Methods for the localization of plant calmodulin by immuno-gold and immuno-peroxidase electron microscopy have been developed. In both corn root-cap cells and meristematic cells, calmodulin was found to be localized i...Methods for the localization of plant calmodulin by immuno-gold and immuno-peroxidase electron microscopy have been developed. In both corn root-cap cells and meristematic cells, calmodulin was found to be localized in the nucleus, cytoplasm, mitochondria as well as in the cell wall, In the meristematic cells, calmodulin was distinctly localized on the plasma membrane, cytoplasmic face of rough endoplasmic rcticulum and polyribosomes. Characteristically, calmodulin was present in the amyloplasts of root-cap cells. The widespread distribution of calmodulin may reflect its plciotropic functions in plant cellular activities.展开更多
The effect of lanthanum ion on membrane permeability of corn root segment is studied.Results shows that treatment of the root segments with LaCl_3·7H_2O can decrease the ion leakage of the root tissue.The leakage...The effect of lanthanum ion on membrane permeability of corn root segment is studied.Results shows that treatment of the root segments with LaCl_3·7H_2O can decrease the ion leakage of the root tissue.The leakage decreases hy increasing the concentration of lanthanum,and the concentration has no further dependence on ion leakages above 25 μmol/L.After treating the root tissue for one hour with lanthanum ion,the amount of leak- age has linear dependence on time within the first 2 h and after two hours the leakage increases.The ion leakage of the tissue dependes on the time of lanthanum treatment.When the duration of treatment is prolonged,the leakage decreases rapidly and the leakage reaches a minimum at 30 minutes.Other rare earth elements can also decrease ion leakage.There is no significant difference in the ion leakage among these elements.展开更多
Seeking high performance adsorbents for highly efficient treatment of wastewater containing organic dyes has become increasingly imperative worldwide.Herein,with a specific surface area(SSA)of 2,745.4 m^(2)·g^(−1...Seeking high performance adsorbents for highly efficient treatment of wastewater containing organic dyes has become increasingly imperative worldwide.Herein,with a specific surface area(SSA)of 2,745.4 m^(2)·g^(−1),trace N-doped porous biochar nanospheres(NPBs)are derived for the first time from affluent waste corn roots,via a hydrothermal conversion followed by a mild calcined activation by K2CO3(KC)in the presence of low virulent melamine.Melamine acts as N source and synergistic activator for significant promotion in SSA,pore volume,and surface defects.The obtained NPBs(CHC-0.5N-4KC-900)are confirmed as superior adsorbents for removal of organic dyes rhodamine B(RhB,qm=1,630.7 mg·g^(−1))and Congo red(CR,qm=1,766.2 mg·g^(−1))as well as their mixtures,within not only a low(<50 mg·L^(−1))but also a high(>50,esp.250–1500 mg·L^(−1))concentration range.The values for qm are far beyond commercially activated carbon(AC)as well as most reported biomass derived carbons,undoubtedly revealing the NPBs as great promising candidate adsorbents for disposal of real industrial wastewater.In addition,the adsorption of RhB is fitted by Langmuir,Freundlich,Temkin,and Dubinin–Radushkevich isotherm models.The kinetic analysis indicates that the adsorption before equilibrium conforms to the pseudo-second-order model,and the hydrogen bonding,electrostatic attraction,and esp.π–πinteraction have contributed to the superior adsorption performance of the NPBs.展开更多
A study was conducted at Akron, CO, USA, on a Weld silt loam in 2004 to quantify the effects of water deficit stress on corn (Zea mays, L.) root and shoot biomass. Corn plants were grown under a range of soil bulk den...A study was conducted at Akron, CO, USA, on a Weld silt loam in 2004 to quantify the effects of water deficit stress on corn (Zea mays, L.) root and shoot biomass. Corn plants were grown under a range of soil bulk density and water conditions caused by previous tillage, crop rotation, and irrigation management. Water deficit stress (Dstress) was quantified by the number of days when the water content in the surface 0.3 m deviated from the water content range determined by the Least Limiting Water Range (LLWR). Root and shoot samples were collected at the V6, V12, and R1 growth stages. There was no significant correlation between Dstress and shoot or root biomass at the V6 growth stage. At the V12 and R1 growth stages, there were negative, linear correlations among Dstress and both root biomass and shoot biomass. The proportional decrease of shoot biomass was greater than the proportional decrease in root biomass, leading to an increase in the root:shoot ratio as water deficit stress increased at all growth stages. Determining restrictive soil conditions using the LLWR may be useful for evaluating improvement or degradation of the soil physical environment caused by soil management.展开更多
