MAGNETOMECHANICAL COUPLING IN THE Fe85B15 AMORPHOUS ALLOY RIBBONS PRODUCED IN LONGITUDINAL AND TRANSVERSE FIELD DURING QUENCHING

The magnetomechanical coupling coefficient of the measured 50 mm long and 4 mm wide strips of the as-quenched Fe85B15 amorphous alloy reaches its maximum values between 0.18 and 0.25. After applying longitudinal or transverse magnetic field (H = 8 kA/m) during quenching process the maximum values of this coefficient increases to 0.4 ± 5 %

METALLIC GLASSES CAST IN MAGNETIC FIELD

Fe-Cr-B metallic glass ribbons were prepared in a magnetic field applied during the melt stage or when the ribbon part had already solidified. The Curie temperature of the alloy was modified by adding Cr to separate the effect of the field on solidification from the influence of magnetic annealing

ANXUR receptor-like kinases coordinate cell wall integrity with growth at the pollen tube tip via NADPH oxidases

It has become increasingly apparent that the extracellular matrix (ECM), which in plants corresponds to the cell wall, can influence intracellular activities in ways that go far beyond their supposedly passive mechanical support. In plants, growing cells use mechanisms sensing cell wall integrity to coordinate cell wall performance with the internal growth machinery to avoid growth cessation or loss of integrity. How this coordination precisely works is unknown. Previously, we reported that in the tip-growing pollen tube the ANXUR receptor-like kinases (RLKs) of the CrRLK1L subfamily are essential to sustain growth without loss of cell wall integrity in Arabidopsis. Here, we show that over-expression of the ANXUR RLKs inhibits growth by over-activating exocytosis and the over-accumulation of secreted cell wall material. Moreover, the characterization of mutations in two partially redundant pollen-expressed NADPH oxidases coupled with genetic interaction studies demonstrate that the ANXUR RLKs function upstream of these NADPH oxidases. Using the H₂O₂-sensitive HyPer and the Ca²⁺-sensitive YC3.60 sensors in NADPH oxidase-deficient mutants, we reveal that NADPH oxidases generate tip-localized, pulsating H₂O₂ production that functions, possibly through Ca²⁺ channel activation, to maintain a steady tip-focused Ca²⁺ gradient during growth. Our findings support a model where ECM-sensing receptors regulate reactive oxygen species production, Ca²⁺ homeostasis, and exocytosis to coordinate ECM-performance with the internal growth machinery

Enhanced induction of microspore embryogenesis after n-butanol treatment in wheat (Triticum aestivum L.) anther culture

The original version is available at http://www.springerlink.com/content/100383/The aim of this study was the improvement of embryo production in wheat anther culture. Three butanol alcohols, n-butanol, sec-butanol and tert-butanol, were evaluated for their effect on microspore embryogenesis in two spring cultivars of wheat, Pavon and Caramba. Application of n-butanol, at 0.1 and 0.2% (v/v) in the induction media for five hours, highly improved embryo production in both cultivars. Sec- and tert-butanol performed similarly to control plates. Regeneration ability was unaffected by any butyl-alcohol treatment. As a consequence of the higher embryo production after n-butanol treatment, the number of green regenerated plants increased up to 5 times in cultivar Pavon and up to 3 times in cultivar Caramba. The percentage of green plants was improved or unaffected by the treatment. Doubled haploid plant production was between 2 and 4 times higher after n-butanol treatment than in control plates. Therefore, n-butanol was successfully applied in the production of wheat doubled haploids. This primary alcohol is known as an activator of phospholipase D and has been previously reported to disrupt cortical microtubules and detach them from the plasma membrane in plants. Its effects on androgenetic induction could confirm the importance of microtubule regulation in plant cell fate, specifically in microspore development. A possible implication of phospholipase D is discussed.http://www.springerlink.com/content/v302947634352057/fulltext.pdfPeer reviewe