MiR393 regulation of auxin signaling and redox-related components during acclimation to salinity in Arabidopsis

One of the most striking aspects of plant plasticity is the modulation of development in response to environmental changes. Plant growth and development largely depend on the phytohormone auxin that exerts its function through a partially redundant family of F-box receptors, the TIR1-AFBs. We have previously reported that the Arabidopsis double mutant tir1 afb2 is more tolerant to salt stress than wild-type plants and we hypothesized that down-regulation of auxin signaling might be part of Arabidopsis acclimation to salinity. In this work, we show that NaCl-mediated salt stress induces miR393 expression by enhancing the transcription of AtMIR393A and leads to a concomitant reduction in the levels of the TIR1 and AFB2 receptors. Consequently, NaCl triggers stabilization of Aux/IAA repressors leading to down-regulation of auxin signaling. Further, we report that miR393 is likely involved in repression of lateral root (LR) initiation, emergence and elongation during salinity, since the mir393ab mutant shows reduced inhibition of emergent and mature LR number and length upon NaCl-treatment. Additionally, mir393ab mutant plants have increased levels of reactive oxygen species (ROS) in LRs, and reduced ascorbate peroxidase (APX) enzymatic activity compared with wild-type plants during salinity. Thus, miR393 regulation of the TIR1 and AFB2 receptors could be a critical checkpoint between auxin signaling and specfic redoxassociated components in order to coordinate tissue and time-specific growth responses and tolerance during acclimation to salinity in Arabidopsis.Instituto de Fisiología Vegeta

Optical And Esr Study Of Er3+ In Linbo3

We report laser-excited optical transitions between the 4S3/2 and 4I15/2 multiplets of Er3+ as an impurity in the LiNbO3 host, together with the optical-absorption spectra at liquid-helium and liquid-nitrogen temperatures. The optical data allow us to determine the crystal-field splittings of those levels and the spin-Hamiltonian parameters for the 4I15/2 lower multiplet. The observed electron-spin resonance and the angular variation of this spectrum agree with the parameters obtained by optical techniques. Both techniques show that only one of the three possible trigonal sites in LiNbO3 is occupied by Er3+ within the experimental sensitivity, in agreement with recent x-ray standing-wave measurements. © 1995 The American Physical Society.5153206320

MiR393 regulation of auxin signaling and redox-related components during acclimation to salinity in Arabidopsis

One of the most striking aspects of plant plasticity is the modulation of development in response to environmental changes. Plant growth and development largely depend on the phytohormone auxin that exerts its function through a partially redundant family of F-box receptors, the TIR1-AFBs. We have previously reported that the Arabidopsis double mutant tir1 afb2 is more tolerant to salt stress than wild-type plants and we hypothesized that down-regulation of auxin signaling might be part of Arabidopsis acclimation to salinity. In this work, we show that NaCl-mediated salt stress induces miR393 expression by enhancing the transcription of AtMIR393A and leads to a concomitant reduction in the levels of the TIR1 and AFB2 receptors. Consequently, NaCl triggers stabilization of Aux/IAA repressors leading to down-regulation of auxin signaling. Further, we report that miR393 is likely involved in repression of lateral root (LR) initiation, emergence and elongation during salinity, since the mir393ab mutant shows reduced inhibition of emergent and mature LR number and length upon NaCl-treatment. Additionally, mir393ab mutant plants have increased levels of reactive oxygen species (ROS) in LRs, and reduced ascorbate peroxidase (APX) enzymatic activity compared with wild-type plants during salinity. Thus, miR393 regulation of the TIR1 and AFB2 receptors could be a critical checkpoint between auxin signaling and specfic redoxassociated components in order to coordinate tissue and time-specific growth responses and tolerance during acclimation to salinity in Arabidopsis.Instituto de Fisiología Vegeta

JIRAM, the Jovian Infrared Auroral Mapper

JIRAM is an imager/spectrometer on board the Juno spacecraft bound for a polar orbit around Jupiter. JIRAM is composed of IR imager and spectrometer channels. Its scientific goals are to explore the Jovian aurorae and the planet's atmospheric structure, dynamics and composition. This paper explains the characteristics and functionalities of the instrument and reports on the results of ground calibrations. It discusses the main subsystems to the extent needed to understand how the instrument is sequenced and used, the purpose of the calibrations necessary to determine instrument performance, the process for generating the commanding sequences, the main elements of the observational strategy, and the format of the scientific data that JIRAM will produce

ONE DIMENSIONAL TRANSFER IN CsNiF3

Le déclin de l'émission intrinsèque dans le ferromagnétique unidimensionnel CsNiF3 est en excellent accord avec le modèle suivant : 1/ transfert rapide, à une dimension, entre ions normaux ; 2/ piègeage lent, assisté par les magnons dans le cas des pièges peu profonds.Decay of the intrinsic emission in the one-dimensional ferromagnet CsNiF3 shows excellent agreement with a model of 1/ fast one-dimensional transfer between normal ions ; 2/ slow trapping, assisted by magnons for shallow traps