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1.
We investigated effects of nutrient addition on several physiological characteristics of 60-cm-tall black spruce (Picea mariana Mill. B.S.P.) layers (i.e., rooted branches of overstory trees) and 20-cm-tall planted seedlings on a clear-cut, N-limited boreal site. After two growing seasons, current-year and one-year-old needles of fertilized trees (layers and seedlings combined) had higher net photosynthetic rates (A(n)) and maximum capacity of Rubisco for CO(2) fixation (V(max)) than unfertilized trees. One-year-old needles of fertilized trees had higher stomatal conductance (g(s)), higher water-use efficiency, and lower intercellular to ambient CO(2) ratio than unfertilized trees. Additionally, fertilized trees had higher predawn and midday shoot water potentials than unfertilized trees. Stomatal conductance of 1-year-old needles was 23% higher in seedlings than in layers, but there were no significant differences in g(s) of current-year needles between the regeneration types. For both needle age-classes, A(n) and V(max) of layers were 25 and 40% higher, respectively, than the corresponding values for seedlings. The higher values of A(n), V(max) and foliar N concentration of layers compared with seedlings after two growing seasons may be associated with the larger root systems of the layers compared with the transplanted seedlings. 相似文献
2.
Andrea Ganthaler Helmut Bauer Andreas Gruber Michaela Mayr Walter Oberhuber Stefan Mayr 《European Journal of Forest Research》2014,133(2):201-211
Norway spruce trees in the subalpine forests of the European Alps are frequently attacked by the needle rust Chrysomyxa rhododendri. The obligate parasite undergoes a complex life cycle with a host shift between rhododendrons (Rhododendron sp.) and Norway spruce [Picea abies (L.) Karsten] and causes a yellowing and defoliation of the current-year needles in summer. Infected trees show several anatomical, morphological and physiological modifications, including a decrease in pigment content and net photosynthesis of infected needles, lower biomass production and reduced radial and height growth. The consequences are diminished timber yield and cripple growth. Because of repeated heavy infections in recent years, forest managers report increasing difficulties in both natural regeneration and afforestation at high elevation sites, where rhododendrons occur. This review gives a summary of the present knowledge about the effects of C. rhododendri infections on Norway spruce, including so far unpublished findings and with particular attention to the phenomena of resistant trees. Implications for subalpine forests and counter strategies are discussed. 相似文献
3.
Mineral nutrition of Norway spruce (Picea abies (L.) Karst.) and beech (Fagus sylvatica L.) was investigated along a transect extending from northern Sweden to central Italy. Nitrogen (N) concentrations of needles and leaves in stands growing on acid soils did not differ significantly between central Italy and southern Sweden (1.0 +/- 0.1 mmol N g(-1) for needles and 1.9 +/- 0.14 mmol N g(-1) for leaves). In both species, foliar N concentrations were highest in Germany (1.2 mmol N g(-1) for needles and 2.0 mmol N g(-1) for leaves) and decreased by 50% toward northern Sweden (0.5 mmol N g(-1)). Both species showed constant S/N and P/N ratios along the transect. Calcium, K and Mg concentrations generally reflected local soil conditions; however, Mg concentrations reached deficiency values in Germany. Leaf area per unit dry weight varied significantly along the transect with lowest values for Norway spruce recorded in northern Sweden and Italy (3.4 m(2) kg(-1)) and a maximum in central Europe (4.7 m(2) kg(-1)). A similar pattern was observed for beech. Despite the low variation in foliar N concentrations on the large geographic scale, local and regional variations in N concentrations equalled or exceeded the variation along the entire continental transect. Furthermore, nutrient contents (i.e., nutrient concentration x dry weight per needle or leaf) showed a greater variation than nutrient concentrations along the transect. Nitrogen contents of Norway spruce needles reached minimum values in northern Sweden (2.4 micro mol N needle(-1)) and maximum values in Denmark (5.0 micro mol N needle(-1)). The N content of beech leaves was highest in Denmark (242 micro mol N leaf(-1)). At the German site, foliar N content rather than N concentration reflected the seasonal dynamics of foliar growth and N storage of the two species. During foliage expansion, there was an initial rapid increase in N content and a decrease in N concentration. This pattern lasted for about 2 weeks after bud break and was followed by 6 weeks during which dry weight and N content of the foliage increased, resulting in a further decrease in N concentration. During summer, dry weight and N content of mature needles of Norway spruce increased further to reach a maximum in autumn, whereas N concentration remained constant. In spring, reallocation of N from 1- and 2-year-old needles was 1.5 and 1.0 micro mol N needle(-1), respectively. This remobilized N was a major source of N for the development of new needles, which had an N content of 1.5 micro mol N needle(-1) after bud break. The seasonal remobilization of N from old foliage decreased with increasing needle age. Needle N content and dry weight decreased progressively with age (1 micro mol N needle(-1) between age classes 2 and 5), whereas N concentrations remained constant. For Norway spruce, annual stemwood production was correlated with needle N content but not with foliar N concentration or with the total amount of N in the canopy. Interspecific and geographical differences in plant nutrition are discussed on the basis of competitive demands for C and N between growth of foliage and wood. 相似文献
4.
