Maatalous- metsätieteellinen tiedekunta

 

Recent Submissions

  • Lizarazo Torres, Clara Isabel (Helsingin yliopisto, 2017)
    Most cropping systems in the Boreal Nemoral region of Europe are characterized by intensified cereal production, which has resulted in a heavy dependence on foreign vegetable protein imports for feed supplementation and high consumption of synthetic fertilizer. This in turn have caused numerous critical environmental impacts such as copious greenhouse gas emissions from fertilizer production and use, heavy reliance on a narrow range of crop protection methods, leading to risks of resistance to agrochemicals, nutrient runoff and losses in soil health locally, and in land-use change abroad. Hence, crop diversification is needed, and this work focuses on the potential to use grain legumes to help meet the demand for the local vegetable protein and to mitigate the environmental impacts resulting from the current narrow diversity on crop rotations and from the feed and fertilizer trade. In this dissertation, three grain legume crops, namely faba bean (Vicia faba L.), narrow-leafed (NL) lupin (Lupinus angustifolius L.) and lentil (Lens culinaris Medik.) were grown in field trials in order to assess their potential adaptation to the Boreal Nemoral region of Europe and to find their best place in the cereal-based crop rotations that are conventional in the region. The research focused on 1) the protein yield potential of each crop and their nutritive quality particularities, 2) the pre-crop effect of cereals on grain legumes, and 3) the exploration of flowering time in faba bean as a key component of adaptation to high latitudes. The results show, that faba bean was the crop with highest protein yield stability, and with higher protein concentration than is achieved at lower latitudes, whereas lentil and narrow-leafed lupin had comparable protein concentration as those achieved in other locations. Nutritive quality of all three crops was within the normal range, and amino-acid and DIAAS scores suggested that cultivar selection is important, since major variations in the content of lysine, cysteine and tryptophan influence the feed and food value. The screening trials revealed that among the available lentil and NL lupin cultivars, earliness is sufficient with some reaching maturity in about 100 days, whereas significant improvement on the earliness of Kontu faba bean is needed in order for the crop to be grown in the northern most part of the Boreal Nemoral region. The crop rotation trial showed that NL lupin produced equally high yields after turnip rape and oat, while faba bean gave higher yields after turnip rape and then after barley. Overall, the pre-crop effect on nutrient composition of NL lupin was less evident than on that of faba bean, the latter having 19, while the former 7 significant differences out of the 88 nutrient uptake variables measured. Among these 26 significant measures, barley was the best pre-crop in 9 variables, and oat in 5. The pre-crop effect was present on both the shoot and seed composition, and it was apparent that the pre-crop effect was able to influence soil nutrient availability and thus uptake. This study shows some insight about best pre-crop for grain legumes, but the effects need to be tested further to elucidate the mechanisms and to verify the reproducibility of such effect on crop sequences. The upgraded flowering model showed that flowering control in faba bean in addition to photoperiod and temperature sum, depends on solar radiation (as measured by PAR or sunshine duration, the former providing a better model fit), and water deficit (as measured by the Sielianinow hydrothermal index K ). Understanding the effect of these two new variables in flowering makes it possible to seek more types of variation in earliness be used to identify sources of variation that can serve as material for the selection and development of new cultivars for high latitudes or short seasons. Overall, this study shows that faba bean and NL lupin have great potential for diversifying crop rotations in the Boreal Nemoral region of Europe, whereas the susceptibility of lentil to the wet autumns typical of the region will make its management challenging. Each of the crops has different advantages, so they complement each other in terms of optimum soil type, nutrient uptake and nutrient composition. It is recommended that their cultivation should be promoted not only to solve the vegetable protein deficit, but also to improve the sustainability of cropping systems in the region.
