Pigment composition in Norway spruce needles suffering from different types of nutrient deficiency

 Concentrations of pigments in needles of yellowish Norway spruce [Picea abies (L.) Karst] trees suffering from either N, Mg or K deficiency in field sites in southeast Norway are reported. The yellowish trees had a considerably lower (roughly 50%) pigment concentration, as well as a lower chlorophyll/carotenoid ratio, compared to green trees within the same sites. Yellowing was interpreted as a general bleaching of colour, as well as a slight turn from the green (chlorophylls) towards yellow (lutein). Concentrations of pigments were highly intercorrelated. N deficiency was especially associated with low α-carotene concentrations. This was interpreted as α-carotene being the most sensitive pigment to stress. However, this pigment might be specifically sensitive to N deficiency. Carbohydrate concentrations were slightly higher in yellowish trees. Received: 5 June 1997 / Accepted: 29 August 1997     

Revitalization experiments in magnesium deficient Norway spruce stands in Austria

Amelioration of degraded forest ecosystems on acidic substrates showing the new type of forest decline is a major goal of forest management. A number of experiments show positive effects of Mg-application to systems suffering from Mg-deficiencies. The current paper compares experiments conducted in the Austrian part of the Bohemian Massif, where both effects on soil solution chemistry and effects on plant nutrition, vitality and growth were investigated. It turned out that any type of Mg-source is able to improve Mg-nutrition of trees; both a neutral salt like KIESERITE as well as alkaline reacting magnesite and dolomite derived materials. A positive reaction of vitality and growth could however only be induced with dolomitic lime or magnesite. Using mineral NPK fertilizers, even with high Mg-content, induced Mg-deficiencies and led to nutritional imbalances. In addition significant NO₃ ^--leaching occured. On the other hand an organic slow release fertilizer (BACTOSOL*) amended with magnesite derived fertilizers (BIOMAG**) led to balanced nutrition and a fast recovery of tree health status, as judged by crown transparency, vitality index and growth rates. In both cases, when either magnesite derived compounds or combinations with the organic slow release fertilizer were applied, NO₃ ^--leaching occured only during the first three years after fertilization. The leaching rates declined afterwards to values comparable to unfertilized plots, while Mg-content of the soil solution could be elevated compared to the CONTROL, showing the sustainability of proper fertilization.     

The influence of ozone on the stomatal and non-stomatal limitation of photosynthesis in Norway spruce,Picea abies (L.) Karst,exposed to soil moisture deficit

Summary Norway spruce, Picea abies (L.) Karst., was exposed to charcoal-filtered air (CF) and non-filtered air + ozone (NF+) and periods of soil moisture deficit from 1985 to 1988 in open-top chambers. Net photosynthesis, stomatal conductance, needle water potential and various shoot properties were measured on 1-year-old shoots during a period of soil moisture deficit. The gas exchange was measured at saturating photosynthetic photon flux density and across a range of CO₂ concentrations. The soil moisture deficit induced a mild drought stress in the plants, expressed by a pre-dawn needle water potential of approximately-0.9 MPa and a substantial reduction in net photosynthesis and gas phase conductance. In the CF treatment, intercellular CO₂ concentration was reduced, but was unaffected in the NF+ treatment. Furthermore, net photosynthesis declined more in response to the soil moisture deficit in the NF+ treatment than in the CF treatment. This is suggested to be attributed to the carboxylation efficiency at the operating point, which was decreased by 47% and 64% in shoots from the CF and the NF+ treatments, respectively. Stomatal limitation of net photosynthesis was increased by drought by 24–45% in the CF treatment, while it was unaffected in the NF+ treatment. Thus, our results imply that the coupling between the stomatal conductance and the photosynthetic rate was changed and that the marginal cost of water per given amount of carbon gain will increase in trees exposed to ozone, during periods of drought.     

Short-term pigment changes in Norway spruce needles

The photosynthetic pigment contents and the chlorophyll fluorescence induction in Norway spruce [ Picea abies (L.) Karst.] needles were monitored at 3 h intervals over a 10 day period. This covered 6 days of high insolation, one day of low insolation, followed by three more days of high insolation. During the first six days only small changes in mean pigment contents were observed but we interpret them as suggesting a daily rhythm in total chlorophyll content with two maxima and minima. The day of low insolation was paralleled by larger pigment changes, mostly an increase in chlorophyll b along with a decrease in carotenoid content. With the resumption of high insolation, pigments gradually return to their previous levels. During the entire period chlorophyll a fluorescence induction remained relatively constant. These short-term responses may reflect features of thylakoid organization in relation to pigment content and suggest possible long-term adaptive mechanisms in non deciduous conifers.     

