Cowpea, Vigna unguiculata is a major staple for millions of households in the tropics. A cowpea land race, “Olaudi” collected from South-Eastern Nigeria was investigated for mitotic indices during cell division. Roo...Cowpea, Vigna unguiculata is a major staple for millions of households in the tropics. A cowpea land race, “Olaudi” collected from South-Eastern Nigeria was investigated for mitotic indices during cell division. Root tips were pre-treated with 8-hydroxyquinoline for three hours, fixed in Carnoy’s solution (alcohol-acetic acid solution 3:1 v/v) for 24 hours, hydrolysed in 1 NHCl and squashed in aceto-orcein. Various stages of mitosis were recorded to determine mitotic activity in dividing cells. Results obtained showed that active cell division occurred between 7.00 AM and 2.00 PM but peaks between 11.00 AM and 1.00 PM. Although cells at the prophase stage were in a continuum, they became observable between 8.00 AM and 3.00 PM, but greater proportion of cells was observed at 12.00 PM. Cells at metaphase were generally observed during a six hours period between 8.00 AM and 1.00 PM, but the peak period was 11.00 AM. Mitotic activity at anaphase commenced around 10.00 AM late morning but plateaus for two hours early afternoon between 12.00 PM and 2.00 PM. Telophase activity was mostly observed at 11.00 AM within a five hour period between 9.00 AM and 2.00 PM. Mitotic index peaked at 1.00 PM with 65.3% of cells in active cell division, with a concomitant high mean germination percentage (63.5%). This study provides useful basic information to guide further cytogenetics research in the genetic improvement of this local cowpea landrace.展开更多
The Cheng index distinguishes indica andjaponica rice based on six taxonomic traits.This index has been widely used for classifi- cation of indica and japonica varieties in China.In this study,a double haploid(DH)popu...The Cheng index distinguishes indica andjaponica rice based on six taxonomic traits.This index has been widely used for classifi- cation of indica and japonica varieties in China.In this study,a double haploid(DH)popula-tion derived from anther culture of ZYQ8/JX17 F,a typical inter-subspecies hybrid,was used to investigate the six taxonomictraits,i.e.leaf hairiness(LH),color of hullwhen heading(CHH),hairiness of hull(HH),length of the first and second panicle internode(LPI),length/width of grain(L/W),andphenol reaction(PH).The morphological in- dex(MI)was also calculated.Based on themolecular linkage map constructed from this展开更多
Background: A number of meningeal neoplastic lesions may radiologically and clinically simulate meningioma, include hemangiopericytomas, solitary fibrous tumors, schwannomas, hematolymphoid lesions, metastases, and ot...Background: A number of meningeal neoplastic lesions may radiologically and clinically simulate meningioma, include hemangiopericytomas, solitary fibrous tumors, schwannomas, hematolymphoid lesions, metastases, and others very rarely, also may clinically mimic meningiomas. Case Description: We present the case of A 28-year-old male patient, with no notable medical history, who presented with worsening headaches for 3 months, imbalance, and visual deficits, An initial MRI revealed extra-axial lesion involving the right Parieto-occipital, The tumor was hypointense on T1-weighted MR images, hyperintense signals on T2-weightedMR images, and heterogeneously enhanced suggestive of a meningioma, total resection was achieved, and the histopathological analysis confirmed the diagnosis of an angioblastic meningioma. However, 15 months later, the patient presented with the same initial visual complaints. A subsequent MRI showed lesion recurrence, leading to a second surgical intervention. The histopathological analysis confirmed the diagnosis of an anaplastic xanthoastrocytoma. Conclusion: This represents an unusual location for an anaplastic pleomorphic xanthoastrocytoma, which should broaden the differential diagnosis of extra-axial lesions.展开更多
