Regulation of K+ Channels in Maize Roots by Water Stress and Abscisic Acid1

Root cortical and stelar protoplasts were isolated from maize (Zea mays L.) plants that were either well watered or water stressed, and the patch-clamp technique was used to investigate their plasma membrane K+ channel activity. In the root cortex water stress did not significantly affect inward- or outward-rectifying K+ conductances relative to those observed in well-watered plants. In contrast, water stress significantly reduced the magnitude of the outward-rectifying K+ current in the root stele but had little effect on the inward-rectifying K+ current. Pretreating well-watered plants with abscisic acid also significantly affected K+ currents in a way that was consistent with abscisic acid mediating, at least in part, the response of roots to water stress. It is proposed that the K+ channels underlying the K+ currents in the root stelar cells represent pathways that allow K+ exchange between the root symplasm and xylem apoplast. It is suggested that the regulation of K+ channel activity in the root in response to water stress could be part of an important adaptation of the plant to survive drying soils.

Mapping the Functional Roles of Cap Cells in the Response of Arabidopsis Primary Roots to Gravity1

The cap is widely accepted to be the site of gravity sensing in roots because removal of the cap abolishes root curvature. Circumstantial evidence favors the columella cells as the gravisensory cells because amyloplasts (and often other cellular components) are polarized with respect to the gravity vector. However, there has been no functional confirmation of their role. To address this problem, we used laser ablation to remove defined cells in the cap of Arabidopsis primary roots and quantified the response of the roots to gravity using three parameters: time course of curvature, presentation time, and deviation from vertical growth. Ablation of the peripheral cap cells and tip cells did not alter root curvature. Ablation of the innermost columella cells caused the strongest inhibitory effect on root curvature without affecting growth rates. Many of these roots deviated significantly from vertical growth and had a presentation time 6-fold longer than the controls. Among the two inner columella stories, the central cells of story 2 contributed the most to root gravitropism. These cells also exhibited the largest amyloplast sedimentation velocities. Therefore, these results are consistent with the starch-statolith sedimentation hypothesis for gravity sensing.

‘Quite destitute and … very desirous of going to North America’ : The Roots and Repercussions of Emigration from Sutherland and Caithness

Peer reviewed

A PCR based method to detect Russula spp. in soil samples and Limodorum abortivum roots in Mediterranean environments

Aim of study. Orchidaceae has the largest number of species of any family in the plant kingdom. This family is subject to a high risk of extinction in natural environments, such as natural parks and protected areas. Recent studies have shown the prevalence of many species of orchids to be linked to fungal soil diversity, due to their myco-heterotrophic behaviour. Plant communities determine fungal soil diversity, and both generate optimal conditions for orchid development. Area of study. The work was carried out in n the two most important natural parks in Alicante (Font Roja and Sierra Mariola), in South-eastern of Spain. Material and Methods. We designed a molecular tool to monitor the presence of Russula spp. in soil and orchids roots, combined with phytosociological methods. Main results. Using a PCR-based method, we detected the presence in the soil and Limodorum abortivum orchid roots of the mycorrhizal fungi Russula spp. The species with highest coverage was Quercus rotundifolia in areas where the orchid was present. Research highlights. We present a useful tool based on PCR to detect the presence of Russula spp. in a natural environment. These results are consistent with those obtained in different studies that linked the presence of the mycorrhizal fungi Russula spp. in roots of the species Limodorum and the interaction between these fungal species and Quercus ilex trees in Mediterranean forest environments.

Endophytic colonization of barley (Hordeum vulgare) roots by the nematophagous fungus Pochonia chlamydosporia reveals plant growth promotion and a general defense and stress transcriptomic response

