Food for thought: how nutrients regulate root system architecture

The spatial arrangement of the plant root system (root system architecture, RSA) is very sensitive to edaphic and endogenous signals that report on the nutrient status of soil and plant. Signalling pathways underpinning RSA responses to individual nutrients, particularly nitrate and phosphate, have been unravelled. Researchers have now started to investigate interactive effects between two or more nutrients on RSA. Several proteins enabling crosstalk between signalling pathways have recently been identified. RSA is potentially an important trait for sustainable and/or marginal agriculture. It is generally assumed that RSA responses are adaptive and optimise nutrient uptake in a given environment, but hard evidence for this paradigm is still sparse. Here we summarize recent advances made in these areas of research

To respond or not to respond? Natural variation of root architectural responses to nutrient signals

The amino acid glutamate (Glu) acts as a fast excitatory neurotransmitter in mammals. Its importance in plant signalling was recognized with the discovery of channel proteins similar to mammalian Glu receptors, as well as distinct changes in root-system architecture in response to very small amounts of soil Glu. Based on natural genetic variation within Arabidopsis, Walch-Liu et al. (2017) have now identified a major locus underpinning this root response, as well as several loci controlling it through gene by environment interactions with nitrate and temperature. It is a significant step towards unraveling crosstalk between signalling pathways that enable plants to adjust their growth and development to multiple environmental stimuli

Detection of Electromagnetic Inclusions using Topological Sensitivity

In this article a topological sensitivity framework for far field detection of a diametrically small electromagnetic inclusion is established. The cases of single and multiple measurements of the electric far field scattering amplitude at a fixed frequency are taken into account. The performance of the algorithm is analyzed theoretically in terms of its resolution and sensitivity for locating an inclusion. The stability of the framework with respect to measurement and medium noises is discussed. Moreover, the quantitative results for signal-to-noise ratio are presented. A few numerical results are presented to illustrate the detection capabilities of the proposed framework with single and multiple measurements.Comment: 31 pages, 5 figure

Simulation, Implementation and Testing of Three-phase Controlled Power Inverter Behavior

With the increase in the use of renewable sources, the study of control schemes for better control of distributed generation systems and grid connection has become very vital to achieve better stability of the system. This thesis provides a study of the control scheme for interconnection between a DC source and an AC grid. A possible control scheme is studied and simulated in Simulink. The system behavior is analyzed by subjecting it to different changes in parameters and grid conditions. The implementation of the scheme is done by using dSpace and Simulink model. Only Low Voltage implementation is performed and tested in this thesis

Containing salinity through irrigation management: the case of the Fordwah area in Pakistan

International audienceLa salinité des sols a toujours été une contrainte de l'agriculture irriguée dans le bassin de l'indus. Traditionnellement, ce phénomène était associé à la remontée d'une nappe, devenue sub-affleurante à certains endroits, avec l'introduction des périmètres irrigués à grande échelle. Le concept de la «menace jumelle» de l'engorgement et de la salinité des sols a impulsé depuis les années 1960 un grand nombre de projets de drainage à grande échelle pour rabattre la nappe. Par ailleurs, pour faire face aux pénuries d'eau, les agriculteurs ont recouru à des pompages individuels dans la nappe dont le niveau a ainsi baissé. Le nombre de forages est estimé à plus de 500 000 et continue d'augmenter. L'utilisation des eaux souterraines, souvent d'une qualité médiocre mais hétérogène dans l'espace, accentue une tendance à la salinisation des sols. L'eau de surface, en revanche, est d'excellente qualité et représente une valeur inestimable pour les paysans ayant des problèmes de salinité et sodicité. Une distribution de l'eau de surface en phase avec les contraintes des paysans en termes de qualité de l'eau de nappe pourrait contribuer à diminuer ces problèmes. (Résumé d'auteur

An Overview of Cancer Treatment Modalities

Cancer is a global issue majorly affecting developing countries. According to a survey, 63% of deaths due to cancer are reported from developing countries. There are different conventional treatment modalities that are available to treat and manage cancer. However, new cancer treatment options are being explored continuously as over 60% of all current experimental trials worldwide are focusing on tumor cure. The success of treatment depends upon the type of cancer, locality of tumor, and its stage of progression. Surgery, radiation-based surgical knives, chemotherapy, and radiotherapy are some of the traditional and most widely used treatment options. Some of the modern modalities include hormone-based therapy, anti-angiogenic modalities, stem cell therapies, and dendritic cell-based immunotherapy. This chapter discusses different traditional and novel treatment modalities to combat different types of cancer

Natural variation at XND1 impacts root hydraulics and trade-off for stress responses in Arabidopsis

Soil water uptake by roots is a key component of plant performance and adaptation to adverse environments. Here, we use a genome-wide association analysis to identify the XYLEM NAC DOMAIN 1 (XND1) transcription factor as a negative regulator of Arabidopsis root hydraulic conductivity (Lp). The distinct functionalities of a series of natural XND1 variants and a single nucleotide polymorphism that determines XND1 translation efficiency demonstrate the significance of XND1 natural variation at species-wide level. Phenotyping of xnd1 mutants and natural XND1 variants show that XND1 modulates Lp through action on xylem formation and potential indirect effects on aquaporin function and that it diminishes drought stress tolerance. XND1 also mediates the inhibition of xylem formation by the bacterial elicitor flagellin and counteracts plant infection by the root pathogen Ralstonia solanacearum. Thus, genetic variation at XND1, and xylem differentiation contribute to resolving the major trade-off between abiotic and biotic stress resistance in Arabidopsis