Inger Ekberg

Relative amounts and enantiomeric compositions of monoterpene hydrocarbons in xylem and needles of Picea abies

Abstract The relative amounts of 23 monoterpene hydrocarbons, including enantiomers, present in extracts of branch xylem and needles from 41 Picea abies plus-trees of widely different origins, were determined. A two-dimensional gas chromatographic system was used for the determination of the enantiomeric compositions of the seven major chiral monoterpenes. Data were evaluated by multivariate data analysis. Large variations were found in the enantiomeric compositions, as well as in the relative amounts of the monoterpenes, both within and among the trees. Trees from the same geographic area did not show a greater similarity in their composition of volatiles than trees from different geographic areas. In the xylem, (−)-β-pinene and (−)-β-phellandrene, and in the needle samples, (−)-α-pinene, (−)-limonene and (−)-camphene, dominated over their (+)-enantiomers. Among-tree variation in enantiomeric composition was higher in xylem samples than in needle samples, except for β-pinene and β-phellandrene.

Genetic control and age‐related changes of juvenile growth characters in Picea abies

In full‐sib families of 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 de...

Genetic correlations among wood, growth capacity and stem traits in Pinus sylvestris.

Wood density and tracheid length are two traits that significantly affect wood products. Genetic correlations were estimated to evaluate the effect on these traits from a selection for traits included in the Swedish Pinus sylvestris L. breeding programme. Measurements from a non-contiguous single-tree plot progeny trial with controlled matings between 30 parent trees was used. Heritabilities were high for the wood traits, intermediate for the growth capacity traits and low for the stem traits, with the exception of branch angle. Wood density showed no or non-significant negative genetic correlations with the growth capacity traits and a positive correlation with relative branch diameter. Tracheid length showed positive genetic correlations with height and a positive correlation with relative branch diameter. A selection that increased height growth at the age of 13 yrs by 10% was expected to decrease mean wood density at 33 yrs by 1%. The expected correlated response to tracheid length from the same selection was a 3% increase in the juvenile and mature wood.

Occurrence and correlations of monoterpene hydrocarbon enantiomers in Pinus sylvestris and Picea abies.

The relative amounts and enantiomeric compositions of monoterpene hydrocarbons in branch and trunk xylem, in needles, and in resin from apical buds in 18 Pinus sylvestris trees have been determined and compared with the terpene content in branch xylem and needles of Picea abies. Besides the high amount of (+)-3-carene, an excess of (+)-α-pinene has been found in P. sylvestris, whereas in P. abies (−)-α-pinene dominates over (+)-α-pinene. In P. sylvestris, clear positive correlations were found between (+)-α-pinene and (+)-camphene in the four tissues analyzed. Good positive correlations were also observed between (−)-α-pinene and (−)-camphene in the two types of xylem, between (+)-α-pinene and (+)-β-pinene in the resin, and between tricyclene and (−)-camphene in resin and needles. In P. abies, positive correlations were found between (+)-α-pinene and (+)-camphene in the branch xylem and between tricyclene and (−)-camphene as well as between (−)-α-pinene and (−)-camphene in the needles. Complex relationships between (−)-α-pinene and (−)-β-pinene were found both in the P. abies and in the P. sylvestris tissues. The importance of the enantiomeric composition of α-pinene for the host selection of Ips typographus, Tomicus piniperda, and Hylobius abietis is discussed.

Somatic Embryogenesis in Norway Spruce (Picea abies)

The genus Picea (family Pinaceae) consists of 36 species and about 100 subspecies and varieties. Picea is widely distributed in the northern hemisphere. Picea abies (L.) Karst, Norway spruce, is widespread in the central and northern parts of Europe and it is the most common tree in Sweden. It thrives in all soils, except heavy clays and badly waterlogged soils. The trees are generally intolerant of pollution. The wood is light in weight, soft, long-fibered, elastic, slightly resinous with a few and scattered and cream-colored or white resin ducts. Picea abies is one of the most important coniferous species in Europe for timber, pulp and paper production. It also has numerous other applications, including general joinery and carpentry, packing cases, boxes, musical instruments, fuel wood, etc. Picea abies plays a vital role in the international trade balance, especially for the Nordic countries.

