摘要:

The distribution and total recovery of15N‐labelled fertilizer nitrogen was studied in a 50‐year‐old mixed coniferous stand, consisting of Scots pine and Norway spruce, located in Uppland, Central Sweden. The experimental plots, with an area of 113 m2each, were separated from the surrounding trees by trenching and emplacement of an aluminium sheet to a depth of 50 cm. The standard nitrogen application rate was 150 kg N ha−1and the nitrogen sources tested were calcium nitrate, ammonium nitrate and urea. Two growing seasons after the application of fertilizer, all the experimental plots were subjected to destructive sampling, including soil, field vegetation and trees, with a view to producing a nitrogen balance sheet for the experimental treatments involved.

ISSN:0282-7581    

DOI:10.1080/02827588809382490

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Nitrogen fixation (C2H2) by free‐living heterotrophic microorganisms in the upper part of the forest soil (0–3 cm) was, on average, twenty times higher below birch than below pine or spruce. The highest fixation that occurred was 1.4 kg Nha−1during the growth period. In most cases the fixation of nitrogen was concentrated to older leaf litter. No activity could be detected in green leaves taken from the canopy or in recently fallen yellow leaves. Relatively low activities in the soil were obtained at sites in the southern part of Sweden, which corresponded to elevated concentrations of lead and copper in the green birch leaves.

ISSN:0282-7581    

DOI:10.1080/02827588809382491

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The terpenic profile for 8 major monoterpenes determined on ten grafted clones of Scots pine grown on three different sites in Sweden. As graft effects could not be detected, oleoresin, samples from primary and secondary grafts were used to study genetic variation. In three quite different environmental conditions, a strong broad sense heritability was demonstrated for 3‐carene, myrcene, limonene andβ‐phellandrene. Pinenes and sabinene seem to be much more dependent on environmental factors. Both site and clone × site interaction have a small effect on overall phenotypic variation. There is a strong positive correlation between concentrations of 3‐carene and terpinolene, which supports a possible pleiotropic effect of the same major gene on the two monoterpenes. The results show that there is no risk of an important bias when the comparison is made between genotypes sampled on very different sites (stands or comparative trials). The relative concentration of monoterpenes is to a great extent independent of environmental conditions.

ISSN:0282-7581    

DOI:10.1080/02827588809382492

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Genetic changes at allozyme loci during the transition from the seed to the seedling stage were studied in a natural stand, where juvenile mortality is high, and in a nursery, where mortality is lower. The seed lots were from a natural stand and a seed orchard ofPinus sylvestrisin Central Finland. From both seed lots bare‐rooted and containerized seedlings were produced in a nursery. Both seed lots were found not to be inbred as measured by fixation indices at allozyme loci. Correspondingly, neither natural stand nor nursery grown seedlings showed evidence of inbreeding. We observed allelic frequency differences between the seed lot and seedlings of natural regeneration at two loci. There was only one allelic frequency change between the seed lots and the bare‐rooted seedling populations, and no differences between the seed lots and the containerized seedlings. This is in accordance with the hypothesis that less selection takes place in the nursery than in the natural stands.

ISSN:0282-7581    

DOI:10.1080/02827588809382493

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The bud development period was estimated using shoot growth data from a Phytotron study in which six full‐sib familiesof Picea abiesL. (Karst.) (Norway spruce) were grown for six growth periods. Simple algebraic relationships based on assumptions of the relationship between shoot growth and bud development were used. The estimated bud development period, defined as the period when the budscale and needle primordia were initiated, decreased as growth periods advanced. Furthermore, the relationship between the period of production of free growth needles and bud scales to that of predetermined needle primordia was surprisingly constant irrespective of the change in free growth. These results indicate that free growth during one year did not encroach on the period of predetermined growth, but instead increased the amount of predetermined growth.

ISSN:0282-7581    

DOI:10.1080/02827588809382494

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

In full‐sib familiesof Picea abies(L.) Karst. (Norway spruce) the dynamics of juvenile growth and the inheritance of the most important growth characters were analysed in six growth periods in climate chambers followed by two additional growing seasons in a nursery. The full‐sib families were of French and North Swedish origin including both within and between provenance crosses. All growth rhythm characters changed over time. For instance, number of days to budbreak increased, whereas days to budset decreased, as growth periods advanced. Concurrent with the changes in growth rhythm, free growth decreased with increasing age. Half of the total variation for different growth rhythm characters within a growth period could in most cases be explained by provenance effects. Early selection is, therefore, meaningful to reduce damage by frost and mortality. Furthermore, the actual distances between family means decreased substantially with increasing age, and the actual length of the shoot elongation period decreased from 31 days during the second growth period to 16 days during the sixth. We suggest therefore that selection together with some treatment in the nursery that alters the growth rhythm of the seedlings are the best ways to increase frost resistance. Tree height was influenced by a set of complex gene actions that changed over time. Provenance effects were important during the first two growth periods. Subsequently, non‐accumulative within provenance family variance took over. If this pattern holds true in general, juvenile selection for height growth in Norway spruce cannot be made as early as that for growth rhythm.

