摘要:

Young birch(Betula pendulaRoth) seedlings were grown in hydroponic cultures to which nutrients were added in amounts that increased exponentially over time. The nutrient additions were adjusted to give three different suboptimal, but stable, relative growth rates (RGR). Levels of glucose, fructose, sucrose and starch and the hormones 3‐Indolyl acetic acid (IAA) and abscisic acid (ABA) were determined in immature (sink) and mature (source) leaves and related to the measured RGR of the seedlings. The results show that ABA increased and IAA decreased in the sink leaves as the RGR of the plants decreased. This occurred in concert with a decrease in soluble sugar levels and starch accumulation in the source leaves. These observations suggest that ABA and IAA may be involved in source‐sink communication in the seedlings, although such causal relationships remain to be proven.

ISSN:0282-7581    

DOI:10.1080/02827589009382618

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Complete diallel crosses were performed in three Norway spruce stands and in one seed orchard. Results are presented for seed yield and 1000 seed weights. Filled seed percentages were higher for open‐pollinated families than for outcrossed full‐sib families and were lowest for selfed families. A large variation was found between the maternal parent trees for this character and a smaller variation between the paternal parents. No distinction could be made between genetic and environmental variation in filled seed percentages. Two out of 34 parents produced no viable seeds after selfing. Seeds from controlled crosses were heavier than seeds from open pollination. The maternal parent accounted for more than 75% of the total variation in 1000 seed weight. In addition, a small, but statistically significant effect of the male parent was found.

ISSN:0282-7581    

DOI:10.1080/02827589009382619

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Sixteen full sib families of Norway spruce(Picea abiesL. Karst.) were measured for height, diameter and wood density (pilodyne method) in a 13‐year‐old field trial located in Jutland/Denmark. Left‐over seed of the same families was resown and after three years tested for growth (height and dry matter production), gas exchange (photosynthesis, respiration and transpiration) and winter frost resistance under controlled conditions. Significant differences between families were obtained in all traits except photosynthesis. No correlation, however, could be found between seedling growth (3 years) and field performance (13 years). Highly significant correlations were obtained between field growth and transpiration on one hand, and water use efficiency of the seedlings on the other (increased growth with decreasing transpiration on one hand, and increasing water use efficiency on the other). Winter frost resistance was significantly correlated to field growth (increasing growth with increasing frost hardiness). By means of water use efficiency and frost resistance, 48% of the variance in field height, 77% in field diameter and 70 % of the variance between families in volume production could be explained. These narrow correlations pinpoint the possibilities in using physiological parameters for early testing and selection in tree breeeding programmes.

ISSN:0282-7581    

DOI:10.1080/02827589009382620

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Eleven 27 to 29‐year‐old Scots pine provenance trials were studied in areas 400 m or less below timberline in northern Sweden. Functions describing geographic variation in the local provenance showed that survival as well as height and volume growth decreased with increasing latitude and elevation. Survival decreased by 7% per degree increase in latitude and 16% per 100 m increase in elevation. Beeting increased the survival by on average 2.4%, but less at high latitudes and altitudes. Tree height and volume per hectare decreased by 0.8 m and 15 m3, respectively, per degree increase in latitude and by 1.3 m and 24 m3, respectively, per 100 m increase in elevation. Transfer functions for provenances at different sites showed that the effect of latitudinal transfer on survival was reduced close to timberline. On average, a southward transfer of one latitudinal degree increased survival by about 7%, which is lower than in previous studies. No altitudinal transfer effects on survival were detected. Volume/ha was increased by southward transfer in northern parts of the area. Spacing had only a slight effect on performance and did not influence the functions presented.

ISSN:0282-7581    

DOI:10.1080/02827589009382621

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The effect of competition on five Norway spruce(Picea abies(L.) Karst.) clones of different provenances growing monoclonally (intragenotypic competition) and in intimate mixtures (intergenotypic competition) at close spacing were studied until the age of five years. In height, root collar diameter, dry weight, and mortality rate, clones reacted differently to the treatments, showing significant inherent competitive differences. A positive competitive reaction between certain clones can raise total increment by overcom‐pensation and can reduce risks by maintaining genetic diversity until harvest.

