Water is essential for the formation of granites, but its origin and role in granite generation (i.e., dehydration vs. water‐fluxed melting) remain uncertain. These issues are addressed by combining ...water abundances and other geochemical indices in zircons from Late Mesozoic granites generated during the destruction of the North China Craton (NCC). The water contents in zircons from the NCC Early Cretaceous granites (763 ppm, median) are much higher than those of the NCC Jurassic granites (424–513 ppm), upper mantle and continental arc magmas (92–477 ppm). More importantly, the higher water contents in the voluminous Early Cretaceous granites also have higher zircon saturation temperatures, εHf(t), and lower δ18O values. These observations suggest a predominantly mantle origin for the water, and water‐fluxed crustal melting, in which larger water ingression produced more voluminous melts. The high‐water flux was likely related to the subduction of the Paleo‐Pacific Plate, which ultimately destabilized the NCC.
Plain Language Summary
The fact that water is essential in generating granites has been known for a long time. However, its detailed role is poorly understood due to heterogeneous source and complex melting reactions involved in the generation of granites. As a fundamental issue of granite genesis, it remains a long‐standing problem to distinguish the two major mechanisms, that is, hydrous‐mineral‐dehydration melting versus external‐water‐added melting. In this study, the water content of zircon combined with other lines of clues of I‐type granites that generated during the destruction of North China Craton (NCC) in Late Mesozoic collectively points to water‐added crustal melting rather than dehydration melting. The isotope composition of zircon suggests a mantle provenance of water. The highest water contents occurred in the Early Cretaceous granites, corresponding to the climax of the NCC destruction. Higher zircon water contents in Early Cretaceous granites indicate higher water‐flux into thelithospheric mantle and overlying crust by the subduction of the paleo‐Pacific plate. Accordingly, water played a significant role in cratonic destruction.
Key Points
Water contents of zircons from North China Craton Jurassic granites are comparable with continental arc magmas
Higher zircon water contents are found in voluminous Early Cretaceous granites generated during the climax of cratonic destruction
Early Cretaceous granites were generated by water‐fluxed crustal melting, the water in which has a predominant mantle origin
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
While chemical variability in volcanic arc lavas erupted perpendicular to the strike of subduction has been observed and studied for many years, how these variations may reflect slab dehydration or ...melting processes is still actively debated. Here we report new data for cross-arc geochemical variations in Quaternary volcanic rocks from the Kurile arc. Correlations among multiple isotopic tracers (B–Sr–Nd–Hf) and key elemental ratios (B/Nb, Ba/Nb, Th/Nb and Hf/Nd) show that these arc lavas reflect the influence of three discernible subduction components. Shallow slab-sourced low-temperature hydrous fluids (high B/Nb, Ba/Nb, and δ11B) and deeper high-temperature hydrous melts (moderate B/Nb, Ba/Nb and δ11B, and low Hf/Nd) show characteristics similar to those seen in Izu-Bonin-Mariana arc lavas and likely reflect similar slab-derived origins. In addition to these components, Kurile volcanic front samples document a component with high Th/Nb and depleted mantle-like Hf/Nd. This component may reflect Kurile forearc mantle that had been metasomatized by shallow slab-derived melts associated with the subduction of the Izanagi-Pacific ridge in the Eocene. We propose a new model to interpret the across-arc geochemical variations in the Kurile arc lavas. Kurile forearc mantle, with high Th/Nb due to Eocene ridge subduction, was added to the subduction channel via subduction erosion by the downgoing Pacific plate. This subduction interface reservoir was subsequently metasomatized by deep-sourced hydrous fluids and melts from the slab beneath the volcanic front. The gradual prograde metamorphic modification of these multiply-metasomatized, subducted materials provides the flux that triggered Kurile volcanic front magmatism.