Tree- and needle-age-dependent variations in antioxidants and photoprotective pigments in Norway spruce needles at the alpine timberline 总被引：1，自引：0，他引：1
To cope with environmental stress, plants are equipped with antioxidative (e.g., ascorbate, glutathione and alpha-tocopherol) and photoprotective (e.g., xanthophyll cycle pigments) defense systems. We investigated the defense capacities of three tree age classes (mature, sapling and seedling) of Norway spruce (Picea abies (L.) Karst.) at a field site near the timberline. Biochemical data were expressed on both a needle dry mass and a surface area basis. Compared with current-year needles, previous-year needles contained higher mass- and area-based concentrations of chlorophylls and alpha-tocopherol, and a larger xanthophyll cycle pool that was in a more epoxidized state. Total glutathione concentration was lower, the glutathione pool was more reduced and the ascorbate pool was more oxidized in previous-year needles than in current-year needles. Needle concentrations of glutathione and alpha-tocopherol increased and chlorophyll concentration decreased with increasing tree age when expressed on a surface area basis. On a dry mass basis, these trends were reversed or nonexistent. The ascorbate pool was more reduced and the glutathione pool was more oxidized in needles of mature trees than in needles of saplings and seedlings. The proportion of protective xanthophyll cycle pigments decreased and the de-epoxidation state increased with increasing tree age. We conclude that tree age and the basis of expression of antioxidant concentration--surface area or dry mass--are important in scaling from seedlings to large trees. 相似文献
5.
Dry mass production in seedlings of Norway spruce infected by the needle rust Chrysomyxa rhododendri
The aim of this study was to assess the losses in productivity of Norway spruce (Picea abies) due to the attack by Chrysomyxa rhododendri, a rust that only penetrates new developing flushes. Three-year-old seedlings were artificially infected once or twice in two consecutive years and the dry mass was determined at the end of the growing season. Dry mass accumulation of all parts including roots was significantly reduced if more than about one-third of the young foliage was infected. Shoot and root dry mass of once severely infected seedlings were 32 and 48% less than that of controls. This deficit could not be compensated during a following rust-free year. When seedlings were infected in two consecutive years, dry mass accumulation was reduced by 58% compared with controls. Results indicate that rejuvenation of and afforestation with Norway spruce can seriously be impaired by Chrysomyxa at the alpine timberline where Rhododendron sp. (the telial host of the parasite) is widespread. 相似文献
6.
There is abundant evidence that evergreen conifers living at high elevations or at high latitudes have longer-lived needles than trees of the same species living elsewhere. This pattern is likely caused by the influence of low temperature in combination with related factors such as a short growing season and low nutrient availability. Because it is not known to what degree such patterns result from phenotypic versus genotypic variation, we evaluated needle longevity for common-garden-grown lowland populations of European Scots pine (Pinus sylvestris L.) of wide latitudinal origin and Norway spruce (Picea abies L.) of wide elevational origin. Nine-year-old trees of 16 Scots pine populations ranging in origin from 47 degrees to 60 degrees N were studied in Kórnik, Poland (52 degrees N) and 18-year-old trees of 18 Norway spruce populations ranging in origin from 670 to 1235 m elevation in southwestern Poland were studied near Morawina, Poland (51 degrees N, 180 m elevation). There was no tendency in either species for populations from northern or high elevation origins to retain needles longer than other populations. All of the Scots pine populations had between 2.5 to 3.0 needle age cohorts and all of the Norway spruce populations had between 6.4 and 7.2 needle age cohorts. Thus, extended needle retention in Scots pine and Norway spruce populations in low-temperature habitats at high elevations and high latitudes appears to be largely an environmentally regulated phenotypic acclimation. 相似文献
7.
