Browsing by Subject "kuusi"

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  • Väisänen, Enni (Helsingfors universitet, 2010)
    Ligniini on maakasveille hyvin tärkeä makromolekyyli. Se on olennainen osa esimerkiksi vettä ja ravinteita kuljettavien puusolukon solujen soluseinää. Ligniini on myös osallisena kasvien puolustuksessa muita organismeja vastaan. Lisäksi se on tärkeä osa metsien ekologiassa ja ihmisen hyödykkeenä. Prosessia, jossa kasvisolun seinään muodostuu ligniiniä, sanotaan puutumiseksi, eli lignifikaatioksi. Tällöin lignifikoituvan solun sisällä syntetoidut ligniinin monomeerit – monolignolit - kuljetetaan solukalvon yli soluseinään, jossa ne polymeroituvat ligniiniksi. Vähitellen kasvisolun soluseinän selluloosan, hemiselluloosien, pektiinien ja rakenne-proteiinien muodostama verkosto tukkiutuu ligniinistä. Lignifikoituessaan solu käy samalla läpi ohjelmoidun solukuoleman. Monolignolien synteesistä tiedetään suhteellisen paljon, samoin kuin ligniinin polymerisaatiosta. Monolignolien kuljetuksesta sen sijaan ei ole tietoa. Eri hypoteesien mukaan monolignolit voivat kulkeutua solukalvon yli joko diffuusion, golgin laitteen rakkuloiden tai kuljettajaproteiinien eli transportterien avulla. Teoria golgin laitteesta on osoitettu epätodennäköiseksi ja diffusiostakaan ei ole todisteita aidoilla solukalvoilla. Siksi pro gradu –tutkielmani tarkoituksena onkin testata hypoteesia transportterivälitteisestä kuljetuksesta. Tutkittavina ovat kasveissa hyvin yleiset ABC-transportterit, joiden tiedetään kuljettavan sekundaarisen aineenvaihdunnan tuotteita. Tutkielmassani testasin ABC-transportterihypoteesia kuusen (Picea abies) ligniiniä tuottavilla A3/85-liuosviljelmäsoluilla sekä bioninformatiikan keinoin. A3/85-soluille syötettiin radioaktiivista fenyylialaniinia – monolignolisynteesin raaka-ainetta – yhdessä ABC-transportteri-inhibiittoreiden (Reversin 121 ja vanadaatti) kanssa. Inhibiittoreilla ei kuitenkaan ollut vaikutusta solujen erittämien fenyylialaniinin fenolituotteiden tai näiden sokerijohdannaisten määrään. Bioinformatiikan keinoin taas yritettiin löytää kuusen (Picea spp.) ja männyn (Pinus spp.) EST-kirjastoista hyviä ABC-transportteriehdokkaita monolignolien kuljetukseen. Erityisesti lignifikoituvassa solukossa esiintyvää, ominaisuuksiltaan sopivaa ABC-transportteria ei kuitenkaan löytynyt. Tämän perusteella kuljetuksesta vastaa todennäköisesti jokin muu transportteri tai kuljetus ei tapahdu lainkaan transportterin välityksellä. Tutkielmassani oli testattavana myös usein esitetty ajatus monolignolien myrkyllisyydestä, josta ei kuitenkaan ole tehty asiaan kuuluvaa selvitystä. Monolignolien odotetulla myrkyllisyydellä saatetaan kasvitieteessä perustella erinäisiä väittämiä, joten ajatuksen paikkansapitävyys on syytä varmistaa. Hypoteesia monolignolien myrkyllisyydestä testasin lisäämällä ligniiniä tuottamattomien tupakan (Nicotiana tabacum) liuosviljelmäsolujen (BY-2) kasvatusalustaan monolignoli koniferyylialkoholia. Koniferyylialkoholi aiheutti solujen lignifikaation sekä tappoi solut korkeissa pitoisuuksissa. Näiden kokeiden perusteella voidaan myrkyllisyys-hypoteesin sanoa olevan mahdollinen, joskin koniferyylialkoholin mahdollinen osallisuus lignifikoituvassa solussa tapahtuvaan ohjelmoituun solukuolemaan täytyy ottaa huomioon.
  • Kallio, Tauno (Suomen metsätieteellinen seura, 1971)
  • Sirén, Gustaf (Suomen metsätieteellinen seura, 1950)
  • Valsta, Lauri. (The Society of Forestry in Finland - The Finnish Forest Research Institute, 1992)
  • Erjala, Pentti; Saramäki, Jussi (Suomen metsätieteellinen seura, 1972)
  • Kallio, Tauno (Suomen metsätieteellinen seura, 1974)
  • Finér, Leena (The Society of Forestry in Finland - The Finnish Forest Research Institute, 1989)
    Biomass, biomass increment and nutrient cycling were studied in (1) a Scots pine (Pinus sylvestris) stand, (2) a Norway spruce (Picea abies) stand and (3) a mixed birch (Betula pubescens)/pine stand on a drained mire at Ilomantsi, eastern Finland in 1979-85. In addition, the effect of NPK and micronutrient fertilizer treatment was studied. Above-ground and root measurements were taken. These data formed the basis of stand biomass and nutrient cycle simulations of fertilized and unfertilized stands. The increases in biomass were greater in (1) and (2) in the fertilized simulation than in the unfertilized one. For (3), the effect of fertilization on biomass increment was small. In six years only part of the applied fertilizer had been fixed in the biomass of the model stands and proportionally less micronutrients than macronutrients. The potassium stores were small compared to the nutrient amounts fixed by the stands. This supports the notion that there is a shortage of potassium on deep-peat soils.
