31 results on '"Markku Nygren"'
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2. Siementen itäminen ja taimien orastuminen männyn äeskylvössä – tapaustutkimus
- Author
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Markku Nygren, Niina Ikonen, and Pekka Helenius
- Subjects
Forestry ,SD1-669.5 - Abstract
Tutkimuksessa seurattiin männyn taimien orastumista neljällä äeskylvöalueella – Heinolassa, Kuorevedellä, Ruovedellä ja Sonkajärvellä. Kymmeneltä uudistusalalta laskettiin elävien männyn taimien lukumäärä muokkausjäljessä satunnaisesti sijoitetuilta 0,6 m2:n koealoilta kolmesti kylvökesänä sekä sitä seuraavan kasvukauden alussa ja lopussa. Kuudella alalla tehtiin käsinkylvöt samalla siemenerällä kuin konekylvöissä. Kylvö-muokkauskoneen toimintaa äeskylvössä seurattiin erillisessä kokeessa käyttämällä värjättyjä siemeniä ja laskemalla äesjäljistä löytyneet siemenet välittömästi kylvön jälkeen. Loppuinventoinnissa toisen vuoden syksyllä taimia oli Heinolan Kommerinkankaalla keskimäärin 2,93, Ruoveden Siikakankaalla 2,99, Kuorevedellä 2,79 ja Sonkajärvellä 0,56 kappaletta äesmetrillä. Tyhjien koealojen osuus vaihteli 14 prosentista 59 prosenttiin. Taimien frekvenssijakaumat olivat oikealle vinoja kaikissa inventoinneissa. Käsinkylvössä orastui noin puolet kylvetystä siemenestä ja kylvökohdissa oli keskimäärin 10–12 sirkkatainta elossa ensimmäisen kasvukauden lopulla. Värjätyn siemenen äeskylvössä kivennäismaapinnalle päätyi noin neljännes kokonaissiemenmäärästä. Tulosten mukaan muokkausjäljen laatuun ja siementen tasaiseen kylväytymiseen äesjälkeen on kiinnitettävä enemmän huomiota. Lisätutkimuksin on selvitettävä kylvökoneen toimintaa kenttäolosuhteissa sekä haettava ratkaisuja, joiden avulla siementen orastumista voidaan varmentaa.
- Published
- 2013
- Full Text
- View/download PDF
3. Liotuskäsittelyiden vaikutus kuusen siementen itämiseen
- Author
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Katri Himanen, Pekka Helenius, and Markku Nygren
- Subjects
Forestry ,SD1-669.5 - Abstract
Tutkimuksessa selvitettiin liotuskäsittelyiden vaikutusta kuusen (Picea abies (L.) Karst.) siementen itämiseen. Työssä tutkittiin kolmen liotustavan (seisova, ilmastettu ja vaihtuva vesi) ja kahden liotusajan (12 ja 24 h) vaikutusta kahden eri-ikäisen siemenerän itämiseen. Siemenet idätettiin petrimaljalla ja turpeessa. Turveidätyksessä seurattiin myös sirkkataimien kuolemista. Lisäksi tutkittiin kolmen liotuslämpötilan (15, 24 ja 29 °C) ja seitsemän liotusajan (0, 12, 24, 36, 48, 60 ja 72 tuntia seisovassa vedessä) yhdistelmän vaikutusta kolmen siemenerän itämiseen petrimaljalla.
- Published
- 2010
- Full Text
- View/download PDF
4. Mycelial inoculation of containerized Norway spruce seedlings with ectomycorrhizal fungi
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Katri Himanen, Markku Nygren, and Taina Pennanen
- Subjects
Forestry - Abstract
An inoculation technique to create ectomycorrhizal symbiosis in 1.5-year-old Norway spruce (Picea abies (L.) Karst.) container seedlings was tested. The mycelia of ectomycorrhizal fungi (EMF) – Tylospora asterophora, Piloderma olivaceum, and Cenococcum geophilum – each grown in a silica dioxide powder carrier, was mixed with a conventional low-humified Sphagnum peat at the time of sowing. Seedlings were grown in four growth media: (1) conventional peat; (2) conventional peat mixed with sterile carrier; (3) conventional peat mixed with carrier containing T. asterophora and C. geophilum, (4) conventional peat mixed with carrier containing P. olivaceum and C. geophilum. The seedling development and EMF colonization was followed during the nursery production. Further, seedlings grown in the four media were planted on a former nursery field, and their development was observed for three years. At the end of the nursery production phase, there were no differences in the seedling height or stem diameter between the growing media. The colonization degree by the introduced EMF was low. The height growth of the seedlings inoculated with T. asterophora + C. geophilum was 16% higher during the first growing season after out-planting compared to seedlings grown in the conventional peat medium, but the effect was transient. At the end of the out-planting experiment, the seedlings grown in conventional peat had the highest proportion of healthy and lowest proportion of dead seedlings. The results emphasize the importance of the growing media for seedling quality and out-planting success. The tested inoculation technique was ineffective in creating substantial levels of EMF colonization.
