Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 4 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2006. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2008. / Härtill 3 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2010. / Härtill 3 uppsatser.

The Pinus sylvestris natural regeneration growth and site characteristics effect were evaluated in the area of VLS ČR, s. p. divize Mimoň-Doksy in september of 2015. The dendrometric parameters of seedlings as listed: the total height, the diameter, the last 5 years height increment, the crown diameter, the quality and vitality of plants and the branch angle) were measured at nine plots. Also microsite characteristics, such as: herbal layer composition, light conditions, litter horizons and distance to the nearest adult tree) were noted at these sites. The 416 seedlings were measured in total. The main site characteristic with significant effect on the mean increment was direct photosynthetical radiation (r = 0,47). Other significat factors were the total and the diffuse photosynthetical radiation, the canopy and the amount of small bushes in herbal layer. There can be also concluded that good light conditions have statistically significant effect on the quality of seedlings. Influence of other site characteristics was not statistically significant.

Abstract The elongation response of Scots pine (Pinus sylvestris L.) seedlings to the removal of blue light (400–500 nm) was studied in field experiments in northern Finland. The seedlings were grown in orange or transparent plexiglass chambers or in ambient control plots. The orange plexiglass removed the blue wavelengths from sunlight, while the others served as controls. The experiment was conducted at sub-arctic (69°N) and mid-boreal (64°N) latitudes with three- and two-year-old seedlings originating from 67°N latitude. The response to blue light depletion was also investigated at the 69°N latitude in the following plant subjects: one-year-old Scots pine seedlings of northern (67°N) and southern (62°N) provenances, deciduous Betula pubescens ssp. czerepanovii and Betula pubescens f. rubra seedlings and herbaceous Epilobium angustifolium and Glechoma hederacea plants. Additionally, diurnal change in light quality at the 69°N latitude during the summer was measured. The elongation of Scots pine seedlings was increased by the removal of blue wavelengths. The increase was more pronounced at the 69°N latitude, while at the 64°N latitude the response was smaller or absent. This is due to increased amount of scattered growth-inhibiting blue light during the nights at the high latitude. The removal of blue light increased stem elongation in northern origin Scots pine seedlings much more compared to the southern origin seedlings, which suggests that the northern provenance is more sensitive to blue light. Irrespective of that, southern origins also suffer from reduced elongation in the north as they migrate according to climatic change scenarios. However, it is obvious that they grow longer than local origins in the north. Morphological variables and photosynthetic pigments confirm that the increased elongation of Scots pine seedlings under blue light depletion is not a result of etiolation or it is only a marginal factor. Also, it was neither dependent on temperature nor photosynthesis and growth resources. Instead, the increased elongation is probably a photomorphogenic regulation response of metabolism. In addition, shade intolerant Scots pine, Betula seedlings and herbaceous Epilobium angustifolium responded stronger to blue light removal compared to the more shade-tolerant herbaceous Glechoma hederacea.

Abstract Natural selection, mutation, recombination, demographic history and chance all have a role in evolution. In natural populations, the outcome of these forces is seen as adaptations, differences between geographic varieties, and as genetic diversity in populations—both at the phenotypic and molecular levels. In this thesis I wanted to examine the roles of the evolutionary forces shaping molecular genetic diversity in trees, with emphasis on a boreal conifer, Scots pine (Pinus sylvestris). Phylogeographic history and past population size changes have a dominant role in molecular diversity of P. sylvestris. The effect of the Last Glacial Maximum (37 000–16 000) was observed in the distribution of mitochondrial DNA variation. In contrast, nuclear DNA was not much affected by the last glacial period. Instead, more ancient demographic events that took place millions of years ago can still be observed in the variation of P. sylvestris nuclear DNA. Not much evidence of positive natural selection was found in pines or trees in general. This is in contrast to strong natural selection that is observed at the phenotypic level. Positive selection is difficult to prove, especially when the genome is still affected by demographic history. Mutation–drift equilibrium may rarely be reached in tree populations.

