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111.
Jehad Abbadi Klaus Dittert Bernd Steingrobe Norbert Claassen 《Journal of plant nutrition》2013,36(19):2459-2483
Potassium uptake efficiency of safflower and sunflower was studied under semi-controlled conditions in loamy and sandy soils. Both species performed better in loamy soil. Safflower had higher agronomic efficiency and higher relative root length under suboptimal K supply. Safflower had higher specific root density and less root radius at all K levels. Safflower had higher relative root-shoot ratio under suboptimal K in loamy soil. Both species had similar K-influx at low and optimal K in loamy soil, while sunflower had higher influx under suboptimal and optimal supplies in sandy soil. Safflower had higher shoot demand in both soils under suboptimal and optimal K. Both species depleted similar amounts of soil solution-K under suboptimal K in sandy soil, while sunflower was more efficient under suboptimal levels in loamy soils. Sunflower depleted more extractable-K under both suboptimal and optimal K. Safflower could be considered K-uptake efficient crop. 相似文献
112.
E. R. Joachim Keller Christine D. Zanke Angelika Senula Andreas Breuing Bernd Hardeweg Traud Winkelmann 《Genetic Resources and Crop Evolution》2013,60(3):913-926
The maintenance of plant genetic resources in living plant collections (genebanks) causes costs due to employment of staff, usage of buildings, equipment and consumables. Since this is especially challenging in vegetatively propagated material, studies were performed for the case of garlic, which is one of the major vegetatively maintained crops in the genebank of IPK Gatersleben. Data were recorded to compare various scenarios of the main strategies field maintenance and cryopreservation. A spreadsheet tool was developed to be used for cost assessment and for drawing conclusions concerning the most effective way of maintenance. Field culture is cheaper in the short term, whereas after a break-even point cryopreservation becomes the more efficient storage method in the long term. This break-even point depends on the particular scenario, which is determined by various factors such as field and in vitro multiplication rates of various genotypes, presence of bulbils in a part of the genepool, the sample size of the accessions as well as the number of stored accessions in cryopreservation. The comparative discussion is exemplified for a 1-year field rotation versus cryopreservation using either in vitro plantlets or a combination of bulbils and unripe inflorescence bases as organ sources. For the more expensive use of in vitro plants cryopreservation becomes less costly than field culture only after 13 years, whereas this is the case already after 8–9 years when using a combination of bulbils in winter and inflorescence bases in summer. 相似文献
113.
Cluster roots are structures formed by many plants adapted to phosphorus (P)-deficient soils. We investigated the combined influence of spatial heterogeneity in soil water and P distribution on the allocation of cluster root formation in white lupin (Lupinus albus L.). In this study, single plants were grown at a low or a high rate of water supply in containers filled with a P-poor sand to which either no P was added or which was fertilized homogeneously or heterogeneously. Furthermore, heterogeneous soil water distribution was established in half of the containers by using a finer instead of a coarser sand in a lateral third of the containers. Plant growth increased with water supply rate, but P fertilization had no influence on shoot biomass production. Although overall cluster root production decreased with increasing homogeneous P supply, localized P fertilization had no effect on cluster root allocation. However, cluster roots were preferentially allocated in the soil sections with lower water availability when overall water supply rate was low. The results suggest that overall cluster root production was a systemic response to initial plant P status, while cluster root growth was stimulated locally in drier patches when overall water supply was limiting plant growth. 相似文献
114.
Isotopically exchangeable P (IEP) is usually considered to be completely plant‐available and the major source of P for plant uptake. The aim of the present study is to test whether plants can, besides IEP, also use non‐IEP and if part of the IEP has an equilibrium concentration in soil solution which is below the minimum concentration, CLmin, and can therefore not be taken up by plants. A pot experiment was carried out with maize for two years on two soils, an acid sandy and a neutral loamy soil, either without P fertilizer or fertilized with ten P sources of different solubility. Throughout both years of the study, pots were kept moist either without plants or planted twice with maize (Zea mays L., cv. Athletico). At the end of the experiment, plant P uptake, P concentration in the soil solution (CL), and P accessible to isotopic exchange within 5 d (E5d) were measured. Plant growth decreased the E5d which was about equal to P uptake by maize for most treatments in the acid soil. But for some treatments, i.e., five in the acid and eight in the neutral soil, P uptake was up to 50% larger than the decrease of E5d, indicating that plants had, besides IEP, also used P from non‐IEP sources. At adequate P supply, both soils had an E5d of about 100 mg P (kg soil)–1, but about 30 to 40 mg kg–1 of this IEP had an equilibrium P concentration in the soil solution below CLmin of 0.1 μmol L–1 at which P would actually not be plant‐available. This study shows that plants take up P mainly from IEP, but not the whole IEP is plant‐available. Furthermore, plants may also use P from non‐IEP sources. 相似文献
115.