- Published
- 2023
5. Thermal and hyperspectral imaging for Norway spruce (Picea abies) seeds screening.
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Jennifer Dumont, Tapani Hirvonen, Ville Heikkinen, Maxime Mistretta, Lars Granlund, Katri Himanen, Laure Fauch, Ilkka Porali, Jouni Hiltunen, Sarita Keski-Saari, Markku Nygren, Elina Oksanen, Markku Hauta-Kasari, and Markku Keinänen
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- 2015
- Full Text
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6. Norway spruce cone crops in uneven-aged stands in southern Finland: A case study
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Kaisa Rissanen, Kalle Eerikäinen, Markku Nygren, Sauli Valkonen, and Timo Saksa
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040101 forestry ,0106 biological sciences ,biology ,Crown (botany) ,Diameter at breast height ,Forestry ,Picea abies ,04 agricultural and veterinary sciences ,15. Life on land ,Management, Monitoring, Policy and Law ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Basal area ,Crop ,Agronomy ,Germination ,Botany ,0401 agriculture, forestry, and fisheries ,Upper third ,Management practices ,Nature and Landscape Conservation - Abstract
Norway spruce cone crops in individual trees from two seed ripening years 2012 and 2014 were studied. Data were collected from five stands in southern Finland, managed by single-tree selection harvests since the 1980s. The upper third of living crown of each individual tree was photographed for digital cone counting with image analysis. The average number of cones per tree for trees bearing any cones was 92 in 2014 and 66 in 2012. Highest cone numbers found per individual tree were 526 in the year 2014 and 364 in the year 2012. Of all trees studied, 55.5% produced cones during both years, 9.6% produced cones once and 34.9% did not produce cones in 2012 or 2014. The number of cones per tree in 2014 was positively correlated with tree diameter at breast height and the presence of cones (at least twenty) in that particular individual two years earlier and negatively correlated with local basal area. The quality of the seed crop in 2014 as determined in two of the stands was poor. Based on X-ray analyses, 44% of seeds were empty, 29% were damaged by insects feeding on seeds (Plemeliella abietina or Megastigmus strobilobius) and only 25% were full and capable of germination. The results have implications for management practices in uneven-aged Norway spruce stands. It is suggested that at each harvest entry, some large, prolific trees should be retained in order to increase the total number of seeds produced in a stand to enhance regeneration and the recruitment of new seedlings.
- Published
- 2017
7. Viability and germination of Scots pine seeds after freezing of harvested cones in vitro
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Katri Himanen, Markku Nygren, and Hanna Ruhanen
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0106 biological sciences ,Global and Planetary Change ,genetic structures ,Ecology ,Seed dispersal ,High water content ,Scots pine ,food and beverages ,Forestry ,General relationship ,Biology ,biology.organism_classification ,01 natural sciences ,010601 ecology ,%22">Pinus ,Horticulture ,Germination ,Botany ,sense organs ,Water content ,After treatment ,010606 plant biology & botany - Abstract
Scots pine (Pinus silvestris L.) cone and seed water contents were analyzed in two consecutive seasons during maturation stage in the autumn and in January and March before seed dispersal. Cones with different water contents were subjected to 2 h of freezing at −30 °C, and seed viability and laboratory germination of seeds from individual cones after treatment were analyzed. Seed water content could be well predicted with the measurement of the cone water content, and the general relationship between these two could be described with a generalized logistic function. On average, the water content of cones was 5%–10% units higher than the seeds inside them. The higher the cone water content at the onset of freezing treatment, the higher the proportion of seeds with apparent damage (based on visual inspection of seeds using X-ray images) in that particular cone. High water content in cones also resulted in decreased germination after freezing treatment. The critical cone water content for 50% germination after freezing at −30 °C was approximately 31.3% (fresh mass basis). This corresponds to 21.6% water content in seeds.
- Published
- 2016
8. Intracone variation explains most of the variance in Picea abies seed weight: implications for seed sorting
- Author
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Pekka Helenius, Katri Himanen, Markku Nygren, and Tiina Ylioja
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0106 biological sciences ,Global and Planetary Change ,Ecology ,biology ,Sorting (sediment) ,Variance (land use) ,Variance component analysis ,food and beverages ,Sowing ,Forestry ,Picea abies ,Felling ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Agronomy ,Botany ,Seed orchard ,010606 plant biology & botany - Abstract
Norway spruce (Picea abies (L.) Karst.) seed is collected from both forest stands after final felling and from seed orchards. To produce high-germinability seed lots that are easy to use in nursery sowing machines, empty, insect-damaged, and other poor-quality seeds are culled. Sorting is done typically by weight or size. Previous studies of conifer seed have indicated wide variation in seed weight between individual trees or clones. However, the intratree or intraclone variations have rarely been taken into account, and intracone variation in seed weight has not been examined. We collected cones from a forest stand and from a clonal seed orchard in central Finland. Each seed from each cone was extracted, weighed, and x-rayed to assess their quality. Trees and clones differed in terms of the proportions of different quality seed. Variance component analysis showed that the intracone variation explained a larger proportion of the total variation in seed weight than did the intercone/intertree or interclone variations. Thus weight-based seed sorting has less effect on the genetic diversity of a seed lot than previously believed. We also conclude that the large differences in proportion of full seed among trees and clones impact the contribution of genotypes in seed and, eventually, in seedling lots.
