RESUMO
Effect of the internal interface layer on the dielectric properties of doped Ba0.6Sr0.4TiO3(BST) films and their simulation research in filters. Based on the interfacial effect in the multi-layer ferroelectric thin film, a different number of internal interface layers was proposed and introduced into the Ba0.6Sr0.4TiO3thin film. First, Ba0.6Sr0.4Ti0.99Zn0.01O3(ZBST) sol and Ba0.6Sr0.4Ti0.99Mg0.01O3(MBST) sols were prepared using the sol-gel method. Ba0.6Sr0.4Ti0.99Zn0.01O3/Ba0.6Sr0.4Ti0.99Mg0.01O3/Ba0.6Sr0.4Ti0.99Zn0.01O3thin films with 2 layer internal interface layer, 4 layer internal interface layer and 8 layer internal interface layer were designed and prepared (I2, I4, I8). The effects of the internal interface layer on the structure, morphology, dielectric properties, and leakage current behavior of the films were studied. The results showed that all the films were of the cubic perovskite BST phase and had the strongest diffraction peak in the (110) crystal plane. The surface composition of the film was uniform, and there was no cracked layer. When the bias of the applied DC field was 600 kV cm-1, the high-quality factor values of the I8 thin film at 10 MHz and 100 kHz were 111.3 and 108.6, respectively. The introduction of the internal interface layer changed the leakage current of the Ba0.6Sr0.4TiO3thin film, and the I8 thin film exhibited the minimum leakage current density. The I8 thin-film capacitor was used as the tunable element to design a fourth-step 'tapped' complementary bandpass filter. When the permittivity was reduced from 500 to 191, the central frequency-tunable rate of the filter was 5.7%.
RESUMO
PIN proteins are auxin export carriers that direct intercellular auxin flow and in turn regulate many aspects of plant growth and development including responses to environmental changes. The Arabidopsis R2R3-MYB transcription factor FOUR LIPS (FLP) and its paralogue MYB88 regulate terminal divisions during stomatal development, as well as female reproductive development and stress responses. Here we show that FLP and MYB88 act redundantly but differentially in regulating the transcription of PIN3 and PIN7 in gravity-sensing cells of primary and lateral roots. On the one hand, FLP is involved in responses to gravity stimulation in primary roots, whereas on the other, FLP and MYB88 function complementarily in establishing the gravitropic set-point angles of lateral roots. Our results support a model in which FLP and MYB88 expression specifically determines the temporal-spatial patterns of PIN3 and PIN7 transcription that are closely associated with their preferential functions during root responses to gravity.
Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Gravitropismo/genética , Raízes de Plantas/crescimento & desenvolvimento , RNA Mensageiro/metabolismo , Fatores de Transcrição/genética , Arabidopsis/crescimento & desenvolvimento , Imunoprecipitação da Cromatina , Ensaio de Desvio de Mobilidade Eletroforética , Glucuronidase/metabolismo , Hibridização In Situ , Organismos Geneticamente Modificados , Raízes de Plantas/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transcrição GênicaRESUMO
The initiation of stomatal lineage and subsequent asymmetric divisions in Arabidopsis require the activity of the basic helix-loop-helix transcription factor SPEECHLESS (SPCH). It has been shown that SPCH controls entry into the stomatal lineage as a substrate either of the MITOGEN-ACTIVATED PROTEIN KINASE (MAPK) cascade or GSK3-like kinase BRASSINOSTEROID INSENSITIVE 2 (BIN2). Here we show that three serine residues of SPCH appear to be the primary phosphorylation targets of Cyclin-Dependent Kinases A;1 (CDKA;1) in vitro, and among them Serine 186 plays a crucial role in stomatal formation. Expression of an SPCH construct harboring a mutation that results in phosphorylation deficiencies on Serine 186 residue failed to rescue stomatal defects in spch null mutants. Expression of a phosphorylation-mimic mutant SPCH(S186D) complemented stomatal production defects in the transgenic lines harboring the targeted expression of dominant-negative CDKA;1.N146. Therefore, in addition to MAPK- and BIN2-mediated phosphorylation on SPCH, phosphorylation at Serine 186 is positively required for SPCH function in regulating stomatal development.
Assuntos
Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/química , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Estômatos de Plantas/crescimento & desenvolvimento , Serina/metabolismo , Motivos de Aminoácidos , Arabidopsis/química , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Regulação da Expressão Gênica de Plantas , Fosforilação , Estômatos de Plantas/química , Estômatos de Plantas/genética , Estômatos de Plantas/metabolismo , Serina/química , Serina/genéticaRESUMO
Stomata are two-celled valves that control epidermal pores whose spacing optimizes shoot-atmosphere gas exchange. They develop from protodermal cells after unequal divisions followed by an equal division and differentiation. The concentration of the hormone auxin, a master plant developmental regulator, is tightly controlled in time and space, but its role, if any, in stomatal formation is obscure. Here dynamic changes of auxin activity during stomatal development are monitored using auxin input (DII-VENUS) and output (DR5:VENUS) markers by time-lapse imaging. A decrease in auxin levels in the smaller daughter cell after unequal division presages the acquisition of a guard mother cell fate whose equal division produces the two guard cells. Thus, stomatal patterning requires auxin pathway control of stem cell compartment size, as well as auxin depletion that triggers a developmental switch from unequal to equal division.