  • Schiestl-Aalto, Pauliina (Helsingin yliopisto, 2017)
    Environmental factors have a dual effect on growth as they affect both the momentary growth rate (direct effect) and the rate of ontogenetic development (indirect effect). Photosynthesis on the other hand is the source of carbon that is needed for growth, respiration and other purposes. There are two opposite theories about the factor determining growth rate: 1) the availability of carbon for growth (source limitation) and 2) limitation that environmental factors cause on tissue ability to grow (sink limitation). Understanding the responses of the growth of tree organs (wood, needles, roots) to environmental and other factors is important to be able to understand the changes in tree growth and carbon balance in changing climatic conditions. The purpose of this study was to define the effects of temperature on Scots pine growth at different temporal scales and to estimate the relative importances of the source and sink effects on growth. For that, a dynamic growth model CASSIA (Carbon Allocation Sink Source InterAction) was constructed. CASSIA was able to predict daily primary and secondary wood and needle growth rate variation with indirect and direct effects of temperature. In addition, the temperature of warm previous late summer was observed to lead to enhanced length of the growth period (in temperature accumulation units) of shoots in the following year. Growth onset during spring was observed to be a continuous process determined by temperature accumulation, instead of momentary temperatures. Short-term growth variations in normal conditions were concluded to be sink limited because CASSIA was able to predict the within year growth with temperature and without direct effect of photosynthesis or stored carbon. On the other hand carbon source effect (gross primary production) was needed to produce the between year variation in growth. According to the results of this study, growth is limited by a complex combination of sink and source effects. Furthermore, environmental factors affect growth at different time scales varying from instantaneous effects to delayed effects from previous year(s). More research is needed to identify the factors determining the carbon flows to different processes.
  • Anasonye, Festus (Helsingin yliopisto, 2017)
    Soils that are contaminated with organic aromatic compounds such as polyaromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 2,4,6-trinitrotoluene (TNT) have previously been treated by combustion at elevated temperatures. Although, combustion is effective, it is expensive due to high energy and equipment requirements. However, innovative technologies such as the use of fungi and/or biochar can offer an alternative option that is friendly to the environment in treating such soils. This thesis evaluates three treatment options to treat these contaminants in soil: 1) the use of fungi growing on pine bark, 2) the use of fungal enzymes, and 3) treatment with both fungi and wood derived biochar. Fungal treatment of TNT-contaminated soil was applied in both laboratory and in pilot scale experiments. In the laboratory experiments, fungi were tested for their capability to grow in soil contaminated with the explosive 2,4,6-trinitrotoluene (TNT) and to accelerate its degradation. TNT concentration in the soil was 1000 mg kg-1. White-rot fungi, Gymnopilus luteofolius, Kuehneromyces mutabilis, and Phanerochaete velutina grew in the contaminated soil and produced a significant amount of manganese peroxidase (MnP) in TNT contaminated soil during that incubation, but no laccase. The most efficient fungus, P. velutina, degraded 80% of TNT in 2.5 months. The soil treatment process was scaled-up in a 0.56 m3 reactor with 0.3 t of TNT-contaminated soil and P. velutina grown on pine bark. TNT concentration in the soil was 1000 mg kg-1 and the soil:fungal inoculum ratio was 30:1. P. velutina degraded 70% of TNT in 49 days, and no further degradation occurred during the next 58 days of incubation. TNT metabolites, namely 4-amino-2,6-diaminotoluene and 2-amino-4,6-diaminotoluene, accounted for less than 0.5% of the original TNT concentration at the end of the incubation. For PCDD/F-contaminated soil, the approach was to treat the soil with either fungal inoculum or crude MnP. Treatment with fungal inoculum proved to be an effective treatment option as PCDD/Fs were degraded 62% and 64% of the WHO-TEQ (World Health Organisation Total Equivalent) value by Stropharia rugosoannulata and P. velutina, respectively, compared to a control where no degradation was observed. However, when PCDD/F-contaminated soil was treated with crude MnP, no degradation was observed even though significant levels of MnP activity were detected in the soil. Treatment of PAH-contaminated soils (humus-poor soil named sloam and humus-rich forest soil) were studied. Pyrene-contaminated soil was amended with wood-derived biochar, and the ability of fungi to grow in the amended soil was tested. Agrocybe praecox and P. velutina survived well in the amended soil and were selected for further studies. In addition, the role of fungi in pyrene sorption to amended soil was investigated. Fungal treatment of pyrene-contaminated soil amended with biochar increased the sorption of pyrene up to 47 56% to biochar amended forest soils compared to the controls (13 25%) incubated without fungi. Strong fungal/biochar synergistic effects were observed in cases of the sorption of pyrene in the amended soils. In non-sterile contaminated forest soil amended with biochar and incubated with one fungus, higher levels of pyrene (50%) was sorbed to the soil compared with a mere 13% in a similar soil without the fungus. In humus-poor sloam amended with biochar and incubated with fungus, only 9 12% pyrene was sorbed to amended soil. Similar results were obtained for both fungi used in the study. They had significant impact on forest soil with a higher organic matter content compared with sloam. Fungal treatment provides a viable treatment option and an alternative to traditional treatment options such as combustion of soils that are contaminated with organic aromatic contaminants. Fungi have shown strong potential to degrade these contaminants in soil. The addition of biochar and fungi to PAH- contaminated soil may help to reduce the risk of leaching of contaminants to ground water and above all to promote remediation of contaminated soils.
