The effects of aluminium and Paxillus involutus Fr. on the growth of Norway spruce [Picea abies (L.) Karst.]

Norway spruce [ Picea aides (L.) Karst.] seed lots were obtained from populations growing on an acid soil in the Black Forest, West Germany (acid), and a calcareous soil in the Schwabische Alb, West Germany (calc). Seedlings were grown in sterile perlite culture containing 0–6 mM aluminium. Hypocotyl extension was inhibited by aluminium in the calcareous seedlings, hut not in the acidic seedlings. In a longer term experiment acidic and calcareous plants were grown for 10 weeks in perlite. Some of the tubes were inoculated with the fungus Paxillus involutus Fr. (designated F +) and some were not (F -). Aluminium sulphate solutions were then added to the tubes to raise the aluminium concentrations to 0–6 mM. Plants were harvested after a further 10 weeks. Fungus was associated with the roots in F+ plants, but mycorrhizas did not form. Growth of acid(F -) was somewhat stimulated by aluminium treatment, but that of calc(F -) was greatly reduced, and the plants were chlorotic. The presence of a rhizospherie fungus (F +) enhanced the growth of the calcareous plants, but had little effect on the acidic plants. Shoot analyses suggested that the greater aluminium sensitivity of the calcareous plants involves an inability to exclude aluminium or to maintain normal levels of calcium and magnesium uptake in its presence. The presence of rhizospheric fungi reduced the effects of aluminium.     

Effects of climate on vertical resin duct density and radial growth of Norway spruce [Picea abies (L.) Karst.]

 Vertical resin duct density in spruce tree-rings was used as a dendroclimatological variable and compared with radial growth. Resin duct density data were statistically stable and distributed with higher mean sensitivity and standard deviation but lower signal-to-noise rate than the corresponding growth rate. Radial growth and resin duct density relationships with climate were investigated using correlation and response function analysis. It was found that resin duct density has a significant positive response to above-normal temperature especially from June to August and a less significant negative response for above-normal precipitation from May – July during the current growing season. Ring width showed a significant negative response to above-normal precipitation from June to August but no response with temperature. Ring width and resin duct density were not related to each other. Sufficient data indicate that vertical resin duct density is a useful variable for dendroclimatology. Received: 14 March 1996 / Accepted: 24 June 1996     

Production of Seeds and Cones and Consequences for Wood Radial Increment in Norway Spruce (Picea Abies (L.) Karst.)

Abstract

The presence of a trade–off between growth and reproduction was tested in four sites in a subalpine Norway spruce (Picea abies (L.) Karst.) forest by measuring annual stem diameter increments at breast height and seed and cone productions during the periods 1962–1985 and 1983–1990, respectively. Trees growing in forest stands near the timber line (about 1900 m above sea level) had the greatest reduction in annual stem diameter increment during mast years; while trees growing at about 1300–1500 m above sea level did not show any reduction. Trees growing at about 1700 m showed only a limited reduction. At the same elevation, trees growing within closed forest stands suffered a greater reduction in stem growth when compared with trees growing at the edge of a cutting.     

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.     

The concentrations of Fe, Zn and Co in successive needle age classes of Norway spruce [Picea abies (L.) Karst.]

The concentrations of Fe, Zn and Co were determined in up to five successive needle age classes in 54 individual Norway spruce trees from eight different sites (soil pH 3.1–7.7). Fe concentrations (12–25 μg in needles from the current year) were lower than most published values, due to the removal of surface contamination prior to analysis. Fe showed a significant positive correlation with Al. Successive needle age classes either had constant values or showed an increase for Fe concentrations; individual trees on a given site were rather uniform in their behaviour. Zn concentrations were 19–40 μg/g. On acid sites, they showed a positive correlation with total soil concentrations. The majority of trees showed decreasing Zn concentrations in successive needle age classes, but constant or increasing concentrations were also found; site homogeneity was less than with Fe. Co concentrations differed between trees on a neutral soil (12 ng/g) and on acid soils (41–174 ng/g). They showed a significant positive correlation with Mn needle concentrations. The changes of Co with needle age in most, but not all, trees were similar to those of Zn. The different changes of Fe, Zn and Co with needle age may be due to a different retranslocation. A modest retranslocation of Fe as opposed to a high retranslocation of Zn and Co (in most trees) is consistent with the observed behaviour. Received: 10 May 1999 / Accepted: 8 September 1999     

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.     

Seasonal variation in the monoterpenes in needles of Picea abies (L.) Karst.

