The permittivity of low grade Panzhuhua ilmenite ore at 2.45 GHz in the temperatures from 20 ℃ up to 100 ℃ was measured using the technology of open-ended coaxial sensor combined with theoretical computation. The re...The permittivity of low grade Panzhuhua ilmenite ore at 2.45 GHz in the temperatures from 20 ℃ up to 100 ℃ was measured using the technology of open-ended coaxial sensor combined with theoretical computation. The results show that both the real （ε′） and imaginary （ε′） part of complex permittivity （ε′-jε′） of the ilmenite significantly increase with temperature. The loss tangent （tanδ） is a quadratic function of temperature, and the penetration depth of ilmenite decreases with temperature increase from 20 ℃to 100 ℃ The increase of the sample temperature under microwave radiation displays a nonlinear relationship between the temperature （T） and microwave heating time （t）. The positive feedback interaction between complex permittivity and sample temperature amplifies the interaction between ilmenite and the microwave radiation. The optimum dimensions for uniform heat deposition vary from 10 cm to 5 cm （about two power penetration depths） in a sample being irradiated from both sides in a 2.45 GHz microwave field when temperature increases from room temperature to 100 ℃展开更多
Transgenic cotton was modified to express a gene derived from the bacterium Bacillus thuringiensis （Bt） to combat agriculturally important Lepidopteran pests. Elevated CO2 is expected to further alter the chemical c...Transgenic cotton was modified to express a gene derived from the bacterium Bacillus thuringiensis （Bt） to combat agriculturally important Lepidopteran pests. Elevated CO2 is expected to further alter the chemical composition of the plant, and this change may affect the role soil fauna plays in decomposition of Bt plants. A 3 months litterbag field study, consisting of four treatments using leaves from Bt cotton and near-isolines of non-Bt cotton grown under ambient and elevated CO2 levels, was conducted to investigate the abundance and community structure of soil Collembola that developed on the decaying leaf material. A total of 4,884 collembolans, including 13 genera of five families, were extracted in the present study. These results suggest that collembolan distribution was relatively uniform among the Bt cotton, elevated concentration of CO2 and control treatments, except for a significant difference in the densities of Onychiurus and Folsomides. No significant effects were detected in the decomposition rate between the two cotton varieties and two CO2 treatments. These findings indicated that transgenic Bt cotton plants and elevated CO2 do not have any adverse effect on the soil collembolans through the decomposition way in soil ecosystem.展开更多
Examining the pollination biology of plant species is not only crucial for enhancing our understanding of their reproductive biology,but also essential for elucidating their adaptation and evolutionary history.Here,we...Examining the pollination biology of plant species is not only crucial for enhancing our understanding of their reproductive biology,but also essential for elucidating their adaptation and evolutionary history.Here,we investigated the breeding system and pollination biology of two closely related species in Actaea.The flower of A.purpurea is unique in the genus with purple and chartaceous(paper-like)sepals,fewer stamens with yellow anthers and purple filaments.Through three seasons of field observation and exclusion experiments,we determined that A.purpurea was primarily pollinated by a hornet species,Vespa bicolor,which also served as the most efficient pollinator.In contrast,A.japonica was primarily pollinated by large flies.Actaea purpurea exhibited a significantly higher cumulative nectar volume than A.japonica,which could be a crucial factor in attracting V.bicolor.A control experiment further demonstrated that removing the nectar leaf(petal)significantly decreased the visiting frequency of V.bicolor.Breeding system studies revealed that both species were self-compatible,yet they primarily underwent outcrossing in natural habitats.Our study presents a compelling case of possible pollinator shift in A.purpurea accompanied by morphological divergence.A more in-depth investigation of this system would offer crucial insights into the extent to which pollinators are involved in the plant speciation process and whether they contribute to reproductive isolation between closely related species.展开更多
Annual wormwood(Artemisia annua L.) is the only viable source of artemisinin,an antimalarial drug.There is a pressing need to optimize production per cultivated area of this important medicinal plant;however,the effec...Annual wormwood(Artemisia annua L.) is the only viable source of artemisinin,an antimalarial drug.There is a pressing need to optimize production per cultivated area of this important medicinal plant;however,the effect of increasing atmospheric carbon dioxide(CO_2) concentration on its growth is still unclear.Therefore,a pot experiment was conducted in a free-air CO2 enrichment(FACE) facility in Yangzhou City,China.Two A.annua varieties,one wild and one cultivated,were grown under ambient(374μmol mol^(-1)) and elevated(577 μmol mol^(-1)) CO_2 levels to determine the dry matter accumulation and macronutrient uptake of aerial parts.The results showed that stem and leaf yields of both A.annua varieties increased significantly under elevated CO_2 due to the enhanced photosynthesis rate.Although nitrogen(N),phosphorus(P),and potassium(K) concentrations in leaves and stems of both varieties decreased under elevated CO_2,total shoot N,P,and K uptake of the two varieties were enhanced and the ratios among the concentrations of these nutrients(N:P,N:K,and P:K) were not affected by elevated CO_2.Overall,our results provided the evidence that elevated CO_2 increased biomass and shoot macronutrient uptake of two A.annua varieties.展开更多
基金Projects(51090385,5114703)supported by the National Natural Science Foundation of ChinaProject(2012DFA70570)supported by the International S&T Cooperation Program of ChinaProject(2011FZ038)supported by the Applied Basic Research Project of Yunnan Province