  • Nikula, Ari (The Finnish Society of Forest Science, 2017)
    The Moose is a valuable game animal in Fennoscandia but also the most severe pest in forest plantations. In this thesis, I examined factors that affect the habitat selection of moose and moose damage at multiple scales. At the plot level, browsing increased with an increasing number of artificially regenerated pines and deciduous trees taller than pines. The damage risk was the highest in plantations with heavy soil preparation. Moose summer home ranges had more fertile sites than the overall study area. Within summer ranges moose, selected non-pine-dominated habitats and mature forests and avoided human settlements. Winter ranges contained more pine-dominated plantations and other young successional stages, more pine dominated peatland forests and less human settlements and agricultural fields. Within winter ranges, moose used more non-pine-dominated plantations and mature forests and less human-inhabited areas than expected. At the home range level, there were no significant differences between sexes, but within home ranges males and females used different habitats during both seasons. The occurrence of damage in nearby landscape decreased the probability to find a landscape without damage and predicted an increase in the number of damaged plantations. Increased food-cover adjacencies of mature forests and plantations increased damage. An increasing proportion of inhabited areas and the length of connecting roads decreased the number of damage at the landscape sizes of 1 km2 and 5 km2. Moose-damaged stands were concentrated in SW and eastern Lapland in Peräpohja Schist Belt and Lapland s Greenstone Belt with nutrient-rich bedrock. There was less damage in landscapes with an abundant amount of pine-dominated thinning forests. Moose damage plantations were located more on fertile bedrock and soils than undamaged ones. Regenerating Scots pine on fine-grained soils derived from nutrient-rich rocks and naturally occupied by Norway spruce might increase damage risk.
  • Liesivaara, Petri (Helsingin yliopisto, 2017)
    The emphasis in crop damage compensation in the EU is moving from government-run programmes and disaster relief to insurances based on public private partnership (PPP). Before 2015 member states had the opportunity to finance crop insurance premium subsidies from national budget under Article 68 of Pillar one regulation. From 2015 onwards, member states have had the option to co-finance premium subsidies with the EU under the conditions defined in the regulation (EU) No 1305/2013 on support for rural development. A publicly funded and administered Crop Damage Compensation (CDC) scheme was designed to cover yield losses in Finland. As a result of European Commission objection and obvious deficiencies in the CDC system, the programme was abolished in the end of 2015. The objetives of this thesis were to 1) study farmers preferences and willingness to pay (WTP) for crop insurance attributes, 2) reveal the effects of the price anchoring problem in crop insurance, 3) provide guidelines for government disaster relief in combination with crop insurances, 4) investigate the factors underlying crop insurance uptake and 5) study the feasibility of index crop insurance based on area yields in Finland. The research results were expected to benefit farmers, the government and insurance companies. An extensive farm survey was conducted to reveal Finnish farmers demand and WTP for crop insurance. Choice Experiment (CE) method was used. In addition, a split sample approach was applied to the price anchoring problem and to examine the effect of government disaster relief on crop insurance schemes. The obtained results revealed that there is demand for crop insurance in Finland. An insurance product was chosen in 46.5% of the cases in the entire CE dataset. Price of insurance is the main factor affecting the choice to insure and the demand was found to be inelastic over the whole price range. The median WTP of Finnish farmers for a 10% increase in the deductible was -1.60 Euros/ha, and if the expected compensation was increased by 100 Euros, farmers WTP increased by 3.40 Euros/ha. The results suggest that the crop insurance markets that are starting to emerge in Finland are dominated by knowledge of premium setting. Our results also revealed that government disaster relief for crop damages would lead to an overall smaller WTP for crop insurance. Multiple farm and farmer characteristics, such as age, farm size and education level, were found to be significant in explaining the choice to insure against crop losses. We also found evidence of an adverse selection problem in future crop insurance schemes in Finland as farmers that had collected CDC payments were more likely to choose crop insurance. In addition the study on the feasibility of area yield index insurance in Finland revealed that its overall efficiency is not high, as half of the farms would not gain any benefit from it.