ISSN:0282-7581    

DOI:10.1080/02827589009382622

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Throughout the study period (November 1985 to August 1987) the needle structure of damaged spruce trees(Picea abiesL. Karst.) was characterized by the reduction in size of chloroplasts at the cellular level and by a gradual advance of the damage at the tissue level. The injury type found in the investigated needles appears to be caused primarily by chronic exposure to a low concentration of oxone.

ISSN:0282-7581    

DOI:10.1080/02827589009382623

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The study was made to assess the relationship between visually estimated defoliation class and a number of other variables depicting the vitality of Norway spruce (n=50). Variables characterizing crown size and conditionweredetermined on the standing trees. Electrical impedance (an indication of the physiological status of a tree) was measured in the inner bark tissue of the living trees. Shoot growth and needle variables were determined from the detached sample branches. Negative correlations were found between defoliation class and the growth parameters (5‐year height, radial and volume growth of the trunk). Positive correlations were observed between the needle loss class and the abundance of branch damage, secondary shoots and impedance values. 18 variables (defoliation excluded) describing tree size and vitality were summarized in a factor analysis incorporating 5 factors. These were interpreted as 1) vitality, 2) foliage discoloration, 3) tree size, 4) needle number and 5) needle size factors. The tree‐specific score values for the first factor were interpreted as “vitality indices”;. The rank correlation between these score values and defoliation degree was 0.835. This result suggests that the defoliation class and vitality parameters contributing to the first factor give a consistent estimate of the tree condition.

ISSN:0282-7581    

DOI:10.1080/02827589009382624

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Seven F2‐families ofB. pendulaand one origin ofB. platyphyllawere planted as 1‐year‐old seedlings on five experimental fields where the density ofMicrotus‐voleswas extremely high. Susceptibility to vole damage was not related to morphological characteristics of seedlings or seedlots. There were, however, significant differences in resistance among the seedlots tested. Voles were selective in replicates in which the level of damage was very high. The cafeteria tests confirm that voles also clearly select among F2‐families ofB. pendula.

ISSN:0282-7581    

DOI:10.1080/02827589009382625

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The changes in the chemical constituents of forest residue chips after seven months of storage under different conditions were determined. Two piles, one indoors and the other outdoors, were set up. Each pile comprised different sections where the chips were stored either loose or compacted. Chemical analyses showed that the Klason lignin contents were increased after storage, especially in the areas where high temperatures were measured. The extractives content declined in most of the tested samples. The uronic acid contents of all the forest residue fractions were clearly reduced after indoor storage. Storage conditions in general affected the needle and bark fractions more drastically than the twigs and wood fractions. The chemical modification of the stored material can be attributed to the microbial activity in the pile as well as to the high temperature which developed in the centre of the different sections leading to various chemical transformations.

ISSN:0282-7581    

DOI:10.1080/02827589009382626

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Analysis of the activity of the substrate‐induced enzyme nitrate reductase in plants can be used to indicate the mode of nitrogen nutrition and the presence of nitrate in the soil. We made two surveys of current and maximally induced shoot nitrate reductase activities (NRA) in different forest types. Dwarf shrubs had little or no NRA.Deschampsia flexuosais, however, a species which can be common in dwarf shrub types and which is capable of high NRA. In short herb types most species had low current NRA and reacted only slightly on induction. This was the case also for some species in tall herb types, while others had high current and maximally induced NRA. Soil analyses showed that the presence of plants with high current NRA coincided with low C/N ratio, high N concentration and relatively high pH. This was most clearly demonstrated along a sharp forest productivity gradient.

ISSN:0282-7581    

DOI:10.1080/02827589009382627

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor