Among orchids, Cymbidiums have got a very high demand in both cut flower and pot plant trade. In the present study the effect of some polysaccharides such as chitosan and NAG （n-acetyl-glucosamine） on organogenesis ...Among orchids, Cymbidiums have got a very high demand in both cut flower and pot plant trade. In the present study the effect of some polysaccharides such as chitosan and NAG （n-acetyl-glucosamine） on organogenesis in protocorm-like-bodies （PLBs） of C. insigne was studied. Synthetic phytohormones such as BA and TDZ （cytokinins） and NAA （auxin） were used for comparison. PLBs of C. insigne were explanted on modified Murashige and Skoog medium supplemented with the single addition of chitosan and NAG, and the combination of BA （benzyladenine） and NAA （1-naphthaleneacetic acid） also with the combination of NAA and TDZ （thidiazuron） among different concentrations. Combination treatments of auxin and cytokinins, the highest percentage of PLBs formation was 73% and shoot formation was 67% when cultured on the medium supplemented with 1.0 mg L1 BA without NAA. Combination treatment of NAA and TDZ, the PLBs formation was 90% and shoot formation was 60% obtained from medium supplemented with 1.0 mg Lt of NAA ＋ 0.1 mg L^-1 TDZ. Single addition of chitosan and NAG with modified MS medium was more effective for new PLBs and shoot formation. The highest percentage of PLBs formation was 87% and shoot formation was 80% obtained from the medium supplemented with 0.1 mg L^-1 chitosan. On the other hand, the PLBs formation rate reached 93% and shoot formation rate was 87% obtained from the medium supplemented with 0.01 mg L^-1 NAG. Application of polysaccharides to in vitro orchid PLBs allows developing new PLBs and shoot to form plantlet without synthetic phytohormones.展开更多
The Ordos block is a stable tectonic unit since the Cenozoic. Whether low-resistivity layers exist in the middle and lower crust of this kind block is an open question. This work attempts to reveal the entire crustal ...The Ordos block is a stable tectonic unit since the Cenozoic. Whether low-resistivity layers exist in the middle and lower crust of this kind block is an open question. This work attempts to reveal the entire crustal structure of the block based on interpretation of magnetotelluric data collected along the profile across this region. The result shows that a layered structure characterizes the crust of the Ordos block, with a low-resistivity layer at depth of about 20km, presumably associated with fluids there. In contrast, in the areas of active tectonics on the east and west of the block, there are no such layered electric structures in the crust, and the low-resistivity zones may be related to the decollement zones (or ductile shear zones) in the crust. The difference in electric structure of crust between the Ordos Block and neighboring areas is of significance to analyze the movement and deformation of varied blocks in the continent.展开更多
Plate subduction is the most magnificent process in the Earth. Subduction zones are important sites for proceeding matter- and energy- transports between the Earth's surface and the interior, continental crust gro...Plate subduction is the most magnificent process in the Earth. Subduction zones are important sites for proceeding matter- and energy- transports between the Earth's surface and the interior, continental crust growth, and crust-mantle interactions. Besides, a number of geological processes in subduction zones are closely related to human beings' daily life, such as volcanic eruptions and earthquakes, formation of mineral deposits. Subduction process thus has long been the centric topic of Earth sciences. The finding in 1980 s that continental crust could be subducted to mantle depths is a revolutionary progress in plate tectonic theory. Compared to oceanic crust, continental crust is colder, drier, lighter, and much more geochemically/isotopically heterogeneous. Hence, continental subduction process would affect the structure, compositions and evolutions of the overlying mantle wedge even more. During continental subduction and subsequent exhumation, fluids and melts can be generated in the(de)hydration process and partial melting process, respectively. These melts/fluids play important roles in crust-mantle interactions, elemental migrations, isotopic fractionations, and mantle metasomatism. By summarizing recent research works on subduction zones in this paper, we present a review on the types, physicochemical conditions and compositions of fluids/melts, as well as the migration behaviors of fluid-related characteristic elements(Nb-Ta-V) and the fractionation behaviors of non-traditional stable isotopes(Li-Mg) in subduction zones. The aim of this paper is to provide the readers an update comprehensive overview of the melt/fluid activities in subduction zones and of Li-Mg isotope systematics in subduction-related rocks and minerals.展开更多