Growth response to different types of NPK-fertilizer in Norway spruce plantations in Western Denmark

In Norway spruce planted on former heathland and fertilized to increase production, a series of experiments (72 sample plots) was established throughout Central and Western Jutland (Denmark) during the springs of 1978 and 79. The sample plots were all fertilized with 120 kg nitrogen in each of two five-year periods. Different types of mixed nitrogen/potassim/phosphorus fertilizer were applied. According to results from fertilization trials in the 1950s and 60s a gain of 3–4 m³ · ha^-1 · year^-1 was expected. In contrast to these earlier findings, only 0, 76 m³ · ha^-1 · year^-1 was gained over the two periods as an average of all sample plots. The initial assumption that nitrogen is the main limiting factor for tree growth in Western Denmark no longer seems valid. The results might indicate that due to increasing nitrogen deposition during the 1970s and 80s, potassium and maybe phosphorus are developing into new minimum factors, limiting tree growth and devitalizing the forest ecosystem. Hence, fertilization on these soils should mainly be considered as a way to compensate such nutrient imbalances.     

Seasonal development of the photosynthetic performance of Norway spruce (Picea abies [L.] Karst.) under magnesium deficiency

In order to investigate the influence of different magnesium nutrition on photosynthesis, one hundred 6-year-old spruce trees derived from one clone were planted in October 1990 into a special out-door experimental construction, where they were cultivated in sand culture with an optimal supply of nutrients, except magnesium, via circulating nutrient solutions. Magnesium was added to the nutrient solutions in three different concentrations, varying from optimal to severe deficient supplies. During the first vegetative period in 1991, photosynthetic performance and carboxylation efficiency were measured under saturating light, controlled CO₂ conditions, optimal temperature and humidity, using a minicuvette system.During summer, the trees under moderate magnesium deficiency developed tip yellowing symptoms on older needles, while the youngest needles remained green with unchanged chlorophyll contents. Trees under severe magnesium deficiency showed yellowing symptoms on all needle age classes combined with decreased chlorophyll contents in the youngest needles as well. In comparison with the controls, the photosynthetic performance of the 1-year-old needles was significantly lower in both deficiency treatments. The same was observed in the youngest needles of the trees under severe deficiency. Trees under moderate deficiency treatment decreased in photosynthetic performance during the summer without reduction of chlorophyll contents. The reduction of photosynthetic rates corresponded to a decrease in carboxylation efficiency, which is taken as a measure of the activity of the enzyme ribulose-1,5-bisphosphate carboxylase. This reduction, together with the observed increase of carbohydrate contents in needles of trees growing under magnesium deficiency, led to the assumption that the photosynthetic carbonfixation is reduced as a consequence of the accumulation of carbohydrates.     

The ectomycorrhizal community structure in high mountain Norway spruce stands

The species composition of ectomycorrhizal (ECM) fungal communities can be strongly influenced by abiotic and biotic factors, which determine interactions among the species such as resource partitioning, disturbance, competition, or relationships with other organisms. To verify whether ectomycorrhization of the root tips and composition of the ECM community in Norway spruce vary according to site features and if ECM species peculiar to these environmental variables can be detected, ten comparable stands differing in bedrock pH and exposure were selected and studied. The results demonstrated that tips vitality and ectomycorrhization degree do not change significantly either on the same tree, or among trees growing in the same stand, whereas they differ greatly with bedrock pH and exposure, even if no spatial or temporal trend were found. ECM species composition revealed instead a significant connection with the two environmental features, with a few species significantly associated to them. The results suggest that pH/exposure patterns play a primary role in the adaptive selection of ECM species constituting the consortium.     

Photoinactivation of catalase in needles of Norway spruce

Catalase IEC 1.11.1.6) activity in Norway spruce ( Picea abies [L.] Karst.) needles was examined under different environmental conditions. When shade-adapted spruce trees were exposed to full sunlight or to high light intensities in growth chambers, the catalase activity decreased. Under continuous light the activity was reduced in comparison to the control grown in light/dark cycles. The reduction of the activity was not temperature dependent. Under field conditions the activity was higher in hranches oriented north than in those oriented south. A diurnal rhythm with a maximum in the night was delected. The reduction in catalase activity also occurred in young white needles of Picea ahies vur. argenteospica . which are free of chlorophyll. It is concluded that in Norway spruce needles there is a ligh:-dependent photoinactivation of catalase. which is not temperature-dependent.     

