The effect of an elevated atmospheric CO(_2) concentration on secondary metabolism and resource allocation in plantago maritima and armeria maritima

There are relatively few reports concerning carbon and nitrogen partitioning into secondary metabolism in plants grown in elevated atmospheric CO(_2). This thesis investigates the effects of changes in atmospheric CO(_2) and soil nitrogen availability on compatible solute accumulation and resource allocation in Plantago maritima and Armeria maritima. It was hypothesised that contrasting metabolic responses to abiotic stress cause a species-specific response in P. maritima and A. maritima in resource allocation. In response to drought, P. maritima accumulates the carbon based compatible Solute sorbitol, whilst A. maritima accumulates the nitrogen based solutes betaine and proline. Over ten weeks, A. maritima was more responsive to changes in C and N availability than P. maritima, especially in the amount of C fixed into leaf matter. After elevated CO(_2) exposure for one year, the biomass of P. maritima increased and of A. maritima decreased, compared to the respective plants at ambient CO(_2). Compatible solute concentrations were increased by drought at ambient CO(_2) but decreased in droughted plants at elevated CO(_2). This was hypothesised to be due to lower transpiration rates. Rates of transpiration in P. maritima decreased in response to elevated CO(_2) but A. maritima did not. Tissue water-potential was also lowered in response to elevated CO(_2). This thesis also examines resource allocation to other major C and N sinks. In P. maritima grown at elevated CO(_2) for one year, total soluble phenolic concentrations increased and the concentration of soluble protein decreased. In A. maritima, phenolic concentrations decreased and protein concentrations increased. The effect of enhanced CO(_2) on the secondary metabolism of P. maritima was investigated in greater detail. Six phenolics were identified using metabolite profiling, namely p-coumaric acid, ferulic acid, caffeic acid, verbascoside, plantamajoside and luteolin. P. maritima exposed to elevated CO(_2) had higher concentrations of some of these individual phenolic compounds and histochemical analysis identified increases in the number of lignified vessels and a decrease of lignified vessel-wall thickness

Effects of nitrogen and calcium fertilization on yield, flavonolignans, and anti-teratoma activity of greenhouse grown Silybum marianum

Silybum marianum (L.) Gaertn. plants were grown in a bag culture system in a greenhouse on the University of Tennessee campus during the Spring of 2001 and the Fall of 2001. For the Spring 2001 experiment, calcium concentration was altered to produce three nitrogen to calcium ratio treatments. For the Fall 2001 experiment, nitrogen concentration was altered to produce three nitrogen treatments. Plant samples were analyzed for anti-teratoma activity in a modified potato-disc bioassay and for chemical composition using capillary electrophoresis. Ca:N ratio treatments had no effect on seed yield (15 g/ plant) or raw plant extract activity. However, nitrogen treatments had significant effects on both yield and raw plant extract actvity, with plants from the highest N treatment (152 mg/L) producing the greatest biomass (421g of pre-anthesis fresh weight per plant), seed yield (102 g/plant) and seed activity. Ethanolic extracts from roots, stems, and young leaves of pre-anthesis plants inhibited growth of teratomas in the potato disc bioassay. However, only the roots contained the flavonolignan compound silybin, which has been credited for the majority of the bioactivity of seed extracts. Seedlings of S. marianum had high levels of activity in the bioassay, matching that of seed extracts, yet only small concentrations of chemical constituents, which were not identified, were found in the extracts

Degrees of members of ∏01 classes

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Models of the ISM in galaxy centers

Part I: M51 is observed at a wavelength of 850 mum, where most radiation is emitted by dust. We find prominent spiral arms and an underlying exponential disk. The properties of the disk and the arms are studied. Part II and III: Gas in Galaxy Centers is exposed to intense radiation from a starburst region, an Active Galactic Nucleus (AGN), or both. The OB stars in starforming regions mostly radiate in the far-ultraviolet (FUV) and accreting black holes mostly in the X-ray regime. FUV and X-ray photons lead to a totally different chemical composition of gas clouds. Therefore, molecules such as H2, CO, HCN and HCO+ emit different line intensities. In the thesis, we model the line emission of the molecules in these gas clouds with Photon Dominated Regions models (FUV: PDR) and X-ray Dominated Region models (X-rays: XDR). These models are applied to nearby active galaxies such as NGC 253 and NGC 1068.Leiden Observatory LKBFUBL - phd migration 201

Behavioral Ecology of Singing in the Heart-Nosed Bat, Cardioderma cor

Although singing has been recently recognized in some bat species, the prevalence and ecological significance of this behavior in bats is still mysterious. Cardioderma cor, the heart-nosed bat, was one of the first bats reported to sing, but little is known about the behavior of this species. Unlike other singing bats, this species roosts in groups during the day but disperses nightly to exclusive foraging areas, whereupon they sing from perches. The goal of this dissertation was to investigate the behavioral ecology of singing in C. cor, addressing key questions such as which bats sing, when and where they sing, and what and why they sing. I conducted a series of experiments to test the hypothesis that C. cor sings to create and defend foraging territories, a behavior commonly observed in songbirds but not mammals. I recorded the singing and sonar behavior of individuals across three field seasons in Tanzania. I mist-netted, tagged, and VHF-tracked 14 individuals to collect movement and singing data. Finally, I conducted acoustic playback experiments with 10 singers. C. cor males showed high fidelity to closely abutting night ranges that varied in size from 0.97 to 5.23 ha. Males foraged early in the evening before singing from preferred perches for up to several hours. I documented two C. cor song types, the most frequent being a “loud” song and less frequently a “soft” song uttered at the height of the dry season. Songs varied within individuals, but each individual’s songs were distinguishable by a unique set of spectral and temporal syllable parameters. C. cor and the sympatric, confamilial yellow-winged bat, Lavia frons, had overlapping foraging territories. However, C. cor’s repertoire was distinctive from that of L. frons’. Song playback experiments with C. cor elicited strong movement responses and changes in singing. Results suggested that song spectral and temporal parameters influenced behavioral responses. The results of this dissertation support the conclusion that C. cor’s singing behavior is consistent with the territory defense hypothesis for the evolution of singing, and suggest that song variability is likely integral to social interactions by facilitating individual discrimination or signaling motivational states

Cultural modification of Chrysanthemum Morifolium Ramat

The capacity of Chrysanthemum morifolium to produce a blue pigmentation through cultural modification involving a specific nutritional regime, soil pH conditions and metallic applications was explored. Two cultivars of cut chrysanthemum and five cultivars of garden chrysanthemum were used as plant material. Aluminum content of the leaves, stems and petals of the garden chrysanthemums was measured to test the ability of these plants to accumulate a metal. No correlations were found between nutritional regime, soil pH conditions, metal application and aluminum content of the plant parts. None of the seven cultivars grown in pot culture showed any blue pigmentation in their petals. The chrysanthemum does not appear to be a metal accumulator and therefore is not a likely candidate for blueing through the use of cultural manipulation

Cultural modification of Chrysanthemum Morifolium Ramat

The capacity of Chrysanthemum morifolium to produce a blue pigmentation through cultural modification involving a specific nutritional regime, soil pH conditions and metallic applications was explored. Two cultivars of cut chrysanthemum and five cultivars of garden chrysanthemum were used as plant material. Aluminum content of the leaves, stems and petals of the garden chrysanthemums was measured to test the ability of these plants to accumulate a metal. No correlations were found between nutritional regime, soil pH conditions, metal application and aluminum content of the plant parts. None of the seven cultivars grown in pot culture showed any blue pigmentation in their petals. The chrysanthemum does not appear to be a metal accumulator and therefore is not a likely candidate for blueing through the use of cultural manipulation