- Published
- 2016
9. Thermal and hyperspectral imaging for Norway spruce (Picea abies) seeds screening
- Author
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Markku Keinänen, Sarita Keski-Saari, Markku Nygren, Laure Fauch, Tapani Hirvonen, Lars Granlund, Ilkka Porali, Katri Himanen, Elina Oksanen, Markku Hauta-Kasari, Jennifer Dumont, Jouni Hiltunen, Maxime Mistretta, and Ville Heikkinen
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medicine.medical_specialty ,biology ,Infrared ,Near-infrared spectroscopy ,Hyperspectral imaging ,Forestry ,Picea abies ,Horticulture ,biology.organism_classification ,Computer Science Applications ,VNIR ,Spectral imaging ,Plant productivity ,Thermal ,medicine ,Environmental science ,Agronomy and Crop Science ,Remote sensing - Abstract
Hyperspectral and thermal lifetime imaging were used to assess spruce seed quality.Viable, empty and infested seeds were resolved with high accuracy with both methods.400-1000nm data was not as informative as 1000-2500nm and thermal decay data.Classification of 93% accuracy was obtained using three wavelengths in SWIR range.The results suggest that high-throughput spruce seed quality testing is possible. The quality of seeds used in agriculture and forestry is tightly linked to the plant productivity. Thus, the development of high-throughput nondestructive methods to classify the seeds is of prime interest. Visible and near infrared (VNIR, 400-1000nm range) and short-wave infrared (SWIR, 1000-2500nm range) hyperspectral imaging techniques were compared to an infrared lifetime imaging technique to evaluate Norway spruce (Picea abies (L.) Karst.) seed quality. Hyperspectral image and thermal data from 1606 seeds were used to identify viable seeds, empty seeds and seeds infested by Megastigmus sp. larvae. The spectra of seeds obtained from hyperspectral imaging, especially in SWIR range and the thermal signal decay of seeds following an exposure to a short light pulse were characteristic of the seed status. Classification of the seeds to three classes was performed with a Support Vector Machine (nu-SVM) and sparse logistic regression based feature selection. Leave-One-Out classification resulted to 99% accuracy using either thermal or spectral measurements compared to radiography classification. In spectral imaging case, all important features were located in the SWIR range. Furthermore, the classification results showed that accurate (93.8%) seed sorting can be achieved with a simpler method based on information from only three hyperspectral bands at 1310nm, 1710nm and 1985nm locations, suggesting a possibility to build an inexpensive screening device. The results indicate that combined classification methods with hyperspectral imaging technique and infrared lifetime imaging technique constitute practically high performance fast and non-destructive techniques for high-throughput seed screening.
- Published
- 2015
10. Effects of seed pre-soaking on the emergence and early growth of containerized Norway spruce seedlings
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Katri Himanen and Markku Nygren
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Larva ,biology ,Biomass ,Growing season ,Forestry ,Picea abies ,biology.organism_classification ,Crop ,chemistry.chemical_compound ,Horticulture ,chemistry ,Germination ,Seedling ,Seed treatment ,Botany - Abstract
To study the effects of seed soaking on seedling emergence and development in Norway spruce [Picea abies (L.) Karst.] two commercial seed lots were soaked for 15 h in aerated water. After soaking, floating and sunken seeds were separated and analyzed prior to being sown in peat-filled containers. Seedling development was followed for one growing season. All sunken seeds were viable according to radiography whereas the floating seeds contained a considerable number of larvae filled and empty seeds. Mean time of emergence of the sunken seeds was approximately 1.5 days shorter than control (i.e. dry) seeds and floating seeds. Soaking had no effect on the time taken for most germinants to emerge in both seed lots, thus failing to synchronize seedling emergence. The later a seedling would emerge, the more likely it was for it to die during the growing season or to be culled at the end of the growing season. Soaking had an inconsistent effect on stem diameter at the end of the growing season and no effect on stem or root biomass. Seedling size uniformity was equal in all treatments. This study suggests that soaking and seed sorting does not guarantee a more uniform seedling crop, but this technique may be useful in upgrading poor quality seed lots of Norway spruce containing a high number of empty or larva infested seeds.
- Published
- 2013
11. Soaking effects on seed germination and fungal infection inPicea abies
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Katri Himanen, Arja Lilja, Anna Rytkönen, and Markku Nygren
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food.ingredient ,Peat ,biology ,Damping off ,food and beverages ,Forestry ,Picea abies ,biology.organism_classification ,Sphagnum ,Trichothecium roseum ,food ,Agronomy ,Germination ,Disease management (agriculture) ,Agar - Abstract
The effect of soaking on germination and occurrence of fungal infections on Norway spruce (Picea abies (L.) Karst.) seeds and germinants was studied in three commercial seed lots. Treatments in which seeds were soaked in water for 24 h or in which the water was changed during the soak did not have an effect on the species diversity or on the abundance of the fungi isolated from the seeds. Different fungi were found in different seed lots. Most of those isolated are saprophytic or weakly pathogenic, but pathogens such as Sirococcus conigenus (D.C.) P.F. Cannon & Minter and Trichothecium roseum (Pers.) Link were also isolated. Soaking increased germination energy but had no effect on final germination percentage. The number of mouldy seeds and germinants with disease symptoms was different among seed lots when seeds were germinated on water agar. When germinated in low humified Sphagnum peat, no differences in the emergence of disease symptoms were observed among seed lots. The frequency of disease...