Summary This investigation was conducted to obtain information about the fluctuations in composition and amount of needle monoterpenes during the development of spruce needles. Studies conducted with two Norway spruce clones clearly revealed the existence of fluctuations. In juvenile needles, the amounts of the oxygenated terpenes increase constantly with age during the first 2 months of needle growth. The hydrocarbon terpenes dominate within the first weeks, some of them even showing a very distinct first maximum within the first 3 weeks after bud burst. All terpenes, including the oxygenated ones, have a maximum in June/July, which favours the hypothesis of a substitution of the hydrocarbons later on. There are significant changes even in mature needles of Norway spruce. The terpene level of 1-year-old needles of the clonal trees increased from spring to early summer and then dropped again towards winter. In addition, fluctuations in mature needles were shown for a set of ten wild trees. Needles of the same age class, which emerged in 1986, were sampled 4 times from 1986 to 1988. The needle terpene concentrations of the 1 -year-old needles were considerably lower in spring at the time of bud burst than in autumn. The terpene level of older needles thus seems to be influenced by biosynthetic and catabolic activities.     

The effect of acid irrigation on enzyme activities of the single partners of ectomycorrhizas from a limed stand of Norway spruce (Picea abies [L.] Karst.)

The aim of our investigations was to elucidate the effects of acid precipitation on some enzymes of the primary metabolism of ectomycorrhizas. Mycorrhizas of the type of Piceirhiza nigra Gronbach and of Russula ochroleuca (Pers.) Fr. and Tuber puberulum Berk. and Br. were collected from a stand of Norway spruce (Picea abies [L.] Karst.) during the growing seasons of 1991 and 1992. The experimental plots had been limed (Ca: 22 kmol ha_-1, Mg: 20 kmol ha_-1) in 1984 and exposed to acid irrigation (pH 2.7–2.8, H₂SO₄: 2 kmol ha_-1 a_-1) from 1984 to 1990. Crude extracts of mycorrhizas were assayed for the activities of glucose-6-phosphate dehydrogenase (G6P-DH, EC 1.1.1.49), 6-phosphogluconate dehydrogenase (EC 1.1.1.44), NADP-dependent isocitrate dehydrogenase (EC 1.1.1.42) and NAD-dependent glutamate dehydrogenase (EC 1.4.1.2). The influence of the experimental treatments on these enzyme activities of the primary metabolism was generally low. For P. nigra, the activity of G6P-DH was decreased on the irrigated plot (photometric determinations). This seems to be a selective effect on the fungal partner, since quantitative enzyme electrophoresis revealed a decrease in the percentage of the fungal enzyme activity in relation to the total enzyme activity, whereas the content of the fungal compound ergosterol was not affected. A decrease in the fungal G6P-DH activity could also be detected in mycorrhizas of Tuber puberulum. There was also a seasonal variation in the proportion of fungal activity of G6P-DH in relation to the total G6P-DH activity. In the photometric assay (total activity) the effect was not discernible. This is indicative of a degree of regulation between the two partners, which could only be detected by quantitative enzyme electrophoresis. In addition, it could be deduced from the electrophoretograms, that in the case of G6P-DH and 6PG-DH the fungal enzyme activity was dominating in all mycorrhizas studied whereas in the case of ICA-DH the fungal band varied from being conspicuous to absent in different species of mycorrhizas. The banding pattern of G6P-DH was reproducibly different for all investigated species of mycorrhizas.     

Effect of artificial soil acidification and liming on growth and nutrient status of mycorrhizal roots of Norway spruce (Picea abies [L.] Karst.)

Effects of soil acidification and liming on biomass responses and free Al, Ca, K, Mg, Mn and P contents of mycorrhizal roots of mature Norway spruce (Picea abies [L.] Karst.) were studied at Höglwald Forest in Southern Germany.At the untreated site, mycorrhizal root biomass was lower in the acid humus (pH = 3.3) than in the less acid upper (0–5 cm) mineral soil (pH 4.1). Mycorrhizal roots from the humus contained 10% of the level free Al in mycorrhizal roots from the upper mineral soil. During seven years of soil acidification the quantity of mycorrhizal roots remained unaffected in the humus and the upper mineral soil, perhaps due to the high buffering capacity of the humus which prevented a significant alteration of the nutrient status of the roots. However, two years after soil acidification had been terminated, the percentage of mycorrhizal roots in the humus decreased, possibly because the free root concentrations of K had decreased.On the other hand, six years after liming, there was a two-fold increase of the annual mean quantity of mycorrhizal roots in the humus. Compensatory liming (acid irrigation after liming) had a similar effect on mycorrhizal root production in the humus. However, two years after acid irrigation had been terminated a decrease of mycorrhizal roots in the upper mineral soil (0–5 cm) was observed. Since the total amount of mycorrhizal roots in the humus and upper mineral soil remained constant, compensatory liming produced a shift in fine roots to the humus layer.The higher mass of living mycorrhizal roots in the upper mineral soil (0–5 cm) as compared to the humus of the untreated plot as well as the increased mass of mycorrhizal roots in the humus after liming or compensatory liming are both attributed to an increase in pH to 4.5 rather than alleviation of Al toxicity.     

