Isotope abundance ratios play an important role in astronomy and planetary sciences, providing insights in the origin and evolution of the Solar System, interstellar chemistry, and stellar nucleosynthesis 1,2 . In contrast to deuterium/hydrogen ratios, carbon isotope ratios are found to be roughly constant (~89) in the Solar System 1,3 , but do vary on galactic scales with 12 C/ 13 C~68 in the current local interstellar medium 4-6 . In molecular clouds and protoplanetary disks, 12 CO/ 13 CO isotopologue ratios can be altered by ice and gas partitioning 7 , low-temperature isotopic ion exchange reactions 8 , and isotope-selective photodissociation 9 . Here we report on the detection of 13 CO in the atmosphere of the young, accreting giant planet TYC 8998-760-1 b at a statistical significance of > 6σ. Marginalizing over the planet's atmospheric temperature structure, chemical composition, and spectral calibration uncertainties, suggests a 12 CO/ 13 CO ratio of ! $ (90% confidence), a significant enrichment in 13 C with respect to the terrestrial standard and the local interstellar value. Since the current location of TYC 8998 b at ≥160 au is far beyond the CO snowline, we postulate that it accreted a significant fraction of its carbon from ices enriched in 13 C through fractionation. Future isotopologue measurements in exoplanet atmospheres can provide unique constraints on where, when and how planets are formed.TYC 8998-760-1 b 10 is a widely-separated planetary mass companion around a young solar analog TYC 8998-760-1 (also known as 2MASS J13251211-6456207) with an age of ~17 Myr 11 . With the recent detection of a second planet 12 , it is part of the first directly imaged multiplanet system around a solar-type star. TYC 8998 b is located at a projected separation of 160 au, with an estimated mass of 14±3 MJ. We observed the planet on two nights, 2019 June 5 and June 19, using Spectrograph for INtegral Field Observations in the Near Infrared (SINFONI) 13,14 installed at the Cassegrain focus of UT3 of the Very Large Telescope of the European Southern Observatory at Cerro Paranal, Chile. The observations were performed in K-band (1.95 -2.45 μm), providing a spectral resolving power (λ/Δλ) of ~4500. We extracted the spectrum of TYC 8998 b from 2.10 to 2.45 μm as detailed in Methods.As shown in Figure 1, the planet spectrum is dominated by molecular features from H2O and CO. The 12 CO v=2-0, 3-1, 4-2 bandheads are visible at 2.2935, 2.3227, and 2.3535 μm respectively. When we compare the observed spectrum with the best-fit model obtained by atmospheric retrieval, an extra emission signature at 2.166 μm is seen in Figure 1c, which is identified as the hydrogen Brackett γ recombination line. This is likely an indication of ongoing accretion of circumplanetary material onto the planet. We estimated a mass accretion rate of 10 -9.4±1.3 M⊙ yr -1 using the Br γ line luminosity (see Methods). Future observations at longer wavelengths and polarimetric data can provide further insights into the circumplanetary disk and accret...

Background: Wild apple, Malus sieversii, is an endangered species and a valuable genetic resource that requires a variety of conservation techniques. This study aimed to investigate the influence of different concentrations of hormones on wild apple regeneration from leaf and stem explants to establish an optimal regeneration system. Results:Leaves and stems derived from seedlings were cultured on several media supplemented with various concentrations of thidiazuron (TDZ) or 6-benzylaminopurine (BA) in different combinations with 1-naphthaleneacetic acid (NAA). The results showed that the most efficient shoot formation media (35% and 90%) were MS medium containing 4.0 mg L −1 TDZ and 1.0 mg L −1 NAA for leaf explants and MS medium containing 1.0 mg L −1 BA without NAA for stem explant. MS medium supplemented with 0.4 mg L −1 BA and 0.1 mg L −1 NAA (for shoot multiplication) and 1/2 MS + 0.1 mg L −1 NAA + 1.5% sucrose (for rooting) were effective media. Shoot regeneration from leaf explants was the most effective when the explants were placed abaxial side down onto the medium and were subjected to a pre-treatment of 3 weeks in darkness.Conclusions: An optimized regeneration system for M. sieversii that allowed regeneration within 2-3 months developed. The protocol developed herein can be used in large-scale clonal propagation for the conservation of wild apple, M. sieversii.

Context. Linking atmospheric characteristics of planets to their formation pathways is a central theme in the study of extrasolar planets. Although the 12C/13C isotope ratio shows little variation in the Solar System, the atmosphere of a super-Jupiter was recently shown to be rich in 13CO, possibly as a result of dominant ice accretion beyond the CO snow line during its formation. Carbon isotope ratios are therefore suggested to be a potential tracer of formation pathways of planets. Aims. In this work, we aim to measure the 12CO/13CO isotopologue ratio of a young, isolated brown dwarf. While the general atmospheric characteristics of young, low-mass brown dwarfs are expected to be very similar to those of super-Jupiters, their formation pathways may be different, leading to distinct isotopologue ratios. In addition, such objects allow high-dispersion spectroscopy at high signal-to-noise ratios. Methods. We analysed archival K-band spectra of the L dwarf 2MASS J03552337+1133437 taken with NIRSPEC at the Keck telescope. A free retrieval analysis was applied to the data using the radiative transfer code petitRADTRANS coupled with the nested sampling tool PyMultiNest to determine the isotopologue ratio 12CO/13CO in its atmosphere. Results. The isotopologue 13CO is detected in the atmosphere through the cross-correlation method at a signal-to-noise of ~8.4. The detection significance is determined to be ~9.5σ using a Bayesian model comparison between two retrieval models (including or excluding 13CO). We retrieve an isotopologue 12CO/13CO ratio of 97−18+25 (90% uncertainty), marginally higher than the local interstellar standard. Its C/O ratio of ~0.56 is consistent with the solar value. Conclusions. Although only one super-Jupiter and one brown dwarf now have a measured 12CO/13CO ratio, it is intriguing that they are different, possibly hinting to distinct formation pathways. Regardless of spectroscopic similarities, isolated brown dwarfs may experience a top-down formation via gravitational collapse, which resembles star formation, while giant exoplanets favourably form through core accretion, which potentially alters isotopologue ratios in their atmospheres depending on the material they accrete from protoplanetary disks. This further emphasises atmospheric carbon isotopologue ratio as a tracer of the formation history of exoplanets. In the future, analyses such as those presented here should be conducted on a wide range of exoplanets using medium-to-high-resolution spectroscopy to further assess planet formation processes.

Relative little is known about the functions of the so-called Dof zinc factors in plants. Here we report on the analysis of OsDof25 and show a function in regulation of the important C4 photosynthesis gene, OsC4PPDK in rice. Over-expression of OsDof25 enhanced the expression of OsC4PPDK in transient expression experiments by binding in a specific way to a conserved Dof binding site which was confirmed by yeast and in vitro binding studies. Expression studies using promoter GUS plants as well as qPCR experiments showed that OsDof25 expressed in different tissues including both photosynthetic and non-photosynthetic organs and that expression of OsDof25 was partially overlapping with the OsC4PPDK gene. Conclusive evidence for a role of OsDof25 in regulation of C4PPDK came from loss-of-function and gain-of-function experiments with transgenic rice, which showed that down-regulation or over-expression of OsDof25 correlated with OsC4PPDK expression and that OsDof25 has functions as transcriptional activator.Electronic supplementary materialThe online version of this article (doi:10.1007/s11103-015-0357-3) contains supplementary material, which is available to authorized users.