《Scandinavian Journal of Forest Research》2012,27(6):501-510
Scots pine ( Pinus sylvestris L.) and Norway spruce [ Picea abies (L.) Karst.] seedlings were exposed to high phosphorus (HP) or low phosphorus (LP) availability for one growing season in the open field, and to combined P availability and elevated ozone (O 3 ) concentrations (0, 55, 110 and 210 ppb for Scots pine and 0, 40, 75 and 150 ppb for Norway spruce, respectively) for 28 days in controlled laboratory chambers. Compared with HP, the LP treatment reduced Scots pine current-year (C) shoot and root dry masses and Norway spruce total dry mass, whereas the highest O 3 concentrations increased the magnesium concentration of Scots pine C needles and P concentrations of the C needles of both tree species. Chlorophyll a, a+b and carotenoid concentrations of Scots pine C needles were significantly higher in the LP treatment compared with HP under the highest O 3 concentration (210 ppb). In the mesophyll tissue of C needles of both tree species, LP treatment increased the size of mitochondria and elevated O 3 -induced granulation of chloroplast stroma and disintegration of cytoplasm. Exposure to elevated O 3 concentrations increased swelling of chloroplast thylakoids and reduced the amount of vacuolar tannin in the LP Scots pine C needles. The results suggest disturbances in needle photosynthetic machinery due to acute exposure to the combination of elevated O 3 and low P availability. However, clear additive effects were found only in needle P concentrations < 1 mg g -1 in short-term O 3 exposure. 相似文献
8.
Needle development and shoot growth were studied in 14- and 20-year-old Sitka spruce (Picea sitchensis (Bong.) Carr.) planted on an oligotrophic peat and fertilized with N, P and K (control), N and P (-K), N and K (-P) or unfertilized (-NPK). Shoot extension, needle number, and the size and number of needle cells were observed throughout the season. Beginning with bud burst in early May, needle growth continued for nine weeks in the control treatment. Needle growth in the mineral deficiency treatments terminated at the same time as in the controls, although it did not begin until up to three weeks later than in the control trees. Needles developed acropetally along the shoot, with basal needles completing their development first. Cell division in needles of control trees lasted about 3 weeks, with cell expansion continuing for a further 3 weeks. Initial mean cell cycle times were shortest for proximal needles following bud burst, but lengthened as the season progressed. Cell number increased from 6600 in the primordia to 200 000 in mature needles. Final needle dimensions and cell number varied according to the position of the needle on the shoot. The largest needles with the most cells were near the middle of the shoot. Relative to the controls, all mineral deficiency treatments reduced shoot length, bud and needle dimensions, and needle cell number, particularly the -P treatment. Potassium and P deficiency treatments reduced primordial cell number by up to 42%, whereas final mean cell size was 30% greater in the -P treatment, 17% greater in the -NPK treatment, but 14% smaller in the -K treatment. Mean cell size was constant for needles at all positions in any particular treatment at any time, so that final needle size was determined by cell number alone. Needle dry weight/fresh weight ratio continued to increase until early August, with significantly higher ratios in the -K and -P treatments than in the controls. 相似文献
9.
Influence of nitrogen and phosphorous availability and ozone stress on Norway spruce seedlings 总被引：1，自引：0，他引：1
Four-year-old Norway spruce (Picea abies L. (Karst.)) seedlings were exposed to ambient and elevated (1.5 x ambient in 1997 and 1.6 x ambient in 1998) ozone concentrations [O3] and three nitrogen (N) and two phosphorus (P) availabilities: "optimal" values (control); 70% of the control N and P values (LN and LP); and 150% of the control N value (HN). Treatments were applied in an open-field ozone fumigation facility during the 1997 and 1998 growing seasons. Effects on growth, mineral and pigment concentrations, stomatal conductance and ultrastructure of needles were studied. The HN treatment increased growth significantly, whereas elevated [O3] had a slight or variable impact on growth and biomass allocation in all N treatments. Although there were no significant effects of the LP treatment on plant growth during the second year, there was a reduction in 1-year-old shoot dry mass in the elevated O3 + LP treatment at the end of the experiment. There were no significant treatment effects on mineral concentrations of current-year and 1-year-old needles at the final harvest. In response to the HN treatment, chlorophyll a and b and carotenoid concentrations increased significantly in current-year needles. Chlorophyll a/b ratio decreased in response to elevated [O3] alone, but increased in seedlings in the O(3) + LP treatment. Stomatal conductance of current-year needles decreased with increasing N availability, but increased in response to elevated [O3]. However, the O3-induced increase in stomatal conductance was less in the LN and LP treatments than in the control treatment. In chloroplasts of current-year needles, increased N availability decreased mean starch grain area, but increased the number of plastoglobuli. We conclude that Norway spruce seedlings are relatively tolerant to slightly elevated [O3], and that nitrogen and phosphorus imbalances do not greatly affect the influence of O3 on this species when the exposure lasts for two growing seasons or less. 相似文献
10.