Influence of UV-B radiation on photosynthetic activity and chlorophyll fluorescence kinetics in Norway spruce [Picea abies (L.) Karst.] seedlings

Norway spruce [Picea abies (L.) Karst.] seedlings were grown in greenhouses with two supplemental levels of ultraviolet-B (UV-B) radiation. Photochemical efficiency of photosystem II and vitality index were determined monthly. At the end of the experiment, growth, chlorophyll content and photosynthetic rates were measured. The data indicate that low temperature in winter affected light dependent processes in experimental plants including control, while the rise of ambient temperatures, moderate this effect. The synergistic effects of UV-B radiation and low temperatures could only be observed in the second winter period. Measurements of net photosynthetic activity in the second winter period showed significant differences between treated and untreated plants.     

Karyotype of Norway spruce by multicolor FISH

The chromosomes (2n = 2x = 24) of Norway spruce are very large since their size reflects the huge amount of genomic DNA (2C = 30 × 10⁹ bp). However, the identification of homologous pairs is hampered by their high degree of similarity at the morphological level. Data so far presented in the literature were not sufficient to solve all the ambiguities in chromosome identification. Several genomic Norway spruce DNA clones containing highly repetitive sequences have been identified and characterised in our laboratory. Three of them were selected for fluorescent in situ hybridization (FISH) experiments because of their strong signals and suitability for chromosome identification: PATR140 hybridized at the centromeric site of three chromosome pairs; PAF1 hybridized in six subtelomeric and two centromeric sites; 1PABCD6 co-localized with the subtelomeric sites identified by PAF1. The statistical analysis of microscopic measurements of chromosomes in combination with the FISH signals of these probes allowed the unambigous construction of Norway spruce karyotype. We also compared the karyotype of Norway spruce with that of other spruce species to infer the number and kind of rearrangements that have occurred during the evolution of these species.Communicated by D.B. Neale     

Evidence for the involvement of biotic factors in the yellowing disease of Norway spruce (Picea abies [L.] Karst.) at higher elevations of the Bavarian Forest

Extensive investigations on the fine root status of declining and healthy spruce were conducted in several stands at higher elevations of the Bavarian Forest heavily affected by needle yellowing. In most of the root parameters recorded, yellowing trees had significantly lower values than neighbouring green trees. Tight correlations were found between decreasing fine root density and crown transparency, degree of yellowing (increasing) and needle Mg (Ca) contents (decreasing), respectively. Although growing on the same substrate, green trees showed much better Mg (Ca) nutrition than yellow trees, indicating that poor fine root status contributes to Mg (Ca) deficiency in yellowing spruce. Experiments with spruce seedlings growing in soil samples from yellowing stands proved that needle symptoms can easily be reproduced on the seedlings under controlled conditions (i.e. in the absence of adverse atmospheric factors). Furthermore, reduced fine root systems and severe root damage were observed on seedlings grown in soils from yellowing stands, but not on those in soils from green stands. Adding a layer of soil from a yellow stand to a soil from a green stand caused a decrease of root parameters. Needle as well as root symptoms in these experiments were largely ameliorated after soils had been heat (autoclaving, sterilisation) or fungicide treated. Plants from treated soils had significantly longer roots and more root tips. The results of our study indicate that Mg deficiency leading to severe needle yellowing in stands at higher elevations of the Bavarian Forest is at least partially mediated by fine root disorders. Also, strong evidence is presented that fine root damage on trees in the affected stands is caused by soilborne micro-organisms, most likely fungi. Their exact identity, however, still remains to be unravelled.     

Effects of ozone on organic acids in needles of Norway spruce and Scots pine

Summary The effect of ozone, needle age, and season on the pH of homogenate and acid contents of Scots pine and Norway spruce needles is presented. In addition enzyme activities of cytochrome C-oxidase (cyt. C-ox), phosphoenolpyruvate-carboxylase (PEPC), shikimic acid-dehydrogenase (SHDH) and malate-dehydrogenase (MDH) were measured in Scots pine needles. In freshly sprouted spruce needles the level of quinic acid is high and the pH of the needle homogenate is low. Shikimic acid starts at low levels, increases with increasing needle age and becomes dominant, whereas the quinic acid content decreases. Malic acid has a marked seasonal trend; no trend was found in citric acid. Ozone (200 g/m³) decreased shikimic acid and quinic acid, whereas pH, malic acid and citric acid increased. Ozone (100 g/m³) had a similar effect, except in the current-year spruce needles. In Scots pine needles ozone led to increased enzymatic activities of cyt. C-ox, PEPC and SHDH, and a decrease in the activity of MDH. This effect was more pronounced in summer than in autumn, but the visible damage was greater in autumn. These effects can be found with other stresses and are not specific for ozone.     