Two rice varieties, Xiushui 110 with high cadmium (Cd) tolerance and Xiushui 11 with low Cd tolerance were used to study the effects of Cd stress on seed germination, seedling growth and amylase activities. The low ca...Two rice varieties, Xiushui 110 with high cadmium (Cd) tolerance and Xiushui 11 with low Cd tolerance were used to study the effects of Cd stress on seed germination, seedling growth and amylase activities. The low cadmium concentration had little effect on seed germination rate. However, cadmium stress could significantly inhibit plumule and radicle growth, especially for radicle growth. Germination index, vigour index, radicle length and amylase activities of Xiushui 11 decreased more significantly with the increasing cadmium level compared with Xiushui 110. The cadmium content in seedlings of Xiushui 11 was higher than that in Xiushui 110 when the cadmium concentration exceeded 5 μmol/L, which caused lower mitotic index in root tips and amylase activities, and more serious cadmium toxicity in Xiushui 11.展开更多
【目的】目前干旱研究多为基于历史干旱事件分析成因与变化趋势,而结合过去与未来长时间序列数据更能揭示干旱变化特点。寻找在基于CMIP5模型输出未来气象数据时模拟干旱指数方法并探究陕西省过去与未来干旱变化特点,为陕西省未来农业...【目的】目前干旱研究多为基于历史干旱事件分析成因与变化趋势,而结合过去与未来长时间序列数据更能揭示干旱变化特点。寻找在基于CMIP5模型输出未来气象数据时模拟干旱指数方法并探究陕西省过去与未来干旱变化特点,为陕西省未来农业水资源管理提供依据。【方法】根据陕西省18个气象站历史数据以及CMIP5模式输出未来气象数据,比较了3种模型模拟参考作物蒸发蒸腾量(ET0),并基于参考作物蒸发蒸腾量(ET0)和降水数据计算标准降水蒸发指数(SPEI)和相对湿润指数(MI)反映干旱程度,比较过去(1958-2018年)与未来(2019-2100年)干旱的时空变化特点。【结果】多元线性回归模型(Multiple Linear Regression, MLR)能较准确的模拟参考作物蒸发蒸腾量(ET0)(RMSE=0.457 mm·d^-1);在RCP2.6和RCP8.5情景下未来干旱指数呈现上升趋势,在RCP8.5情景下,21世纪40年代存在干旱指数的突变年份;陕西省未来干旱程度降低,年内干旱分布更加不均匀;未来时期夏玉米生长季干旱程度减小,冬小麦生长季干旱程度增加。【结论】在不同RCP情景下,未来干旱变化特征存在差异,相同RCP情景下,SPEI和MI反映的干旱特征变化基本一致,但部分时段存在变化差异。为有效应对气候变化对旱作作物产量造成的负面影响,应当增强土壤蓄水保墒能力,尤其加强冬小麦生长季的抗旱工作。展开更多
In this study on the mutagenic effects of different concentrations of chromium trioxide (CrO3) on Vicia faba root tip, micronucleus assay and chromosome aberration assay were used to determine the mitotic indexes, mic...In this study on the mutagenic effects of different concentrations of chromium trioxide (CrO3) on Vicia faba root tip, micronucleus assay and chromosome aberration assay were used to determine the mitotic indexes, micronucleus rate and chromosome aberration rate of Vicia faba root tip cells. The results showed that the effects of CrO3 concentration on the mitotic indexes were complicated. CrO3 increases the micronucleus rate of Vicia faba root tip cells. It was found that within certain range of CrO3 concentration the micronucleus rate increased systematically with increased concentration of CrO3, but that the micronucleus rate decreased at higher level of CrO3 and that CrO3 also caused various types of chromosome aberration at a rate which increased systematically with increased concentration of CrO3. We concluded that CrO3 has significant mutagenic effect on Vicia faba root tip cells.展开更多
[目的/意义]期刊评价有助于优选高质量期刊,为高水平的馆藏资源建设提供参考。已有的期刊评价指标主要考虑期刊引文的集中性而忽视了其均衡性特征,为丰富已有的期刊评价体系,文章提出一种新的评价指标--期刊平均影响力指标(MI)。[方法/...[目的/意义]期刊评价有助于优选高质量期刊,为高水平的馆藏资源建设提供参考。已有的期刊评价指标主要考虑期刊引文的集中性而忽视了其均衡性特征,为丰富已有的期刊评价体系,文章提出一种新的评价指标--期刊平均影响力指标(MI)。[方法/过程]在前人研究的基础上,利用改进的泰尔指数修正期刊平均被引频次,构建MI指数。并以Web of Science与Scopus两个数据库同时收录的图书情报领域48种期刊为例,计算其MI指数,并与JIF、CiteScore、SNIP、SJR和h指数进行对比。[结果/结论]结果表明,MI指数综合考虑了期刊的载文量、总被引频次和文献被引的均衡性,使得评价结果更加科学合理,从而为研究期刊影响力提供了一种新方法。展开更多