Felix?Krujatz Andreas?Haarstrick Bernd?N?rtemann Tillman?GreisEmail author 《Water, air, and soil pollution》2012,223(3):1281-1293
Plant growth-promoting rhizobacteria (PGPR) play an important role in the biodegradation of natural and xenobiotic organic
compounds in soil. They can also alter heavy metal bioavailability and contribute to phytoremediation in the presence or absence
of synthetic metal chelating agents. In this study, the inhibitory effect of Cd2+ and Ni2+ at different concentrations of Ca2+ and Mg2+, and the influence of the widely used chelator EDTA on growth of the PGPR Pseudomonas brassicacearum in a mineral salt medium with a mixture of four main plant exudates (glucose, fructose, citrate, succinate) was investigated.
Therefore, the bacteriostatic effect of Cd2+, Ni2+ and EDTA on the maximum specific growth rate and the determination of EC50 values was used to quantify inhibitory impact.
At high concentrations of Ca2+ (800 μmol L-1) and Mg2+ (1,250 μmol L-1), only a small inhibitory effect of Cd2+ and Ni2+ on growth of P. brassicacearum was observed (EC50 Cd2+, 18,849 ± 80 μmol L−1; EC50 Ni2+, 3,578 ± 1,002 μmol L−1). The inhibition was much greater at low concentrations of Ca2+ (25 μmol L−1) and Mg2+ (100 μmol L−1) (EC50 Cd2+, 85 ± 0.5 μmol L−1 and EC Ni2+, 62 ± 1.8 μmol L−1). For the chosen model system, a competitive effect of the ions Cd2+ and Ca2+ on the one hand and Ni2+ and Mg2+ on the other hand can be deduced. However, the toxicity of both, Cd2+ and Ni2+, could be significantly reduced by addition of EDTA, but if this chelating agent was added in stoichiometric excess to the
cations, it also exhibited an inhibitory effect on growth of P. brassicacearum. 相似文献
116.
Impact of pea growth and arbuscular mycorrhizal fungi on the decomposition of 15N-labeled maize residues 总被引:1,自引:0,他引:1
Ramia Jannoura Bernd Kleikamp Jens Dyckmans Rainer Georg Joergensen 《Biology and Fertility of Soils》2012,48(5):547-560
A pot experiment was carried out (1) to compare C and N yield of different plant parts, nutrient concentrations, and root colonization between the non-mycorrhizal mutant P2 (myc ?) and the symbiotic isoline Frisson (myc +), (2) to investigate the effects of arbuscular mycorrhizal fungi and growing pea plants on microbial decomposition of 15N-labeled maize residues, and (3) to follow the distribution of the added substrate over different soil fractions, such as particulate organic matter, soil microbial biomass, and microbial residues. Yields of C in straw, grain, and roots of myc + peas were significantly higher by 27%, 11%, and 92%, respectively, compared with those of myc ? peas. The δ13 C values in the different plant parts were significantly higher in myc + than in myc ? tissue with and without maize. Application of labeled maize residues generally resulted in 15N enrichment of pea plants. At the end of the experiment, the ergosterol concentration in roots of mature peas did not differ between the two isolines, indicating similar colonization by saprotrophic fungi. The decomposition of added maize residues was significantly reduced by the myc ? peas, but especially by myc + peas. The formation of microbial residue C was increased and that of microbial residue N was reduced in the presence of plants. The insufficient N supply to soil microorganisms reduced decomposition of maize residues in the presence of peas, especially myc + peas. 相似文献
117.
Red lead (Pb3O4)‐ and ZnO‐containing anticorrosion paints in the past have been extensively applied to high‐voltage steel pylons which has led to heavy metal (HM) soil contaminations in their vicinity. Since pylons are commonly found on agricultural land, there is a potential risk of HM plant uptake. This is promoted by the fact that in contrast to the moderate total Pb contents (several 100 mg kg–1) in three nutrient‐poor and acidic pylon soils the Pb amounts extractable with NH4NO3 were extremely high, reaching almost 20% of total Pb. A 18‐week field pot trial (three harvests in a six‐week interval) using Lolium multiflorum was conducted to study the HM plant uptake and the efficiency of the four soil additives, lime (LI), Novaphos (NP), water‐treatment sludge (WS), and ilmenite residue (IR) in reducing the plant uptake and NH4NO3‐extractability of Pb and Zn in the soils. Lead concentrations in L. multiflorum shoots grown in the untreated soils reached maximum values of 128 mg (kg dry weight)–1. Novaphos was most efficient in decreasing shoot Pb (–90%) followed by LI (–78%) and WS (–73%). For Zn, too, LI (–82%), NP, and WS (both –66%) substantially reduced plant uptake. Ilmenite residue was generally only poorly efficient. The dry‐matter yield in the NP, LI, and WS treatments was significantly increased. While the relationship between Pb‐NH4NO3 and Pb‐plant was high when considering the three harvests separately (R > 0.93) a poor relationship (R = 0.63) exists over all harvests together. This was attributed to different transpiration rates affecting the HM flux into the plants, since the temperature regime changed greatly during the cultivation period. For Zn, no such close relationship between the NH4NO3‐extractable soil fraction and shoot Zn was found, most likely due to antagonistic effects from Mg which greatly varied in the three soils. 相似文献
118.
Anastasia Shchegolikhina Stephan Schulz Bernd Marschner 《Journal of Soils and Sediments》2012,12(8):1280-1291
Purpose
The structure and properties of the soil organic matter and its interactions with solutes may be altered by changes in soil chemistry and by the aging of soil. The main objective of this study was to investigate the effect of long-term aging and cation saturation of soil on the extractability and degradability of two hydrophobic xenobiotics in soil. In addition, it was tested if drying or freezing of soils can accelerate the relevant aging processes.Materials and methods
The sandy topsoil was treated by either 0.1?M NaCl, CaCl2, AlCl3 solutions or water and samples were sterilized by ??-radiation and spiked with 14C-labeled nonylphenol (NP) or phenanthrene (Phe) at 10???g?g?1 of soil. Samples were then used in four parallel experimental setups: (1) 9?months of aging under sterile conditions, (2) inoculation by native original soil with further 7?months of aging (bioaging), (3) drying and wetting or (4) freezing and thawing of soils. After different time intervals, the extractability of xenobiotics with water, cyclodextrin, and ethanol was investigated.Results and discussion
During 9?months of aging under sterile conditions a continuous decrease of NP and Phe extractability and an increase of the non-extractable fraction occurred. During the 7?months of biologically active aging, the mineralization of NP was lower than of Phe while more NP remained extractable than Phe. In comparison to the sterile aging, the bioaging led to a less formation of non-extractable residues of NP and Phe. The long-term sterile aging effects on NP-extractability were also achieved by short-term freezing and thawing of the soils, while aging of Phe was better mimicked by drying?Cwetting cycles. The effects of cation saturation of soils on xenobiotics extractability were less pronounced.Conclusions
Sterile aging, bioaging, freezing, and thawing facilitate the formation of the non-extractable fraction of NP and Phe in the soils. Different cation treatments alter soil properties, but the effects on aging of NP and Phe in soils were negligible. 相似文献119.
Members of the marine dinoflagellate genus Alexandrium are known to exude allelochemicals, unrelated to well-known neurotoxins (PSP-toxins, spirolides), with negative effects on other phytoplankton and marine grazers. Physico/chemical characterization of extracellular lytic compounds of A. tamarense, quantified by Rhodomonas salina bioassay, showed that the lytic activity, and hence presumably the compounds were stable over wide ranges of temperatures and pH and were refractory to bacterial degradation. Two distinct lytic fractions were collected by reversed-phase solid-phase extraction. The more hydrophilic fraction accounted for about 2% of the whole lytic activity of the A. tamarense culture supernatant, while the less hydrophilic one accounted for about 98% of activity. Although temporal stability of the compounds is high, substantial losses were evident during purification. Lytic activity was best removed from aqueous phase with chloroform-methanol (3:1). A “pseudo-loss” of lytic activity in undisturbed and low-concentrated samples and high activity of an emulsion between aqueous and n-hexane phase after liquid-liquid partition are strong evidence for the presence of amphipathic compounds. Lytic activity in the early fraction of gel permeation chromatography and lack of activity after 5 kD ultrafiltration indicate that the lytic agents form large aggregates or macromolecular complexes. 相似文献
120.
Helene Fast Seefeldt Andreas Blennow Birthe Møller Jespersen Bernd Wollenweber Søren Balling Engelsen 《Journal of Cereal Science》2009
The accumulation of mixed linkage barley (1 → 3) (1 → 4)-β-d-glucan (BG) during grain filling at eight stages was studied using standard reference methods and infrared spectroscopy. Two mutant barley genotypes having higher (starch mutant lys5f) and lower (high lysine mutant lys3a) BG content than the normal control Cork were studied. The Cork and lys3a genotypes showed a linear BG accumulation throughout the grain filling to reach a maximum of approximately 6 and 4% BG (w/w) dry matter, respectively. However, lys5f mutant exhibited an exponential increase in BG synthesis to a maximum of approximately 18% BG (w/w) dry matter 30 days after flowering (DAF), seemingly compensating for a decreased synthesis of starch. 相似文献