Effects of vapour pressure deficit and soil water content on leaf water potential between selected provenances of Eucalyptus microtheca in an irrigated plantation, eastern Kenya

Summary

Leaf morphological and physiological responses of Quercus aquifolioides along an altitudinal gradient

Abstract

Orbis sensualium pictus

Tshekki J. A. Comenius (Komenský) julkaisi 1680 käänteentekevän oppikirjan, jossa latinaa opetettiin kuvien avulla, Suomessa kirja ilmestyi 1684-1698 useina painoksina piispa Johannes Gezeliuksen kustantamana. - Osa kirjan kuvista väritetty myöhemmin.

Orbis sensualium pictus = Then synlige werlden

Tsekkiläissyntyinen protestanttinen teologi ja kasvatustieteilijä Johann Amos Comenius julkaisi 1600-luvun puolivälissä kuuluisan oppikirjansa Orbis sensualium pictus (Näkyvä maailma). Kirja oli tarkoitettu latinan kielen alkeiden opiskeluun. Sen käänteentekevä metodi pohjautui havainnollisiin kuviin, joiden pienet, numeroin varustetut yksityiskohdat viittasivat niihin liittyviin selittäviin teksteihin ja sanoihin. Taivaankappaleet, luonto, liikennevälineet, käsityöt, maailmanuskonnot, tavat ja moraali, ihmiskehon rakenne – sanalla sanoen koko luomakunta kaikkine vivahduksineen kuvattiin Comeniuksen kirjan kömpelön kulmikkaissa, mutta havainnollisissa puupiirroksissa. Kuvat ja käsitteet yhdistävänä "pienoisensyklopediana" se pyrki muuttamaan kiduttavan päähän pänttäämisen lapsille hauskaksi tiedon hankkimiseksi. Orbis sensualium pictus levisi kaikkialle Eurooppaan ja ilmestyi myös Suomessa 1680-luvulla useana latinalais-ruotsinkielisenä painoksena. Kirja painettiin Turun piispan Johannes Gezelius vanhemman kirjapainossa, ja sen puupiirrosten painolaatat oli leikattu Turussa käyttäen esikuvana alkuperäisteoksen saksalaisia varhaispainoksia.

Fractionation of Wood Extracts

The aim of this thesis was to fractionate wood extracts into pure fractions using membrane technology, to observe membrane behaviour in solvents and to study the effect of conditioning on membrane performance. Four different wood extracts were used in the performed filtrations. In the literature part, the focus was on the effect of different solvent properties on polymeric membranes, especially on their retention and flux. Solute properties, such as shape, polarity and charge, were examined. Transport models, membrane stability and ways to improve the stability, when solvents were filtered, were also discussed. The experimental part consisted of a series of filtrations, where the effect of the wood extracts and solvent concentration on solute retention was observed. Polymeric and ceramic membranes were tested under different conditions and the solute analyses were performed with GC and GC-MS. It was discovered that it is possible to fractionate wood extracts using membrane technology to some extent, but more research must be done to understand the mechanisms behind the various interactions between the solvent and the membrane. Conditioning was also considered as an important part of the membrane pre-treatment.

Leaf-Targeted Ferredoxin-NADP+-Oxidoreductase (FNR): Electron Transfer Properties and Thylakoid Association in Arabidopsis thaliana

Photosynthetic reactions are divided in two parts: light-driven electron transfer reactions and carbon fixation reactions. Electron transfer reactions capture solar energy and split water molecules to form reducing energy (NADPH) and energy-carrying molecules (ATP). These end-products are used for fixation of inorganic carbon dioxide into organic sugar molecules. Ferredoxin-NADP⁺ oxidoreductase (FNR) is an enzyme that acts at the branch point between the electron transfer reactions and reductive metabolism by catalyzing reduction of NADP+ at the last step of the electron transfer chain. In this thesis, two isoforms of FNR from A rabidopsis thaliana, FNR1 and FNR2, were characterized using the reverse genetics approach. The fnr1 and fnr2 mutant plants resembled each other in many respects. Downregulation of photosynthesis protected the single fnr mutant plants from excess formation of reactive oxygen species (ROS), even without significant upregulation of antioxidative mechanisms. Adverse growth conditions, however, resulted in phenotypic differences between fnr1 and fnr2. While fnr2 plants showed downregulation of photosynthetic complexes and upregulation of antioxidative mechanisms under low-temperature growth conditions, fnr1 plants had the wild-type phenotype, indicating that FNR2 may have a specific role in redistribution of electrons under unfavorable conditions. The heterozygotic double mutant (fnr1xfnr2) was severely devoid of chloroplastic FNR, which clearly restricted photosynthesis. The fnr1xfnr2 plants used several photoprotective mechanisms to avoid oxidative stress. In wild-type chloroplasts, both FNR isoforms were found from the stroma, the thylakoid membrane, and the inner envelope membrane. In the absence of the FNR1 isoform, FNR2 was found only in the stroma, suggesting that FNR1 and FNR2 form a dimer, by which FNR1 anchors FNR2 to the thylakoid membrane. Structural modeling predicted formation of an FNR dimer in complex with ferredoxin. In this thesis work, Tic62 was found to be the main protein that binds FNR to the thylakoid membrane, where Tic62 and FNR formed high molecular weight complexes. The formation of such complexes was shown to be regulated by the redox state of the chloroplast. The accumulation of Tic62-FNR complexes in darkness and dissociation of complexes from the membranes in light provide evidence that the complexes may have roles unrelated to photosynthesis. This and the high viability of fnr1 mutant plants lacking thylakoid-bound FNR indicate that the stromal pool of FNR is photosynthetically active.