Effects of elevated CO2 concentration ([CO2]) on carbon assimilation and needle biochemistry of fertilized and unfertilized 25-30-year-old Scots pine (Pinus sylvestris L.) trees were studied in a branch bag experiment set up in a naturally regenerated stand. In each tree, one branch was enclosed in a bag supplied with ambient [CO2] (360 micromol mol(-1)), a second branch was enclosed in a bag supplied with elevated [CO2] (680 micromol(-1)) and a control branch was left unbagged. The CO2 treatments were applied from April 15 to September 15, starting in 1993 for unfertilized trees and in 1994 for fertilized trees, which were treated with N in June 1994. Net photosynthesis, amount and activity of Rubisco, N, starch, C:N ratio and SLA of needles were measured during the growing season of 1995. Light-saturated net photosynthetic rates of 1-year-old and current-year shoots measured at ambient [CO2] were not affected by growth [CO2] or N fertilization. Elevated [CO2] reduced the amount and activity of Rubisco, and the relative proportion of Rubisco to soluble proteins and N in needles of unfertilized trees. Elevated [CO2] also reduced the chlorophyll concentration (fresh weight basis) of needles of unfertilized trees. Soluble protein concentration of needles was not affected by growth [CO2]. Elevated [CO2] decreased the Rubisco:chlorophyll ratio in unfertilized and fertilized trees. Starch concentration was significantly increased at elevated [CO2] only in 1-year-old needles of fertilized trees. Elevated [CO2] reduced needle N concentration on a dry weight or structural basis (dry weight minus starch) in unfertilized trees, resulting in an increase in needle C:N ratio. Fertilization had no effect on soluble protein, chlorophyll, Rubisco or N concentration of needles. The decrease in the relative proportions of Rubisco and N concentration in needles of unfertilized trees at elevated [CO2] indicates reallocation of N resources away from Rubisco to nonphotosynthetic processes in other plant parts. Acclimation occurred in a single branch exposed to high [CO2], despite the large sink of the tree. The responses of 1-year-old and current-year needles to elevation of growth [CO2] were similar. 相似文献
11.
Photosynthetic O(2) evolution and chlorophyll a fluorescence were measured in 1-year-old needles of unfertilized and fertilized trees of Norway spruce (Picea abies (L.) Karst.) during recovery of photosynthesis from winter inhibition in northern Sweden. Measurements were made under laboratory conditions at 20 degrees C. In general, the CO(2)-saturated rate of O(2) evolution was higher in needles of fertilized trees than in needles of unfertilized trees over a wide range of incident photon flux densities. Furthermore, the maximum photochemical efficiency of photosystem (PS) II, as indicated by the ratio of variable to maximum fluorescence (F(V)/F(M)) was higher in needles of fertilized trees than in needles of unfertilized trees. The largest differences in F(V)/F(M) between the two treatments occurred before the main recovery of photosynthesis from winter inhibition in late May. The rate of O(2) evolution was higher in needles of north-facing branches than in needles of south-facing branches in the middle of May. Simultaneous measurements of O(2) exchange and chlorophyll fluorescence indicated that differences in the rate of O(2) evolution between the two treatments were paralleled by differences in the rate of PS II electron transport determined by chlorophyll fluorescence. We suggest that, during recovery of photosynthesis from winter inhibition, the balance between carbon assimilation and PS II electron transport was maintained largely by adjustments in the nonphotochemical dissipation of excitation energy within PS II. 相似文献
12.
