Characterization and Properties of a Protochlorophyllide Ester in Leaves of Dark Grown Barley with Geranylgeraniol as Esterifying Alcohol

The protochlorophyllide ester isolated from dark grown barley leaves was shown to contain geranylgeraniol as esterifying alcohol. No phytylester was found. The qualitative analyses were performed with combined gas chromatography-mass spec-trometry. Chromatographic separation and spectrofluorometric determination of the protochlorophyll and chlorophyll pigments before and after irradiation of the dark grown leaves with light flashes at 2°C showed that part of the protochlorophyllide ester was photoconverted to chlorophyll a.     

Changes in the Content of Phytyl and Geranylgeranyl Esters of Germinating Polytrichum commune Spores

Polytrichum commune spores contained esterified phytol and geranylgeraniol, 706 and 114 μg, respectively, per 100 mg dry weight of freshly collected spores. After storage for 9 months the level of esterified phytol of the spores was decreased by c. 600 μg, whereas the level of esterified geranylgeraniol was more or less unchanged. The changes in the level of esterified prenols during germination follow the same pattern in freshly collected and in 9 month-old spore material. An immediate steep decrease between 0 and 3 h was followed by an increase in the level of esterified phytol between 3 and 12 h and by a constant value for esterified geranylgeraniol during the same period. Between 12 and 48 h the level of both types of esterified prenols decreased. In the freshly collected spores the amount of esterified prenols increased after 48 h of germination, in the older spores after 72 h. Free phytol was found in trace amounts in dry and germinating spores and in the protonema.     

Effect of Storage in Darkness and in Light on the Content of Membrane Lipids of Potato Tubers

The lipid composition of tubers from the potato varieties Bintje and Desirée was investigated during storage. Storage in total dark ness after harvest gave only small changes in the amounts of triglycerides. monogalactosyl diglycerides and digalactosyl digtycerides. Storage in light resulted in changes in these lipids and in their fatty acid composition. The absolute amount and the relative content of linolenic acid in the galactolipids increased. A simultaneous and equivalent decrease in the percentage of linoleic acid took place without any marked percentage changes in the other major fatty acids. The light induced changes of the lipids, which occur simultaneously with greening of the tuber, are discussed and related to the development of thylakoid membrane systems in the plastids.     

Interactions of chlorophyll a and terpenoid alcohols with chloroplast acyl lipids in monomolecular films

Surface pressure-area measurements of purified chlorophyll a and monogalactosyl diacylglycerol in mixed monolayers were performed at 20°C with an automatic recording surface film balance at a constant compression rate. In addition structural parts of the chlorophyll and the monogalactosyl diacylglycerol as phytol and geranylgeraniol on one hand and different fatty acids on the other were studied pure and in mixed films. All components studied formed stable monomolecular films. Chlorophyll a and monogalactosyl diacylglycerol showed miscibility. Phytol was immiscible with synthetized monogalactosyl diacylglycerol containing only stearic acid. Mixed monolayers of phytol and monogalactosyl diacylglycerol isolated from barley containing 83 mol % a-linolenic acid showed a strong interaction. An increased miscibility and association were found between phytol and fatty acids with increasing unsaturation. The results are discussed as a model for the localization of part of chlorophyll a in the thylakoid membrane.     

Long-term culturing of plants with aseptic roots Determination of rape root exudates

Abstract A plant culture system allowing growth of aseptic roots has been designed. One version of the system comprises vessels developed for plant root-microorganism interaction studies in series. A second version has been built for measurements of different physiological parameters of the shoot and root system during growth periods of at least 2 months. The system was tested by determining soluble organic carbon glucose and sucrose in the root exudates of rape plants (Brassica napus L.) grown for 3 weeks in the culture system. The plants were cultivated with a sterile or a non-sterile root system, or with a root system infected with Verticillium dahliae Kleb.     

Concordant genetic breaks, identified by combining clustering and tessellation methods, in two co-distributed alpine plant species

Natural genetic breaks may indicate limitations to gene flow or the presence of contact zones of previously isolated populations. Molecular evidence suggests that genetic breaks have aggregated in distinct geographical areas. We propose a new application of well-established statistical methods for analysing multilocus genetic data to identify intraspecific genetic breaks. The methodological approach combines Bayesian clustering with a spatially explicit maximum-difference algorithm to visualize and quantify breaks between clusters. We used amplified fragment length polymorphism data of two co-distributed, silicicolous alpine plant species, Geum montanum and Geum reptans , exhaustively sampled on a consistent, regular grid over their entire range of the European Alps and the Carpathians. We found a distinct and highly similar allocation of genetic breaks in both species. The pattern of breaks did not conform to scenarios of glacial refugial survival, alternatively in peripheral refugia or on nunataks, as expected because of the species' ecologies (late-successional low alpine vs. early-successional high alpine). Our findings rather substantiated the postulate of a general pattern of genetic breaks in alpine plants and corresponded well with biogeographical regions formerly described. Our approach could serve as a tool not only for landscape genetics and comparative phylogeography, but also for floristics or faunistics to compare biogeographic with phylogeographic breaks.     

The Occurrence of Phytylpyrophosphate and Acyl Esters of Phytol in Irradiated Dark-Grown Barley Seedlings and Their Possible Role in Biosynthesis of Chlorophyll

Dark-grown barley seedlings which had been irradiated for 6 to 8 h have been shown to contain fatty acid esters of phytol. No such esters could be found in non-irradiated seedlings. The fatty acids were saturated or had only one double bond. The most prominent acid was palmitic acid. Isolated etio-chloroplasts from non-irradiated and irradiated barley seedlings also contained phytylpyrophosphate. The ratio of free phytol to phytylpyrophosphate is only little changed when the seedlings are irradiated for 6 to 8 h. The chemical identifications of free phytol and the phytol derivatives are based upon combined gas chromatography/mass spectrometry.     

Lipids, carbohydrates and amino acids exuded from the axenic roots of rape seedlings exposed to water-deficit stress

Abstract. Rape ( Brassica napus [L.]) plants were cultivated for 25 d with axenic roots in a growth system with quartz sand and circulating nutrient solution. After a water stress period of 24h. fresh nutrient solution was added and root exudates were collected 3d later. The stress did not cause significant differences in the weights between the stressed and the control plants. The stressed plants tended to exude more soluble organic carbon than the control plants. This was not reflected in the amounts of low molecular weight carbohydrates exuded. A significantly lower proportion of the soluble organic carbon exuded by the stressed plants was made up of amino acids in comparison with the control plants, 7% and 28% respectively. Exuded hydrophobic substances could be recovered from the sand particles. The stressed plants exuded more sterols than the control plants, and an increased number of polar lipid types. The exudates of the stressed and control plants also differed regarding their fatty acid composition.     

Crystalloid formation in protochlorophyll-accumulating plastids from the inner seed coat of Cyclanthera explodens

The development of fruit, seed and plastids in the inner seed coat of Cyclanthera explodens Naud. was studied. Large amounts of protochlorophyll, in at least three different in vivo-forms, accumulated during maturation and was 14 mg/g fresh weight of the inner seed coat in mature seeds. In earlier stages plastid-membrane-lipids increased simultaneously with the pigment. This could also be seen in electron micrographs as an increased amount of membranes. During later stages the amount of pigment continued to increase without an increase in the lipids. At this stage large crystalloids were found in the plastids. The data presented led to the conclusion that the protochlorophyll form fluorescing at 691 nm is crystalline.