Abstract Although microbes are generally found as endophytes in many plant tissues, the plant shoot meristems have been considered virtually sterile. Plant tissue culture, which utilizes mostly the meristems, has nevertheless given numerous references to microbial existence in these tissues. Since the bud-derived tissue cultures of Scots pine (Pinus sylvestris L.) also become easily occupied by microbes, microbial presence was considered to be one potential cause of the low regeneration capacity of tissues from mature trees. The origin of the microbes occurring in tissue cultures of buds of Scots pine was established in this study. One of the microbes, classified as Hormonema dematioides (Ascomycota), was localized in the scale tissues of a bud. Several other microbes were detected, and were associated especially with the meristematic tissues of Scots pine buds. This group was comprised of the yeast Rhodotorula minuta, and bacteria belonging to Methylobacterium spp., the Pseudomonas fluorescens subgroup, and a Mycobacterium sp. These endophytes were located particularly in the outermost cells of meristems, in the epithelial cells of resin ducts, and in the cells of the developing stem, in the vicinity of the meristems. These endophytes were less frequently found in the vascular tissue or in the intercellular spaces of cells, which are typical locations for the previously known endophytic bacteria. The meristem-associated endophytes were discovered to affect growth of pine tissues, and some of them produced substances that are suitable as precursors for phytohormone synthesis. Additionally, pure cultures of both bacterial and fungal endophytes showed antagonism in vitro against pathogens. When the correlation between the presence endophytes and the degeneration of bud-derived tissue cultures of Scots pine was studied, it was discovered that the endophytes grew uncontrollably once a tissue culture was initiated from the bud. A high level of chitinase production was also detected in these tissue cultures, which was considered to be indicative of a defense reaction. However, the endophytes were not found to colonize excessively in every tissue, but all bud-derived tissue cultures of Scots pine eventually degenerate. Therefore, it was concluded that the endophytes may not exclusively be considered responsible for the degeneration of the cultures.

The aim of this master´s thesis was the evaluation of options that should lead to the elimination of the harmful effects of the white grubs of Melolontha hippocastani to the gradational area of Moravian Sahara (part of forest maintenance LS Stážnice, the Bzenec district). The effectiveness of chosen preparations (Force 1,5 G and Actara 25 WP) on the white grubs of Melolontha hippocastani was observed and conducted under controlled conditions in the ´container experiment´ with 380 seedlings of Pinus sylvestris. This experiment was repeatedly conducted five times over a period of 3 years. The results show that the most effective preparation against the white grubs is Actara 25 WG (200 up to 400 g/ha/600 l water) in the form of watering. This preparation in the form of spraying was ineffective. Inconsistent results were reached with the preparation Force 1,5 G. At the same time, the vertical movements of white grubs during their development stages in the soil were being observed over the period of 2015–2018. This observation took place in the drill holes of the following proportions 50 x 50 x 60–140 cm. The results confirmed that the depth of wintering of the white grubs and their movements during their vegetative state depends on the soil´s temperature and moisture, and the available sources of food to the current instar of the white grub.

Åldern på borrprover från tall (Pinus sylvestris) på utvalda hällmarksberg belägna på Åby säteris gamla utmarker studerades enligt en årsringsanalys (korsdatering med pekår, se t.ex. Niklasson, Zackrisson & Östlund 1994) i syfte att undersöka trädsuccessionen i lokal skala. Enligt Fries (1951, 1958), som studerade skogssuccessionen i Sotenäs genom pollenanalyser och historiska källor var hällmarkerna kala fram till mitten av 1800-talet p.g.a. hårt skogsutnyttjande (Fries, 1958, s. 43). Även Lindner (1935) beskriver regionalt hällmarkerna som skogslösa under samma tidsperiod. (Lindner 1935, s. 159-165).Resultaten från borrningarna visar att merparten träd grodde under perioden 1800-1850 med en topp i föryngringen på 1860-talet. En jämförelse mellan tillväxten av de borrade äldre träden och unga tallar från både öppen och sluten skog, visade att de borrade träden troligtvis vuxit i relativt öppna förhållanden, men att hällmarksbergen dock har haft en viss skogsvegetation även innan 1800-talet, vilket indikerar ett avtagande av den tidigare skogsdecimeringen och en␣ökande skogsföryngring på hällmarksutmarkerna kring Åby säteri nästan 100 år tidigare än vad både Fries och Lindner beskriver. Säteriverksamheten kan ligga till stor grund i detta då skog kunde hämtas på annat håll. / Tree core samples from Scots pine (Pinus sylvestris) growing on mountains on the former outfields of Åby manor were analysed according to crossdating of annual rings (e.g. Niklasson, Zackrisson & Östlund 1994) in order to examine the forest succession in a local scale. According to extensive pollen analyses by Fries the rocky outcrops were bare because of the harsh harvesting of the forest until 1850 (Fries, p. 43). Lindner (1935 also described the surrounding rocky outcrops as bare during the same period of time.The results in this studie shows that several trees had germinated before 1800-1850 with a peak of the regeneration in 1860. When comparing the average growth of the analysed older Scot pines and young Scot pines from both open and secluded forests it showed that the analysed older trees had germinated on relative open grounds, with some some forest vegetation, on the outfields before 1800, giving hard evidence of a decreasing misuse of the forest and an increased regeneration on the rocky outcrops of Åby manor almost 100 years earlier than the results according to Fries and Lindner. The manor function could have helped keeping the forest since trees could be collected elsewhere.