文摘Cowpea, Vigna unguiculata is a major staple for millions of households in the tropics. A cowpea land race, “Olaudi” collected from South-Eastern Nigeria was investigated for mitotic indices during cell division. Root tips were pre-treated with 8-hydroxyquinoline for three hours, fixed in Carnoy’s solution (alcohol-acetic acid solution 3:1 v/v) for 24 hours, hydrolysed in 1 NHCl and squashed in aceto-orcein. Various stages of mitosis were recorded to determine mitotic activity in dividing cells. Results obtained showed that active cell division occurred between 7.00 AM and 2.00 PM but peaks between 11.00 AM and 1.00 PM. Although cells at the prophase stage were in a continuum, they became observable between 8.00 AM and 3.00 PM, but greater proportion of cells was observed at 12.00 PM. Cells at metaphase were generally observed during a six hours period between 8.00 AM and 1.00 PM, but the peak period was 11.00 AM. Mitotic activity at anaphase commenced around 10.00 AM late morning but plateaus for two hours early afternoon between 12.00 PM and 2.00 PM. Telophase activity was mostly observed at 11.00 AM within a five hour period between 9.00 AM and 2.00 PM. Mitotic index peaked at 1.00 PM with 65.3% of cells in active cell division, with a concomitant high mean germination percentage (63.5%). This study provides useful basic information to guide further cytogenetics research in the genetic improvement of this local cowpea landrace.
文摘The Cheng index distinguishes indica andjaponica rice based on six taxonomic traits.This index has been widely used for classifi- cation of indica and japonica varieties in China.In this study,a double haploid(DH)popula-tion derived from anther culture of ZYQ8/JX17 F,a typical inter-subspecies hybrid,was used to investigate the six taxonomictraits,i.e.leaf hairiness(LH),color of hullwhen heading(CHH),hairiness of hull(HH),length of the first and second panicle internode(LPI),length/width of grain(L/W),andphenol reaction(PH).The morphological in- dex(MI)was also calculated.Based on themolecular linkage map constructed from this
文摘Background: A number of meningeal neoplastic lesions may radiologically and clinically simulate meningioma, include hemangiopericytomas, solitary fibrous tumors, schwannomas, hematolymphoid lesions, metastases, and others very rarely, also may clinically mimic meningiomas. Case Description: We present the case of A 28-year-old male patient, with no notable medical history, who presented with worsening headaches for 3 months, imbalance, and visual deficits, An initial MRI revealed extra-axial lesion involving the right Parieto-occipital, The tumor was hypointense on T1-weighted MR images, hyperintense signals on T2-weightedMR images, and heterogeneously enhanced suggestive of a meningioma, total resection was achieved, and the histopathological analysis confirmed the diagnosis of an angioblastic meningioma. However, 15 months later, the patient presented with the same initial visual complaints. A subsequent MRI showed lesion recurrence, leading to a second surgical intervention. The histopathological analysis confirmed the diagnosis of an anaplastic xanthoastrocytoma. Conclusion: This represents an unusual location for an anaplastic pleomorphic xanthoastrocytoma, which should broaden the differential diagnosis of extra-axial lesions.
基金supported by the Project of National Key Basic Research and Development, China (Grant No. 2002CB410804)the Natural Science Foundation of Guizhou Province, China (Grant No. 20072058)the Foundation for Young Scholars Scientists of Guizhou University (Grant No. X060036), China.
