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Berlin Brandenburg

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  • 1
    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
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  • 2
    Language: English
    In: Plant and Soil, 1996, Vol.184(2), pp.291-298
    Description: During a seven-month period the effect of different nitrogen (N) availability in soil on growth and nutrient uptake was studied in three-year-old Norway spruce ( Picea abies [L.] Karst.) trees. The plants were grown in pots on N-poor forest soil supplied with various amounts and forms (inorganic and organic) of N. Increasing supply of inorganic N (as NH 4 NO 3 ) increased the formation of new shoots and shoot dry weight. The root/shoot dry weight ratio of new growth was drastically decreased from 1.6 in plants without N supply to 0.5 in plants supplied with high levels of NH 4 NO 3 . This decrease in root/shoot dry weight ratio was associated with distinct changes in root morphology in favour of shorter and thicker roots. The addition of keratin as organic N source did neither affect growth nor root morphology of the trees. The amount of N taken up by plants was closely related to the supply of inorganic N, and trees supplied with highest levels of NH 4 NO 3 also had the highest N contents in the dry matter of needles and roots. In contrast, N contents in needles of trees grown without additional N, or with keratin supply, were in the deficiency range. Supply of NH 4 NO 3 decreased the contents of phosphate (P) and potassium (K) and therefore markedly increased N/P and N/K ratios in the needles. On the other hand, the contents of calcium (Ca), magnesium (Mg), and manganese (Mn) in the needles were increased in the plants supplied with inorganic N, suggesting high soil availability and promotion of uptake of these divalent cations by high nitrate uptake. The observed effects on root/shoot dry weight ratio, root morphology, and mineral nutrient composition of the needles indicated that high inorganic N supply may increase above-ground productivity but at the same time decrease the tolerance of trees against soil-borne (e.g. deficiency of other mineral nutrients) stress factors.
    Keywords: foliar nutrient contents ; nitrogen ; Picea abies ; root growth ; root morphology ; root/shoot ratio
    ISSN: 0032-079X
    E-ISSN: 1573-5036
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  • 3
    In: Tree Physiology, 2009, Vol. 29(2), pp.199-206
    Description: Nutrient sources in soils are often heterogeneously distributed. Although many studies have examined the root responses to local N and P enrichments in the soil, less research was conducted on root responses to Mg patches. New roots of pre-grown Mg-insufficient and Mg-sufficient plants of Norway spruce ( Picea abies [L.] Karst.) and Scots pine ( Pinus sylvestris L.) seedlings were allowed to grow into four other pots of equal size, which were placed under the tree-bearing pot. Soils in the lower pots were either unfertilised, or supplied with Mg, or NPK or a mixture of NPKMg sources. Plants were harvested after 9 months of growth. Compared to the corresponding controls (Mg versus unfertilised and NPKMg versus NPK), Mg additions did not have a significant effect on either root dry matter, total root length (TRL) or specific root length (SRL), irrespective of tree species and plant Mg nutritional status. In contrast, NPK and NPKMg additions significantly increased the root dry matter and TRL in the nutrient-rich soil patch, and decreased SRL in Norway spruce. However, the observed root morphological changes did not occur in Scots pine. Root Mg concentrations were increased in Mg-rich soil patches, but those accumulations varied with tree species. Mg accumulation in a marked patch was measured only in newly grown roots of Mg-sufficient Norway spruce, whereas a more homogenous distribution of Mg concentration was observed for all newly grown roots in Mg-insufficient trees in the four soil treatments. In Scots pine, Mg accumulations occurred in both Mg-insufficient and Mg-sufficient plants. These results suggest that Mg patches in the soil may not lead to a local increase in root growth, but to Mg uptake and root Mg accumulation. Tree roots react differently to Mg patches in comparison to their response to N or P patches in the soil.