Strand M 《Tree physiology》1997,17(4):221-230
Photosynthetic O(2) evolution at high irradiances (approximately 600-1000 micro mol m(-2) s(-1)) and O(2) uptake in darkness were measured in needles of control, irrigated and irrigated-fertilized trees of Norway spruce (Picea abies (L.) Karst.). Measurements were made at 20 degrees C and at high CO(2) concentrations. The results suggest that, at given times of the year, a major part of the variation in gross photosynthesis of current-year and one-year-old needles across treatments is associated with differences in needle N content. Furthermore, the rate of O(2) uptake measured after 5 or 10 min in darkness was positively correlated with both the preceding rate of gross O(2) evolution and the N content in fully expanded current-year needles. Measurements of chlorophyll a fluorescence, taken simultaneously with measurements of O(2) evolution in current-year sun needles, showed that Stern-Volmer quenching of minimum fluorescence and the ratio of variable to maximum fluorescence in the dark- and light-adapted state were strongly correlated with the gross rate of O(2) evolution. This suggests that the increased rate of gross photosynthesis in needles of irrigated-fertilized trees was associated with adjustments in the thermal energy dissipation within photosystem II. 相似文献
13.
To elucidate early drought responses in needles of Norway spruce (Picea abies (Karst.) L.), we subjected 1-year-old seedlings to gradual desiccation for 6 weeks. Four weeks of drought treatment caused a small but significant decrease in photosystem II quantum yield of light-adapted needles (phi(a)) compared with that of well-watered controls. Six weeks of drought treatment reduced phi(a) and the photosystem II quantum yield of dark-adapted needles (phi) by 50 and 8%, respectively, and reduced shoot water potential by 0.7 MPa, but had no measurable effect on needle relative water content. After two weeks of drought treatment, and before there was a discernible effect of drought on phi or a statistically significant effect on shoot water potential, needles were analyzed for changes in protein composition. Five out of several hundred detected proteins in needles of drought-treated plants showed consistent changes compared with control leaves. The proteins were identified by LC-MS/MS as components of the oxygen-evolving complex (oxygen evolving enhancer protein 2), ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit, and one protein of unknown function, whose mRNA was found in a previous screen of wound- and methyl-jasmonate-induced bark proteins. 相似文献
14.
We compared shoot and needle morphology and photosynthesis in Picea glehnii (Friedr. Schmidt) M.T. Mast. and Picea jezoensis (Sieb. et Zucc.) Carr. trees planted on immature volcanic ash and well-developed brown forest soils to investigate whether species differences in morphological and physiological plasticity affected tree growth on different soil types. Height growth of P. glehnii was reduced by about 10% on volcanic ash compared with forest soil, whereas that of P. jezoensis was reduced by more than 60%. Needle morphology of P. glehnii was unaffected by soil type. In contrast, needles of P. jezoensis trees growing on volcanic ash were shorter, narrower and thicker, with less dry mass and area, than those of trees growing on forest soil, and specific needle area was lower, indicating lower foliar light-interception efficiency. In both species, changes in needle morphology with increasing irradiance were similar in trees growing on both soil types, indicating that plasticity of needle morphology was unaffected by soil type. In both species, shoot mass and shoot silhouette area were lower and needle mass per unit shoot mass was higher in trees growing on volcanic ash than in trees growing on forest soil. Trees of both species had more needles per unit shoot length, lower shoot silhouette to projected needle area ratios and lower shoot silhouette areas per unit shoot mass (SAM) on volcanic ash than on forest soil, indicating lower shoot-level light-interception efficiency. For P. glehnii, the response of shoot morphology to increasing irradiance was similar on both soil types, with the exception of SAM, which showed lower plasticity in trees growing on volcanic ash. In contrast, shoot-level morphological plasticity of P. jezoensis was reduced in trees growing on volcanic ash. Light-saturated maximum photosynthetic rate (P(max)) of P. glehnii was unaffected by soil type, whereas mass-based P(max) of P. jezoensis was lower in trees growing on volcanic ash than in trees growing on forest soil. In P. jezoensis trees growing on forest soil, area-based P(max) increased with increasing irradiance, but this response was not observed in trees growing on volcanic ash. As a result, area-based P(max) at the top of the canopy was 39 to 54% lower in trees growing on volcanic ash than in trees growing on forest soil. Our results indicate that constraints on morphological acclimation to high irradiances may contribute to reduced height growth of P. jezoensis on volcanic ash. 相似文献
15.