  • Nieminen, Emmi (Helsingin yliopisto, 2017)
    This thesis examines the optimal economic management of the Baltic Sea fisheries and contributes to the existing literature with its novel bioeconomic and game theoretic applications enhancing more holistic fisheries management than traditionally, and thus taking a step towards ecosystem-based management. Such management can be interpreted as integrated management of the ecosystem instead of concentrating on a single issue in isolation. This approach is fulfilled in four separate dimensions: Firstly, the thesis studies the optimal management of several species instead of focusing on only one species. Secondly, the focus is not only on management in a single country; instead, the thesis has a wider scope and analyse the prospects of cooperation among several countries. Thirdly, the problems are modelled by taking into account the long-term perspective, i.e., by maximising the resource rent over a long time period and by analysing the possible effects of climate change. Fourthly, this thesis applies a cross-sectoral approach and examines several sectors affecting the ecosystem (fisheries and energy sectors) instead of only focusing on one. This thesis highlights the importance of linking economics to biology and its significance to fisheries management. In fact, fisheries management based on society s profit maximising bioeconomic objectives with biologic constraints are often more conservative for a fish stock than management relying solely on biologic advice. The increased profitability of the fisheries industry could furthermore be improved by international coordination among fishing nations. The positive effects of bioeconomic management would be even greater when the fish stocks are weak, which may be the future in the Baltic Sea with the continuing effects of climate change. Additionally, this thesis takes into consideration the positive value of migratory fish for the recreational river anglers. When those values are included, it is often profitable from the society's point of view to enable the upstream migration even in regulated rivers producing hydropower. The optimal measures targeted to enhance the migration depend on the number of the dams in the river: the more dams, the more profitable to trap and transport fish over the dam instead of constructing fishways.
  • Pietarinen, Paavo (Helsingin yliopisto, 2017)
    The focus of medical research has steadily shifted from population-based medicine to personalized medicine in recent years. It has become clear that interindividual variability plays a big role in treatment responses. For example, CYP2D6 is involved in the metabolism of 20-25% of clinically used drugs, and the CYP2D6 mediated metabolic rate varies widely between people. Chronic myeloid leukemia (CML) is the only leukemia with highly effective targeted treatment. However, some patients become resistant or intolerant to the first-line treatment, and personalized treatment adjustment is sometimes necessary. The purpose of this thesis was to study how genetic and functional screening can be utilized in personalized-medicine research. In Study I, we genotyped 857 Finnish volunteers for 10 CYP2D6 genetic variants. We found that the frequencies of CYP2D6 variants differ from our neighboring populations. More importantly, genotype-based classification of CYP2D6 metabolic activity showed a high frequency of ultra-rapid metabolizer (UM) genotype (7.2%), which was the consequence of the high prevalence of CYP2D6 duplications. In contrast, the frequencies of poor metabolizer (PM) (2.3%) and intermediate metabolizer (IM) (3.0%) genotypes were relatively low, which indicates that Finns have a high capacity for CYP2D6 mediated metabolism in general. In Studies II and III, we explored the drug sensitivity profiles of chronic myelogenous leukemia (CML) in blast crisis (BC) and chronic phase (CP) utilizing cell line and patient primary cell samples in a high-throughput drug screening platform. The median drug responses of the BC CML cell line and patient samples correlated well. By comparing the drug responses in these samples, we were able to identify several compounds (e.g., NAMPT, VEGFR, and MEK inhibitors), which were highly effective in all samples. Testing the drug sensitivities of CP CML samples and comparing them to BC CML samples revealed CP CML cells to be clearly less sensitive in general. Most surprisingly, CP CML samples seemed to be resistant to tyrosine kinase inhibitors (TKIs). We also studied the variance of absorption, distribution, metabolism, and excretion (ADME) genes in CP CML patients with poor responses to TKI treatment. In our study population of poor responders (n=21), we discovered several gene variants significantly more frequently in poor responders than in the healthy control population. Furthermore, we identified novel ADME gene variants that have not been reported previously. Interestingly, some of these novel variants may be CML cell-specific somatic mutations. To conclude, in this thesis, we showed clinically relevant CYP2D6 variation in the Finnish population, which should be taken into consideration when prescribing drugs that are CYP2D6 substrates. We saw also that high-throughput drug screening is an effective way of studying individual drug responses in patient cells. We think that the findings of this thesis can be used to improve personalized medicine research.