- Published
- 2013
12. Boiling water scarification plus stratification improves germination of Iliamna rivularis (Malvaceae) seeds
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Katri Himanen, Markku Nygren, and R. Kasten Dumroese
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Horticulture ,Stratification (seeds) ,Germination ,Iliamna rivularis ,Boiling ,Ornamental plant ,Botany ,Dormancy ,Biology ,biology.organism_classification ,Scarification ,Malvaceae - Abstract
Scarification with boiling water plus stratification was most effective in improving germination of Iliamna rivularis (Douglas ex Hook.) Greene (Malvaceae) in an experiment that compared 3 treatments. Seeds from 15 sites representing 5 western US states were used in the experiment. Initial response of the seedlots to the treatments was similar, apart from one seedlot. The control treatment (intact seeds) yielded poor germination (1.8%). Mechanical scarification (part of the seedcoat removed) improved germination (average germination 49%), but not as much as the combination of boiling the seeds for 120 s plus stratifying them 28 d at 4 °C (average germination 70%). Germinants from the boiling plus stratification treatment appeared to be more vigorous. Impermeability of the seedcoat is the main factor preventing germination, but the response of embryos to stratification may suggest some physiological dormancy. These treatments can be adapted to nursery production of this species, which has ornamental potential and ecological importance.
- Published
- 2012
13. Seed soak-sorting prior to sowing affects the size and quality of 1.5-year-old containerized Picea abies seedlings
- Author
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Markku Nygren and Katri Himanen
- Subjects
Horticulture ,Geography ,Dry weight ,biology ,Seedling ,Ecological Modeling ,Shoot ,Greenhouse ,Sowing ,Growing season ,Forestry ,Picea abies ,biology.organism_classification - Abstract
We studied the effect of soak-sorting Norway spruce ( (L.) H. Karst.) seeds on emergence, development and quality of container seedlings in two commercial seed lots. The seeds, separated by soaking into bottom and surface fractions, were sown in June, and the seedlings were grown during two growing seasons under typical Finnish nursery conditions. The first summer seedlings were grown in a greenhouse and outdoors for the second, full growing season. All sunken seeds were full and viable according to radiography, whereas the floating seeds contained 2% and 13% larvae-filled and 8% and 11% anatomically immature seeds, depending on the seed lot. Seedlings grown from the bottom fraction seed emerged 2.5â3.5 days earlier than seedlings of storage dry (i.e. control) seed. Height, diameter, and shoot and root dry mass of the seedlings were affected by soaking after both the first and second growing seasons. The largest seedlings originated from the bottom fraction. The proportion of saleable seedlings was four percentage points higher in the bottom fraction than in the other seedlings. The effects of soaking found in this study are more notable than as previously reported for Norway spruce seedlings. This suggests that soaking and soak-sorting may be most useful when the growing conditions are stressful, i.e. when seeds are sown in summer rather than 1-year-old seedling crops sown in spring under the climate conditions typical of Finland.Picea abies
- Published
- 2015
14. Tocopherols, tocotrienols and fatty acids as indicators of natural ageing inPinus sylvestrisseeds
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Anu Hopia, Päivi Tammela, Markku Nygren, Pirjo Salo-Väänänen, Heikki Vuorela, and Into Laakso
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2. Zero hunger ,0106 biological sciences ,chemistry.chemical_classification ,0303 health sciences ,Degree of unsaturation ,biology ,Vitamin E ,medicine.medical_treatment ,Scots pine ,food and beverages ,Fatty acid ,Forestry ,biology.organism_classification ,01 natural sciences ,%22">Pinus ,03 medical and health sciences ,chemistry ,Ageing ,Botany ,medicine ,Fatty acid composition ,Tocopherol ,Food science ,030304 developmental biology ,010606 plant biology & botany - Abstract
During long-term storage, Scots pine (Pinus sylvestris L.) seeds are susceptible to ageing, leading to declined vigour and poor germinability. To characterize biochemical changes associated with this ageing, vitamin E and fatty acid compositions of Scots pine seeds stored for 3–31 years were analysed. The seeds contained seven homologues of the vitamin E family: α-, β-, δ- and γ-tocopherols (T) and α-, δ- and γ-tocotrienol (T3). The major tocopherol was γ-T, constituting on average 62.1% of total vitamin E. Total vitamin E concentration was markedly lower in older seeds, e.g. 21-year-old seeds contained 52% less vitamin E than the reference for high-quality seed. The α-T concentration was affected the most by seed age, whereas the γ-T concentration decreased more gradually and the concentrations of the other E vitamers seemed to remain relatively constant during natural ageing. Ageing also induced changes in the fatty acid composition of the seeds, e.g. a 29.6% reduction in the unsaturation/satur...