We previously traced 10B-enriched boric acid from shoots to roots to demonstrate the translocation of boron (B) in Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) seedlings. To gain a more detailed understanding of B translocation, we sought: (1) to demonstrate B retranslocation directly, by showing that foliar-applied 10B is located in the new growth after dormancy; and (2) to assess whether shoot-applied B affects growth in the long term. We applied 10B-enriched boric acid to needles of Scots pine and Norway spruce seedlings. After a dormancy period and 9 weeks of growth, small but significant increases in the 10B isotope were found in the new stem and needles of both species. In Scots pine, the total B concentration of the new stem was also increased. Both species contained polyols, particularly pinitol and inositol. Boron-polyol complexes may provide a mechanism for mobilizing B in these species. To determine the long-term effects of applied B, seedlings were grown for two growing seasons after the application of 10B to shoots. In Norway spruce, the proportion of 10B in the root systems and current needles of the harvest year was slightly higher than in the controls, and in Scots pine root systems, marginally so. The B treatment had no effect on growth of Norway spruce seedlings. In Scots pine seedlings, the B treatment caused a 33% increase in total dry mass and significantly increased the number of side branches. 相似文献
16.
Non-mycorrhizal Norway spruce seedlings (Picea abies Karst.) and Norway spruce seedlings colonized with Paxillus involutus Fr. were grown in an axenic silica sand culture system. After successful mycorrhizal colonization, the seedlings were exposed to 200 or 800 micro M AlCl(3) for 10 weeks. In both non-mycorrhizal and mycorrhizal seedlings, exposure to Al significantly reduced root growth and the uptake of Mg and Ca. After 5 weeks of exposure to 800 micro M Al, the mycorrhizal seedlings had significantly higher chlorophyll concentrations than the non-mycorrhizal seedlings, although no difference in Mg nutrition was apparent. After 10 weeks of exposure to Al, both non-mycorrhizal and mycorrhizal seedlings exhibited needle chlorosis and reduced photosynthetic activity. However, the aluminum-induced reduction in shoot growth was largely ameliorated by colonization with P. involutus. We conclude that mycorrhizal colonization modifies the phytotoxic effects of Al in Norway spruce seedlings. However, differences in physiological responses to Al between mycorrhizal and non-mycorrhizal seedlings may be largely reduced in the long term as a result of impaired mineral nutrient uptake. 相似文献
17.
Both drought and root pruning (RP) increased the number of cones induced when black spruce (Picea mariana (Mill.) B.S.P.) grafts were injected with gibberellins A(4/7) (GA), but their effects on predawn shoot water potential and current-year needle development differed. Drought decreased predawn shoot water potential (Psi(pd)), but only during the period when irrigation was withheld, and it had no effect on the growth or gas exchange properties of current-year needles. Conversely, root pruning had little effect on Psi(pd), but it resulted in trees with smaller current-year needles that had lower nitrogen and chlorophyll concentrations and reduced rates of gas exchange up to the later stages of shoot elongation compared with needles of control trees. These findings are discussed in relation to potential effects on the development of induced cones in the following growth cycle. 相似文献
18.
Effects of magnesium deficiency and variation in nitrate to ammonium ratio on needle histology and chlorophyll concentration were investigated in current-year and one-year-old needles of clonal Norway spruce trees (Picea abies (L.) Karst.). Six-year-old trees were grown for one year in sand culture with circulating nutrient solutions containing a sufficient (0.2 mM) or a limiting (0.04 mM) concentration of Mg. The nitrogen concentration was not varied (5 mM), but the NO(3) (-)/NH(4) (+)-ratio was adjusted to 0.76 in Mg-sufficient and to 1.86, 0.76 or 0.035 in Mg-limited plants. Visible symptoms of Mg deficiency occurred only in current-year needles, indicating adequate Mg nutrition before the experiment. Under conditions of Mg limitation, chlorophyll and Mg concentrations were lowest in needles of trees supplied with NH(4) (+) as the major nitrogen source and highest in needles of trees supplied with NO(3) (-) as the major nitrogen source. In current-year and one-year-old needles, starch accumulation induced by Mg deficiency was increased when NH(4) (+) was the major nitrogen source. The accumulation of tannin spherules in current-year needles, which occurred in response to Mg deficiency, also increased with decreasing NO(3) (-)/NH(4) (+)-ratios. Deficient Mg supply caused premature aging in tissues of the vascular bundle, as indicated by modifications of the cambium and increased amounts of collapsed sieve cells. The number of collapsed sieve cells was slightly lower in needles grown in a NH(4) (+)-dominated nutrient regime than in needles grown in a NO(3) (-)-dominated nutrient regime. We conclude that was not directly toxic to Norway spruce trees at the applied concentrations. However, effects of Mg deficiency were considerably greater in an NH(4) (+)-dominated nutrient regime than in a NO(3) (-)-dominated nutrient regime. 相似文献
19.