  • Kontturi, Juha (Helsingin yliopisto, 2017)
    The type III polyketide synthases (PKSs) are a group of enzymes involved in the production of structurally diverse secondary metabolites, polyketides in plants. Compounds, such as chalcones, chromones, stilbenes and coumarins possess a variety of important biological roles for the plants, such as protection against oxidative stress, pests and diseases, herbivory and UV irradiation. From the human use perspective, polyketides or their derivatives serve as antifungal compounds, immunosuppressants, anticancer drugs, antibiotics and insecticides. Type III PKS are small (40-45 kDa) proteins functioning as homodimers. They catalyze the sequential decarboxylative condensation reaction between malonyl-CoA and a variety of CoA-linked starter molecules in a biosynthesis, which closely resembles fatty acid biosynthesis. Gerbera (Gerbera hybrida) expresses three genes encoding chalcone synthases (CHS), which are enzymes involved in the biosynthesis of flavonoids in plants. In addition, it has three genes encoding 2-pyrone synthases (G2PS1-3), which differ from the CHSs with altered substrate specificity and the amount of decarboxylative malonyl-CoA condensation reactions. It was previously shown that G2PS1 is a triketide synthase, responsible for the biosynthesis of 4-hydroxy-6-methyl-2-pyrone (triacetolactone, TAL), a putative precursor for two antimicrobial compounds, gerberin and parasorboside in gerbera. In this study, the G2PS2 and G2PS3 were functionally characterized as pentaketide synthases and their role in the biosynthesis of another antimicrobial compound, 4-hydroxy-5methylcoumarin (HMC) was demonstrated. Using protein modelling and mutagenesis studies, the structural differences in the active site cavity of gerbera 2-pyrone synthases were demonstrated. The gerbera type III PKS family was extended by characterizing two additional 2-pyrone synthases and determining their expression patterns. The newly discovered GASCL1 and GASCL2 are anther specific chalcone synthase like enzymes (ASCLs), which in many other plant species have been shown to take part to the biosynthesis of sporopollenin, the main component of a exine layer of the pollen grain. The last part of the thesis focus on glycosyltransferses (GTs), a group of enzymes that catalyze the addition of a sugar moiety to the plant secondary metabolites, including the products of the gerbera type III PKSs.
  • Reuter, Lauri (Helsingin yliopisto, 2016)
    Recombinant proteins are used as pharmaceuticals, enzymes and components of nanotechnology. The exceptional properties of fungal hydrophobins make them interesting for many of those uses. They also transfer some of their functionalities to fusion proteins enabling completely new applications. In general, plants are a potential platform for manufacturing recombinant proteins even in agricultural scale. This work explores production of hydrophobin fusion proteins in a plant cell factory: the tobacco bright yellow 2 cells (BY-2). The hydrophobin fusion technology has been mainly based on a single hydrophobin molecule the Trichoderma reesei HFBI. This work expanded the toolkit with several new molecules. When expressed in plants the hydrophobin fusion partners induced formation of protein bodies, in relation to the accumulation levels. In addition to HFBI, only HFBII and HFBIV interacted with non-ionic surfactant to selectively separate fusion proteins in surfactant based two phase separation. In Nicotiana benthamiana HFBII improved accumulation of green fluorescent protein (GFP) and Protein A in comparison to both HFBI-fused and non-fused proteins. However, HFBI, HFBII and HFBIV fusion partners all slightly reduced the yield of transferrin. Both HFBI-Protein A and transferrin-HFBIV were produced in BY-2 suspension cells with good yields. Furthermore, continuous selection resulted also in a cell line yielding 1.1 g/l GFP-HFBI. This is the first report on a plant cell culture reaching gram per litre yields. The BY-2 propagation was successfully scaled-up to 600 litre culture volume in classical stirred tank bioreactors. The aqueous two phase separation from plant cell extract was successfully scaled to 20 l volume. The fusion proteins retained functional properties from both fusion partners. The HFBI-Protein A enabled harvesting of antibodies in solution using aqueous two phase separation. The HFBIV fused transferring retained its capability to bind iron and interact with the transferrin receptor. Coating with transferrin-HFBIV resulted in uptake of the silicon nanoparticles in human cancer cells. This work builds foundation for utilization of BY-2 suspension cells in industrial manufacturing of recombinant proteins and on the other hand opens interesting new applications for bi-functional hydrophobin fusion proteins.