Recent cooling and recession of Norway spruce (Picea abies (L.) Karst.) in the forest—alpine tundra ecotone of the Swedish Scandes

Abstract. Repeated crown condition surveys, 1974–94, of subalpine clonal groups of Norway spruce ( Picea abies (L.) Karst.) were carried out in the Swedish Scandes. Complementary analyses concerned radial and vertical growth, sexual regeneration and range limit responses of other plant species. Significant defoliation of spruce progressed linearly over the period of study, reaching cumulative values of about 85%. It is inferred that defoliation was preconditioned by decreasing radial growth since the thermal climax in 1937 and was proximately initiated by the extremely cold winter of 1965/66 and paralleled by consistently declining radial growth and staggering vertical increase. It appears that severe and prolonged ground freezing invoked winter desiccation (xylem cavitation), extensive needle loss and reduced radial growth. Hypothetically, from circumstantial evidence, these processes are interrelated in a positive feedback system, implying increasing sensitivity to climatic stress and decreasing ability to take advantage of positive climatic anomalies. Thus, the total demise of the supranival stems is cautiously predicted, by linear regression of the 20-yr defoliation pattern, to be less than a decade ahead. The recession of P. abies , clearly relevant in a landscape perspective, conforms with analogous responses of Pinus sylvestris L. and Betula pubescens Ehrh. ssp. tortuosa (Ledeb.) Nyman and a significant altitudinal range-limit retraction of certain silvine field-layer species. The structural development examined in this study concurs with long-term climate cooling and cold events and strongly contrasts with simulations of the performance of this system in response to a putative enhanced'greenhouse'effect.     

Patterns of Nucleotide Diversity at Photoperiod Related Genes in Norway Spruce [Picea abies (L.) Karst.]

The ability of plants to track seasonal changes is largely dependent on genes assigned to the photoperiod pathway, and variation in those genes is thereby important for adaptation to local day length conditions. Extensive physiological data in several temperate conifer species suggest that populations are adapted to local light conditions, but data on the genes underlying this adaptation are more limited. Here we present nucleotide diversity data from 19 genes putatively involved in photoperiodic response in Norway spruce (Picea abies). Based on similarity to model plants the genes were grouped into three categories according to their presumed position in the photoperiod pathway: photoreceptors, circadian clock genes, and downstream targets. An HKA (Hudson, Kreitman and Aquade) test showed a significant excess of diversity at photoreceptor genes, but no departure from neutrality at circadian genes and downstream targets. Departures from neutrality were also tested with Tajima''s D and Fay and Wu''s H statistics under three demographic scenarios: the standard neutral model, a population expansion model, and a more complex population split model. Only one gene, the circadian clock gene PaPRR3 with a highly positive Tajima''s D value, deviates significantly from all tested demographic scenarios. As the PaPRR3 gene harbours multiple non-synonymous variants it appears as an excellent candidate gene for control of photoperiod response in Norway spruce.     

Influence of soil acidification and liming on selected enzymes of the carbohydrate metabolism and the contents of two major organic acids of mycorrhizal roots of Norway spruce (Picea abies [L.] Karst.)

Effects of soil acidification and liming on the activities of three enzymes of the carbohydrate metabolism and the quantities of two of the major organic acids of mycorrhizal roots of Norway spruce (Picea abies [L.) Karst.) were studied at Höglwald Forest in southern Germany. The enzymes investigated were glucosephosphate isomerase, pyruvate kinase and 6-phosphogluconate dehydrogenase. The organic acids studied were citric acid and malic acid.Annual mean activities of the three enzymes were equal in mycorrhizal roots of the humus and the upper mineral soil. But in autumn and winter the activities of each of the three enzymes were higher than in summer. Of the various soil treatments only soil acidification affected the activities of the three enzymes. It stimulated activities by a factor of 1.5 in mycorrhizal roots of the humus but had no effect on mycorrhizal roots from the upper mineral soil.Mycorrhizal roots in the humus contained approximately 10 times more citrate and two times more malate than mycorrhizal roots from the upper mineral soil (0–5 cm). In mycorrhizal roots from the humus citrate and malate were of similar concentrations. In mycorrhizal roots from the upper mineral soil malate was approximately four times more concentrated than citrate. In the humus the citric acid concentration of mycorrhizal roots decreased under soil acidification by a factor of 1.4 while it increased under liming and compensatory liming (acid irrigation after liming) by a factor of 1.5. Malic acid concentrations increased exclusively under liming in mycorrhizal roots of the humus by a factor of 1.3.     

Identification of Gibberellins in Norway Spruce (Picea abies [L.] Karst.) by Combined Gas Chromatography-Mass Spectrometry

Gibberellins A₁ (GA₁), A₃ and A₉ were identified from extracts of shoots of 6-month old Norway spruce (Picea abies) seedlings by the use of sequential reverse and normal phase high performance liquid chromatography (HPLC), bioassay, radioimmunoassay (RIA) and combined gas chromatography-mass spectrometry (GC-MS). The bioassay and RIA were used after fractionation by HPLC to detect the GA-containing fractions, which were then examined by GC-MS. The GAs identified are considered to be endogenous.