Plant growth-promoting rhizobacteria (PGPR) colonize plant roots and promote plant growth by producing and secreting various chemical regulators in the rhizosphere. With the recent interest in sustainable agriculture,...Plant growth-promoting rhizobacteria (PGPR) colonize plant roots and promote plant growth by producing and secreting various chemical regulators in the rhizosphere. With the recent interest in sustainable agriculture, an increasing number of researchers are investigating ways to improve the efficiency of PGPR use to reduce chemical fertilizer inputs needed for crop production. Accordingly, greenhouse studies were conducted to evaluate the impact of PGPR inoculants on biomass production and nitrogen (N) content of corn (Zea mays L.) under different N levels. Treatments included three PGPR inoculants (two mixtures of PGPR strains and one control without PGPR) and five N application levels (0%, 25%, 50%, 75%, and 100% of the recommended N rate of 135 kg N ha−1). Results showed that inoculation of PGPR significantly increased plant height, stem diameter, leaf area, and root morphology of corn compared to no PGPR application under the same N levels at the V6 growth stage, but few differences were observed at the V4 stage. PGPR with 50% of the full N rate produced corn biomass and N concentrations equivalent to or greater than that of the full N rate without inoculants at the VT stage. In conclusion, mixtures of PGPR can potentially reduce inorganic N fertilization without affecting corn plant growth parameters. Future research is needed under field conditions to determine if these PGPR inoculants can be integrated as a bio-fertilizer in crop production nutrient management strategies.展开更多
为研究秸秆饲料收获机工作时玉米根土复合体受力变化情况,利用离散元法建立了整根玉米根系颗粒粘结模型。根据玉米根系物理特性,选取Hertz-Mindlin with Bonding颗粒接触模型;为准确获取离散元仿真参数,采用根系剪切试验与离散元仿真相...为研究秸秆饲料收获机工作时玉米根土复合体受力变化情况,利用离散元法建立了整根玉米根系颗粒粘结模型。根据玉米根系物理特性,选取Hertz-Mindlin with Bonding颗粒接触模型;为准确获取离散元仿真参数,采用根系剪切试验与离散元仿真相结合的方法,对离散元参数进行标定。以根系峰值剪切力为响应值,采用Design Expert软件依次设计Plackett-Burman试验、最陡爬坡试验与Box-Behnken试验,得到最优仿真参数,即颗粒间剪切模量为6.6MPa、粘结刚度为1.139×10^(6)N/m^(3)、极限应力为1.1885MPa。结果表明:仿真值与实际值相对误差为2.12%,仿真标定结果真实可信。最终,根据根系实际尺寸,采用颗粒快速填充方法建立整根玉米根系模型,旨在为后续秸秆饲料收获机械离散元仿真提供参考依据。展开更多
文摘Methods for the localization of plant calmodulin by immuno-gold and immuno-peroxidase electron microscopy have been developed. In both corn root-cap cells and meristematic cells, calmodulin was found to be localized in the nucleus, cytoplasm, mitochondria as well as in the cell wall, In the meristematic cells, calmodulin was distinctly localized on the plasma membrane, cytoplasmic face of rough endoplasmic rcticulum and polyribosomes. Characteristically, calmodulin was present in the amyloplasts of root-cap cells. The widespread distribution of calmodulin may reflect its plciotropic functions in plant cellular activities.
文摘The effect of lanthanum ion on membrane permeability of corn root segment is studied.Results shows that treatment of the root segments with LaCl_3·7H_2O can decrease the ion leakage of the root tissue.The leakage decreases hy increasing the concentration of lanthanum,and the concentration has no further dependence on ion leakages above 25 μmol/L.After treating the root tissue for one hour with lanthanum ion,the amount of leak- age has linear dependence on time within the first 2 h and after two hours the leakage increases.The ion leakage of the tissue dependes on the time of lanthanum treatment.When the duration of treatment is prolonged,the leakage decreases rapidly and the leakage reaches a minimum at 30 minutes.Other rare earth elements can also decrease ion leakage.There is no significant difference in the ion leakage among these elements.
基金supported by the State Key Laboratory of Chemical Engineering,China(No.SKL-ChE-21A02)State Key Laboratory of Organic-Inorganic Composites,China(No.oic-202101009)+2 种基金the Natural Science Foundation of Shandong Province,China(No.ZR2022MB075)the National Natural Science Foundation of China(No.22075304)Beijing Natural Science Foundation,China(No.3222050).