- Published
- 2005
15. Volatile Compound analysis of ageingPinus sylvestris L. (Scots pine) seeds
- Author
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Raimo Hiltunen, Heikki Vuorela, Into Laakso, Markku Nygren, Anu Hopia, and Päivi Tammela
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0106 biological sciences ,chemistry.chemical_classification ,biology ,Monoterpene ,010401 analytical chemistry ,Scots pine ,food and beverages ,General Chemistry ,biology.organism_classification ,01 natural sciences ,Hexanal ,Terpenoid ,0104 chemical sciences ,Horticulture ,chemistry.chemical_compound ,chemistry ,Lipid oxidation ,Germination ,Botany ,Composition (visual arts) ,Volatile organic compound ,010606 plant biology & botany ,Food Science - Abstract
The volatile compound profiles of 11 Scots pine (Pinus sylvestris L.) seed lots were determined by solid phase microextraction combined with GC-MS analysis. Typical monoterpene constituents of pine volatile oils were identified, and total monoterpene content of these seeds was measured semi-quantitatively as peak area. Considerable variation in monoterpene composition was found between seeds of different origin, especially in two major constituents, 3-carene and α-pinene. The relative concentrations of these compounds varied between 0-67 and 16-52%, respectively. Comparison of total monoterpene amounts showed that reduced monoterpene content was typical for aged, poorly germinating seeds. However, high germinability was not always associated with a high monoterpene content. Therefore, no clear dependency between monoterpene content and seed ageing could be estab- lished based on this data. The possible protective role of monoterpenes in pine seed ageing during long-term storage is discussed. In addition, a drastic increase in volatile lipid oxidation products was found in the oldest seed lots. In 20 year-old seeds, the percentage of hexanal, an oxidation product of fatty acids, was 3% of the total volatiles, whereas in 31 year-old seeds it was 17%. No hexanal or other lipid oxidation products were detected in younger seeds. Copyright © 2003 John Wiley & Sons, Ltd.
- Published
- 2003
16. Siementen itäminen ja taimien orastuminen männyn äeskylvössä – tapaustutkimus
- Author
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Pekka Helenius, Niina Ikonen, and Markku Nygren
- Subjects
Forestry ,General Medicine ,SD1-669.5 - Abstract
Tutkimuksessa seurattiin männyn taimien orastumista neljällä äeskylvöalueella – Heinolassa, Kuorevedellä, Ruovedellä ja Sonkajärvellä. Kymmeneltä uudistusalalta laskettiin elävien männyn taimien lukumäärä muokkausjäljessä satunnaisesti sijoitetuilta 0,6 m2:n koealoilta kolmesti kylvökesänä sekä sitä seuraavan kasvukauden alussa ja lopussa. Kuudella alalla tehtiin käsinkylvöt samalla siemenerällä kuin konekylvöissä. Kylvö-muokkauskoneen toimintaa äeskylvössä seurattiin erillisessä kokeessa käyttämällä värjättyjä siemeniä ja laskemalla äesjäljistä löytyneet siemenet välittömästi kylvön jälkeen. Loppuinventoinnissa toisen vuoden syksyllä taimia oli Heinolan Kommerinkankaalla keskimäärin 2,93, Ruoveden Siikakankaalla 2,99, Kuorevedellä 2,79 ja Sonkajärvellä 0,56 kappaletta äesmetrillä. Tyhjien koealojen osuus vaihteli 14 prosentista 59 prosenttiin. Taimien frekvenssijakaumat olivat oikealle vinoja kaikissa inventoinneissa. Käsinkylvössä orastui noin puolet kylvetystä siemenestä ja kylvökohdissa oli keskimäärin 10–12 sirkkatainta elossa ensimmäisen kasvukauden lopulla. Värjätyn siemenen äeskylvössä kivennäismaapinnalle päätyi noin neljännes kokonaissiemenmäärästä. Tulosten mukaan muokkausjäljen laatuun ja siementen tasaiseen kylväytymiseen äesjälkeen on kiinnitettävä enemmän huomiota. Lisätutkimuksin on selvitettävä kylvökoneen toimintaa kenttäolosuhteissa sekä haettava ratkaisuja, joiden avulla siementen orastumista voidaan varmentaa.
