Pirjo Karunen

Polyunsaturated hydrocarbons from Polytrichum commune spores

Abstract Polytrichum commune Hedw. spores were found to contain the polyunsaturated hydrocarbons normal all- cis -6,9,12,15-heneicosatetrane (20· ± 0·5 μg/100 mg spores) and normal all- cis -3,6,9,12,15-heneicosapentaene (22·5 ± 1·2 μg/100 mg spores), N - alkanes were present only in minor amounts.

Lipids and hydroxycinnamic acids in cell walls of Eriophorum vaginatum

Abstract The contents of aliphatic and aromatic compounds in alkaline hydrolysates from cell wall preparations of leaves of Eriophorum vaginatum varied between 27 and 10 mg/g dry wt depending on the age of the tissue. The amounts were highest in living green leaves at the end of the growth period and lowest in highly decayed leaf remains (mainly leaf bases) located below the peat surface. Living roots contained less alkaline hydrolysis products than the green leaves, and the decaying roots even less. The absolute and relative amounts of individual compounds differed in the hydrolysis products from mature and senescent leaves and leaves at various stages of decomposition. This suggests that the compounds are liberated from the cell walls or transformed to other constituents less susceptible to alkaline hydrolysis at different rates during tissue decay. Those that appear to be lost most rapidly are hydroxycinnamic acids ( p -coumaric and ferulic acids),9,10-epoxy-18-hydroxyoctadecanoic and 9,16- and 10,16-dihydroxyhexadecanoic acids. Compounds that are lost less rapidly are C 18 ω-hydroxy acids and certain long chain α,ω-dicarboxylic and fatty acids, those lost most slowly are very long chain (C 22 -C 28 ) ω-hydroxy acids. In roots also, both the absolute and relative amounts of very long chain ω-hydroxy acids were highest in the decaying cell walls.

Lipid and pigment patterns in germinating Polytrichum commune spores

Abstract Although there is some information on the lipid constituents in the leafy and woody parts of mosses 1 no attention—up until now—has been paid to the lipids in the moss spores even though mosses are of particular interest as they contain arachidonic acid. 2–4 The primary interest, in this study, is directed to the changes of the lipid and pigment patterns in germinating spores of Polytrichum commune Hedw. and detailed results of the study will be published later.

Senescence-related Changes in the Composition of Free and Esterified Sterols and Alcohols in Sphagnum fuscum

Summary The content and composition of sterols, triterpenoid alcohols, n-aliphatic alcohols and hydrocarbons were studied by GC and GC/MS in the green (capitulum) and senescent parts of Sphagnum fuscum . The content of esterified sterols and triterpenoid alcohols, on a dry weight basis, was highest in the capitulum (740 μg · g -1 d.wt.) and very low in older parts (90 μg · g -1 d.wt. in the 3—6 cm segment and 20 μg · g -1 d.wt. in the 21—24 cm segment). Likewise the content of free sterols and triterpenoid alcohols was high in the capitulum (680 μg · g -1 d.wt.) and decreased with increased shoot age (380 μg and 240 μg · g -1 d.wt. in the 3—6 cm and 21—24 cm segments, respectively). The dominant components of the esterified sterols and triterpenoid alcohols were an unidentified component B (33.8%), cycloartenol (16.2%), methylene cycloartanol (9.5%), stigmasterol (16.2%) and campesterol (9.5%). At the depth of 21—24 cm esterified sitosterol was dominant. The major components among the free sterols and triterpenoid alcohols in the capitulum were stigmasterol (56.5%), campesterol (15.9%), sitosterol (10.9%) and an unidentified compound A (17.4%). The proportion of free sitosterol increased with increased shoot age (41.7% in the 21—24 cm segment) as did the proportion of free triterpenoid alcohols (cycloartenol and methylene cycloartanol), the level of which was extremely low in the capitulum. The contents of both free and esterified phytol (200 μg and 360 μg · g -1 d.wt., respectively) were highest in the capitulum and decreased with increased shoot age. At the depth of 21—24 cm only traces of free phytol and very small amounts of esterified phytol (20 μg · g -1 d.wt.) were found. The contents of hydrocarbons and n-alcohols of the esters were at about the same level in the capitulum and the 3—6 cm segment (i.e. 360 μg and 340 μg · g -1 d.wt. n-alcohols and 260 μg and 230 μg · g -1 d.wt. hydrocarbons, respectively), but distinctly lower in the 21—24 cm segment (170 μg · g -1 d.wt. n-alcohols and 100 μg · g -1 d.wt. hydrocarbons). The content of free n-alcohols was highest in the 3—6 cm segment (230 μg · g -1 d.wt.). The first signs of decay of S. fuscum shoots at the microscopic level ( i.e. occasionally damaged stem centre) were observed at the depth of 21—24 cm.