Inheritance of autumn frost hardiness in Pinus sylvestris L. seedlings

SummaryInheritance of frost hardiness was analysed making use of a 12×12 incomplete factorial mating design. Owing to space limitations only 59 families could be tested in four experiments. To link the four experiments, some families were common to two or more experiments. The seedlings were grown in climate chambers under conditions inducing autumn hardening. The plants were exposed to a freezing temperature of −10 °C for three hours at night lengths of 11–13 h. A statistical model was developed for analyses of variance of our data. The genetic variation and the variation due to the cultivation regimes during autumn hardening were of the same magnitude. The additive effects were the most important ones for induction of frost damage. No interaction following long-distance crossing was noted. Mixed model equations were used for ranking of the parents. The results obtained support a polygenic inheritance of frost hardiness. The large within-population variation offers good opportunities for hardiness breeding.

Genetic correlations for growth rhythm and growth capacity at ages 3–8 years in provenance hybrids of Picea abies

Genetic correlations were calculated between five phenologicai traits and two growths capacity traits at the ages 3–8 years in a nursery trial with full‐sib families of Picea abies (L.) Karst. from a 9 × 9 factorial mating. The parents originated from three regions, northern Sweden, central Sweden and central Europe, each region being represented by six parents. Out of the possible 81 crosses 57 were analysed. Genetic correlations were calculated between traits within a year at population and within‐population levels and between the same trait over years, both among and within populations. At the population level, most correlations were close to one. Within populations between individual parent trees, the correlations between the timing of the growth initiation and the growth midpoint stages were positive and strong with one exception. In most years these stages were also strongly positively correlated with growth cessation. Correlations between growth rhythm and duration of the shoot elongation period we...

Phytochrome types in Picea and Pinus. Expression patterns of PHYA-related types

Knowledge of the genes in gymnosperms encoding the apoproteins of the plant photoreceptor phytochrome is currently scanty as for gymnosperm nuclear protein coding sequences in general. Here we report two complete cDNA-derived sequences which code for two different types of gymnosperm phytochrome. One sequence stems from Norway spruce (Picea abies) and the other from Scots pine (Pinus sylvestris). More detailed studies have shown that both types of phytochrome gene are present in Norway spruce. From phylogenetic analyses, these types appear to branch off from progenitors that are also the common ancestors of the angiosperm PHYA/PHYC and PHYB/PHYD/PHYE lineages. Partial phytochrome sequences of other gymnosperms cluster with either the one type or the other of the gymnosperm phytochrome genes characterized here. Southern blot analysis of Picea DNA using probes derived from the full-length Picea gene indicated a family of at least five members. Whether they code for new types may be doubted since only two phylogenetic clusters were found. Studies using RNA-PCR of Picea RNA extracted from either light- or dark-grown seedlings indicated that the steady-state levels of the transcripts of two PHYA/C-related genes were hardly affected by light.

T-DNA presence and opine production in tumors of Picea abies (L.) Karst induced by Agrobacterium tumefaciens A281

The hypervirulent Agrobacterium tumefaciens strain A281 formed frequent tumors (31%) on Picea abies (Norway spruce), an economically important tree species in Swedish forests. Three-month-old seedlings were inoculated and tumors were established that grew hormone-independently in culture. Tumors contained agropine and mannopine/mannopinic acid as determined by acid pH paper electrophoresis. In addition, DNA hybridization studies showed that the DNA from these tumor lines contained sequences homologous to Ti plasmid T-DNA, whereas wild-type spruce seedling DNA did not. These results suggest that Agrobacterium vectors can be used for gene transfer into this important forest species.

Consistency of phenology and growth of intra‐ and interprovenance families of Picea abies

In a nursery trial with trees from a 9 x 9 factorial mating, height and seven phenological characters were studied during growth periods 3–8. Three regions, northern Sweden, central Sweden and central Europe, were each represented by six parents. Out of the possible 81 crosses 57 were realized. The analysis of variance revealed that the error component of variance was mostly low compared to the sum of the genetic components, and that the additive components dominated. For the height character the population component dominated. The interaction components, female population x male population and female x male within population, were for all characters much smaller than the additive components, except for number of sylleptic shoots (= free growth). The estimated GCA‐values were for all characters consistent during the testing period. The number of sylleptic shoots more or less disappeared during the end of the test period. Except for this trait our data suggest that the laborious phenological examination ca...