Kooperativer Bibliotheksverbund

Berlin Brandenburg

and
and

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Nitrogen
Type of Medium
Language
Year
  • 1
    Language: English
    In: Plant and Soil, 2013, Vol.364(1), pp.341-355
    Description: Aims: The aim was to quantify the nitrogen (N) transferred via the extra-radical mycelium of the arbuscular mycorrhizal fungus Glomus intraradices from both a dead host and a dead non-host donor root to a receiver tomato plant. The effect of a physical disruption of the soil containing donor plant roots and fungal mycelium on the effectiveness of N transfer was also examined. Methods: The root systems of the donor (wild type tomato plants or the mycorrhiza-defective rmc mutant tomato) and the receiver plants were separated by a 30 mu m mesh, penetrable by hyphae but not by the roots. Both donor genotypes produced a similar quantity of biomass and had a similar nutrient status. Two weeks after the supply of super(15)N to a split-root part of donor plants, the shoots were removed to kill the plants. The quantity of N transferred from the dead roots into the receiver plants was measured after a further 2 weeks. Results: Up to 10.6 % of donor-root super(15)N was recovered in the receiver plants when inoculated with the arbuscular mycorrhizal fungus (AMF). The quantity of super(15)N derived from the mycorrhizal wild type roots clearly exceeded that from the only weakly surface-colonised rmc roots. Hyphal length in the donor rmc root compartments was only about half that in the wild type compartments. The disruption of the soil led to a significantly increased AMF-mediated transfer of N to the receiver plants. Conclusions: The transfer of N from dead roots can be enhanced by AMF, especially when the donor roots have been formerly colonised by AMF. The transfer can be further increased with higher hyphae length densities, and the present data also suggest that a direct link between receiver mycelium and internal fungal structures in dead roots may in addition facilitate N transfer. The mechanical disruption of soil containing dead roots may increase the subsequent availability of nutrients, thus promoting mycorrhizal N uptake. When associated with a living plant, the external mycelium of G. intraradices is readily able to re-establish itself in the soil following disruption and functions as a transfer vessel.
    Keywords: Arbuscular mycorrhiza ; Reduced mycorrhizal colonisation (rmc) mutant ; Extra-radical mycelium ; Root turnover ; Solanum lycopersicum
    ISSN: 0032-079X
    E-ISSN: 1573-5036
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Language: English
    In: Mycorrhiza, 2013, Vol.23(2), pp.107-117
    Description: Labeled nitrogen ( 15  N) was applied to a soil-based substrate in order to study the uptake of N by Glomus intraradices extraradical mycelium (ERM) from different mineral N (NO 3 − vs. NH 4 + ) sources and the subsequent transfer to cowpea plants. Fungal compartments (FCs) were placed within the plant growth substrate to simulate soil patches containing root-inaccessible, but mycorrhiza-accessible, N. The fungus was able to take up both N-forms, NO 3 − and NH 4 + . However, the amount of N transferred from the FC to the plant was higher when NO 3 − was applied to the FC. In contrast, analysis of ERM harvested from the FC showed a higher 15  N enrichment when the FC was supplied with 15 NH 4 + compared with 15 NO 3 − . The 15  N shoot/root ratio of plants supplied with 15 NO 3 − was much higher than that of plants supplied with 15 NH 4 + , indicative of a faster transfer of 15 NO 3 − from the root to the shoot and a higher accumulation of 15 NH 4 + in the root and/or intraradical mycelium. It is concluded that hyphae of the arbuscular mycorrhizal fungus may absorb NH 4 + preferentially over NO 3 − but that export of N from the hyphae to the root and shoot may be greater following NO 3 − uptake. The need for NH 4 + to be assimilated into organically bound N prior to transport into the plant is discussed.
    Keywords: Arbuscular mycorrhiza ; Cowpea ; Nitrate/ammonium transfer ; Fungal compartment
    ISSN: 0940-6360
    E-ISSN: 1432-1890
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Language: English
    In: Nutrient Cycling in Agroecosystems, 2011, Vol.91(3), pp.327-337
    Description: The nitrogen (N) use efficiency of field vegetable production systems needs to be increased in order to, reduce the detrimental effects of N losses on other ecosystems, save on production costs, and meet the limits set by the German government concerning N balance surpluses. Winter catch crops (CCs) have been shown to be a useful tool for reducing N losses in many agricultural production systems. This study was designed to test the effects of different CCs: rye ( Secale cereale L.), fodder radish ( Raphanus sativus L. var. oleiformis Pers.), bunch onion ( Allium cepa L.), and sudangrass ( Sorghum sudanense Stapf), planted at different sowing dates (early, late), on the N balance of 2-year vegetable crop rotation systems. The crop rotations started with a cauliflower ( Brassica oleracea L. var. botrytis L.) crop, which was fertilized with N in a conventional manner. The experiments took place at three different sites in Germany. Results revealed that the average N balance surplus, when taking into consideration, fertilization, soil mineral N, and aboveground plant biomass N, was 217 kg N ha −1 in the control treatments without a CC. This high value was mainly a consequence of large quantities of crop N and soil mineral N remaining after the harvest of the cauliflower. In spite of these high N surpluses, the application of CC only reduced the N balance surplus, on average across all sites and experiments, by 13 kg N ha −1 , when compared to the control treatments. The type of CC and the sowing date had only minor effects on the N balance. The findings of this study suggest that for many sites the application of CCs does not solve the problem of high N balance surpluses in intensive field vegetable production systems.
    Keywords: Catch crop ; Crop rotation ; Vegetable production ; Nitrogen losses ; Leaching ; Nitrogen balance
    ISSN: 1385-1314
    E-ISSN: 1573-0867
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Language: English
    In: Journal of Plant Nutrition, 05 March 2010, Vol.33(5), pp.736-751
    Description: A semi-hydroponic culture was used to compare growth and cation nutrition of mycorrhizal (Paxillus involutus) and non-mycorrhizal Scots pine seedlings. When roots and hyphae grew together, concentrations and contents of macronutrients in needles and roots were not significantly different between...
    Keywords: Ectomycorrhiza ; Plant Growth ; Nutrients ; Pinus Sylvestris ; Botany
    ISSN: 0190-4167
    E-ISSN: 1532-4087
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Language: English
    In: Mycorrhiza, 2011, Vol.21(5), pp.341-349
    Description: Arbuscular mycorrhizal (AM) fungi influence the expression of defence-related genes in roots and can cause systemic resistance in plants probably due to the induced expression of specific defence proteins. Among the different groups of defence proteins, plant food allergens were identified. We hypothesized that tomato-allergic patients differently react to tomatoes derived from plants inoculated or not by mycorrhizal fungi. To test this, two tomato genotypes, wild-type 76R and a nearly isogenic mycorrhizal mutant RMC, were inoculated with the AM fungus Glomus mosseae or not under conditions similar to horticultural practice. Under such conditions, the AM fungus showed only a very low colonisation rate, but still was able to increase shoot growth of the wild-type 76R. Nearly no colonisation was observed in the mutant RMC, and shoot development was also not affected. Root fresh weights were diminished in AM-inoculated plants of both genotypes compared to the corresponding controls. No mycorrhizal effects were observed on the biomass and the concentration of phosphate and nitrogen in fruits. Real-time quantitative polymerase chain reaction analysis revealed that six among eight genes encoding for putative allergens showed a significant induced RNA accumulation in fruits of AM-colonised plants. However, human skin reactivity tests using mixed samples of tomato fruits from the AM-inoculated and control plants showed no differences. Our data indicate that AM colonisation under conditions close to horticultural practice can induce the expression of allergen-encoding genes in fruits, but this does not lead necessarily to a higher allergenic potential.
    Keywords: Allergy ; Defence proteins ; Glomus mosseae ; RNA accumulation ; Skin prick test
    ISSN: 0940-6360
    E-ISSN: 1432-1890
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Language: English
    In: Journal of Plant Nutrition and Soil Science, June 2010, Vol.173(3), pp.353-359
    Description: In most plant species, nutrient uptake is facilitated upon root association with symbiotic arbuscular mycorrhizal (AM) fungi. The aim of the present experiment was to test how the form in which nitrogen (N) is supplied to the growth medium affects substrate pH, AM development, and contribution of the symbiosis to phosphorus (P) uptake from sparingly available or soluble resources. Cowpea ( L. Walp) plants inoculated or noninoculated with AM fungi ( sp.) were grown in pots with a sand substrate supplied with nutrient solution. The nutrient solution was prepared either with a high or a low concentration of soluble P, and NO‐N : NH‐N ratios of 9:1 or 5:5. The substrate supplied with low‐P nutrient solution was either or not additionally amended with ground rock phosphate. Despite a high level of root colonization, AM fungi used in the present study did not appear to increase plant availability of rock phosphate. It cannot be excluded that the ability of AM root systems to acquire P from sparingly available resources differs depending on the plant and fungal genotypes or environmental conditions. The absence from the growth substrate of P‐solubilizing microorganisms able to associate with AM mycelia might also have been a reason for this observation in our study. Increased supply of NH relative to NO improved plant P availability from rock phosphate, but also had a negative effect on the extent of AM‐fungal root colonization, irrespective of the plant P‐nutritional status. Whether increasing levels of NH can also negatively affect the functioning of the AM symbiosis in terms of plant element uptake, pathogen protection or soil‐structure stabilization deserves further investigation.
    Keywords: Arbuscular Mycorrhiza ; Nitrate‐To‐Ammonium Ratio ; Rock Phosphate ; Vigna Unguiculata
    ISSN: 1436-8730
    E-ISSN: 1522-2624
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Language: English
    In: Biology and Fertility of Soils, 2010, Vol.46(2), pp.159-167
    Description: One of the challenges in organic farming systems is to match nitrogen (N) mineralization from organic fertilizers and crop demand for N. The mineralization rate of organic N is mainly determined by the chemical composition of the organic matter being decomposed and the activity of the soil microflora. It has been shown that long-term organic fertilization can affect soil microbial biomass (MB), the microbial community structure, and the activity of enzymes involved in the decomposition of organic matter, but whether this has an impact on short-term N mineralization from recently applied organic substances is not yet clear. Here, we sampled soils from a long-term field experiment, which had either not been fertilized, or fertilized with 30 or 60 t ha −1 year −1 of farmyard manure (FYM) since 1989. These soil samples were used in a 10-week pot experiment with or without addition of FYM before starting (recent fertilization). At the start and end of this experiment, soil MB, microbial basal respiration, total plant N, and mineral soil N content were measured, and a simplified N balance was calculated. Although the different treatments used in the long-term experiment induced significant differences in soil MB, as well as total soil C and N contents, the total N mineralization from FYM was not significantly affected by soil fertilization history. The amount of N released from FYM and not immobilized by soil microflora was about twice as high in the soil that had been fertilized with 60 t ha −1 year −1 of FYM as compared with the non-fertilized soil ( p  〈 0.05).