Plant crop yields are negatively conditioned by a large set of biotic and abiotic factors. An alternative to mitigate these adverse effects is the use of fungal biological control agents and endophytes. The egg-parasitic fungus Pochonia chlamydosporia has been traditionally studied because of its potential as a biological control agent of plant-parasitic nematodes. This fungus can also act as an endophyte in monocot and dicot plants, and has been shown to promote plant growth in different agronomic crops. An Affymetrix 22K Barley GeneChip was used in this work to analyze the barley root transcriptomic response to P. chlamydosporia root colonization. Functional gene ontology (GO) and gene set enrichment analyses showed that genes involved in stress response were enriched in the barley transcriptome under endophytism. An 87.5 % of the probesets identified within the abiotic stress response group encoded heat shock proteins. Additionally, we found in our transcriptomic analysis an up-regulation of genes implicated in the biosynthesis of plant hormones, such as auxin, ethylene and jasmonic acid. Along with these, we detected induction of brassinosteroid insensitive 1-associated receptor kinase 1 (BR1) and other genes related to effector-triggered immunity (ETI) and pattern-triggered immunity (PTI). Our study supports at the molecular level the growth-promoting effect observed in plants endophytically colonized by P. chlamydosporia, which opens the door to further studies addressing the capacity of this fungus to mitigate the negative effects of biotic and abiotic factors on plant crops.

The roots of economic challenges facing Egypt in the aftermath of the 25th January revolution. Jean Monnet Occasional Paper No. 9/2014

Introduction. Since the 25th of January 2011 revolution the Egyptian economy has been suffering on all fronts. Almost all the economic indicators have been pointing towards a deteriorating situation, and in many cases have reached the trough. Yet, the economy is still surviving. This is mainly due to the unprecedented support of some of Arab Gulf countries, whose unconditional aid has helped to mitigate the deteriorating economic conditions. The economic challenges facing Egypt have been exacerbated after the 20th of January revolution mainly because of the deteriorating political and security conditions which have interrupted the functioning of the economy. Yet, this is not to say that revolution has caused these challenges. In fact, the challenges that the Egyptian has been facing have deep roots in its socio-political-economic context, which this paper aims to explain. The revolution and its aftermath have brought to the forefront challenges which have always been mitigated by short-term solutions that never dealt seriously with their roots. Moreover, the revolution has brought additional problems associated with the macroeconomic imbalances. As a result, the challenges became more complex especially in light of the need to balance the social and economic aspects. The paper proceeds as follows; in section one we pinpoint the main challenges faced by Egypt where we identify the symptoms and causes of such challenges. In section two we discuss the roots of such challenges. Finally, we conclude and provide our understanding of how Egypt is expected to face its challenges in the near future.

Preventing collapse in Ukraine: The EU should finance the grass roots directly. CEPS Commentary, 10 December 2014

With the aim of averting the total collapse of the Ukrainian economy, Daniel Gros and Steven Blockmans urge the EU to ​offer a minimum of macro-financial assistance to improve governance, fight corruption and harmonise laws with the EU acquis, while beefing up financing channelled directly to the grass roots.

The systemic roots of Russia’s recession. Bruegel Policy Contribution ISSUE 2015/15, OCTOBER 2015

The Russian economy grew rapidly between 2000 and 2007, but growth decelerated after the 2008-09 global financial crisis, and since mid-2014 Russia has moved into recession. A number of short-term factors have caused recession: lower oil prices, the conflict with Ukraine, European Union and United States sanctions against Russia and Russian counter-sanctions. However Russia's negative output trends have deeper structural and institutional roots. They can be tracked back about a decade to when previous market-reform policies started to be reversed in favour of dirigisme, leading to further deterioration of the business and investment climate. • Russia must address its short-term problems, but in the medium-to-long term it must deal with its fundamental structural and institutional disadvantages: oil and commodity dependence and an unfriendly business and investment climate underpinned by poor governance. Compared to many other commodity producers, Russia is better placed to diversify its economy, mostly due to its excellent human capital. Ruble depreciation makes this task easier

Suite du Répertoire du Théâtre Français, avec un choix des pièces de plusiers autres théâtres, arrangées et mises en ordre

The third of a series of collections of French drama, the first two being the Répertoire général du Théâtre Français, 67 v., 1818; the 4th Collection des théâtres français. Fin du Répertoire, 45 v., 1829; and the 5th Chefs-d'oeuvres du répertoire des melodrames, 20 v., 1824.

Une pièce unique du Musée Kraus de Florence /

"Edition des 'Annales de l'Alliance Scientifique Universelle.'"

Réponse du représentant du peuple Marin a un écrit intitulé Muséum central des arts : pièces relatives à l'administration de cet établissement, imprimées par ordre du directoire exécutif.

Imprint from colophon.