    Keywords: Coniferous Tree ; Nutrient Concentrations ; Nutrient - Enriched Soil ; Nutrient Patches ; Plant Nutritional Status ; Root Growth ; Root Plasticity
    ISSN: 0829-318X
    E-ISSN: 1758-4469
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  • 4
    Language: English
    In: Trees, 1991, Vol.5(1), pp.14-21
    Description: Relationships between root zone temperature, concentrations and uptake rates of NH 4 + and NO 3 − were studied in non-mycorrhizal roots of 4-year-old Norway spruce under controlled environmental conditions. Additionally, in a forest stand NH 4 + and NO 3 − uptake rates along the root axis and changes in the rhizosphere pH were measured. In the concentration (C min ) range of 100–150 μM uptake rates of NH 4 + were 3–4 times higher than those of NO 3 − The preference for NH 4 + uptake was also reflected in the minimum concentration (C min ) values. Supplying NH 4 NO 3 , the rate of NO 3 − uptake was very low until the NH 4 + concentrations had fallen below about 100 μM. The shift from NH 4 + to NO 3 − uptake was correlated with a corresponding shift from net H + production to net H + consumption in the external solution. The uptake rates of NH 4 + were correlated with equimolar net production of H + . With NO 3 − nutrition net consumption of H + was approximately twice as high as uptake rates of NO 3 − In the forest stand the NO 3 − concentration in the soil solution was more than 10 times higher than the NH 4 + concentration (〈100 μM), and the rhizosphere pH of non-mycorrhizal roots considerably higher than the bulk soil pH. The rhizosphere pH increase was particularly evident in apical root zones where the rates of water and NO 3 − uptake and nitrate reductase activity were also higher. The results are summarized in a model of water and nutrient transport to, and uptake by, non-mycorrhizal roots of Norway spruce in a forest stand. Model calculations indicate that delivery to the roots by mass flow may meet most of the plant demand of nitrogen and calcium, and that non-mycorrhizal root tips have the potential to take up most of the delivered nitrate and calcium.
    Keywords: Ammonium ; Calcium ; Nitrate ; Picea abies ; Rhizosphere pH
    ISSN: 0931-1890
    E-ISSN: 1432-2285
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  • 5
    In: Tree Physiology, 1997, Vol. 17(1), pp.39-45
    Description: The spatial distribution of plant-available mineral nutrients in forest soils is often highly heterogeneous. To test the hypothesis that local nutrient enrichment of soil leads to increased root proliferation in the nutrient-rich soil zone, we studied the effects of nutrient enrichment on the growth and nutrient concentrations of Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco), Scots pine ( Pinus sylvestris L.) and Norway spruce ( Picea abies (L.) Karst.) roots. Three-year-old seedlings were grown for 9 months in split-root containers filled with nutrient-poor forest mineral soil, with one side supplemented with additional mineral nutrients. Root dry weight and root length in Scots pine and Norway spruce were increased in the nutrient-supplemented soil compared with the nonsupplemented side, whereas root growth in Douglas-fir was unaffected by nutrient enrichment. Of the three species examined, Norway spruce exhibited the highest root and shoot growth and the highest nutrient demand. Specific root length (m g −1 ) and the number of root tips per unit root length were not affected by local nutrient addition in any of the species. Despite increased root growth in Norway spruce and Scots pine in nutrient-supplemented soil, their root systems contained similar nutrient concentrations on both sides of the split-root container. Thus, coniferous trees may respond to local nutrient supply by increased root proliferation, but the response varies depending on the species, and may only occur when trees are nutrient deficient. As a response to local nutrient enrichment, increases in root dry matter or root length may be better indicators of pre-existing nutrient deficiencies in conifers than increases in root nutrient concentrations.
