Mars Regolith Simulant Ameliorated by Compost as In Situ Cultivation Substrate Improves Lettuce Growth and Nutritional Aspects

Heavy payloads in future shuttle journeys to Mars present limiting factors, making self-sustenance essential for future colonies. Therefore, in situ resources utilization (ISRU) is the path to successful and feasible space voyages. This research frames the concept of planting leafy vegetables on Mars regolith simulant, ameliorating this substrate’s fertility by the addition of organic residues produced in situ. For this purpose, two butterhead lettuce (Lactuca sativa L. var. capitata) cultivars (green and red Salanova®) were chosen to be cultivated in four dierent mixtures of MMS-1 Mojave Mars simulant:compost (0:100, 30:70, 70:30 and 100:0; v:v) in a phytotron open gas exchange growth chamber. The impact of compost rate on both crop performance and the nutritive value of green- and red-pigmented cultivars was assessed. The 30:70 mixture proved to be optimal in terms of crop performance, photosynthetic activity, intrinsic water use eciency and quality traits of lettuce. In particular, red Salanova® showed the best performance in terms of these quality traits, registering 32% more phenolic content in comparison to 100% simulant. Nonetheless, the 70:30 mixture represents a more realistic scenario when taking into consideration the sustainable use of compost as a limited resource in space farming, while still accepting a slight significant decline in yield and quality in comparison to the 30:70 mixture

Biochemical, Physiological and Anatomical Mechanisms of Adaptation of Callistemon citrinus and Viburnum lucidum to NaCl and CaCl2 Salinization

Callistemon citrinus and Viburnum lucidum are very appreciated and widespread ornamental shrubs for their abundant flowering and/or brilliant foliage. The intrinsic tolerance to drought/salinity supports their use in urban areas and in xeriscaping. Despite adaptive responses of these ornamental species to sodium chloride (NaCl) have been extensively explored, little is known on the effects of other salt solution, yet iso-osmotic, on their growth, mineral composition and metabolism. The present research aimed to assess responses at the biochemical, physiological and anatomical levels to iso-osmotic salt solutions of NaCl and CaCl2 to discriminate the effects of osmotic stress and ion toxicity. The two ornamental species developed different salt-tolerance mechanisms depending on the salinity sources. The growth parameters and biomass production decreased under salinization in both ornamental species, independently of the type of salt, with a detrimental effect of CaCl2 on C. citrinus. The adaptive mechanisms adopted by the two ornamental species to counteract the NaCl salinity were similar, and the decline in growth was mostly related to stomatal limitations of net CO2 assimilation rate, together with the reduction in leaf chlorophyll content (SPAD index). The stronger reduction of C. citrinus growth compared to V. lucidum, was due to an exacerbated reduction in net photosynthetic rate, driven by both stomatal and non stomatal limitations. In similar conditions, V. lucidum exhibited other additional adaptive response, such as modification in leaf functional anatomical traits, mostly related to the reduction in the stomata size allowing plants a better control of stomata opening than in C. citrinus. However, C. citrinus plants displayed an increased ability to retain higher Cl- levels in leaves than in roots under CaCl2 salinity compared to V. lucidum, thus, indicating a further attempt to counteract chloride toxicity through an increased vacuolar compartmentalization and to take advantages of them as chip osmotica

Effect of water salinity and osmolytes application on growth and ornamental value of Viburnum lucidum L

The scarcity of good quality water frequently led to the use of saline water for the irrigation of ornamental shrubs. Therefore, their salt tolerance needs to be investigated, along with the possibility to counteract the effect of salinity exposure on plant growth and ornamental quality, possibly due to reduced growth, and nutritional imbalances. Under salt stress conditions, plants can activate mechanisms helping to withstand it, such as the production of several organic solutes that play a role in the osmotic adjustment. Aiming to this extent the exogenous application of osmolytes, such as glycine betaine (GB) and L-proline (L-P), has been tested on potted plants of Viburnum lucidum L. grown under saline irrigation. The experiment was designed as a factorial combination of two nutrient solutions (non-salt control, or 200 mM NaCl) and three osmoprotectant treatments (untreated, GB 2.5 mM, or L-P 5 mM application). Shoot and root biomass were negatively affected by salinity (-37 and -29%, respectively), but not the shoot/root ratio. A significant and positive effect of osmolytes application was found on the shoot biomass of plants treated with GB (+46%). Lateral sprouting total length per plant was also reduced by saline irrigation (-60%), but the GB application resulted in a significant increase (+102%). A positive effect of GB application was also found on the total leaf area (LA) per plant that was increased by 182% under saline conditions. Root/shoot ratio did not change with salinity. L-P application resulted in a significant increase of both shoot and root biomass per unit of LA (+40 and +85%, respectively) in comparison with the untreated control and GB

A simple and accurate allometric model to predict single leaf area of twenty-one European apricot cultivars

Research in fruit tree physiology and breeding often requires accurate and non-destructive methods for estimating leaf area (LA). The development of unbiased allometric model from linear measurements [leaf length (L) and/or width (W)] to predict individual LA of apricot irrespective of cultivars is still lacking. The models were built using LA, L, and W data measured in 3,040 leaves collected on trees of nineteen apricot cultivars (calibration experiment). Model(s) were validated on 520 apricot leaves collected from the trees of two additional cultivars (validation experiment). LA prediction models based only on L measurements (L or L2) were not suitable for estimating LA of apricot. A significant improvement in LA prediction was observed when the model including W2 as an independent variable was adopted. However, the coefficients of one dimension LA model (W2) were affected by leaf shape (L:W ratio) and consequently were excluded. To develop an accurate LA model for apricot, independent of leaf shape groups, the product L×W was used as an independent variable. The linear model LA = 1.193 + 0.668 (L×W) exhibited the highest R2, the smallest mean square error (MSE) and predicted residual error sum of squares (PRESS). In the model validation, correlation coefficients showed that there was a highly reliable relationship between the predicted and the observed LA values, giving an underestimation of 2.9% in the prediction. The LA model using LW as independent variable can be successfully adopted in research on apricot, since it provides an accurate, simple and non-destructive estimation of LA across apricot cultivars without the use of any expensive device