Experimental evidence of a deleterious soil microflora associated with Norway spruce decline in France and Germany

Norway spruce (Picea abies (L.) Karst.) seedlings were grown in a glasshouse pot experiment in soils from 11 declining and 7 healthy spruce stands from France and Germany. In soils from 9 declining stands, seedlings showed decline symptoms (needle yellowing). Soil pasteurization suppressed the symptoms, and reinoculation of the pasteurized soil with a rhizospheric extract from the corresponding stand re-induced yellowing. This suggests that a deleterious soil microflora is associated with spruce decline. The occurrence of this microflora seems to be correlated with the main chemical characteristics of the soils (low pH, low saturation of the adsorbing complex, low exchangeable Ca²⁺ and Mg²⁺, and high level of exchangeable Al). ei]R F Huettl     

Nitrogen and drought effects on ectomycorrhizae of Norway spruce [Picea abies L.(Karst.)]

Effects of N addition and drought on ectomycorrhizae of Norway spruce trees were investigated in an outdoor pot lysimeter study. Three levels of N were applied as ammonium nitrate in irrigation water for five years; ambient rainwater (N0) and 5 (N5) and 15 (N15) times this N concentration. Mean annual N addition during the five years corresponded to 5, 27 and 82 kg·ha^-1·y^-1 for the N0, N5 and N15 treatments, respectively. During the third and fifth growth seasons two levels (lengths) of drought were artificially induced in addition to a watered control. Soil cores taken from each pot lysimeter were analyzed for mycorrhizal colonization and ectomycorrhizae were categorized according to macroscopic morphology. Drought decreased mycorrhizal colonization significantly. There was a significant interaction of drought and N effects on reduction of the mycorrhizal colonization. Although all of the mycorrhiza types were influenced by drought, only Cenococcum geophilum showed a significant change. N treatment alone did not show any significant effect either on mycorrhizal colonization or mycorrhizal types.     

Effects of Mg(OH)2-fertilization on nutrient cycling in a heavily damaged Norway spruce ecosystem (NE Bavaria/FRG)

Main objective of this study was to test the effects of Mg(OH)₂-fertilization in a Norway spruce ecosystem showing severe symptoms of Mg-deficiency.The site is characterized by high atmospheric inputs with deposition rates of 1.25 kg H, 42 kg S, and 32 kg N per ha and year. The typic Dystrochrept derived from granite is acidified down to greater depths. The pH-values in soil solution of the organic surface layer and the upper mineral soil are around 3.5. Concentrations of Al, SO₄ ^2-, and especially NO₃ ^- and DOC are very high. The element balance indicates a significant influence of N-inputs and processes of N-turnover on the chemical status of the soil and probably on tree nutrition. Nitrification in the upper mineral soil leads to a transformation of a major part of NH₄ ⁺ into NO₃ ^-, which is quantitatively leached, resulting in an ecosystem-internal H⁺-production of 1.8 keq ha^-1yr^-1. NO₃ ^- and SO₄ ^2- govern the seepage output from the ecosystem.Mg(OH)₂ fertilization resulted in manifold increased Mg²⁺ concentrations in soil solution down to 70 cm soil depth and to a significant increase of pH down to 25 cm mineral soil depth. Nitrate concentrations were elevated after fertilization, but decreased within 15 months below the level of the control plot. As a mean over the whole experimental period, N-output was not increased by fertilization. Despite an elevated internal proton production due to nitrification, acid buffering in the soil was clearly increased, but enhanced Al-mobilization was not observed. Mg/Al- and Ca/H-ratios in soil solution indicate much more favourable conditions for fine root growth. Fertilization also increased the amount of exchangeable Mg down to 40cm mineral soil depth. Mg contents in current-year needles increased after three vegetation periods. Thirty months after application, only 10% and 4% of the fertilized Mg had left the organic surface layer and the mineral soil with seepage water output, respectively.     

Development of biomass proportions in Norway spruce (Picea abies [L.] Karst.)

This study tests the hypotheses that (1) the above-ground structure of Norway spruce (Picea abies [L] Karst.) is derivable from the functional balance theory, and that (2) crown ratio is a key source of structural variation in trees of different age and social position. Twenty-nine trees were measured in three stands (young, middle-aged, and mature), with three thinning treatments (unthinned, normal, and intensive) in the two older stands. There was a strong linear relationship between the total cross-sectional area of branches and that of stem at crown base. Foliage mass was linearly related with stem basal area at crown base. Also an allometric relationship was found between foliage mass and crown length. The mean length (weighted by basal area) of branches obeyed an exponential function of crown length. The parameters of most of these relationships were independent of slenderness (tree height/breast height diameter) and tree age However, total branch cross-sectional area per stem cross-sectional area in the young trees was greater than in the older trees. The young trees also had slightly shorter branches than predicted by the mean branch length equation. This was probably caused by branch senescence which had not yet started in the young stand. The older trees had a relatively long lower crown segment which was growing slowly and senescing. It was proposed that a segmented crown structure is characteristic of shade tolerant tree species, and that the structural model could be further developed by making the two segments explicit.