文摘The permittivity of low grade Panzhuhua ilmenite ore at 2.45 GHz in the temperatures from 20 ℃ up to 100 ℃ was measured using the technology of open-ended coaxial sensor combined with theoretical computation. The results show that both the real （ε′） and imaginary （ε′） part of complex permittivity （ε′-jε′） of the ilmenite significantly increase with temperature. The loss tangent （tanδ） is a quadratic function of temperature, and the penetration depth of ilmenite decreases with temperature increase from 20 ℃to 100 ℃ The increase of the sample temperature under microwave radiation displays a nonlinear relationship between the temperature （T） and microwave heating time （t）. The positive feedback interaction between complex permittivity and sample temperature amplifies the interaction between ilmenite and the microwave radiation. The optimum dimensions for uniform heat deposition vary from 10 cm to 5 cm （about two power penetration depths） in a sample being irradiated from both sides in a 2.45 GHz microwave field when temperature increases from room temperature to 100 ℃
文摘Transgenic cotton was modified to express a gene derived from the bacterium Bacillus thuringiensis （Bt） to combat agriculturally important Lepidopteran pests. Elevated CO2 is expected to further alter the chemical composition of the plant, and this change may affect the role soil fauna plays in decomposition of Bt plants. A 3 months litterbag field study, consisting of four treatments using leaves from Bt cotton and near-isolines of non-Bt cotton grown under ambient and elevated CO2 levels, was conducted to investigate the abundance and community structure of soil Collembola that developed on the decaying leaf material. A total of 4,884 collembolans, including 13 genera of five families, were extracted in the present study. These results suggest that collembolan distribution was relatively uniform among the Bt cotton, elevated concentration of CO2 and control treatments, except for a significant difference in the densities of Onychiurus and Folsomides. No significant effects were detected in the decomposition rate between the two cotton varieties and two CO2 treatments. These findings indicated that transgenic Bt cotton plants and elevated CO2 do not have any adverse effect on the soil collembolans through the decomposition way in soil ecosystem.
基金supported by the National Natural Science Foundation of China(31870194)the Innovation Capability Support Program of Shaanxi(Program No.2023KJXX-019)the Fundamental Research Funds for the Central Universities(GK202301008 to J.Q.Zhang).
文摘Examining the pollination biology of plant species is not only crucial for enhancing our understanding of their reproductive biology,but also essential for elucidating their adaptation and evolutionary history.Here,we investigated the breeding system and pollination biology of two closely related species in Actaea.The flower of A.purpurea is unique in the genus with purple and chartaceous(paper-like)sepals,fewer stamens with yellow anthers and purple filaments.Through three seasons of field observation and exclusion experiments,we determined that A.purpurea was primarily pollinated by a hornet species,Vespa bicolor,which also served as the most efficient pollinator.In contrast,A.japonica was primarily pollinated by large flies.Actaea purpurea exhibited a significantly higher cumulative nectar volume than A.japonica,which could be a crucial factor in attracting V.bicolor.A control experiment further demonstrated that removing the nectar leaf(petal)significantly decreased the visiting frequency of V.bicolor.Breeding system studies revealed that both species were self-compatible,yet they primarily underwent outcrossing in natural habitats.Our study presents a compelling case of possible pollinator shift in A.purpurea accompanied by morphological divergence.A more in-depth investigation of this system would offer crucial insights into the extent to which pollinators are involved in the plant speciation process and whether they contribute to reproductive isolation between closely related species.
基金This research was supported by the National Na- tural Science Foundation of China （No. 41301209）, the National Basic Research Program （973 Program） of China （No. 2014CB954500）, the Natural Science Foun- dation of Jiangsu Province, China （Nos. BK20131051 and BK20140063）, Project of Frontier Fields during the Thirteenth Five-Year Plan Period of the Institute of Soil Science, Chinese Academy of Sciences, and the Agricultural Science and Technology Independent In-novation Fund in Jiangsu Province, China （No. cx13- 5062）. The FACE system instruments were supplied by the National Institute of Agro-Environmental Sci- ences and the Agricultural Research Center of Tohoku Region, Japan.
文摘Annual wormwood(Artemisia annua L.) is the only viable source of artemisinin,an antimalarial drug.There is a pressing need to optimize production per cultivated area of this important medicinal plant;however,the effect of increasing atmospheric carbon dioxide(CO_2) concentration on its growth is still unclear.Therefore,a pot experiment was conducted in a free-air CO2 enrichment(FACE) facility in Yangzhou City,China.Two A.annua varieties,one wild and one cultivated,were grown under ambient(374μmol mol^(-1)) and elevated(577 μmol mol^(-1)) CO_2 levels to determine the dry matter accumulation and macronutrient uptake of aerial parts.The results showed that stem and leaf yields of both A.annua varieties increased significantly under elevated CO_2 due to the enhanced photosynthesis rate.Although nitrogen(N),phosphorus(P),and potassium(K) concentrations in leaves and stems of both varieties decreased under elevated CO_2,total shoot N,P,and K uptake of the two varieties were enhanced and the ratios among the concentrations of these nutrients(N:P,N:K,and P:K) were not affected by elevated CO_2.Overall,our results provided the evidence that elevated CO_2 increased biomass and shoot macronutrient uptake of two A.annua varieties.