Lipid polymers from the turf-forming moss Dicranum elongatum

Abstract The green part of Dicranum elongatum contained polymerized lipids amounting to 1.4 mg/g dry cell-wall preparation. The major monomer classes were hydroxy acids (44.9%) and fatty acids (39.7%), and the minor classes α,ω-dicarboxylic acids and fatty alcohols. The underground shoot parts encrusted with rhizoids contained a smaller amount of polymerized lipids (1.1–0.9 mg), with the important classes fatty acids, α,ω-dicarboxylic acids and hydroxy acids with 16 carbon atoms. The content of long-chain ω-hydroxy acids with 18 carbon atoms or more increased with shoot age, being highest in the oldest, decaying part of the turf. Similar age-dependent increases, although more conspicuous, occur in the turfs of two Sphagnum mosses but not in the wefts of two forest mosses.

Esterified long-chain hydroxy acids in green and senescent parts of the peat moss Sphagnum fuscum

Abstract The bifunctional long-chain acids in extracts and alkaline hydrolysates of extractive-free tissues from the green and senescent parts of Sphagnum fuscum were investigated by GC and GC/MS. A series of C14– C26hydroxy acids was liberated by alkaline hydrolysis of senescent tissue demonstrating the presence of insoluble polymeric lipid esters in the moss. In the corresponding hydrolysates of the topmost green parts of the shoot the amounts of these acids were significantly smaller. It is suggested that the presence of such polymeric esters in S. fuscum contributes to the cell-wall resistance of this peat-forming moss.

Content of Polymerized Lipids in Stems and Leafy Branches of Sphagnum fuscum

Summary Segments of Sphagnum fuscum shoots from the depth of 18–20 cm at Karevansuo bog, SW-Finland, contained 2.2 mg · g-1 DW polymerized lipids, of which 93 % were derived from the leafy branches and 7 % from the stem part. The composition of the polymer monomers was qualitatively similar in the leafy branches and stems (i.e. long-chain hydroxy acids, dicarboxylic acids, fatty acids and fatty alcohols), but quantitative variation occurred between the monomer groups. The lipid polymers of the cell wall preparations from leafy branches were characterized by a high proportion of hydroxy acid monomers (62%), with 18-hydroxyoctadec-9-enoic acid and 9, 16+10, 16-dihydroxyhexadecanoic acids as major members. The stem was characterized by high proportions of hydroxy acids (43.5 %) and fatty acids (43.5 %).

Thylakoid Membrane Composition and Photoinactivation of CO2 Fixation in Moss Protonemata as Influenced by the Growth Temperature

The lipid content of the thylakoid membranes has been assumed important in photosynthetic processes at low temperatures. A higher lipid to protein ratio of the thylakoid membranes in leaves of cold-grown as compared to warm-grown higher plants (1) has been supposed to optimize photosynthesis at low growth temperatures by maintaining the proper fluidity of the thylakoid membranes (2). This may be crucial because even some pigment-protein complexes migrate between appressed and non-appressed membrane regions (3, 4) thus controlling photosynthesis under fluctuating environmental conditions.

Comparison of Chill-Induced and Room Temperature Photoinhibition

Bright light induces photoinhibition of photosynthesis. When plants are subjected to chilling temperature, symptoms of photoinhibition are often observed to appear even in moderate light (for a review, see oquist & al.1). It is often thought, that the role of low temperature is only to accelerate photoinhibition. In this study, we distinguish between high light induced photoinhibition and the inhibition caused by the combination of low temperature and light.