Database of solar radio bursts observed by solar radio spectro-polarimeter AMATERAS

International audienceObservations of solar radio bursts is a useful tool to study non-thermal electron acceleration and the plasma environment in the solar corona. The radio bursts in a frequency range from 150 to 500 MHz with fine temporal and spectral resolutions (10 ms and 61 kHz) have been observed with the AMATERAS radio spectro-polarimeter installed at the Iitate Planetary Radio Telescope since 2010. Here we review results obtained from the AMATERAS observation and introduce the database which is open to the public. The AMATERAS receiver consists of a wide-band and low-noise front-end receiver and a digital spectrometer. Both right and left-hand polarized components are simultaneously observed. The combination of a large aperture area of the telescope and the digital receiver enables us to observe the radio burst with high dynamic range and fine spectral resolution. After a daily observation of the Sun, a data processing pipeline generates low and high resolution data sets. The low resolution data with reduced resolutions of 1 s, 1 MHz, and 8 bits is converted to the FITS format and distributed through the AMATERAS Data Center. Quick look (PNG format) and meta-data of the FITS-format file are registered to the Virtual European Solar and Planetary Access (VESPA) and Inter-university Upper atmosphere Global Observation NETwork (IUGONET) database. The high resolution data set has fine resolutions of 10 ms and 61 kHz, but the dynamic range is reduced to be 8 or 16 bits depending on the intensity of the radio burst observed. It is currently provided on request basis

TDZ-induced direct shoot organogenesis and somatic embryogenesis on cotyledonary node explants of lentil (Lens culinaris Medik.)

An efficient and simple procedure for inducing high frequency direct shoot organogenesis and somatic embryogenesis in lentil from cotyledonary node explants (without both the cotyledons) in response to TDZ alone is reported. TDZ at concentration lower than 2.0 μM induced shoot organogenesis whereas at higher concentration (2.5–15 μM) it caused a shift in regeneration from shoot organogenesis to somatic embryogenesis. The cotyledonary node and seedling cultures developed only shoots even at high concentrations of BAP and TDZ, respectively. TDZ at 0.5 and 5.0 μM was found to be optimal for inducing an average of 4–5 shoots per cotyledonary node in 93 % of the cultures and 55 somatic embryos in 68 % of the cultures, respectively. The somatic embryos were germinated when transferred to lower TDZ concentration (0.5–1.0 μM). The shoots were rooted on MS basal medium containing 2.5 μM IBA. The plantlets were obtained within 8 weeks from initiation of culture and were morphologically similar to seed-raised plants. The possible role of stress in thidiazuron induced somatic embryogenesis is discussed