- Published
- 2013
17. Effect of prechilling on the dormancy of Betulapendula seeds
- Author
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Markku Nygren, Hannu Rita, Kari Leinonen, and Veikko Vanhatalo
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photoperiodism ,Global and Planetary Change ,Horticulture ,chemistry.chemical_compound ,Ecology ,Chemistry ,Germination ,Seed treatment ,Botany ,Dormancy ,Forestry ,Light effect - Abstract
The effect of prechilling on the germination response to temperature was investigated by germinating prechilled (at 5 °C) and unchilled seeds of Betulapendula Roth (silver birch) at temperatures of 10, 15, 20, 25, and 30 °C in darkness. Unchilled and prechilled seeds produced 50% germination at temperatures of 26.7 and 15.3 °C, respectively. Two experiments were organized to study the effects of a range of prechilling temperatures (0–12 °C) on release of dormancy. The level of dormancy in the seeds was tested at 12 °C using 6- and 18-h photoperiods. The optimal prechilling temperatures were between 1.0 and 3.3 °C. As the prechilling temperature increased, the effect of prechilling decreased so that the upper effective limit was between 8.7 and 12.0 °C. The effect of prechilling time on dormancy release was studied in an experiment where seeds prechilled at 2.4, 5.5, and 12.4 °C for 6, 12, 21, and 42 days were germinated at 12 °C using 6- and 18-h photoperiods. The germination probability (in logit scale) was directly related to the logarithm of the number of prechilling days. In seeds prechilled at 2.4 °C the requirement for a long photoperiod for germination was removed in 21 days, whereas 42 days were needed in seeds prechilled at 5.5 °C.
- Published
- 1996
18. Nuclear DNA content of Pinus sylvestris (L.) as determined by laser flow cytometry
- Author
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Leena Mannonen, Markku Nygren, Jari P. T. Valkonen, and Anne Ylönen
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0106 biological sciences ,0303 health sciences ,medicine.diagnostic_test ,Embryo ,Plant Science ,General Medicine ,Biology ,01 natural sciences ,Flow cytometry ,Nuclear DNA ,%22">Pinus ,03 medical and health sciences ,chemistry.chemical_compound ,Tissue culture ,chemistry ,Insect Science ,Botany ,Genetics ,medicine ,Animal Science and Zoology ,Propidium iodide ,Hordeum vulgare ,DNA ,030304 developmental biology ,010606 plant biology & botany - Abstract
Nuclear DNA content was determined in nuclei isolated from needles, stems and roots of in vitro grown seedlings and from megagametophytes and embryo of mature seeds in three accessions of Pinus sylvestris L. One accession was from Inari, northern Finland at timber line, and two accessions were from the Alpine region in Italy. Nuclei were mechanically isolated by a chopping method, stained with propidium iodide, and DNA content was determined using an EPICS PROFILE laser flow cytometer. Nuclei isolated from leaves of barley (Hordeum vulgare L. cv. Sultan; 2C=11.12 pg) were used as an internal standard for measurement of pine nuclei. Mean 1C nuclear DNA content of P. sylvestris was 27.88 pg as determined from megagametophyte tissue. Mean 2C value was 52.25 pg as determined from stem and root tissue, and 55.58 pg as determined from embryo tissue. The ratio of 2C to 1C value was 1.87 and 1.99, respectively. Extracts of nuclei from needles contained propidium iodide-absorbing debris which may have interfered with measurements and resulted in lower 2C values than those obtained from stem and root.
- Published
- 1994
19. Temperature control of germination in the seeds ofPicea abies
- Author
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Kari Leinonen, Hannu Rita, and Markku Nygren
- Subjects
0106 biological sciences ,Temperature control ,010504 meteorology & atmospheric sciences ,Forestry ,Picea abies ,Biology ,biology.organism_classification ,01 natural sciences ,Degree (temperature) ,Horticulture ,13. Climate action ,Germination ,Threshold temperature ,Botany ,Darkness ,010606 plant biology & botany ,0105 earth and related environmental sciences - Abstract
The effect of constant and fluctuating temperatures on germination of Norway spruce (Picea abies (L.) Karst.) seeds collected from three individual trees was tested in darkness using a temperature‐gradient incubator. The germination probability of seeds was modeled between + 6.3 and + 29.1°C. Between minimum (+10°C) and optimum (+21°C) temperatures the probability fit well with a logistic curve reaching 50% germination at + 14.3°C. At temperatures above + 21°C the probability decreased, and the differences between trees were significant. At temperatures between + 10 and + 23°C the day degrees [S n k (T ‐ 6°C)] with threshold temperature +6°C predicted germination rate reasonably well. At temperatures above +23°C germination rate was delayed significantly. The temperature fluctuation around mean temperature + 11.6°C did not effect the degree days required for germination. The increasing temperature fluctuation around mean temperature +24.3°C delayed germination. The seeds remaining dormant below and above ...
- Published
- 1993
20. Liotuskäsittelyiden vaikutus kuusen siementen itämiseen
- Author
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Markku Nygren, Katri Himanen, and Pekka Helenius
- Subjects
Forestry ,Biology ,SD1-669.5 - Abstract
Tutkimuksessa selvitettiin liotuskäsittelyiden vaikutusta kuusen (Picea abies (L.) Karst.) siementen itämiseen. Työssä tutkittiin kolmen liotustavan (seisova, ilmastettu ja vaihtuva vesi) ja kahden liotusajan (12 ja 24 h) vaikutusta kahden eri-ikäisen siemenerän itämiseen. Siemenet idätettiin petrimaljalla ja turpeessa. Turveidätyksessä seurattiin myös sirkkataimien kuolemista. Lisäksi tutkittiin kolmen liotuslämpötilan (15, 24 ja 29 °C) ja seitsemän liotusajan (0, 12, 24, 36, 48, 60 ja 72 tuntia seisovassa vedessä) yhdistelmän vaikutusta kolmen siemenerän itämiseen petrimaljalla.