•Kurile arc lavas contain three subduction components.•Forearc mantle was metasomatized by shallow slab melt during Eocene ridge subduction.•Forearc mantle is eroded by recent subduction and fluxed by hydrous fluid/melt.•Decomposition of subducted forearc mantle triggered the volcanic front volcanism.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Water content and oxygen isotopes in zircon provide crucial constraints on magma source and process, yet they can be significantly modified by zircon metamictization, which causes secondary water ...absorption into the zircon crystal and the concomitant oxygen isotope changes. Therefore, it is imperative to develop a screening scheme to select the least-metamict zircons for the analyses. We propose a screening scheme based on our study on the Suzhou A-type granite (South China) through integrating Raman spectroscopy, water and trace element measurements, and oxygen isotope analysis. The results show that the primary water content is retained in zircon when the full-width at half maximum (FWHM) is <8 cm-1 or the Raman shift is >1007 cm-1 of ν3(SiO4) vibration band, while the primary δ18O is preserved at <10 cm-1 FWHM or >1005.5 cm-1 Raman shift. Changes in trace element concentrations in Suzhou zircons are different from previous observations in metamict zircons but most likely related to magma evolution, which implies that trace elements are insensitive to metamictization. Primary δ18O in Suzhou zircons (4.5-6.0 ppm) fall into the mantle range, indicating a dominant mantle contribution to Suzhou granites. Primary water content was estimated at ca. 650-1400 ppm, significantly higher than those of typical I-type granite (400-736 ppm) and upper mantle-derived zircons (81-177 ppm). The high primary zircon water content was not controlled by the sub-solidus process, temperature, pressure, and cation charge balance but considered to reflect the high-water content in melts. This suggests a hydrous origin for the Suzhou A-type granite, which challenges the conventional view of anhydrous petrogenesis for A-type granites.
Pepper （Capsicum annuum. L.） is a widely cultivated vegetable crop worldwide and has the second largest planting area and the first largest vegetable output and value in China. Pepper root-knot ...nematode （Meloidogyne spp.） is one of the most serious pests of pepper, which caused huge losses every year. Previous studies showed that the Me3 gene is resistant to a wide range of Meloidogyne species, including M. arenaria, M. javanica, and M. incognita. HDA149, a double haploid pepper genotype, harboring the root-knot nematode resistance gene Me3, was used to construct bacterial artificial chro- mosome library （BAC） via the vector of CopyControFM pCC1 in this study. The library consists of 210 200 BAC clones and is equivalent to 5.3 pepper genomes. The average insert size is 95 kb, and most of them are 90-120 kb; but the empty clones are less than 3%. In order to screen the BAC library easily, 550 super pools with 384 BAC clones of each pool were further developed in this study. Specific primers from Me3 gene locus were used for BAC library screening, and more than 20 positive BAC clones were obtained. Then the selected positive BAC clones were analyzed by restriction enzyme digestion, BAC-end sequencing, marker development, and new positive BAC clones exploration, respectively. Finally, the contig with total length of about 300 kb linked to the Me3 locus was constructed based on chromosome walking strategy, which made a solid foundation for the cloning of the important root-knot nematode resistance gene Me3.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Primary water and oxygen isotope composition are important tools in tracing magma source and evolution. Metamictization of zircon due to U-Th radioactive decay may introduce external secondary water ...to the crystal, thereby masking the primary water and oxygen isotope signature. Recently, Raman-based screening has been established to select the low-degree metamict zircons. However, such an approach may not be appropriate for ancient samples, in which nearly all zircons are metamict. It was reported that thermal annealing can potentially heal crystals and retrieve primary water content and δ18O information from metamict zircons, given the weaker hydrogen bond of secondary water than that of primary water. Heating experiments at temperatures of 200-1000 °C over a period of 2-10 h reveal that annealing can effectively recover primary water and oxygen isotopes from metamict zircons. Primary water in crystalline and metamict zircons remains intact when heated at <700 °C, while secondary water can be effectively expelled from metamict zircons when heated at 600 °C for >4 h, which represent the optimal annealing treatment condition. Hydrothermally altered zircon is an exception. It only yields the minimum estimate of its primary water contents at 600 °C over a period of >4 h, probably due to partial primary water loss during metamictization for hydrothermal zircons. Moreover, the proportion of low-δ18O (<4.7 per mille) zircon grains that may be influenced by secondary water dropped from ∼21% < 600°C to DF9% when annealed < 700°C. This study therefore provides the basis for applying zircon water δ18O proxies to geologically ancient samples.