  • Hallaksela, Anna-Maija (Suomen metsätieteellinen seura, 1984)
  • Luomajoki, Alpo (The Society of Forestry in Finland - The Finnish Forest Research Institute, 1993)
    Anthesis was studied at the canopy level in 10 Norway spruce stands from 9 localities in Finland from 1963 to 1974. Distributions of pollen catches were compared to the normal Gaussian distribution. The basis for the timing studies was the 50 per cent point of the anthesis-fitted normal distribution. Development up to this point was given in calendar days, in degree days (>5 °C) and in period units. The count of each parameter began on March 19 (included). Male flowering in Norway spruce stands was found to have more annual variation in quantity than in Scots pine stands studied earlier. Anthesis in spruce in northern Finland occurred at a later date than in the south. The heat sums needed for anthesis varied latitudinally less in spruce than in pine. The variation of pollen catches in spruce increased towards north-west as in the case of Scots pine. In the unprocessed data, calendar days were found to be the most accurate forecast of anthesis in Norway spruce both for a single year and for the majority of cases of stand averages over several years. Locally, the period unit could be a more accurate parameter for the stand average. However, on a calendar day basis, when annual deviations between expected and measured heat sums were converted to days, period units were narrowly superior to days. The geographical correlations respect to timing of flowering, calculated against distances measured along simulated post-glacial migration routes, were stronger than purely latitudinal correlations. Effects of the reinvasion of Norway spruce into Finland are thus still visible in spruce populations just as they were in Scots pine populations. The proportion of the average annual heat sum needed for spruce anthesis grew rapidly north of a latitude of ca. 63° and the heat sum needed for anthesis decreased only slighty towards the timberline. In light of flowering phenology, it seems probable that the northwesterly third of Finnish Norway spruce populations are incompletely adapted to the prevailing cold climate. A moderate warming of the climate would therefore be beneficial for Norway spruce. This accords roughly with the adaptive situation in Scots pine.
  • Pulkkinen, Pertti (Suomen metsätieteellinen seura, 1991)
  • Greis, Ilppo; Kellomäki, Seppo (Suomen metsätieteellinen seura, 1981)
  • Kallio, Tauno; Tamminen, Pekka (Suomen metsätieteellinen seura, 1974)
  • Kubin, Eero; Kemppainen, Lauri (The Society of Forestry in Finland - The Finnish Forest Research Institute, 1991)
    Air and soil temperatures were measured in 1974-85 in 3 clear felled areas and 3 neighbouring forest stands dominated by Norway spruce (Picea abies) in N. Finland. Daily temperatures were measured with thermograph plotters and maximum and minimum thermometers in meteorological screens (2 m above the ground), and a Grant device at 10 cm above the ground and at 5, 50 and 100 cm below ground level. Clear felling had no significant influence on air temperature at 2 m above the ground. The daily air temperature maxima at 10 cm were greater in the clear fell area than in the forest; the daily temperature minima at 10 cm were less in the clear fell area. Night frosts were more common in the clear fell area. Daily soil temperatures at 5 cm depth were 2-3 degrees C greater in the clear fell area than in the forest; temperatures at 50 cm and 100 cm depth were 3-5 degrees C greater. A sparse sapling stand developed from plantings and natural regeneration. Consequently, the differences between the clear fell area and the forest did not diminish during the 12 years following clear felling.
  • Rikala, Risto; Jozefek, Helen J. (Suomen metsätieteellinen seura, 1990)
  • Höyhtyä, Riitta; Hänninen, Heikki (Suomen metsätieteellinen seura, 1991)
  • Kubin, Eero; Kemppainen, Lauri (The Society of Forestry in Finland - The Finnish Forest Research Institute, 1994)
    The effect of scarification, ploughing and cross-directional plouhing on temperature conditions in the soil and adjacent air layer have been studied during 11 consecutive growth periods by using an unprepared clear-cut area as a control site. The maximum and minimum temperatures were measured daily in the summer months, and other temperature observations were made at four-hour intervals by means of a Grant measuring instrument. The development of the seedling stand was also followed in order to determine its shading effect on the soil surface. Soil preparation decreased the daily temperature amplitude of the air at the height of 10 cm. The maximum temperatures on sunny days were lower in the tilts of the ploughed and in the humps of the cross-directional ploughed sites compared with the unprepared area. Correspondingly, the night temperatures were higher and so the soil preparation considerably reduced the risk of night frost. In the soil at the depth of 5 cm, soil preparation increased daytime temperatures and reduced night temperatures compared with unprepared area. The maximum increase in monthly mean temperatures was almost 5 °C, and the daily variation in the surface parts of the tilts and humps increased so that excessively high temperatures for the optimal growth of the root system were measured from time to time. The temperature also rose at the depths of 50 and 100 cm. Soil preparation also increased the cumulative temperature sum. The highest sums accumulated during the summer months were recorded at the depth of 5 cm in the humps of cross-directional ploughed area (1127 dd.) and in the tilts of the ploughed area (1106 dd.), while the corresponding figure in the unprepared soil was 718 dd. At the height of 10 cm the highest temperature sum was 1020 dd. in the hump, the corresponding figure in the unprepared area being 925 dd. The incidence of high temperature amplitudes and percentage of high temperatures at the depth of 5 cm decreased most rapidly in the humps of cross-directional ploughed area and in the ploughing tilts towards the end of the measurement period. The decrease was attributed principally to the compressing of tilts, the ground vegetation succession and the growth of seedlings. The mean summer temperature in the unprepared area was lower than in the prepared area and the difference did not diminish during the period studied. The increase in temperature brought about by soil preparation thus lasts at least more than 10 years.
  • Pukkala, Timo; Kolström, Taneli (Suomen metsätieteellinen seura, 1991)