Ribulose-l,5-bisphosphate carboxylase activity and influence of air pollution in spruce

Methods were established, which render possible a simultaneous determination of ri-bulose-l,5-bisphosphate (RuBP) carboxylase (EC 4.1.1.39) activity and chlorophyll content of Norway spruce (Picea abies Karst.) needles from a detergent-containing aqueous crude extract. Spruce RuBP carboxylase was tentatively characterized with regard to kinetic properties. Recovery experiments employing purified wheat RuBP carboxylase proved quantitative extraction of the enzyme from spruce foliage. Five timber stands consisting of 35–62 years old spruce, two of which exhibited the typical symptoms of recent spruce decline, were compared. For the needle generations 1 to 4 the enzyme activities as well as chlorophyll and protein concentrations were determined. The results do not indicate an involvement of RuBP carboxylase in spruce decline.     

The effects of SO2 and O3 on the foliar nutrition of Scots pine, Norway spruce and Sitka spruce in the Liphook open-air fumigation experiment

Foliar elements were analysed in Scots pine, Sitka spruce and Norway spruce over a 6 year period before and during continuous exposure to SO₂ and O₃ in an open-air fumigation experiment. Sulphur dioxide treatment elevated foliar sulphur concentration in all species, and there were increases in foliar nitrogen in the two spruce species but not in pine. The concentrations of cations were frequently increased by SO₂ treatment, but there was no correlation between the sulphur concentration of needles and their total cation charge. SO₂-related elevations of foliar magnesium were correlated with the concentration of this element in soil solution, but the mechanism by which other cations were enhanced remains unclear. The only consistent effects on nutrient ratios were for SO₂ treatments to increase sulphur/cation ratios.     

The rate of protein synthesis in needles of Norway spruce (Picea abies): Light stimulation, regulation through photophosphorylation, stress enhancement

The incorporation of ¹⁴C-leucine into the total-protein fraction of needles of Norway spruce (Picea abies [L.] Karst.) during short time incubation was used as a measure of protein synthesis in the light and in the dark. Light saturation curves, obtained for needles of different ages (new flush and 1 and 2 years old) or at different seasons (summer-winter) followed the Michaelis-Menten algorithm, exhibiting marked differences with regard to light saturation (V_max) and the half-saturation constant (K_{5. 2}). The light saturation curves of ATP level (mg g^?1 fresh weight) and of leucine incorporation into protein (nmol mg^?1 h^?1) matched each other, suggesting that photophosphorylation may be decisive for the rate of protein synthesis in the light. This is confirmed by the action spectrum of leucine incorporation. which resembled an action spectrum of leaf photosynthesis, and also by partial inhibition of protein synthesis by 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), an inhibitor of non-cyclic photophosphorylation. Light stimulated protein synthesis showed pronounced seasonal fluctuations with a summer maximum. Furmigation of 5 years old spruce trees for 3 months with SO₂ in combination with O₃ and/or NO₂ caused a distinct enhancement of the protein synthesis rate in the light and, at a reduced absolute level, also in the dark. A similar result was obtained for 40 to 70 years old spruce stands when healthy and sick trees were compared: the latter being afflicted by the novel type of forest decline, which is characterized by yellowish bronze discolouration of sun-exposed older needles and partial loss of older needle generations (3 to 4 years old). The 1 year old needles of the unhealthy trees showed a markedly increased ¹⁴C-leucine incorporation rate which, in the dark, was even more pronounced than in the light. Stress-physiological mechanisms, which could possibly explain this stimulation, are discussed.     

A rooting inhibitor present in Norway spruce seedlings grown at high irradiance - a putative cytokinin

Cuttings from seedlings of Picea abies L. (Karst.) grown under high light (HL). rooted slowly and incompletely, whereas rooting in cuttings from seedlings grown under low light (LL) was rapid and almost complete. Immunoaffinity chromatograpriy (IAC) with antibodies against isopentenyl adenosine ([9-RIiP) and trans-zeatin riboside (I9R]Z) was used to isolate cytokinin-like compounds from extracts of the cuttings. These compounds were separated by HPLC and quantified with a UV-detector. [9R]iP-type and [9R]Z-type compounds were also quantified using an enzyme immunoassay (ELISA). Levels of both [9R]iP-type and [9R]Z-type cytokinins were considerably higher in seedlings grown under HL than in those grown under LL. An unidentified compound (X), occurring in high amounts in the hypocotyls of HL seedlings and isolated by IAC and HPLC, inhibited rooting in cuttings from LL seedlings. Compound X was metabolised during the rooting period. Although X was retained on the imnimmoaffinity column, it did not bind to the antibodies to the degree necessary to allow quantification by ELISA. Treatment with acid phosphatase (EC 3.1.3.2) and β-glucosidase (EC 3.2.1.21) converted X into other unknown compounds. Some of these cross-ieacted with [9R)iP antibodies in ELISA.     

Response to three seasons of elevated ozone in the progeny of healthy and unhealthy Norway spruce trees from a plantation with the 'top dying' syndrome

We tested a hypothesis that elevated ozone was an eliciting or contributing factor in outbreaks of the 'top dying' (or 'subtop dying') syndrome in Norway spruce ( Picea abies ). Progeny were used from open-pollinated trees within a stand with the 'top dying' syndrome. The mother trees were classified in relation to the expression of the 'top dying' syndrome, and progeny from the healthiest and least healthy thirds of the population were exposed to high and low concentrations of ozone for three seasons. Elevated ozone did not affect height growth of the trees. It did not measurably affect net photosynthesis, stomatal conductance or instantaneous water use efficiency. Chlorophyll and carotenoid contents were also not significantly affected by ozone concentration. In the first year, instantaneous water use efficiency was lower in the progeny of the unhealthy mother trees than in the healthy mother trees. Furthermore, the unhealthy mother trees tended to produce longer annual shoots and showed more winter damage at the end of the experiment. None of these parameters were related to ozone concentration in the atmosphere. These results do not support a hypothesis that elevated ozone is a significant contributory factor or an eliciting factor in the development of the syndrome.     