The expression of mitogen-activated protein kinase （mapk） double-stranded RNA in cucumber is effective in controlling infestations of the root-knot nematode Meloidogyne incognita. However, little is ...known about the ecological effects of transgenic plants. Here, we analyzed the diversity of 16S rDNA genes derived from the rhizosphere archaea of transgenic cucumber plants as an indicator of ecological change. A total of 17 and 18 operational taxonomic units were detected in the rhizospheres of non-transgenic cucumber and mapk dsRNA-expressing plants, respectively. No significant difference was observed between the two groups according to Shannon and Simpson indices. In soil samples of the two rhizospheres, the dominant group was Crenarchaeota at the phylum level, with Staphylothermus, Methanococcus, Pyrodictium and Sulfolobus the abundant taxa at the genus level. These results suggest that expressing mapk double-stranded （ds） RNA in cucumber has no apparent effect on the diversity of rhizosphere archaea, and provide powerful evidence for the ecological safety of transgenic cucumber expressing mapk dsRNA.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China （20134320120013）;the Natural Science Foundation of Hunan Province, China （14JJ3095）
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
To solve the problem organization’s insider threats which was brought by internal staff through identity spoofing. A method of dynamic real-time authentication was presented. By faking exceptions of ...mouse to build dynamic authentication, when continuously consecutive authentication were abnormal, user was forced into fixed scene certification which was building of memory game. An identity verification experiment, in which 15 participants were involved, showed that the performance of proposed method was encouraging with FAR of 1.8% and FRR of 3.0% and authentication time of 8.12 s for authentication. The experiment shows that the method is not only real-time but also has a better user experience and accuracy.
Arsenic (As) contamination in a paddy environment can cause phytotoxicity and elevated As accumulation in rice (Oryza sativa). The mechanism of As detoxification in rice is still poorly understood.
...We isolated an arsenate (As(V))-sensitive mutant of rice. Genomic resequencing and complementation identified OsCLT1, encoding a CRT-like transporter, as the causal gene for the mutant phenotype.
OsCLT1 is localized to the envelope membrane of plastids. The glutathione and γ-glutamylcysteine contents in roots of Osclt1 and RNA interference lines were decreased markedly compared with the wild-type (WT). The concentrations of phytochelatin PC2 in Osclt1 roots were only 32% and 12% of that in WT after As(V) and As(III) treatments, respectively. OsCLT1 mutation resulted in lower As accumulation in roots but higher As accumulation in shoots when exposed to As(V). Under As(III) treatment, Osclt1 accumulated a lower As concentration in roots but similar As concentration in shoots to WT. Further analysis showed that the reduction of As(V) to As(III) was decreased in Osclt1. Osclt1 was also hypersensitive to cadmium (Cd).
These results indicate that OsCLT1 plays an important role in glutathione homeostasis, probably by mediating the export of γ-glutamylcysteine and glutathione from plastids to the cytoplasm, which in turn affects As and Cd detoxification in rice.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Summary
Nitrogen (N) is one of the key essential macronutrients that affects rice growth and yield. Inorganic N fertilizers are excessively used to boost yield and generate serious collateral ...environmental pollution. Therefore, improving crop N use efficiency (NUE) is highly desirable and has been a major endeavour in crop improvement. However, only a few regulators have been identified that can be used to improve NUE in rice to date. Here we show that the rice NIN‐like protein 4 (OsNLP4) significantly improves the rice NUE and yield. Field trials consistently showed that loss‐of‐OsNLP4 dramatically reduced yield and NUE compared with wild type under different N regimes. In contrast, the OsNLP4 overexpression lines remarkably increased yield by 30% and NUE by 47% under moderate N level compared with wild type. Transcriptomic analyses revealed that OsNLP4 orchestrates the expression of a majority of known N uptake, assimilation and signalling genes by directly binding to the nitrate‐responsive cis‐element in their promoters to regulate their expression. Moreover, overexpression of OsNLP4 can recover the phenotype of Arabidopsis nlp7 mutant and enhance its biomass. Our results demonstrate that OsNLP4 plays a pivotal role in rice NUE and sheds light on crop NUE improvement.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
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