  • Uotila, Karri (Helsingin yliopisto, 2017)
    The purpose of the work done for this thesis was to construct and develop the concept of cost-efficient Juvenile Stand Management (JSM) for planted Norway spruce (Picea abies L. Karst) stands. The principles of time based management were followed, by integrating regeneration activities as a cost-efficient value chain and by minimizing non-value-adding work with straightforward decision making based on Forest Management Plan (FMP) data. The effects of soil preparation and Early Cleaning (EC) on further development of the stands were studied in intensive field experiments. Extensive survey data from juvenile stands were used to develop methods applicable for efficient decision making in JSM. The survey data were used to model the effects of site and stand attributes on the need for EC and labor time consumption of PreCommercial Thinning (PCT). Timing of JSM had major effect on its costs; a delay in PCT increased the labor time needed to manage a stand by 8.3% annually. Moreover, 61 70% of the saplings in a typical Norway spruce stand were considered to need EC years before the need for PCT arose. EC was also found to be an effective release treatment as it subsequently increased the diameter growth of crop trees by 21 32%. However, a two-stage management regimen, which included EC and PCT, appeared to be somewhat more labor consuming than the PCT only option. The soil preparation method had a major effect on the number of trees to be removed in EC, and spot mounding led to a less labor consuming JSM program than disc trenching. Thus, spot mounding appeared to be a less costly activity overall even though it initially appeared a more expensive method than disc trenching. The results showed that interactions in regeneration chain activities are important for cost-effective wood production. Furthermore, a priori information can have practical implications in decision making for JSM. Several site or stand attributes were found to explain the need for EC or for labor consumption of PCT. However, the models developed in this study are rather inaccurate for reliable a priori estimation. The modeling data in further research should go beyond the data of traditional FMP. Big data offers promising opportunities, but data collection and storage need to include data with the relevant attributes.
  • Kokko, Pauliina (Helsingin yliopisto, 2017)
    Achieving and maintaining national self-sufficiency in milk and meat play important roles in ensuring future food security. Currently, Finland is self-sufficient in milk. However, beef production, which is strongly related to dairy production, has fallen below consumption mainly because of a decreased number of dairy cows and low profitability. Even though the efficiency and productivity in dairy herds have increased substantially during the last decades, the profitability of milk, and especially combined milk and beef production, has remained low. In addition, the environmental challenges facing the dairy cattle industry are increasing;the environmental impacts of dairy farming are of growing public concern and production is likely to be affected by new environmental legislation and constraints in the future. To meet the future challenge of safeguarding food security with more intensive use of resources, new breeding and production strategies for milk and beef production are needed. The main goal of this thesis was to investigate sustainable breeding and production strategies for increasing the productivity and efficiency in dairy herds in order to improve profitability and contribute to mitigation of the environmental impact of milk and beef production. More specific objectives were to derive economic values of feed efficiency traits along with several production and functional traits in Finnish milk production and to evaluate economic benefits of including additional feed efficiency, growth, and carcass traits in the breeding goal for combined milk and beef production systems. Moreover, the possibilities of different production strategies for increasing beef production from dairy herds and mitigating overall greenhouse gas emissions from beef production were assessed. The derivation of economic values of different traits for the Finnish Ayrshire breed using a bio-economic approach showed that milk yield with the highest relative economic value (29-40% of the sum of standardized economic values over all traits) strongly dominated the breeding goal under the Finnish production and economic conditions in 2011. However, the moderate relative economic values (given in parentheses) found for the traits not currently included in the breeding goal: daily gain of animals in the rearing and fattening periods (4-5% both), residual feed intake (RFI) trait group (6-7%) as well as mature live weight (LW) of cows (6- 11%), indicate that the inclusion of these traits in the breeding goal for Finnish milk production systems could result in economic benefits. The economic impact of including additional feed efficiency and beef production traits in the breeding goal for the combined milk and beef production systems was assessed using a deterministic approach with the derived economic values. According to the results, the inclusion of a better growth performance of fattening animals and growing replacement heifers in the breeding goal while simultaneously preventing higher LW of cows would be the most promising option to improve the profitability of the combined milk and beef production systems. When considering the studied feed efficiency-related traits, the inclusion of smaller LW of cows in the breeding goal seems to be more beneficial than the inclusion of RFI traits in production systems where growth and carcass traits are subject to selection. This finding is also supported by the faster availability of LW of cows for selection and its lower recording costs. However, with the breeding goal that excludes growth and carcass traits, adding LW of cows alone to the breeding goal had a negative effect on the profit of the breeding program. Therefore, for production systems where growth and carcass traits are not subject to selection, selecting for RFI traits could be more profitable even with only small economic benefits. However, before any further conclusions can be made about the consequences of selection for RFI traits, more information on the genetic correlations between RFI traits and current breeding goal traits as well as on the most cost-effective selection methods for feed efficiency is needed. Finnish beef production was modeled to study the potential of different production options to enhance beef production originating from dairy operations.The most efficient way to enhance beef production, and consequently, to mitigate greenhouse gas emissions from beef production would be to increase the use of crossbreeding with beef bulls in dairy herds carrying out inseminations with Y chromosome sorted beef semen. However, in order to increase the current rate of crossbreeding, procedures that would ensure a sufficient number of replacement heifers and clear economic benefits from the production of crossbred calves to dairy farmers are needed. When considering the studied strategies that enable the increased use of crossbreeding in dairy herds, reducing the herd replacement rate showed the most potential for enhancing beef production, even though it would require substantially higher use of crossbreeding. The current global tendency towards specialized dairy and beef production systems will likely further reduce beef production from dairy herds, potentially leading to an increasing negative environmental impact of livestock production. The results of this thesis support that combined milk and beef production would likely be the most viable and sustainable way to achieve self-sufficiency in beef while maintaining sufficient milk production in Finland. Therefore, the current dairy production systems should be developed more towards systems that efficiently produce milk and beef rather than increased specialization.
  • Koskinen, Markku (Helsingin yliopisto, 2017)
    In this study, the effects of restoration of forestry-drained peatlands on the nutrient and organic carbon exports and methane dynamics of the restored sites are explored. The study consists of four sub-studies. Two of the sub-studies are concerned with the effects on water quality and export of elements of restoration and were conducted on a catchment scale. One of the studies was conducted in the laboratory, and assessed the release of elements from peat samples under anaerobic inundation simulating the effects of a rising water table after restoration or logging. The fourth study was again a field study, in which the differences in methane emissions between undrained, drained and restored spruce swamp forests were assessed. In all, 24 different pristine, drained and restored sites are featured in the study, one site being present in two of the sub-studies. The results indicate potentially large effects of restoration especially on the nutrient rich spruce-dominated sites, which had the highest restoration-induced increases in organic carbon and nutrient exports in the catchment studies, and which also exhibited high methane emissions after restoration, higher than in the undrained or drained state. The results should prompt research into the techniques applied in restoration of such sites and into the processes which lie behind these large effects.
  • Chan, Tommy (Helsingin yliopisto, 2016)
    Chan, Tommy 2016. Dynamic variations in bark hydraulics understanding whole tree processes and its linkage to bark hydraulic function and structure. University of Helsinki, Department of Forest Sciences A mature tree stem generally consists of a column of wood that is composed of a series of annual incremental layers and enclosed in a covering of bark. The dynamic variations of the bark are complex due to its structure and function: the thick outer-bark acts as a protective barrier against the abiotic and biotic environment; while the phloem is where sugar transport occurs. Much of the bark variation is due to the transport of sugars and its related processes. The xylem pathway, which transports water in the opposite direction, is connected to the phloem in parallel along the entire length of the stem. The immediate connection between these two transport pathways suggests a functional linkage. The purpose of this thesis is to study the dynamic processes that occur within the bark and its interaction with other internal tree processes and the external environment. These interactions have not been thoroughly quantified, especially on an intra-annual (e.g. daily) scale. The thesis consists of four papers, of which one is a modelling paper and three are experimental studies. Growth is estimated with the model by separating the water-related influences from measured inner-bark, revealing a growth signal proxy for cambial stem growth. Using this signal, a correlation study to microclimate variables is examined in one paper; and to assumed growth respiration in a second paper. The remaining two papers explore the seasonality of photosynthesis and respiration, and bark stem dynamics during the spring recovery period. As a conclusion of this thesis, these papers show how inextricably linked individual tree processes and the environmental are to the changes within the bark. The culmination of this thesis opens new opportunities to further understand the dynamics of bark hydraulics and ecophysiological processes by implementing field measurements and state-of-the-art modelling. Keywords: xylem, phloem, growth, respiration, photosynthesis, spring recovery
  • Chamlagain, Bhawani (Helsingin yliopisto, 2016)
    Vitamin B12 (later B12) intake is insufficient in developing countries, and globally, vegetarians and vegans are also at risk of B12 deficiency. Occurring naturally only in foods of animal origin, new affordable and sustainable dietary sources of B12 are needed to ensure sufficient intake. The only known food-grade producers of active B12, Propionibacterium freudenreichii strains, however, are yet to be exploited to enrich plant-based foods with B12. The B12 production capacity of P. freudenreichii depends on the strain, and the availability of the B12 lower ligand (5,6-dimethylbenzimidazole, DMBI) is a key factor for the production of active B12. Bread can be considered as a potential food for B12 fortification; yet the stability of in situ-produced B12 incorporated during breadmaking processes is not known. Current analytical methods such as the microbiological assay (MBA) lack the required specificity and the existing high-performance liquid chromatography (HPLC) methods are only capable of measuring higher B12 levels in fortified foods and supplements. The determination of active B12 in fermented foods, however, needs sensitive and selective methods. An ultra-HPLC (UHPLC) method was developed and validated to measure the active B12 contents. The identity of the B12 form was confirmed with an ion-trap or quadrupole time-of-flight mass spectrometry (MS). The B12 production