- Published
- 2010
21. Statistical opportunities for comparing stand structural heterogeneity in managed and primeval forests: an example from boreal spruce forest in southern Finland
- Author
-
Timo Kuuluvainen, Kari Leinonen, Antti Penttinen, Markku Nygren, The Finnish Society of Forest Science, Suomen metsätieteellinen seura, and Finlands Forstvetenskapliga Samfund
- Subjects
0106 biological sciences ,010504 meteorology & atmospheric sciences ,talousmetsät ,tilastomenetelmät ,boreaaliset metsät ,010603 evolutionary biology ,01 natural sciences ,statistical analysis ,boreal forests ,lcsh:Forestry ,0105 earth and related environmental sciences ,biodiversity ,Spruce forest ,geography.geographical_feature_category ,Agroforestry ,Picea abies ,Ecological Modeling ,stand characteristics ,Forestry ,aarniometsät ,15. Life on land ,Old-growth forest ,luonnon monimuotoisuus ,Structural heterogeneity ,kuusi ,forest stands ,Geography ,Boreal ,lcsh:SD1-669.5 - Abstract
Part II Biodiversity The horizontal and vertical stand structure of living trees was examined in a managed and in a primeval spruce-dominated forest in southern Finland. Tree size distributions (DBHs, tree heights) were compared using frequency histograms. The vertical distribution of tree heights was illustrated as tree height plots and quantified as the tree height diversity (THD) using the Shannon-Weaver formula. The horizontal spatial pattern of trees was described with stem maps and quantified with Ripley’s K-function. The spatial autocorrelation of tree sizes was examined with semivariogram analysis. In the managed forest the DBH and height distributions of trees were bimodal, indicating a two-layered vertical structure with a single dominant tree layer and abundant regeneration in the understory. The primeval forest had a much higher total number of trees which were rather evenly distributed in different diameter and tree height classes. The K-function summaries for trees taller than 15 m indicated that the primeval stand was close to complete random pattern. The managed stand was regular at small distances (up to 4 m). The semivariograms of tree sizes (DBH, tree height) showed that the managed forest had a clear spatial dependence in tree sizes up to inter-tree distances of about 12 meters. In contrast, the primeval spruce forest had a variance peak at very short inter-tree distances (< 1 m) and only weak spatial autocorrelation at short inter-tree distances (1–5 m). Excluding the understory trees (h < 15 m) from the analysis drastically changed the spatial structure of the forest as revealed by semivariograms. In general, the structure of the primeval forest was both horizontally and vertically more variable and heterogeneous compared to the managed forest. The applicability of the used methods in describing fine-scale forest structure is discussed.
- Published
- 1996
22. The reproductive process in boreal forest trees
- Author
-
Markku Nygren, John C. Zasada, and Terry L. Sharik
- Subjects
Secondary succession ,Taiga ,Logging ,Environmental science ,Forestry ,Windthrow ,Ecological succession ,Fire ecology ,Black spruce ,Basal area - Published
- 1992
23. Männyn ja kuusen siementen massan vaihtelusta
- Author
-
Markku Nygren
- Subjects
040101 forestry ,kuusi ,siemenen paino ,Picea abies ,mänty ,Ecological Modeling ,paino ,0401 agriculture, forestry, and fisheries ,Forestry ,Pinus sylvestris ,vaihtelu ,04 agricultural and veterinary sciences ,siemen - Published
- 1990
24. Effect of shading on leaf structure and photosynthesis in young birches, Betula pendula Roth. and B. pubescens Ehrh
- Author
-
Markku Nygren and Seppo Kellomäki
- Subjects
Canopy ,Specific leaf area ,Growing season ,Forestry ,Management, Monitoring, Policy and Law ,Biology ,Photosynthesis ,chemistry.chemical_compound ,Light intensity ,chemistry ,Betula pendula ,Chlorophyll ,Botany ,Shading ,Nature and Landscape Conservation - Abstract
The canopy structure and within-stand light conditions of several young birch (Betula pendula Roth. and B. pubescens Ehrh.) stands were studied. In addition, 2-year-old silver birch seedlings were subjected to varying degrees of artificial shading for one growing season in order to interpret the results of the former experiments. The shading increased the specific leaf area and the thickness of leaf mesophyll was reduced by increased shading. Similarly, the maximum photosynthetic rate and the light intensity for photosynthetic saturation were decreased in shading. Both phenomena seemed to be associated with the increase in specific leaf area and the decrease in the amount of chlorophyll per unit of leaf area.
