Mn, Zn, Fe, S, P, Si and Al) was observed, indicating a very low complexation ability of the acidic, neutral and basic amino acids. This was supported by results from a solution equilibria computer model which also predicted low levels of amino acid complexation with solutes present in the soil solution. On comparison with the Fe(OH)3 and equilibria data obtained for the organic acid, citrate, it was concluded that amino acids released into the rhizosphere have a limited role in the direct acquisition of nutrients by plants. The effectiveness of root exudates such as amino acids, phytosiderophores and organic acids in nutrient mobilization from the rhizosphere is discussed with reference to rhizosphere diffusion distances, microbial degradation, rate of complexation and the root's capacity to recapture exudate-metal complexes from the soil. 相似文献
27.
Simultaneous high-biomass protein production and nutrient removal using Spirulina maxima in sea water supplemented with anaerobic effluents 总被引:1,自引:0,他引:1
E. J. Olguín B. Hernández A. Araus R. Camacho R. González M. E. Ramírez S. Galicia G. Mercado 《World journal of microbiology & biotechnology》1994,10(5):576-578
Maximum protein accumulation (71%, w/w) and nutrient removal by a mutant strain of Spirulina maxima growing on sea water supplemented with anaerobically treated pig slurry was achieved at 30°C with constant illumination (60 to 70 Em-2s-1), using a flow rate of 14.5 cm s-1 (20 rev. min-1 of a paddle wheel). Total phosphates were decreased by 99% and all ammonia-N was removed under these conditions.The authors are with the Department of Environmental Biotechnology, Institute of Ecology, Aptd Postal 63, Xalapa, Ver., Mexico 相似文献
28.
The effects of highly and moderately acid soils on total biomass, biomass partitioning, fine root characteristics and nutritional
status of beech seedlings (Fagus sylvatica L.) were studied in a growth chamber experiment. In Haplic Arenosols seedlings grew slowly but equally well without damage
symptoms in a highly acid and a moderately acid soil horizon. The moderately acid Ah+Bw-horizon of a Eutric Cambisol was favourable to seedling growth. The fine root development was reduced in the highly acid
A+Bw-horizon of a Dystric Cambisol and in the Ah+E-horizon of a Haplic Podzol, the latter of which also caused increased mortality. Seedling growth in the B2-horizon of the Haplic Podzol was vigorous, in spite of a higher level of extractable Al and lower base saturation as compared
with the Ah+E-horizon. These results are interpreted in relation to soil acidity, soil Al and nutritional status of the seedlings. We
conclude that neither Al-toxicity nor nutrient deficiency cause the damage symptoms observed in the Ah+E-horizon of a Haplic Podzol and the fine root reduction in the A+Bw-horizon of a Dystric Cambisol. The damage symptoms of the PZhA treatment seems to be more the result of H-toxicity or H-related factors other than nutrient shortage or Al-toxicity. Other
pH-related toxic factors are discussed. 相似文献
29.
Plasma and liver selenium of Wistar rats were determined after 1, 3, and 6 mo supplementation with 0.5, 2, 6, or 15 ppm selenium
as sodium selenite in drinking water. Plasma selenium was not different from control values at additional intake of 0.5 ppm
but increased above usual levels at higher intakes. A highly significant correlation was observed between the total quantity
of selenium ingested and plasma selenium after 1 mo treatment (r=0.99,p<0.01), but was less pronounced after 3 and 6 mo (0.94,p<0.05, and 0.78,p<0.05, respectively). The decrease in plasma selenium with time of treatment was more pronounced at higher intakes. There
was also a highly significant correlation between total selenium intake and liver selenium concentration (r=0.99,p<0.01) after 1 mo of treatment, but this time liver selenium did not change with time, and the correlation remained highly
significant throughout the investigation. Liver selenium therefore appears as a more sensitive and more representative measure
of selenium intake than plasma selenium. Most supplements did not affect body weight and survival of animals, except when
the diet was supplemented with 15 ppm for 6 mo; however, alterations in biochemical parameters concerning lipid status and
hepatic function were observed at levels above 2.0 ppm. 相似文献
30.
An ecosystems approach to base-rich freshwater wetlands,with special reference to fenlands 总被引:1,自引:1,他引:0
Geert van Wirdum 《Hydrobiologia》1993,265(1-3):129-153
A survey of base-rich wetlands in The Netherlands is presented. The main area of their occurrence is the low-lying Holocene
part of the country, until some thousand years ago a large and coherent wetland landscape: the Holland wetland. The development
of various parts of the Holland wetland into marshes, fens and bogs can be understood from hydrological relations in mire
basins, as recognized in the distinction of primary, secondary and tertiary mire basin stages. Presently, the remnants of
the Holland wetland are separate base-rich wetlands. The succession of their vegetation reflects various abiotic conditions
and human influences. Three main developmental periods are distinguished as regards these factors. The first, geological period
of mire development is seen as a post-glacial relaxation, with the inertia due to the considerable mass of wetland as a stabilizing
factor. Biological “grazing” influences, as an aspect of utilization by humans, converted base-rich wetlands to whole new
types in the second, historical period. Presently, mass and harvesting have decreased in importance, and actual successions
in terrestrializing turbaries seem to reflect rapidly changing environmental conditions. Human control could well become the
most important factor in the future development of wetland nature. The present value of open fen vegetation strongly depends
on the continuation of the historical harvesting. The development of wooded fen may help to increase the mass of wetland in
the future. Best results in terms of biodiversity are expected when their base state is maintained through water management.
The vegetation and hydrology of floating fens in terrestrializing turbaries is treated in some more detail. Various lines
and phases in the succession are distinguished. Open fen vegetation at base-rich, yet nutrient-poor sites is very rich in
species threatened elsewhere. The fast acidification of certain such fens is attributed to hydrological and management factors.
This acidification is illustrated in the profile of a floating raft sample. At the scale of these small fens, the elemental
structure comprising base-rich fen, transitional fen and bog vegetation, is not as stable as it was in the large Holland wetland.
A critical role seems to be played by the supply of bases with the water influx. The changing base state is supposed to change
the nutrient cycling to such an extent that it would be correct to call this trophic excitation of the ecosystem, rather than
just eutrophication. Eutrophication indicates a quantitative reaction to an increased nutrient supply, the internal system
being unaltered. The drainage of fens, resulting in an increased productivity of the vegetation, provides another example
of excitation, to the effect that the functional system is dramatically changed internally. 相似文献