文摘Among orchids, Cymbidiums have got a very high demand in both cut flower and pot plant trade. In the present study the effect of some polysaccharides such as chitosan and NAG （n-acetyl-glucosamine） on organogenesis in protocorm-like-bodies （PLBs） of C. insigne was studied. Synthetic phytohormones such as BA and TDZ （cytokinins） and NAA （auxin） were used for comparison. PLBs of C. insigne were explanted on modified Murashige and Skoog medium supplemented with the single addition of chitosan and NAG, and the combination of BA （benzyladenine） and NAA （1-naphthaleneacetic acid） also with the combination of NAA and TDZ （thidiazuron） among different concentrations. Combination treatments of auxin and cytokinins, the highest percentage of PLBs formation was 73% and shoot formation was 67% when cultured on the medium supplemented with 1.0 mg L1 BA without NAA. Combination treatment of NAA and TDZ, the PLBs formation was 90% and shoot formation was 60% obtained from medium supplemented with 1.0 mg Lt of NAA ＋ 0.1 mg L^-1 TDZ. Single addition of chitosan and NAG with modified MS medium was more effective for new PLBs and shoot formation. The highest percentage of PLBs formation was 87% and shoot formation was 80% obtained from the medium supplemented with 0.1 mg L^-1 chitosan. On the other hand, the PLBs formation rate reached 93% and shoot formation rate was 87% obtained from the medium supplemented with 0.01 mg L^-1 NAG. Application of polysaccharides to in vitro orchid PLBs allows developing new PLBs and shoot to form plantlet without synthetic phytohormones.
基金sponsored by Earthquake Research Project for Public Affair(2008419010)the National Natural Science Foundation of China(40374032, 40534023)+4 种基金the Basic Scientific Research Special Program of the Institute of Geology,CEA(DFIGCEA0607117)the Basic Scientific Research Fund of the State Level Institutes for Commonweal (DF-IGCEA-0607-1-17)the National Basic Research Program(2004CB418402),Chinathe National Key Basic Research Program (95-13-02-02)the Key Program of the Natural Science Foundation of China (40534023)
文摘The Ordos block is a stable tectonic unit since the Cenozoic. Whether low-resistivity layers exist in the middle and lower crust of this kind block is an open question. This work attempts to reveal the entire crustal structure of the block based on interpretation of magnetotelluric data collected along the profile across this region. The result shows that a layered structure characterizes the crust of the Ordos block, with a low-resistivity layer at depth of about 20km, presumably associated with fluids there. In contrast, in the areas of active tectonics on the east and west of the block, there are no such layered electric structures in the crust, and the low-resistivity zones may be related to the decollement zones (or ductile shear zones) in the crust. The difference in electric structure of crust between the Ordos Block and neighboring areas is of significance to analyze the movement and deformation of varied blocks in the continent.
基金jointly supported by the National Basic Research Program of China(Grant No.2015CB856102)the National Natural Science Foundation of China(Grant Nos.41473033,41172067,41273037)
文摘Plate subduction is the most magnificent process in the Earth. Subduction zones are important sites for proceeding matter- and energy- transports between the Earth's surface and the interior, continental crust growth, and crust-mantle interactions. Besides, a number of geological processes in subduction zones are closely related to human beings' daily life, such as volcanic eruptions and earthquakes, formation of mineral deposits. Subduction process thus has long been the centric topic of Earth sciences. The finding in 1980 s that continental crust could be subducted to mantle depths is a revolutionary progress in plate tectonic theory. Compared to oceanic crust, continental crust is colder, drier, lighter, and much more geochemically/isotopically heterogeneous. Hence, continental subduction process would affect the structure, compositions and evolutions of the overlying mantle wedge even more. During continental subduction and subsequent exhumation, fluids and melts can be generated in the(de)hydration process and partial melting process, respectively. These melts/fluids play important roles in crust-mantle interactions, elemental migrations, isotopic fractionations, and mantle metasomatism. By summarizing recent research works on subduction zones in this paper, we present a review on the types, physicochemical conditions and compositions of fluids/melts, as well as the migration behaviors of fluid-related characteristic elements(Nb-Ta-V) and the fractionation behaviors of non-traditional stable isotopes(Li-Mg) in subduction zones. The aim of this paper is to provide the readers an update comprehensive overview of the melt/fluid activities in subduction zones and of Li-Mg isotope systematics in subduction-related rocks and minerals.
