采用问卷调研和文献检索相结合的方法,分析我国6 个马铃薯主产区氮肥施用量、基肥量、追肥次数、马铃薯产量等因素,对马铃薯氮肥利用率现状进行了分析评价,探讨提高马铃薯氮肥偏生产力的有效途径。结果表明:不同产区马铃薯氮肥偏生产力...采用问卷调研和文献检索相结合的方法,分析我国6 个马铃薯主产区氮肥施用量、基肥量、追肥次数、马铃薯产量等因素,对马铃薯氮肥利用率现状进行了分析评价,探讨提高马铃薯氮肥偏生产力的有效途径。结果表明:不同产区马铃薯氮肥偏生产力差异较大,东北区为184 kg · kg^-1、西南区110 kg · kg^-1、中原区104 kg · kg^-1、华南区99 kg · kg^-1、西北区95 kg ·kg^-1、华北区84 kg · kg^-1;氮肥施用过量是氮肥偏生产力低的主要原因;通过采取“大配方、小调整”区域配肥技术、土壤测试与植株营养诊断相结合的氮肥推荐方案、新型肥料和有机肥配施的施肥方式进行马铃薯产量潜力的充分挖掘是实现减氮增效的有效技术途径。展开更多
A preliminary screening for garlic viruses in garlic plants in Hunan,China,using existing monoplex（simplex） reverse transcription-polymerase chain reaction（RT-PCR） procedures detected four viruses/virus groups.The...A preliminary screening for garlic viruses in garlic plants in Hunan,China,using existing monoplex（simplex） reverse transcription-polymerase chain reaction（RT-PCR） procedures detected four viruses/virus groups.These viruses/virus groups were Onion yellow dwarf virus（OYDV）,Leek yellow stripe virus（LYSV）,Shallot latent virus（SLV） and allexiviruses（e.g.,garlic viruses A,B,C,D,E,X）.Sequence analysis of the projected allexivirus amplicons revealed the allexivirus in the infected garlic plants was Garlic virus D（GarV-D）,which shared 92-97%sequence identities with various isolates from the world.A multiplex RT-PCR（mRT-PCR） was therefore developed to simultaneously detect and differentiate the four viruses/virus groups.To achieve this,four primer pairs targeting allexiviruses,OYDV,LYSV and SLV were designed.The anticipated amplicon sizes are 183 bp（allexiviruses）,265 bp（OYDV）,404 bp（LYSV） and 592 bp（SLV）,respectively.All primer pairs produced virus-specific fragments in both simplex and multiplex formats,thus confirming the efficacy of the newly developed mRT-PCR for detection of these viruses.The mRT-PCR further was evaluated by applying it to garlic plant samples collected in two geographic locations in Hunan.Allexiviruses,OYDV,LYSV and SLV were detected in 50.9,40.3,28.3 and 58.5%of leaf samples,respectively;and mixed infections with two or more viruses accounted for 54%of the garlic samples.The results obtained by mRT-PCR were confirmed by simplex RT-PCR assays.In conclusion,this newly developed mRT-PCR provides a rapid,sensitive and reliable method for the detection and identification of major garlic viruses.展开更多
To investigate whether ethylene is involved in tomato plants in response to the invasion of viroid, tomato cv. Pearson and its ethylene-insensitive mutant Never ripe （Nr） was challenged with Tomato chlorotic dwarf v...To investigate whether ethylene is involved in tomato plants in response to the invasion of viroid, tomato cv. Pearson and its ethylene-insensitive mutant Never ripe （Nr） was challenged with Tomato chlorotic dwarf viroid （TCDVd）. Both Pearson and Nr plants developed various symptoms including dwarf, bunch, reduced leaf size, leaf chlorosis, and necrosis at 3-wk-post-inoculation and thereafter even though the stunting in Nr was not as severe as in Pearson plants. The sizes of fruits were also significantly reduced in the viroid-infected plants. Treatments of Pearson with ethephon, an ethylene-releasing compound, mimicked TCDVd in induction of stunting and pathogenesis-related （PR） genes in the plants. Pretreatment of Pearson plants prior to TCDVd-inoculation or ethephon application with silver thiosulfate （STS）, an ethylene action inhibitor, partially suppressed the viroid- or ethephon-induced symptoms as well as PR gene expression. In addition, Nr and STS-treated Pearson exhibited a slightly lower viroid titre in comparison to the control Pearson plants. These results suggest that ethylene is involved but plays a limited role in TCDVd-induced symptom development.展开更多
文摘采用问卷调研和文献检索相结合的方法,分析我国6 个马铃薯主产区氮肥施用量、基肥量、追肥次数、马铃薯产量等因素,对马铃薯氮肥利用率现状进行了分析评价,探讨提高马铃薯氮肥偏生产力的有效途径。结果表明:不同产区马铃薯氮肥偏生产力差异较大,东北区为184 kg · kg^-1、西南区110 kg · kg^-1、中原区104 kg · kg^-1、华南区99 kg · kg^-1、西北区95 kg ·kg^-1、华北区84 kg · kg^-1;氮肥施用过量是氮肥偏生产力低的主要原因;通过采取“大配方、小调整”区域配肥技术、土壤测试与植株营养诊断相结合的氮肥推荐方案、新型肥料和有机肥配施的施肥方式进行马铃薯产量潜力的充分挖掘是实现减氮增效的有效技术途径。
基金supported by the Non-Profit Industry Financial Program of Ministry of Agriculture of China(20130328)to Prof.Liu Yong and Prof.Dai Liangyingthe Natural Science Foundation of Hunan Province,China to Prof.Hu Xinxi(11JJ2018)
文摘A preliminary screening for garlic viruses in garlic plants in Hunan,China,using existing monoplex（simplex） reverse transcription-polymerase chain reaction（RT-PCR） procedures detected four viruses/virus groups.These viruses/virus groups were Onion yellow dwarf virus（OYDV）,Leek yellow stripe virus（LYSV）,Shallot latent virus（SLV） and allexiviruses（e.g.,garlic viruses A,B,C,D,E,X）.Sequence analysis of the projected allexivirus amplicons revealed the allexivirus in the infected garlic plants was Garlic virus D（GarV-D）,which shared 92-97%sequence identities with various isolates from the world.A multiplex RT-PCR（mRT-PCR） was therefore developed to simultaneously detect and differentiate the four viruses/virus groups.To achieve this,four primer pairs targeting allexiviruses,OYDV,LYSV and SLV were designed.The anticipated amplicon sizes are 183 bp（allexiviruses）,265 bp（OYDV）,404 bp（LYSV） and 592 bp（SLV）,respectively.All primer pairs produced virus-specific fragments in both simplex and multiplex formats,thus confirming the efficacy of the newly developed mRT-PCR for detection of these viruses.The mRT-PCR further was evaluated by applying it to garlic plant samples collected in two geographic locations in Hunan.Allexiviruses,OYDV,LYSV and SLV were detected in 50.9,40.3,28.3 and 58.5%of leaf samples,respectively;and mixed infections with two or more viruses accounted for 54%of the garlic samples.The results obtained by mRT-PCR were confirmed by simplex RT-PCR assays.In conclusion,this newly developed mRT-PCR provides a rapid,sensitive and reliable method for the detection and identification of major garlic viruses.
基金Teresa Molen (MSc) fortechnical support, Dr. Nie Bihua for data analysis, andthe greenhouse staff of the Potato Research Centre of Agriculture and Agri-Food Canada for maintenance ofthe plant materialsThe research was supported by Agriculture and Agri-Food of Canada under the Peer-Reviewed Project #50 to Dr. Nie Xianzhou
文摘To investigate whether ethylene is involved in tomato plants in response to the invasion of viroid, tomato cv. Pearson and its ethylene-insensitive mutant Never ripe （Nr） was challenged with Tomato chlorotic dwarf viroid （TCDVd）. Both Pearson and Nr plants developed various symptoms including dwarf, bunch, reduced leaf size, leaf chlorosis, and necrosis at 3-wk-post-inoculation and thereafter even though the stunting in Nr was not as severe as in Pearson plants. The sizes of fruits were also significantly reduced in the viroid-infected plants. Treatments of Pearson with ethephon, an ethylene-releasing compound, mimicked TCDVd in induction of stunting and pathogenesis-related （PR） genes in the plants. Pretreatment of Pearson plants prior to TCDVd-inoculation or ethephon application with silver thiosulfate （STS）, an ethylene action inhibitor, partially suppressed the viroid- or ethephon-induced symptoms as well as PR gene expression. In addition, Nr and STS-treated Pearson exhibited a slightly lower viroid titre in comparison to the control Pearson plants. These results suggest that ethylene is involved but plays a limited role in TCDVd-induced symptom development.