capacity of 27 P. freudenreichii and 3 Propionibacterium acidipropionici strains was first studied in whey-based medium (WBM), and three of these P. freudenreichii strains were chosen to study B12 production in three aqueous cereal matrices prepared from malted barley (BM; 33% w/v), barley flour (BF; 6% w/v) and wheat aleurone (AM). Riboflavin (RF) and nicotinamide (NAM) as food-grade replacements for DMBI were investigated in WBM and cereal matrices. The stability of in situ-produced B12 and added cyanocobalamin (CNCbl) and hydroxocobalamin (OHCbl) during straight-dough, sponge-dough and sourdough breadmaking was studied. The developed UHPLC method employing an Acquity high-strength silica (HSS) T3 column showed excellent separation of active B12 from its analogues. A low limit of detection (0.075 ng/inj) enabled the measurement of the B12 levels in cell extracts directly and following immunoaffinity purification in extracts of fermented cereal matrices and B12-fortified baking samples. Analysis with UHPLC MS confirmed the production of active B12 by all 27 P. freudenreichii strains in WBM and 3 P. freudenreichii strains in cereal matrices. P. acidipropionici strains, however, produced an inactive form (pseudovitamin B12), thus making them unsuitable for active B12 fortification in foods. The level of B12 production in WBM varied considerably between the strains (0.45‒3.35 µg/mL), which increased up to 4-fold in 12 of the 27 P. freudenreichii strains following supplementation with RF and NAM. In many of these strains, the B12 yield was higher with RF and NAM co-supplementation than with DMBI. In cereal matrices without supplementation, the produced levels of active B12 (9‒37 ng/g) with P. freudenreichii strains were nutritionally significant. The B12 production increased many-fold, reaching up to 430 ng/g in BM, 39 ng/g in BF and 114 ng/g by adding cobalt (Co) and reached 712 ng/g in BM and 180 ng/g in AM with RF and NAM co-supplementation with Co. The incorporated in situ-produced B12 was retained during straight-dough breadmaking and the loss of 29% during sourdough baking was similar to the losses observed for relatively stable CNCbl. However, the added OHCbl decreased by 21%, 31% and 44% respectively in straight-dough, sponge-dough and sourdough breadmaking. These results showed that B12 produced in situ and incorporated during breadmaking was well retained in the bread prepared by the conventional breadmaking processes. This thesis shows that UHPLC combined with MS allows for the accurate identification and quantitation of low levels of active B12 in fermented food matrices (≥1 ng/g). P. freudenreichii strains could be utilised for in situ production of active B12 in cereal matrices and WBM. The availability of RF and NAM could considerably improve B12 production. The produced levels could easily fulfil the recommended dietary allowance set for B12 (e.g. 2‒2.4 µg/day for adults), and could be well retained in bread in the commonly used breadmaking processes.
  • Tanhuanpää, Topi (Helsingin yliopisto, 2016)
    Urban forests provide various ecosystem services. However, they also require fairly intensive management, which can be supported with up-to-date tree-level data. Until recently, the data have been collected using traditional field measurements. Laser scanning (LS) techniques provide efficient means for acquiring detailed three-dimensional (3D) data from the vegetation. The objective of this dissertation was to develop methods for mapping and monitoring urban forests at tree level. In substudy I, a method (MS-STI) utilizing multiple data sources was developed for extracting tree-level attributes. The method combined airborne laser scanning (ALS), field measurements, and tree locations. The field sample was generalized using the non-parametric nearest neighbor (NN) approach. The relative root mean square error (RMSE) of diameter at breast height (DBH) varied between 18.8 33.8%. The performance of MS-STI was assessed in substudy II by applying it to an existing tree register. 88.8% of the trees were successfully detected, and the relative RMSE of DBH for the most common diameter classes varied between 21.7 24.3%. In substudy III, downed trees were mapped from a recreational forest area by detecting changes in the canopy. 97.7% of the downed trees were detected and the commission error was 10%. Species group, DBH, and volume were estimated for all downed trees using ALS metrics and existing allometric models. For the DBH, the relative RMSE was 20.8% and 34.1% for conifers and deciduous trees respectively. Finally, in substudy IV, a method utilizing terrestrial laser scanning (TLS) and tree basic density was developed for estimating tree-level stem biomass for urban trees. The relative RMSE of the stem biomass estimates varied between 8.4 10.5%. The dissertation demonstrates the applicability of LS data in assessing tree-level attributes for urban forests. The methods developed show potential in providing the planning and management of urban forests with cost-efficient and up-to-date tree-level data.