《Forest Ecology and Management》1988,24(4):263-281
The research site, Wingst Compartment 123B, is a 68-year-old Norway spruce (Picea abies (Karst.)) stand located in the coastal area of northern Germany. This area receives high atmospheric inputs of ammonium and also has relatively high ozone concentrations (0.061 mg m−3).Ten trees were categorized as healthy to slightly damaged (3–29% needle loss) or severely damaged (49–71% needle loss). Apparent net photosynthetic rates were measured on detached branches at light saturation (1000 μE m−2 s−1). Needles were analyzed for chlorophyll, N, C, Ca, Mg, K, Zn, Mn and Fe.When compared to the healthy-to-slightly-damaged trees, the severely damaged trees tended to have higher rates of net apparent photosynthesis in the 1 and 2-year-old needles and similar rates in the current-year needles. All three needle ages from the severely damaged trees had higher average stomatal conductances to water vapor (gs. Although the damaged trees had significantly less total chlorophyll in all needle ages sampled, there was no statistically significant difference in the chlorophyll a:b ratio between the healthy and severely damaged trees.Nitrogen contents of the current-year needles were slightly lower in the severely damaged trees. Carbon and calcium levels did not significantly differ between the damage classes, although the average Ca content of all younger needles was generally under the recommended sufficiency levels. The current-year needles of the severely damaged trees had significantly less magnesium (0.42–0.46 mg Mg g−1) than those of the healthy trees, and all trees had Mg values in the deficiency range (< 0.7 mg g−1). The severely damaged trees also had lower average potassium levels in the older needles.The annual volume increment per unit crown surface area declined with increasing crown damage. Trees with a 50% needle loss showed a 62% loss of volume increment.Soil investigations revealed conditions of high soil acidity and poor nutrient capacity. The low pH values (pH < 3.8) in 64% of all samples indicated a high risk of acid toxicity for plant roots in the investigated area.The significance of these results relative to the current ideas concerning forest decline is discussed. 相似文献
20.
Norway spruce seedlings (Picea abies Karst.) were grown in low light for one year, under conditions of adequate and limiting nutrition, then transferred to high light. Three months after transfer we measured photosynthesis, leaf nitrogen concentration, leaf chlorophyll concentration and leaf mass per area (LMA) of current-year and 1-year-old shoots; silhouette area ratio (SAR, the ratio of shoot silhouette area to projected needle area) was also measured in current-year shoots. At the foliage level, the effects of light and nutrient treatments differed markedly. Light availability during foliage expansion primarily affected LMA and SAR (morphological acclimation at the needle and shoot level, respectively). By contrast, nutrient supply in high light affected photosynthetic capacity per unit of leaf tissue (physiological acclimation at the cellular level) but did not affect LMA and SAR. The capacity for shade-sun acclimation in foliage formed before transfer to high light differed greatly from that of foliage formed following the transfer. The morphological inflexibility of mature needles (measured by LMA) limited their shade-sun acclimation potential. In contrast, at high nutrient supply, shoots that developed just after the change in photosynthetic photon flux density largely acclimated, both morphologically and physiologically, to the new light environment. The acclimation response of both current- and 1-year-old shoots was prevented by nutrient limitation. Analysis of growth at the whole-plant level largely confirmed the conclusions drawn at the shoot level. We conclude that nutrient shortage subsequent to the opening of a canopy gap may strongly limit the acclimation response of Norway spruce seedlings. Successful acclimation was largely related to the plant's ability to produce sun foliage and adjust whole-plant biomass allocation rapidly. 相似文献