A pot experiment was conducted to evaluate the effects of phosphorus fertilizer in inhibiting the copper toxicity to maize(Zea mays L.) in neutral purple soil. Results indicated that the growth of the shoot and roots ...A pot experiment was conducted to evaluate the effects of phosphorus fertilizer in inhibiting the copper toxicity to maize(Zea mays L.) in neutral purple soil. Results indicated that the growth of the shoot and roots of maize plant was obviously reduced by copper and the height and biomass were significantly negatively correlated to the application levels of copper (r=-0.899**^-0.994**) at no P and low P (100 mg kg-1).However, the maize biomass was relatively increased and the high Cu (100 and 200 mg kg-1) induced toxicity of maize was greatly alleviated in all treatments with medium P (300 mg kg-1) and high P (500 mg kg-1).To maintain the normal growth of maize plant (≥3.68 g pot-1), the critical application rates of phosphorus fertilizer should be 160, 210, 300 and 500 mg P kg-1 at 10, 50, 100 and 200 mg Cu kg-1 levels of the soil,respectively. The increases in polyphenol oxidase and catalase activities in maize leaf and dehydrogenase activity in roots by phosphorus fertilizer were in the order of medium p>high p>low p>no P. Activities of polyphenol oxidase and catalase were significantly positively correlated to the application levels of copper (r=0.892**~0.924**), whereas that of dehydrogenase was just reverse (r=-0.966**) at no P. Medium and high P repressed the influence of copper on activities of three enzymes. Phosphorus fertilizer reduced the copper concentrations of maize roots and leaf and the change ranges of the P/Cu ratio of maize roots and the P/Cu, N/Cu and K/Cu ratios of maize leaf. The three ratios of maize leaf were 256±71.5, 2643±839 and 1133±440 at normal growth of maize plant, respectively. Soil available Cu could be markedly cut down by application of phosphorus fertilizer, especiallly at high phosphorus level.展开更多
An all-solid-state Pr:KY3F10(Pr:KYF) laser pumped by blue laser(471 nm) has been demonstrated.With the incident pump power of 2.6 W,the maximum output power at 610 nm is 213 mW.Moreover,the intracavity second-harmonic...An all-solid-state Pr:KY3F10(Pr:KYF) laser pumped by blue laser(471 nm) has been demonstrated.With the incident pump power of 2.6 W,the maximum output power at 610 nm is 213 mW.Moreover,the intracavity second-harmonic generation(SHG) is also achieved with the maximum ultraviolet(UV) power at 305 nm of 11 mW by using a β-BaB2O4(BBO) nonlinear crystal.展开更多
An efficient method for attosecond extreme ultraviolet source generation under the two-color multi-cycle weak pulse has been theoretically presented by using the concept of the plasmonic field enhancement in the vicin...An efficient method for attosecond extreme ultraviolet source generation under the two-color multi-cycle weak pulse has been theoretically presented by using the concept of the plasmonic field enhancement in the vicinity of metallic nanostructures. The results show that by properly choosing the inhomogeneity of the two-color multi-cycle(20 fs) weak pulse(1013W/cm2), not only the harmonic cutoff has been extended, resulting in a broadband XUV continuum, but also the single short quantum path has been selected to contribute to the harmonic. As a result, two isolated XUV pulses with durations of 68 as and 66 as can be obtained.展开更多
文摘A pot experiment was conducted to evaluate the effects of phosphorus fertilizer in inhibiting the copper toxicity to maize(Zea mays L.) in neutral purple soil. Results indicated that the growth of the shoot and roots of maize plant was obviously reduced by copper and the height and biomass were significantly negatively correlated to the application levels of copper (r=-0.899**^-0.994**) at no P and low P (100 mg kg-1).However, the maize biomass was relatively increased and the high Cu (100 and 200 mg kg-1) induced toxicity of maize was greatly alleviated in all treatments with medium P (300 mg kg-1) and high P (500 mg kg-1).To maintain the normal growth of maize plant (≥3.68 g pot-1), the critical application rates of phosphorus fertilizer should be 160, 210, 300 and 500 mg P kg-1 at 10, 50, 100 and 200 mg Cu kg-1 levels of the soil,respectively. The increases in polyphenol oxidase and catalase activities in maize leaf and dehydrogenase activity in roots by phosphorus fertilizer were in the order of medium p>high p>low p>no P. Activities of polyphenol oxidase and catalase were significantly positively correlated to the application levels of copper (r=0.892**~0.924**), whereas that of dehydrogenase was just reverse (r=-0.966**) at no P. Medium and high P repressed the influence of copper on activities of three enzymes. Phosphorus fertilizer reduced the copper concentrations of maize roots and leaf and the change ranges of the P/Cu ratio of maize roots and the P/Cu, N/Cu and K/Cu ratios of maize leaf. The three ratios of maize leaf were 256±71.5, 2643±839 and 1133±440 at normal growth of maize plant, respectively. Soil available Cu could be markedly cut down by application of phosphorus fertilizer, especiallly at high phosphorus level.
基金supported by the National Natural Science Foundation of China (No.61108029)
文摘An all-solid-state Pr:KY3F10(Pr:KYF) laser pumped by blue laser(471 nm) has been demonstrated.With the incident pump power of 2.6 W,the maximum output power at 610 nm is 213 mW.Moreover,the intracavity second-harmonic generation(SHG) is also achieved with the maximum ultraviolet(UV) power at 305 nm of 11 mW by using a β-BaB2O4(BBO) nonlinear crystal.
基金Supported by the Scientific Research Fund of Liaoning University of Technology of China under Grant No.X201319the Scientific Research Fund of Liaoning Provincial Education Department under Grant No.L2014242
文摘An efficient method for attosecond extreme ultraviolet source generation under the two-color multi-cycle weak pulse has been theoretically presented by using the concept of the plasmonic field enhancement in the vicinity of metallic nanostructures. The results show that by properly choosing the inhomogeneity of the two-color multi-cycle(20 fs) weak pulse(1013W/cm2), not only the harmonic cutoff has been extended, resulting in a broadband XUV continuum, but also the single short quantum path has been selected to contribute to the harmonic. As a result, two isolated XUV pulses with durations of 68 as and 66 as can be obtained.