    Keywords: Douglas - Fir ; Local Nutrient Supply ; Norway Spruce ; Nutrient Concentrations ; Root Growth ; Root Morphology ; Scots Pine
    ISSN: 0829-318X
    E-ISSN: 1758-4469
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  • 6
    Language: English
    In: Journal of Plant Nutrition and Soil Science, June 1999, Vol.162(3), pp.301-307
    Description: To understand the effect of increased soil N supply on tree growth and nutrient uptake, three‐year‐old Norway spruce seedlings were grown in pots on low‐nutrient mineral forest soil supplemented with N in mineral or organic form. Outdoor shaded growth conditions were used, to test the hypothesis that shaded plants are particularly susceptible to high soil N supply. Plants were harvested eleven months after planting. Shoot growth was not affected by the N supply, but N concentrations in needles and roots were increased in plants supplied with mineral N (150 or 300 mg N [kg soil]). Root growth was drastically reduced and root/shoot ratios were decreased in plants with higher N uptake. A high supply of mineral N to soil also decreased the concentrations of other essential elements (P, K) in the needles and thus had effects on plant growth which may impair the stress resistance of trees. Organic N in the form of keratin (150 mg N [kg soil]) did not influence plant growth significantly. The adverse effects of high mineral N supply were particularly pronounced under shaded conditions in comparison to results from other experiments using higher light intensity and temperature conditions. Einfluß des Stickstoffangebots im Boden auf Wachstum und Nährstoffaufnahme von Jungfichten unter schattigen Bedingungen Die Auswirkungen eines erhöhten Stickstoffangebots auf Wachstum und Nährstoffaufnahme von dreijährigen Fichtenjungpflanzen wurden in einem Gefäßversuch unter schattigen Freilandbedingungen untersucht. Dabei wurde die Vermutung getestet, daß beschattete Fichten besonders empfindlich auf ein hohes Stickstoffangebot reagieren. Nach elf Monaten Versuchsdauer hatte die Stickstoffversorgung des Bodens keinen signifikanten Einfluß auf das Sproßwachstum. Die Stickstoffkonzentrationen in Nadeln und Wurzeln waren jedoch erhöht, wenn dem Boden mineralischer Stickstoff zugegeben worden war (150 bzw. 300 mg N [kg Boden]). Die mit mineralischem Stickstoff versorgten Pflanzen zeigten ein stark vermindertes Wurzelwachstum und ein verringertes Wurzel‐/Sproßverhältnis. In diesen Pflanzen waren auch die Nadelkonzentrationen an Phosphor und Kalium deutlich vermindert. Keratin als organische Stickstoffquelle (150 mg N [kg Boden]) hatte keinen Einfluß auf das Baumwachstum. Die negativen Effekte hoher Gehalte an mineralischem Stickstoff im Boden waren in diesem Versuch stärker ausgeprägt als in ähnlichen Versuchen unter optimalen Licht‐ und Temperaturbedingungen.
    Keywords: Ammonium ; Induced Nutrient Deficiency ; Nitrate ; Picea Abies ; Root Growth ; Shoot/Root Ratio
    ISSN: 1436-8730
    E-ISSN: 1522-2624
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  • 7
    In: Physiologia Plantarum, December 1997, Vol.101(4), pp.764-769
    Description: In numerous locations in Europe spruce trees are exposed to high loads of nitrogen. The present study was performed to characterize the distribution of nitrogen compounds under these conditions. For this purpose Norway spruce ( [L.] Karst.) trees were cultivated under close‐to‐natural conditions of a forest understory in soil from an apparently nitrogen‐limited field site in the Black Forest either with, or without supplementation of nitrogen as ammonium nitrate. After 11 and 20 months, growth, total nitrogen contents of the biomass, and total soluble non‐proteinogenic nitrogen compounds (TSNN, i.e. nitrate, ammonium, soluble proteinogenic and non‐proteinogenic amino compounds) in needles, xylem sap and phloem exudate were analysed. After 20 months of growth, N‐fertilization had slightly enhanced the biomass of current‐, but not of 1‐year‐old shoots. At both harvests, total N‐content of 1‐year‐old needles was increased by N‐fertilization, whereas current‐year needles were not significantly affected. By contrast, TSNN was elevated by N‐fertilization in both current‐year and 1‐year‐old needles. The increase in TSNN was mainly attributed to an accumulation of arginine. Xylem sap analysis showed that the increase in TSNN of the needles was a consequence of enhanced nitrogen assimilation of the roots rather than the shoot. Since also TSNN in phloem exudates was enhanced, it appears that N‐fertilization elevates the cycling pool of amino compounds in young Norway spruce trees. However, this pool seems to be subject to metabolic interconversion, since mainly glutamine and aspartate are transported in the xylem from the roots to the shoot, but arginine accumulated in the needles and the phloem.
    Keywords: Arginine ; Aspartate ; Glutamine ; Nitrogen Cycling ; Nitrogen Supply ; Phloem Exudate ; Picea Abies ; Spruce ; Xylem Sap
    ISSN: 0031-9317
    E-ISSN: 1399-3054
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