    Keywords: Decomposition ; Microbial biomass ; Organic fertilization ; Soil adaptation
    ISSN: 0178-2762
    E-ISSN: 1432-0789
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Language: English
    In: Symbiosis, 2017, Vol.73(3), pp.191-200
    Description: We investigated the effect of mineral nitrogen forms on transfer of nitrogen (N) and zinc (Zn) from attached compartments to rhodes grass ( Chloris gayana ) colonised with arbuscular mycorrhizal fungi (AMF). After being pre-cultivated in substrates with adequate nutrient supply and either AMF inoculated (+AM) or left non-inoculated (−AM), rhodes grass was positioned adjacent to an outer compartment holding a similar substrate but applied with labelled nitrogen ( 15 N) either as ammonium (NH 4 + ) or nitrate (NO 3 − ), and a high supply of Zn (150 mg kg −1 DS). Plant roots together with fungal mycelium were either allowed to explore the outer compartment (with root access) or only mycorrhizal hyphae were allowed (without root access). Within each access treatment, biomasses of rhodes grass were not significantly affected by AMF inoculation or N form. AMF contribution to plant 15 N uptake was about double in NH 4 + compared with NO 3 − -supplied treatments while the mycorrhizal influence on plant Zn uptake was insignificant. Without root access, the shoot 15 N/Zn concentration ratio was up to ten-fold higher in +AM than –AM treatments and this ratio increase was clearly more pronounced in NH 4 + than NO 3 − -supplied treatments. In conclusion, rhodes grass in symbiosis with the tested AMF acquired more N when supplied with ammonium. Moreover, there is clear indication that although the AMF have transported both nutrients (N and Zn), N was preferentially transferred as compared to Zn. We confirmed that, while rhodes grass is not able to prevent excessive Zn uptake via roots under conditions of high Zn, mycorrhiza is able to avoid excessive Zn supply to the host plant when the fungus alone has access to contaminated patches.
    Keywords: Arbuscular mycorrhiza ; Ammonium ; Nitrate ; Mycorrhizal nutrient uptake ; (Rhodes grass)
    ISSN: 0334-5114
    E-ISSN: 1878-7665
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Language: English
    In: Journal of agricultural and food chemistry, 28 May 2008, Vol.56(10), pp.3538-45
    Description: The aim of the present study was to test whether variations in the root environment affect the content of health-related organosulfur compounds, total phenolic compounds, and flavonol glycoside concentrations in onions. For this purpose, greenhouse-grown onions ( Allium cepa L.) were either inoculated with a commercial arbuscular mycorrhizal inoculum or a sterile inoculum and were provided with two NH(4)(+):NO(3)(-) ratios as a nitrogen source. Onion growth, arbuscular mycorrhizal colonization rate, sugars, and nutrient element concentrations were also quantified. The plant antioxidant activity and quercetin monoglucoside and organosulfur compound concentrations increased with dominant nitrate supply. Furthermore, mycorrhizal colonization increased the antioxidant activity and also concentrations of the major quercetin glucosides. The present study provides clear evidence that antioxidant activity, quercetin glycosides, and organosulfur compounds can be increased in sufficiently supplied onion plants by dominant nitrate supply or application of arbuscular mycorrhizal fungi. This was probably due to increased precursor production and induced defense mechanisms.
    Keywords: Mycorrhizae -- Growth & Development ; Nitrates -- Administration & Dosage ; Onions -- Chemistry ; Phenols -- Analysis ; Sulfur Compounds -- Analysis
    ISSN: 0021-8561
    E-ISSN: 15205118
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Language: English
    In: Plant and Soil, 1996, Vol.186(2), pp.361-369
    Description: The response of carbohydrate metabolism in 3-year-old Norway spruce plants to an increased amount of nitrogen supply to a N-poor forest soil was investigated in a pot experiment. After 7 months of treatment we found a decreased amount of starch in both needles and roots, together with decreased amounts of sucrose in needles of those plants grown under an enhanced inorganic N supply. In addition, the activity and the protein amount of the anaplerotic enzyme phospho enol pyruvate carboxylase (PEPC) and the activity of NADP-dependent isocitrate dehydrogenase (IDH) were clearly increased. The activity of sucrose phosphate synthase (SPS) and the pool size of fructose 2,6-bisphosphate (F26BP) were not affected by high supply of inorganic N. These data indicate a shift of carbon flow from starch formation towards an enhanced provision of carbon skeletons for N assimilation and shoot growth. In parallel, we found decreased contents of fungus-specific compounds (ergosterol, mannitol, trehalose) in roots, which are indicators of a decreased colonization by ectomycorrhizal fungi, probably as a result of a changed allocation and partitioning of photoassimilates due to an increased N supply.
    Keywords: ectomycorrhiza ; fungus-specific compounds ; isocitrate dehydrogenase ; nitrogen ; Picea abies ; phosphopyruvate carboxylase
    ISSN: 0032-079X
    E-ISSN: 1573-5036
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages