The influence of plant fertilisation regime on plant-aphid-parasitoid interactions

This thesis examines effects of plant fertilisation regime on herbivore and parasitoid performance for two aphids, Macrosiphum euphorbiae and Myzus persicae, and one parasitoid wasp, Aphidius ervi. Herbivore performance was measured as adult fresh weight and intrinsic rate of increase. Parasitoid performance was measured as length of hind tibia, sex ratio, and in a series of choice experiments also parasitoid development time and parasitization rate was measured. Comparisons were made between the performance of M. euphorbiae on two different plant species, petunia and sweet pepper, between the performance of the aphids M. euphorbiae and M. persicae on sweet pepper, and between the performance of A. ervi in M. euphorbiae and in M. persicae on sweet pepper. The performance of M. euphorbiae was better on petunia than on sweet pepper. On petunia a positive effect of plant content of potassium and indications of a positive effect of nitrogen fertilisation were found while on sweet pepper both nitrogen and of potassium had negative influence. On both plant species, however, a negative influence of sulphur was found. The two aphid species reacted differently to fertilisation and plant content of nutrients. For M. euphorbiae fresh weight was decreased by fertilisation while for M. persicae the influence varied with experiment. For M. persicae a high N:K ratio was favourable while for M. euphorbiae plant contents of N and K were both negative. Plant content of sulphur and potassium influenced tibia length of A. ervi positively in M. euphorbiae. In M. persicae plant fertilisation was positive but the composition of the plant fertilisation did not seem important for the parasitoid. Plant fertilisation enhanced parasitization rate in M. euphorbiae but not in M. persicae. Parasitoid performance was, however, more improved by fertilisation in M. persicae than in M. euphorbiae. The parasitoid both preferred, and developed faster in, M. persicae compared to M. euphorbiae. The results of this study show that it is possible to influence both aphid performance and performance of A. ervi with plant fertilisation but the influence varies with both plant and aphid species

Mitochondria directly influence fertilisation outcome in the pig

The mitochondrion is explicitly involved in cytoplasmic regulation and is the cell's major generator of ATP. Our aim was to determine whether mitochondria alone could influence fertilisation outcome. In vitro, oocyte competence can be assessed through the presence of glucose-6-phosphate dehydrogenase (G6PD) as indicated by the dye, brilliant cresyl blue (BCB). Using porcine in vitro fertilisation (IVF), we have assessed oocyte maturation, cytoplasmic volume, fertilisation outcome, mitochondrial number as determined by mtDNA copy number, and whether mitochondria are uniformly distributed between blastomeres of each embryo. After staining with BCB, we observed a significant difference in cytoplasmic volume between BCB positive (BCB+) and BCB negative (BCB-) oocytes. There was also a significant difference in mtDNA copy number between fertilised and unfertilised oocytes and unequal mitochondrial segregation between blastomeres during early cleavage stages. Furthermore, we have supplemented BCB- oocytes with mitochondria from maternal relatives and observed a significant difference in fertilisation outcomes following both IVF and intracytoplasmic sperm injection (ICSI) between supplemented, sham-injected and non-treated BCB- oocytes. We have therefore demonstrated a relationship between oocyte maturity, cytoplasmic volume, and fertilisation outcome and mitochondrial content. These data suggest that mitochondrial number is important for fertilisation outcome and embryonic development. Furthermore, a mitochondrial pre-fertilisation threshold may ensure that, as mitochondria are diluted out during post-fertilisation cleavage, there are sufficient copies of mtDNA per blastomere to allow transmission of mtDNA to each cell of the post-implantation embryo after the initiation of mtDNA replication during the early postimplantation stages

Changes of yield responses and soil test values in Finnish soils in relation to cumulative phosphorus and potassium balances

Field experiments with five rates of annual P fertilisation were carried out at 24 sites in Finland 1977-1994. A summary of the yield results was calculated on the basis of the amounts of P recommended to cereals according to STP in early 1990s. The effects of repeated K fertilisation were studied at 21 sites in 1977-1994

Inequality and sustainable consumption: Bridging the gaps

This article examines the potential for cross-fertilisation between the sustainable consumption (SC) scholarship and the environmental justice (EJ) scholarship. The article first maps the two areas of scholarship, discussing the cognitive, social marketing and social provisioning systems literatures of SC and the empirical and conceptual literature on EJ. The article then discusses the potential for cross-fertilisation between the two areas of scholarship. It indicates how SC scholarship can benefit from the social justice sensitivity of the EJ scholarship and how the latter area of scholarship can gain a whole new area of empirical research focusing on social justice aspects of consumption. The article seeks to demonstrate the social and policy significance of the cross-fertilisation by comparing the consumption and EJ implications of carbon taxation and personal carbon allowance trading as tools of carbon management. The article suggests that to be fair both strategies of carbon management require complementary (albeit different) measures that address background inequalities and capabilities to act in the setting created by the instruments

Fertilisation with compost: effects on soil phosphorus sorption and on phosphorus availability in acid soils.

Phosphate mineral fertilisers are manufactured from non-renewable resources.Soil fertilisation with composts is considered a good source of reuse nutrients such as phosphorus (P). The aim of this work was to evaluate the effect of compost fertilisation on soil P sorption and consequently on P availability. It was done an incubation experiment followed by a sorption experiment in a low-P acid soil fertilised with compost (CP) or single superphosphate (SSP). The P application rates were: 0, 6.5, 13, 26 and 52 (kg∙P∙ha−1). In CP treatments, the rates 26 and 52 kg∙P∙ha−1 were achieved by adding SSP to CP since it was not allowed to incorporate into soil more than 170 kg∙N∙ha−1 from organic amendments. Although SSP has a higher proportion of easily available P than CP (86% vs 50%), the results showed that after 140 days of soil incubation, the available P was higher in CP treatments compared with SSP at the same rate of P application. The sorption experiment showed that after incubation of the fertilised soils, the P sorption maximum had lower values in treatments with CP in combination with SSP compared with only SSP fertilisation and the bonding energy had a deeper decrease in the same treatments. Also, the Standard Phosphate Requirement decreased in the CP in combination with SSP treatments. The reduction of soil P sorption capacity after compost addition to soil highlights the need of reducing P fertilisation rates to achieve similar levels of available P compared with only SSP fertilisation.info:eu-repo/semantics/publishedVersio

The in vitro fertilisation law

After twenty years of unregulated in vitro fertilization (IVF) practice and nine years of political debate, Malta finally has a law regulating IVF practice. The Bioethics Consultative Committee played a significant part in reaching the social consensus necessary for the passage of this Act which needed to be in line with the social value norms held by Maltese society. The law does not only regulate IVF procedures but also touches on other bioethical issues such as embryo testing, gamete donation, cloning, hybrid and chimera use, germ line gene therapy and embryonic stem cell use which have all been made illegal.peer-reviewe

A model-based constraint on CO₂ fertilisation

We derive a constraint on the strength of CO2 fertilisation of the terrestrial biosphere through a “top-down” approach, calibrating Earth system model parameters constrained by the post-industrial increase of atmospheric CO2 concentration. We derive a probabilistic prediction for the globally averaged strength of CO2 fertilisation in nature, for the period 1850 to 2000 AD, implicitly net of other limiting factors such as nutrient availability. The approach yields an estimate that is independent of CO2 enrichment experiments. To achieve this, an essential requirement was the incorpo- ration of a land use change (LUC) scheme into the GENIE Earth system model. Using output from a 671-member ensemble of transient GENIE simulations, we build an emulator of the change in atmospheric CO2 concentration change since the preindustrial period. We use this emulator to sample the 28-dimensional input parameter space. A Bayesian calibration of the emulator output suggests that the increase in gross primary productivity (GPP) in response to a doubling of CO2 from preindustrial values is very likely (90 % confidence) to exceed 20 %, with a most likely value of 40–60 %. It is important to note that we do not represent all of the possible contributing mechanisms to the terrestrial sink. The missing processes are subsumed into our calibration of CO2 fertilisation, which therefore represents the combined effect of CO2 fertilisation and additional missing processes. If the missing processes are a net sink then our estimate represents an upper bound. We derive calibrated estimates of carbon fluxes that are consistent with existing estimates. The present-day land–atmosphere flux (1990–2000) is estimated at −0.7 GTC yr−1 (likely, 66 % confidence, in the range 0.4 to −1.7 GTC yr−1). The present-day ocean–atmosphere flux (1990–2000) is estimated to be −2.3 GTC yr−1 (likely in the range −1.8 to −2.7 GTC yr−1). We estimate cumulative net land emissions over the post-industrial period (land use change emissions net of the CO2 fertilisation and climate sinks) to be 66 GTC, likely to lie in the range 0 to 128 GTC

UK donor registries

Fertility services have been formally regulated in the UK since 1991, following implementation of the Human Fertilisation and Embryology Act 1990 (“The Act”). The Act established a statutory regulatory agency, the Human Fertilisation and Embryology Authority (HFEA), whose responsibilities include licensing certain forms of fertility treatment and to maintain a register of information (s31). The register includes details relating to donors, recipients of donated gametes and embryos, and children born as a result of all donor procedures provided by a licensed treatment centr

Controlling broad-leaved dock (Rumex obtusifolius) in grass clover mixtures

This article describes three experiments on the control of broad-leaved dock. Experiment 1: Dock seeds were ensiled in grass silages of different dry matter percentages; 23, 34 and 60% respectively. All silages showed a decline of seed vitality in time. Grass clover with dock seeds should be ensiled at a low dry matter percentage or remain in the silage bin for a longer period than 8 weeks. Experiment 2: In a potassium fertilisation trial on grass clover the development of dock was followed. After two years of potassium fertilisation, the number of dock and the root mass was not significant different between the fertilised and the unfertilised plots. It is concluded that potassium fertilisation at a low potassium status does not positively influence the dock development. Experiment 3: In a resown grass clover, dock seedlings were cut at three frequencies; 2, 4 and 6 weeks. After 3 months the number of seedlings had decreased the same in all treatments. However the root biomass of the seedlings was significantly affected. It is concluded that frequent cutting has a negative effect on root biomass but should be practised for a longer period than 12 weeks to have an effect on seedling numbers