The response of Norway spruce seedlings to simulated acid mist

Four pot experiments are reported in which Norway spruce ( Picea abies (L.) Karst) seedlings, of different nutrient status, were treated with acid mist for one growing season in open-top chambers (OTCs). Combinations of H⁺, SO₄²⁻, NH₄⁺ and NO₃⁻ were applied at different frequencies of application and supplying different doses of S and N kg ha⁻¹. Plant growth, visible injury, frost hardiness and nutrient status were observed. These experiments were undertaken to improve our understanding of the interaction of environmental factors such as nutrition and mist-exposure frequency on seedling response to N and S deposition.
Both acidity (pH 2·7) and SO₄²⁻ ions were necessary to induce visible injury. Mist containing SO₄²⁻, H⁺ and to a lesser extent NH₄⁺ significantly reduced winter frost hardiness. Increasing the misting frequency, and to a lesser extent the overall dose, increased the likelihood of acid mist causing visible injury and reducing frost hardiness. Post-planting stress, low N status and needle juvenility increased the likelihood of acid mist causing visible injury. Increased plant vitality, adequate N status and growth rate reduced the likelihood of acid-mist-induced reductions in frost hardiness.
Principles underlying the responses of spruce seedlings treated in controlled conditions to acid mist are discussed.     

Diagnosis of damage to Norway spruce (Picea abies) through biochemical criteria

Bioindication can be carried out at different hierarchical levels, eg. cell, organism, and ecosystem. While the monitoring of damage by visible criteria (e.g. loss of needles) is connected with the organism as a whole, the monitoring of damage by biochemical indicators is above all connected with cell metabolism.
The degree of vitality of a tree can be ascertained through the integration of a number of biochemical parameters. Furthermore, a differential diagnosis of a particular stress pattern can be carried out because of the feedback pattern of several biochemical indicators. In order to describe and interpret biochemical or physiological changes that have been caused by a number of factors, multivariate statistical methods are being used more frequently. Apart from cluster and discriminant analysis, it is especially factor analysis which provides a helpful tool when dealing with problems in the field of environmental analysis. Factor analysis can be used for an integrating as well as a differentiating assessment.
Within the framework of forest damage research, numerous changes at the level of cell metabolism have been detected to which a bioindicative character can be attached. A number of physiological and biochemical parameters with bioindicative character concerning Norway spruce are presented.     

Above-ground space sequestration determines competitive success in juvenile beech and spruce trees

A 2-yr phytotron study was conducted to investigate the intra- and inter-specific competitive behaviour of juvenile beech (Fagus sylvatica) and spruce (Picea abies). Competitiveness was analysed by quantifying the resource budgets that occur along structures and within occupied space of relevance for competitive interaction. Ambient and elevated CO(2) and ozone (O(3)) regimes were applied throughout two growing seasons as stressors for provoking changes in resource budgets, growth and allocation to facilitate the competition analysis. The hypothesis tested was that the ability to sequester space at low structural cost will determine the competitive success. Spruce was a stronger competitor than beech, as displayed by its higher above-ground biomass increments in mixed culture compared with monoculture. A crucial factor in the competitive success of spruce was its ability to enlarge crown volume at low structural costs, supporting the hypothesis. Interspecific competition with spruce resulted in a size-independent readjustment of above-ground allocation in beech (reduced leaf : shoot biomass ratio). The efficient use of resources for above-ground space sequestration proved to be a parameter that quantitatively reflects competitiveness.     

Histochemical and biochemical approaches to the study of phenolic compounds and peroxidases in needles of Norway spruce (Picea abies)

The three youngest age-classes of needles of Norway spruce ( Picea abies ) were collected from four sites in the Krusne Hory Mountains (Czech Republic) characterized by different levels of damage caused by environmental pollution. Histochemical methods did not reveal any differences in localization of phenolics among the needles. Mesophyll cells close to the epidermis of needles and cells around resin ducts and substomatal cavities often accumulated higher amounts of phenolics than the rest of the mesophyll cells, but this was independent of age and damage. Needles of different age- and damage-class did not show any marked changes in general lignification pattern. However, a lower intensity of histochemical detection of lignin was observed in needles from the most damaged site. This finding was confirmed by chemical analysis using thioglycolic acid. Generally, the amount of lignin in mesophyll cells was lower in damaged trees than in healthy ones. Using the Folin–Ciocalteau method, no significant differences in the total content of phenolics were observed in the needles, although HPLC revealed marked alterations in the forms of seven phenolic acids. Concentrations of conjugated forms of phenolic acids (esters and glycosides) were higher in damaged needles (255.9 μg g⁻¹ f. wt) than in healthy needles (189.8 μg g⁻¹ f. wt). By contrast, content of esterified phenolic acids incorporated into cell walls was higher in needles from healthy trees (101.1 μg g⁻¹ f. wt) than in damaged needles (78.3 μg g⁻¹ f. wt). Marked differences were also observed in the activity of soluble peroxidases, although the activity of ionically bound forms was approximately the same in healthy and damaged needles. The total amounts of chlorophylls and carotenoids decreased as environmental damage increased.