ISSN:0282-7581    

DOI:10.1080/02827588809382495

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Annual ring data from northern Finland was analysed in order to reveal possible trends in ring width development due to changes in environmental factors. The data was analysed using a four component multiplicative model. The components are: tree age, climatic conditions, tree position and changes in environmental conditions. Since the effect of tree age and position in the stand could be easily eliminated the main problem was thus to eliminate the effect of climatic conditions on ring width. This was based on the dependence of the daily radial increment and daily maximum temperature. The component associated with changing environmental factors, especially to CO2enrichment, was determined using the model. The basal area development of the trees was calculated from measured and estimated ring widths. Depending on the value of the autocorrelation parameter, the effect of changes in environmental factors on the basal area increment of the trees is between 15.5–43.3%during the period from 1950 to 1983.

ISSN:0282-7581    

DOI:10.1080/02827588809382496

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Root cuttings from 10‐year‐old European aspen(Populus tremulaL.) were rooted in decomposedSphagnumpeat and sand. The root cuttings were exposed to different temperatures (10 and 25°C) and a light intensity of 300 umol m−2s−1for 83 days. Five levels of root depth were used: 2, 4, 6, 8 and 16 cm. Suckers of another clone of 15‐year‐old European aspen were exposed to different light intensities (300, 150, 75 and 30 umolm−2s−1) for 120 days. The percentage of sprouting aspen cuttings was highest in the upper part of the peat (2–6 cm). The total number of suckers was highest at 4 and 6 cm root depths. Dry weights of suckers at 4 and 6 cm root depths were 4200 and 3 840 mg at 25°C and 340 and 180 mg at 10°C, respectively, but were negligible at other root depths. Cuttings produced more suckers when exposed to 25°C than to 10°C. Most of the suckers were produced during 15–25 days after planting. Dry weights of suckers exposed to 300, 150, 75 and 30 umolm−2s−3were 1831, 2280, 1107 and 323 mg, respectively. A practical implication of the relation between temperature level and sucker production and height is avoiding large openings in stands where aspens have been cut. When preventing aspen suckers the aspen ought to be cut in young dense thinning stands where temperature and light intensity are lower than on open areas such as clear cuts.

ISSN:0282-7581    

DOI:10.1080/02827588809382497

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Nine seed lots each of Norway spruce(Picea abiesL.), and Scots pine(Pinus sylvestrisL.) were treated with combinations of the growth regulators: Indole‐3‐acetic acid, indole‐3‐butyric acid, etephone, kinetin, fusicoccin, and the gibberellins A1A3A4/7, and A9. GA9GA4/7and fusicoccin significantly promoted the germination of five Norway spruce, and three Scots pine, seed batches. Independent of species, the germinability of seeds treated with auxins, etephone, kinetin, GA1and GA3were unaffected or reduced. The rate of germination was stimulated for both species when treated with GA9or GA4/7. The germination percentage for Scots pine seeds was enhanced by GA9but not by GA4/7. Neither of the two GAs enhanced the germination percentage of Norway spruce seeds.

ISSN:0282-7581    

DOI:10.1080/02827588809382498

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Incubation with acetone and dichloromethane had little effect on the germination of different lots of Norway spruce seeds. This was not the case with Scots pine where almost half the seed lots tested were adversely affected by acetone and dichloromethane. The auxins indole‐3‐acetic acid (IAA) and indole‐3‐butyric acid (IBA) were applied to Scots pine seeds in acetone, dichloromethane and phosphate‐citrate buffer. The uptake of the two compounds was most rapid from acetone. Although the uptake from dichloromethane was slower than from acetone it reached the same level after 6 h. Uptake of the growth regulators from buffer was significantly lower than from the organic solvents. The accumulation of IAA and IBA into the seeds from both acetone and dichloromethane was linear between 0.5 and 10 mM, and between 0.5 and 15 mM from buffer. IAA and IBA levels in infused seeds declined over a 5‐day germination period, the former more rapidly than the latter. The metabolic activity of the IAA degradation system was as effective in seeds after immersion in the organic solvents as seeds immersed in buffer.

ISSN:0282-7581    

DOI:10.1080/02827588809382499

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor