Marja Roitto

Marja Roitto
University of Helsinki | HY · Ruralia Institute and Helsinki Insitute of Sustainability Science

PhD

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46
Publications
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831
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Publications

Publications (46)
Presentation
Maissi (Zea mays L.) on yksi maailman tärkeimmistä viljelykasveista ja sitä käytetään yleisesti nautakarjan karkearehuna. Vaikka maissi on Suomessa viljelyalueensa pohjoisrajalla, on suomalaisten viljelijöiden kiinnostus rehumaissin viljelyä kohtaan lisääntynyt voimakkaasti viime vuosikymmenten aikana. Säilörehumaissin keskeisin etu on se, että sen...
Article
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The aim of the study was to quantify total extractive contents and lipophilic compounds, stilbenes, and lignans in Scots pine stem wood, stem bark, branch biomass, and sawmill residues in four climatic regions of Finland to evaluate the most optimal sources of extractives for bio-based chemical biorefining and bioenergy products. Data were derived...
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Purpose Beef and dairy production systems produce several by-products, such as fertilizers, bioenergy, hides, and pet foods, among which the environmental impacts arising from production should be allocated. The choice of allocation method therefore inevitably affects the results of life cycle assessment (LCA) for milk and beef. The aims of this st...
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Background and Objectives: More frequent and severe droughts are occurring due to climate change in northern China. In addition to intensity and duration, the timing of droughts may be decisive for its impacts on tree growth, mortality, and the whole forest ecosystem. The aim of this study was to compare the effect of drought occurring in the early...
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This study aimed to identify and quantify phenolic and resin acid extractive compounds in Scots pine stemwood and sawmill residues in four climatic regions of Finland to evaluate their most optimal sources for bio-based chemical biorefining and bioenergy products. The sample consisted of 140 trees from 28 stands, and sawdust lots from 11 log stands...
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Winter precipitation and soil freeze–thaw events have been predicted to increase in boreal regions with climate change. This may expose tree roots to waterlogging (WL) and soil freezing (Fr) more than in the current climate, and therefore affect tree growth and survival. Using a whole-tree approach, we studied the responses of silver birch (Betula...
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Background and Objectives: Drought occurs more frequently in Northern China with the advent of climate change, which might increase the mortality of tree seedlings after afforestation due to hydraulic failure. Therefore, investigating water relations helps us understand the drought tolerance of tree seedlings. Electrical impedance spectroscopy (EIS...
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Soil waterlogging is predicted to increase in the future climate in boreal regions due to increased precipitation. Snowmelt periods in winter may also become more common and further increase the amount of water in soil. It is not well known how waterlogging and soil freezing during winter affect the physiology, phenology and growth of trees. Our ai...
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Increased risk of soil waterlogging in winter and spring at northern latitudes will potentially affect forest production in the future. We studied gas exchange, chlorophyll content index, chlorophyll fluorescence, nutrient concentration and biomass accumulation in 1-year-old silver (Betula pendula Roth) and pubescent birch (Betula pubescens Ehrh.)...
Conference Paper
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Birch wood demonstrates a multitude of interesting chemical extractives with techno-chemical benefits or bioactive effects. They provide potential functionalities for several types of industrial chemicals, such as wood adhesives, paints or wood protection agents, plant-protective products, detergents, cosmetics, beverages, and pharmaceutical or nut...
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The warmer winters of the future will increase snow-melt frequency and rainfall, thereby increasing the risk of soil waterlogging and its effects on trees in winter and spring at northern latitudes. We studied the morphology of roots and leaves of 1-year-old silver birch (Betula pendula Roth) and pubescent birch (Betula pubescens Ehrh.) seedlings e...
Conference Paper
Full-text available
Birch wood demonstrates a multitude of interesting chemical extractives with techno-chemical benefits or bioactive effects. They provide potential functionalities for several types of industrial chemicals, such as wood adhesives, paints or wood protection agents, plant-protective products, detergents, cosmetics, beverages, and pharmaceutical or nut...
Conference Paper
Full-text available
Scots pine is the main tree species in Finnish forests making it the country’s most abundant source of forest lignocellulosic biomass. The traditional industrial use of Scots pine wood has been in miscellaneous sawn timber products and as raw material in wood-based panels, pulp, paper and paperboard industries. With much attention been paid on the...
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Climate warming scenarios predict a decreased snow cover and more rain instead of snow in boreal areas in winter. These conditions may affect soil freezing processes. We studied how watering of the soil before and after soil thawing affects fine roots and shoots of Scots pine saplings during the follow-up season. A growth chamber experiment was car...
Article
Frozen soil is predicted to change in the boreal areas with climate warming. We studied growth, longevity and mortality of fine roots at different levels of frozen soil in winter followed by a delayed soil thawing in spring in a 47-year-old stand of Picea abies (L. Karst.) in the boreal zone. The treatments, repeated over two winters, were: (i) nat...
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Context Waterlogging is predicted to become more com-mon in boreal forests during winter and early spring with climate change. So far, little is known about the waterlogging tolerance of boreal tree species during their winter dormancy. & Aim The aim was to quantify the degree of waterlogging tolerance of 1-year-old dormant Norway spruce (Picea abi...
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Depending on the soil preparation method applied and peat characteristics, Scots pine (Pinus sylvestris L.) seedlings planted in prepared spots on forestry-drained peatlands may become more susceptible to extreme weather events such as drought or flooding. Only by studying its coping strategies can we eventually design methodology better suited for...
Article
Climate change may cause a decrease in snow cover in northern latitudes. This, on the other hand, may result in more severe soil frost even in areas where it is not common at present, and may lead to increased stress on the tree canopy. We studied the effects of snow removal and consequent changes in soil frost and water content on the physiology o...
Article
Nickel (Ni) may impair plant water balance through detrimental effects on the belowground level. Bilberry (Vaccinium myrtillus L.) plants were grown in a mesic heath forest-type soil and subjected to Ni sulphate (NiSO4·6H2O) concentrations of 0, 10, 50, 100 and 500 mg m−2 during an entire growing season in northern Finland (65°N). Biomass of belowg...
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Identification of factors explaining diversity in plant responses to industrial pollution is crucial for predicting fates of polluted ecosystems. Meta-analysis based on 203 publications demonstrated that plants growing near point polluters showed similar decreases in characters reflecting growth (-13.1%) and reproduction processes (-8.5%). In herba...
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Phenolic compounds often accumulate in foliar tissues of deciduous woody plants in response to previous insect defoliation, but similar responses have been observed infrequently in evergreen conifers. We studied the effects of defoliation on the foliar chemistry of Scots pine (Pinus sylvestris L.) and cocoon mass, and survival of the pine sawfly (D...
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Growth of the host and its symbiont is often closely linked and so host damage may negatively affect the symbiont. While negative effects of aboveground herbivory on belowground fungal symbionts have been reported in several woody and herbaceous plants, here we report, for the first time, on differential effects of the timing of foliar damage on ec...
Chapter
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Meta-analysis of data extracted from 125 published studies conducted around 70 polluters located in 17 countries. The data were collected from 44 species of vascular plants; the most intensively investigated species was Pinus sylvestris (44% of studies). The overall effect of air pollution on plant growth and reproduction was negative, although som...
Article
Vaikka yrttien sisältämät raskasmetallit eivät olekaan tavalliselle kuluttajalle terveysriski, niillä on merkitystä erityisesti silloin, kun myydään rohdosteollisuudelle raaka-ainetta. Euroopassa yrttien raskasmetalli- ja aromipitoisuuksia on tutkittu paljon. Kalkituksen vaikutusta yrttien sisäiseen laatuun sen sijaan on tutkittu suhteellisen vähän...
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Studies were done on the effects of elevated soil concentrations of copper (Cu) and (Ni) on foliar carbohydrates and phenolics in Scots pine (Pinus sylvestris L.). Four year-old seedlings were planted in pots filled with metal-treated mineral forest soil in early June. The experimental design included all combinations of four levels of Cu (0, 25, 4...
Article
Scots pine (Pinus sylvestris) seedlings were planted in soil originating from two localities with different background levels of nickel and copper. In addition, some of the seedlings were exposed to additional nickel (20.5 mg Ni/l of soil) or copper (63.5 mg Cu/l of soil), or a combination of both Ni and Cu, via soil without direct shoot exposure d...
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Boreal forest trees are highly dependent on root-colonizing mycorrhizal fungi. Since the maintenance of mycorrhizal symbiosis implies a significant carbon cost for the host plant, the loss of photosynthetic leaf area due to herbivory is expected to reduce the host investment in mycorrhizae. We tested this hypothesis in a common garden experiment by...
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The lead (Pb), cadmium (Cd) and mercury (Hg) concentrations of fifty medicinal plant and herb species were analysed in 1988-1990. The data consisted of 230 Finnish samples from cultivations in several locations and altogether 168 samples from Austria, Germany, Great Britain, Hungary, Italy, Poland, Czechoslovakia and Turkey. In the pooled samples f...
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Effects of artificial defoliation on defensive needle chemistry in Scots pine (Pitus sylvestris L.) were evaluated with particular emphasis on peroxidases, phenolic compounds, soluble sugars, polyamines, and foliar nitrogen levels. The study was carried out on a nutrient-poor Scots pine stand with 8- to 25-year-old trees. Defoliation treatment cons...