- Published
- 1983
25. The maturation of Pinus sylvestris seeds in relation to temperature climate in Northern Finland
- Author
-
Heikki Henttonen, Markku Nygren, R. Ojansuu, and Markku Kanninen
- Subjects
0106 biological sciences ,010504 meteorology & atmospheric sciences ,biology ,fungi ,Scots pine ,food and beverages ,Climatic variables ,Forestry ,15. Life on land ,Northern finland ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Degree (temperature) ,%22">Pinus ,Crop ,Agronomy ,13. Climate action ,Mean radiant temperature ,0105 earth and related environmental sciences - Abstract
The probability of achieving an anatomically mature seed crop of Scots pine (Pinus sylvestris L.) in Northern Finland has been studied on the basis of earlier data and meteorological observations. The meteorological data over the period of 1951–1980 was used to calculate the probability of having a mature seed crop in various parts of Northern Finland. The climatic variables used were: (a) June‐August mean temperature (b) June—September mean temperature, and (c) annual temperature sum (+5°C base temperature). A non‐linear relationship between the percentage of mature seeds in a seed crop and the annual temperature sum was detected, indicating that 50% mature seed crop was achieved at appr. 890 degree days. The results suggest that the probability of having 50% mature seed crop is approximately 0.02–0.03 near the polar timber line. The probability of the occurrence of such years is, however, considerably higher in lowlands and lake districts even near the timber line.
- Published
- 1986
26. Männyn siementen syyskeräys
- Author
-
Markku Nygren
- Subjects
040101 forestry ,mänty ,Ecological Modeling ,0401 agriculture, forestry, and fisheries ,Forestry ,Pinus sylvestris ,varastointi ,lämpötila ,04 agricultural and veterinary sciences ,Biology ,siemen ,itävyys ,lepotila - Published
- 1986
27. Germination characteristics of autumn collected Pinus sylvestris seeds
- Author
-
Markku Nygren, The Finnish Society of Forest Science, Suomen metsätieteellinen seura, and Finlands Forstvetenskapliga Samfund
- Subjects
0106 biological sciences ,dormancy ,mänty ,seed maturation ,seed germination ,seeds ,Biology ,01 natural sciences ,väitöskirjat ,opinnäytteet ,pines ,lepotila ,040101 forestry ,seed dormancy ,Seed dormancy ,food and beverages ,temperature ,Pinus sylvestris ,itäminen ,04 agricultural and veterinary sciences ,%22">Pinus ,Horticulture ,germination ,Chilling requirement ,Agronomy ,Germination ,0401 agriculture, forestry, and fisheries ,Dormancy ,chilling requirement ,syksy ,siemen ,harvesting date ,light ,General Agricultural and Biological Sciences ,010606 plant biology & botany - Abstract
Tests on seeds from a natural stand and from a clone archive, with various photoperiods and temperature regimes, showed that germination was delayed at low temperature (10 degrees C) and in darkness. This effect diminished the later in autumn seeds were collected.
- Published
- 1987
28. Metsikön varhaiskehityksen dynamiikka
- Author
-
Annikki Mäkelä, Seppo Kellomäki, Pertti Hari, Eeva Korpilahti, Pirkko Ilonen, Markku Kanninen, Markku Nygren, The Finnish Society of Forest Science, Suomen metsätieteellinen seura, and Finlands Forstvetenskapliga Samfund
- Subjects
040101 forestry ,0106 biological sciences ,mänty ,stand characteristics ,Pinus sylvestris ,mallit ,04 agricultural and veterinary sciences ,computer techniques. development ,simulation ,kasvu ,010603 evolutionary biology ,01 natural sciences ,growth models ,0401 agriculture, forestry, and fisheries ,Environmental science ,fotosynteesi ,kehitys ,General Agricultural and Biological Sciences ,increment ,metsiköt - Published
- 1982
29. Havupuiden syyskylvöistä
- Author
-
Markku Nygren
- Published
- 1970
30. Metsä- ja hybridihaapakloonien tunnistaminen morfologisten ominaispiirteiden avulla
- Author
-
Kari Leinonen, Hanna Alanen, Markku Nygren, and Egbert Beuker
- Subjects
Environmental science ,General Medicine - Published
- 1970
31. Aging in Pinus sylvestris L. seeds: changes in viability and lipids
- Author
-
Raimo Hiltunen, Päivi Tammela, Heikki Vuorela, Anu Hopia, and Markku Nygren
- Subjects
0106 biological sciences ,animal structures ,Biology ,complex mixtures ,01 natural sciences ,Biochemistry ,Electrolytes ,Botany ,Vitamin E ,040101 forestry ,Electrolyte leakage ,fungi ,Scots pine ,food and beverages ,Pinus sylvestris ,04 agricultural and veterinary sciences ,biology.organism_classification ,Lipids ,%22">Pinus ,Cycadopsida ,Fertility ,Seeds ,0401 agriculture, forestry, and fisheries ,Delayed growth ,sense organs ,010606 plant biology & botany ,Woody plant - Abstract
Aging of Scots pine seeds (Pinus sylvestris L.) leads to changes in seed quality, such as loss of germinability, delayed growth and abnormality in developing seedlings. The knowledge of biochemical changes responsible for these aging processes is plentiful in some seeds, which are of world-wide interest, but for pine seeds these studies are rare. The aim of the present study, was to analyse pine seeds of varying ages in order to identify biochemical changes occurring in aged pine seeds, and to see if a correlation existed between these results and traditionally used seedquality parameters, such as germinability and electrolyte leakage.
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