How advertising on social media can help boost support for European integration

The European Parliament has produced a series of videos to inform European citizens about the benefits of European integration. But do campaigns like this have a real impact on public support? Enrique Hernández and Roberto Pannico present findings from a new study which showed two of the videos to citizens in Spain. They found that participants who watched the videos were more likely to express increased support for European integration and Spain’s EU membership, but that this effect did not persist over time

On time and meaningful partisanship: Stability, strength, and sway of attachment to new parties

New parties pose a challenge to the claim that time is an essential element in the construction of partisanship. By definition, new parties have not been around for much time, so the opportunities for the construction of meaningful attachments could be considered limited. In this paper, we test this expectation, unpacking the dynamics and implications of the attachment to new parties. Using panel data collected in Spain during a period of profound party system change, we estimate the extent to which partisanship with new parties is stable and strong, works as a heuristic for preference formation, and predicts vote choice. Our data suggest that attachments to new parties can be as meaningful as those that citizens have with old parties. These findings seem particularly relevant in a context where new parties are on the rise.info:eu-repo/semantics/publishedVersio

Voting under EMU: economic perceptions, responsibility attribution and EU politicisation

The article analyses the effects of Economic and Monetary Union (EMU) on economic voting. Theories of responsibility attribution suggest that voters are less likely to consider the economic situation when they realise that the national government is not completely in charge of economic policy. However, some aspects of the theory are being questioned, and its empirical application to EMU has yielded inconclusive results. The article uses experimental data from six EU countries to provide both a theoretical and a methodological contribution to the debate. Theoretically, we argue that to analyse the effects of EMU on economic voting, it is important to consider voters’ and parties’ positions on EU integration. The Europeanisation of economic policy has become a politicised issue over the last years. Consequently, voters are likely to combine functional considerations about who is in charge of economic policy with political considerations about the desirability of this distribution of responsibility. Methodologically, the article provides an analysis of the conditionality of economic voting that considers different sources of endogeneity. The results confirm the relevance of economic perceptions in voting and provide some support for the idea that voters’ EU positions matter when it comes to the effects of EMU on voting.info:eu-repo/semantics/publishedVersio

Experimental Evidence of EU Issue Voting

The chapter focuses on the consequences of EU politicization on electoral behaviour. It investigates whether and under which conditions EU citizens consider their EU positions when casting a vote in national elections. First, we use a conjoint experiment to investigate the magnitude of EU issue voting in six EU countries. This design allows us to cope with possible endogeneity problems while simulating the complexity of the task faced by real voters. Second, we link the media data presented in the previous chapters to the experiment’s results to explore how EU issue voting is influenced by the informational context. The main results and several robustness checks show that in almost all the countries analysed respondents are more likely to vote for a party that shares their own position on the EU than for a party that does not. However, it seems that not all types of voter-party incongruence have the same electoral consequences. Finally, the findings also suggest a relationship between media content and EU issue voting.info:eu-repo/semantics/publishedVersio

The Left–Right Dimension, Europe and Voting in Bailout Europe

This chapter investigates several questions concerning the relative importance of EU issue voting in Greece, Ireland, Portugal and Spain. First, the relationship between EU issue proximity and left–right proximity for voting behaviour. Second, the importance of both these issues contrasting mainstream and challenger parties. Third, whether EU parliamentary debates, measured in terms of tone, moderate the importance of EU issue voting. We use post-election online panel surveys collected in 2019–2020 in each of the bailout countries to analyse these questions. Our results show that, in all countries surveyed, EU issue voting does cross-cut the left–right dimension. Yet, left–right proximity has a higher impact on likelihood to vote for a party than EU issue proximity in all countries. Ireland stands out due to the relative irrelevance of both issues in explaining vote choice. European issue proximity to parties’ positions is a significant predictor of voting behaviour, but not a more important determinant of likelihood to vote than left–right for challenger parties. Finally, the tone employed by parties in EU parliamentary debates matters: For parties which have a more negative tone, EU proximity determines vote choice more strongly than for parties with a positive or neutral EU tone in parliament.info:eu-repo/semantics/publishedVersio

Double-Edged Bullets: The Conditional Effect of Terrorism on Vote for the Incumbent

Terrorism often seeks to impact democratic politics. This article explores how it can influence the electoral fortunes of the incumbent. Existing research is contradictory. Models of retrospective voting predict a negative impact, as terrorism is detrimental to voters' welfare. However, the well-known 'rally around the flag' effect suggests otherwise: following a terrorist attack, voters often cling to the incumbent. We reconcile these arguments and argue that while both effects can coexist, the retrospective assessment is more durable than the rally around the flag. Using data on all deadly domestic terrorist attacks in Spain between 1977 and 2008, matched with municipal-level national election results, we show how exposure to strikes that occur during the last quarter of the term benefit the incumbent, while more temporally distant attacks are electorally harmful. In line with our theory, we find a more pronounced temporal heterogeneity for indiscriminate attacks and those that target civilians