文摘Two rice varieties, Xiushui 110 with high cadmium (Cd) tolerance and Xiushui 11 with low Cd tolerance were used to study the effects of Cd stress on seed germination, seedling growth and amylase activities. The low cadmium concentration had little effect on seed germination rate. However, cadmium stress could significantly inhibit plumule and radicle growth, especially for radicle growth. Germination index, vigour index, radicle length and amylase activities of Xiushui 11 decreased more significantly with the increasing cadmium level compared with Xiushui 110. The cadmium content in seedlings of Xiushui 11 was higher than that in Xiushui 110 when the cadmium concentration exceeded 5 μmol/L, which caused lower mitotic index in root tips and amylase activities, and more serious cadmium toxicity in Xiushui 11.
文摘【目的】目前干旱研究多为基于历史干旱事件分析成因与变化趋势,而结合过去与未来长时间序列数据更能揭示干旱变化特点。寻找在基于CMIP5模型输出未来气象数据时模拟干旱指数方法并探究陕西省过去与未来干旱变化特点,为陕西省未来农业水资源管理提供依据。【方法】根据陕西省18个气象站历史数据以及CMIP5模式输出未来气象数据,比较了3种模型模拟参考作物蒸发蒸腾量(ET0),并基于参考作物蒸发蒸腾量(ET0)和降水数据计算标准降水蒸发指数(SPEI)和相对湿润指数(MI)反映干旱程度,比较过去(1958-2018年)与未来(2019-2100年)干旱的时空变化特点。【结果】多元线性回归模型(Multiple Linear Regression, MLR)能较准确的模拟参考作物蒸发蒸腾量(ET0)(RMSE=0.457 mm·d^-1);在RCP2.6和RCP8.5情景下未来干旱指数呈现上升趋势,在RCP8.5情景下,21世纪40年代存在干旱指数的突变年份;陕西省未来干旱程度降低,年内干旱分布更加不均匀;未来时期夏玉米生长季干旱程度减小,冬小麦生长季干旱程度增加。【结论】在不同RCP情景下,未来干旱变化特征存在差异,相同RCP情景下,SPEI和MI反映的干旱特征变化基本一致,但部分时段存在变化差异。为有效应对气候变化对旱作作物产量造成的负面影响,应当增强土壤蓄水保墒能力,尤其加强冬小麦生长季的抗旱工作。
文摘In this study on the mutagenic effects of different concentrations of chromium trioxide (CrO3) on Vicia faba root tip, micronucleus assay and chromosome aberration assay were used to determine the mitotic indexes, micronucleus rate and chromosome aberration rate of Vicia faba root tip cells. The results showed that the effects of CrO3 concentration on the mitotic indexes were complicated. CrO3 increases the micronucleus rate of Vicia faba root tip cells. It was found that within certain range of CrO3 concentration the micronucleus rate increased systematically with increased concentration of CrO3, but that the micronucleus rate decreased at higher level of CrO3 and that CrO3 also caused various types of chromosome aberration at a rate which increased systematically with increased concentration of CrO3. We concluded that CrO3 has significant mutagenic effect on Vicia faba root tip cells.
文摘[目的/意义]期刊评价有助于优选高质量期刊,为高水平的馆藏资源建设提供参考。已有的期刊评价指标主要考虑期刊引文的集中性而忽视了其均衡性特征,为丰富已有的期刊评价体系,文章提出一种新的评价指标--期刊平均影响力指标(MI)。[方法/过程]在前人研究的基础上,利用改进的泰尔指数修正期刊平均被引频次,构建MI指数。并以Web of Science与Scopus两个数据库同时收录的图书情报领域48种期刊为例,计算其MI指数,并与JIF、CiteScore、SNIP、SJR和h指数进行对比。[结果/结论]结果表明,MI指数综合考虑了期刊的载文量、总被引频次和文献被引的均衡性,使得评价结果更加科学合理,从而为研究期刊影响力提供了一种新方法。