文摘Seeking high performance adsorbents for highly efficient treatment of wastewater containing organic dyes has become increasingly imperative worldwide.Herein,with a specific surface area(SSA)of 2,745.4 m^(2)·g^(−1),trace N-doped porous biochar nanospheres(NPBs)are derived for the first time from affluent waste corn roots,via a hydrothermal conversion followed by a mild calcined activation by K2CO3(KC)in the presence of low virulent melamine.Melamine acts as N source and synergistic activator for significant promotion in SSA,pore volume,and surface defects.The obtained NPBs(CHC-0.5N-4KC-900)are confirmed as superior adsorbents for removal of organic dyes rhodamine B(RhB,qm=1,630.7 mg·g^(−1))and Congo red(CR,qm=1,766.2 mg·g^(−1))as well as their mixtures,within not only a low(<50 mg·L^(−1))but also a high(>50,esp.250–1500 mg·L^(−1))concentration range.The values for qm are far beyond commercially activated carbon(AC)as well as most reported biomass derived carbons,undoubtedly revealing the NPBs as great promising candidate adsorbents for disposal of real industrial wastewater.In addition,the adsorption of RhB is fitted by Langmuir,Freundlich,Temkin,and Dubinin–Radushkevich isotherm models.The kinetic analysis indicates that the adsorption before equilibrium conforms to the pseudo-second-order model,and the hydrogen bonding,electrostatic attraction,and esp.π–πinteraction have contributed to the superior adsorption performance of the NPBs.
文摘A study was conducted at Akron, CO, USA, on a Weld silt loam in 2004 to quantify the effects of water deficit stress on corn (Zea mays, L.) root and shoot biomass. Corn plants were grown under a range of soil bulk density and water conditions caused by previous tillage, crop rotation, and irrigation management. Water deficit stress (Dstress) was quantified by the number of days when the water content in the surface 0.3 m deviated from the water content range determined by the Least Limiting Water Range (LLWR). Root and shoot samples were collected at the V6, V12, and R1 growth stages. There was no significant correlation between Dstress and shoot or root biomass at the V6 growth stage. At the V12 and R1 growth stages, there were negative, linear correlations among Dstress and both root biomass and shoot biomass. The proportional decrease of shoot biomass was greater than the proportional decrease in root biomass, leading to an increase in the root:shoot ratio as water deficit stress increased at all growth stages. Determining restrictive soil conditions using the LLWR may be useful for evaluating improvement or degradation of the soil physical environment caused by soil management.
文摘Plant growth-promoting rhizobacteria (PGPR) colonize plant roots and promote plant growth by producing and secreting various chemical regulators in the rhizosphere. With the recent interest in sustainable agriculture, an increasing number of researchers are investigating ways to improve the efficiency of PGPR use to reduce chemical fertilizer inputs needed for crop production. Accordingly, greenhouse studies were conducted to evaluate the impact of PGPR inoculants on biomass production and nitrogen (N) content of corn (Zea mays L.) under different N levels. Treatments included three PGPR inoculants (two mixtures of PGPR strains and one control without PGPR) and five N application levels (0%, 25%, 50%, 75%, and 100% of the recommended N rate of 135 kg N ha−1). Results showed that inoculation of PGPR significantly increased plant height, stem diameter, leaf area, and root morphology of corn compared to no PGPR application under the same N levels at the V6 growth stage, but few differences were observed at the V4 stage. PGPR with 50% of the full N rate produced corn biomass and N concentrations equivalent to or greater than that of the full N rate without inoculants at the VT stage. In conclusion, mixtures of PGPR can potentially reduce inorganic N fertilization without affecting corn plant growth parameters. Future research is needed under field conditions to determine if these PGPR inoculants can be integrated as a bio-fertilizer in crop production nutrient management strategies.
文摘为研究秸秆饲料收获机工作时玉米根土复合体受力变化情况,利用离散元法建立了整根玉米根系颗粒粘结模型。根据玉米根系物理特性,选取Hertz-Mindlin with Bonding颗粒接触模型;为准确获取离散元仿真参数,采用根系剪切试验与离散元仿真相结合的方法,对离散元参数进行标定。以根系峰值剪切力为响应值,采用Design Expert软件依次设计Plackett-Burman试验、最陡爬坡试验与Box-Behnken试验,得到最优仿真参数,即颗粒间剪切模量为6.6MPa、粘结刚度为1.139×10^(6)N/m^(3)、极限应力为1.1885MPa。结果表明:仿真值与实际值相对误差为2.12%,仿真标定结果真实可信。最终,根据根系实际尺寸,采用颗粒快速填充方法建立整根玉米根系模型,旨在为后续秸秆饲料收获机械离散元仿真提供参考依据。
