We investigated the biological roles of the Arabidopsis (Arabidopsis thaliana) GROWTH-REGULATING FACTOR (GRF) and GRF-INTERACTING FACTOR (GIF) transcriptional complex in the development of gynoecia and anthers. There are nine GRFs and three GIFs in Arabidopsis, and seven GRFs are posttranscriptionally silenced by microRNA396 (miR396). We found that overexpression of MIR396 in the gif1 gif2 double mutant background (gif1 gif2 35S:MIR396) resulted in neither ovary nor pollen. Histological and molecular marker-based analyses revealed that the mutant gynoecial primordia failed to develop carpel margin meristems and mature flowers lacked the ovary, consisting only of the stigma, style, and replum-like tissues. The mutant anther primordia were not able to form the pluripotent archesporial cells that produce pollen mother cells and microsporangia. Multiple combinations of GRF mutations also displayed the same phenotypes, indicating that the GRF-GIF duo is required for the formation of those meristematic and pluripotent cells. Most GRF proteins are localized and abundant in those cells. We also found that the weak gynoecial defects of pinoid-3 (pid-3) mutants were remarkably exacerbated by gif1 gif2 double mutations and 35S:MIR396, so that none of the gynoecia produced by gif1 gif2 pid-3 and 35S:MIR396 pid-3 developed ovaries at all. Moreover, gif1 gif2 double mutations and 35S:MIR396 also acted synergistically with 1-N-naphthylphthalamic acid in forming aberrant gynoecia. The results altogether suggest that the GRF-GIF duo regulates the meristematic and pluripotent competence of carpel margin meristems and the archesporial cell lineage and that this regulation is implemented in association with auxin action, ultimately conferring reproductive competence on Arabidopsis.
Seoul in South Korea is once again a maritime port. The Korean War effectively severed the city's connection with the Yellow Sea in 1953 when the Han River estuary became part of the military demarcation line between North and South Korea. However, through some inspired planning and innovative engineering, a recently built flood-diversion channel has just been converted into an 18 km navigable shipping route from Incheon on the coast to the heart of the capital – complete with significant port and warehousing facilities at each end. This paper describes the evolution of Gyeong-in Waterway from a minor drainage channel to a major multi-purpose waterway.
In this paper, a Ka-band 8 W power amplifier module with WR-28 waveguide input and output ports is implemented and measured using four 2 W power amplifier modules and 4:1 waveguide power combiners with high isolation of 25 dB at 35 GHz. The 2 W power amplifier modules are fabricated using waveguide-to-microstrip transitions and show output power of 32.5~33.3 dBm and power gain of 26.9~28.7 dB at 35 GHz. Four 2 W power amplifier modules are combined through 4:1 waveguide power combiners with resistive septum and the combined power shows 39.0 dBm(8 W) under 6 V drain bias and 39.6 dBm(9.1 W) under 6.5 V drain bias at 35 GHz. , 국내의 경우 최근에서야 40 dBm 출력의 전력증폭기 모듈이 개발 되었다 [2] . 고출력 전력증폭기 모듈을 구현하기 위해 개별 MMIC 칩들을 알루미나(Alumina) 기판에서 전 력 합성하는 방법은 큰 마이크로스트립 전송 선로의
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