Article
Reduction in the photosynthetic capacity of plants is presumed to negatively affect their fungal symbionts. To test this hypothesis under natural conditions, we artificially removed 100% of previous year needles in two successive years on Scots pine trees (Pinus sylvestris L.) to simulate pine sawfly attack. Despite a decline in the shoot growth of...
Article
M. 2002. Developmental plasticity in birch leaves: defolia-tion causes a shift from glandular to nonglandular trichomes. – Oikos 98: 437– 446. The structures on leaf surfaces, e.g. trichomes, can act as effective antiherbivory mechanisms as chemical repellents. Structural defences usually represent constitutive resistance, but there are also a few...
Article
Herbivory is generally assumed to negatively influence mycorrhizal fungi because of reduced photosynthate to support mycorrhizae following defoliation. We examined effects of 60% and 100% defoliation (excluding current year needles) on tree growth and ectomycorrhizal associations of 10–15 year old Scots pines (Pinus sylvestris). Over 98% of short r...
Article
Scots pine seedlings were exposed to wet-deposited nickel (Ni) and removal of lichen cover in a dry heath Scots pine forest. Ni deposition affected the colonization of roots by indigenous ectomycorrhizal fungi in contrasting ways in intact and skimmed quadrats. Highest frequencies of tubercle morphotypes of ectomycorrhiza were found in quadrats exp...
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A field experiment was conducted in a dry heath forest dominated by Scots pine (Pinus sylvestris L.) and a mat-forming lichen (Cladina stellaris (Opiz) Brodo) to assess the effect of wet-deposited nickel (Ni) on pine seedlings and soil microorganisms, and to explore whether an intact lichen mat could act as a buffer against heavy metal deposits. Pi...
Article
The impact of experimentally sprayed aqueous nickel solution on the concentrations of potassium, calcium, magnesium and nickel in three horizontal strata (top, 0-20 mm; middle, 20-40 mm; and base, 40-60 mm) of the cushion-forming lichen Cladina stellaris was investigated. The experimental nickel deposition range used corresponded with that from the...
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A gradient survey was carried out in order to compare peroxidase activity in Scots pine (Pinus sylvestris) needles in relation to distance from the industrial centre of Monchegorsk, on the Kola Peninsula in north-western Russia. Apoplastic and total peroxidase activity and sulphur (S), nickel (Ni) and copper (Cu) content in the needles of mature tr...
Article
The physiology and stress metabolism of woody plants exposed to gaseous air pollutants in open-top chambers are reviewed, with special reference to structural and biochemical alterations in needle tissues. The effects of ozone, sulphur dioxide, nitrogen oxides and carbon dioxide on conifers are discussed. The responses to pollutants are modified by...
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M. 2005: Dif-ferential performance of two geometrids on previously defoliated Scots pine. — Ann. Zool. Fennici 42: 497–503. We studied the effect of previous defoliations of Pinus sylvestris on the performance of two geometrid moths, Bupalus piniarius and Macaria liturata, using a field experi-ment. Prior to the experiment, we found defoliation to...
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The aim of this literature review was to pool data on heavy metal accumula- tion in herbs, spices and medicinal plants in Europe. A comparative study performed by MTT Agrifood Research Finland in 1990 showed that lead concentration in Finnish herbs was clearly lower that in herbs produced in other parts in Europe. Cadmium concentrations did not dif...
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Snow is known to act as an important insulator of forest soils against frost in northern latitudes. Consequently, the lack of a snow layer may result in more severe soil frost, thereby increasing freezing injuries to tree roots. Frozen soil may cause stress in spring, when the demand for evapo-transpiration is high. We studied the effects of the ti...
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The goal of this thesis was to examine the ecophysiological responses of Scots pine (Pinus sylvestris L.), with an emphasis on the oxidative enzyme peroxidase and plant phenolics to environmental stresses like elevated levels of nickel (Ni) and copper (Cu), and herbivory. The effects of Ni and Cu were studied in a gradient survey at a sulphur dioxi...

Questions

Questions (3)
Question
Could you recommend research publications on the energy consumption of phosphorus fertilizers? There is a lot of information on the energy consumption of nitrogen fertilizers, but research on phosphorus and potassium fertilizers is difficult to find.
Question
Is it possible to find studies about palm oil in the beginning of the value chain where post harvest losses are evaluated, especially in big production countries Indonesia and Malaysia? Post-harvest food loss here refers to a decrease in quantity and/ or quality of food mass on the supply side of the food chain
Question
We are studying chemical composition of mature Scots pine (Pinus sylvestris) wood (bark is excluded). Nothing much was what we got condensed tannins by an acid butanol assay. Would anyone know any literature on this topic - condensed tannins and Scots pine wood?

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https://www2.helsinki.fi/fi/tutkimusryhmat/kotielaintiede/tukeva-tulevaisuuden-kestavat-karkearehuvalinnat