Postemergence application of nicosulfuron for weed control in maize fields can cause great damage to certain maize inbred lines and hybrids. Two maize genotypes, tolerant inbred(HBR) and sensitive inbred(HBS), were fo...Postemergence application of nicosulfuron for weed control in maize fields can cause great damage to certain maize inbred lines and hybrids. Two maize genotypes, tolerant inbred(HBR) and sensitive inbred(HBS), were found to significantly differ in their phenotypic responses to nicosulfuron, with the EC50(50% effective concentration) values differed statistically(763.6 and 5.9 g a.i. ha–1, respectively). Pre-treatment with malathion, a known cytochrome P450 inhibitor, increased nicosulfuron injury in both HBR and HBS. Our results support the hypothesis that nicosulfuron selectivity in maize is associated with cytochrome P450 metabolism. Further analysis of the maize genome resulted in the identification of 314 full length cytochrome P450 monooxygenase(CYP) genes. These genes were classified into 2 types, 10 clans and 44 families. The CYP71 clan was represented by all A-type genes(168) belonging to 17 families. Nine clans possessed 27 families containing 146 non-A-type genes. The consensus sequences of the heme-binding regions of A-type and non-A-type CYP proteins are ‘PFGXGRRXCPG’ and ‘FXXGPRXCXG’, respectively. Illumina transcriptome sequence results showed that there were 53 differentially expressed CYP genes on the basis of high variation in expression between HBS and HBR, nicosulfuron-treated and untreated samples. These genes may contribute to nicosulfuron tolerance in maize. A hierarchical clustering analysis obtained four main clusters named C1 to C4 in which 4, 15, 21, and 13 CYP genes were found in each respective cluster. The expression patterns of some CYP genes were confirmed by RT-q PCR analysis. The research will improve our understanding of the function of maize cytochrome P450 in herbicide metabolism.展开更多
A general cascade package is used to handle the J/φ and φ' production and absorption for different Et bins in S-U and Pb-Pb collisions.We study the combined effect of nuclear absorption and final state interacti...A general cascade package is used to handle the J/φ and φ' production and absorption for different Et bins in S-U and Pb-Pb collisions.We study the combined effect of nuclear absorption and final state interaction with co-movers on the J/φ and φ' suppression.The experimental data of J/φ production can be fitted for different Er-bins in S-U collisions and for lower Eτ-bins in Pb-Pb collisions.However,φ' data for high Eτ-bins in both S-U and Pb-Pb collisions can not be explained.展开更多
以表面张力、扩展直径、干燥时间和最大持液量为评价指标,测定植株油类喷雾助剂GY-Tmax、矿物油类助剂GY-T12及有机硅类助剂GY-S903喷雾助剂不同添加量对40 g/L烟嘧磺隆可分散油悬浮剂药液物理性状的影响。结果表明,3种助剂均能显著降...以表面张力、扩展直径、干燥时间和最大持液量为评价指标,测定植株油类喷雾助剂GY-Tmax、矿物油类助剂GY-T12及有机硅类助剂GY-S903喷雾助剂不同添加量对40 g/L烟嘧磺隆可分散油悬浮剂药液物理性状的影响。结果表明,3种助剂均能显著降低其药液的表面张力,增加其扩展直径,GY-S903对其影响最大。3种助剂对药液的干燥时间和最大持液量的影响存在显著差异。添加0.25%～0.75%的GY-Tmax,在保证对玉米田杂草防治效果相当的情况下,烟嘧磺隆用量可减少50%;添加0.03%～0.07%的GY-S903及0.3%～0.6%的GY-T12可使烟嘧磺隆用量减少40%。在整个生育期内,未发现40 g/L烟嘧磺隆可分散油悬浮剂30 g ai/hm^2添加喷雾助剂各处理对玉米的明显受害症状,烟嘧磺隆添加GY-Tmax较30 g ai/hm^2烟嘧磺隆增产6.6%～7.6%,增产作用最强。GY-S903对烟嘧磺隆的增产作用与GY-T12相当,较30 g ai/hm^2烟嘧磺隆处理分别增产4.3%～7.0%及3.9%～7.4%。展开更多
基金funded by the National Natural Science Foundation of China (31501660)the Technology Research and Development Program of Hebei, China (17226507D)the Foundation of Institute of Cereal and Oil Crops of Hebei Academy of Agriculture and Forestry, China (LYS2015001)
文摘Postemergence application of nicosulfuron for weed control in maize fields can cause great damage to certain maize inbred lines and hybrids. Two maize genotypes, tolerant inbred(HBR) and sensitive inbred(HBS), were found to significantly differ in their phenotypic responses to nicosulfuron, with the EC50(50% effective concentration) values differed statistically(763.6 and 5.9 g a.i. ha–1, respectively). Pre-treatment with malathion, a known cytochrome P450 inhibitor, increased nicosulfuron injury in both HBR and HBS. Our results support the hypothesis that nicosulfuron selectivity in maize is associated with cytochrome P450 metabolism. Further analysis of the maize genome resulted in the identification of 314 full length cytochrome P450 monooxygenase(CYP) genes. These genes were classified into 2 types, 10 clans and 44 families. The CYP71 clan was represented by all A-type genes(168) belonging to 17 families. Nine clans possessed 27 families containing 146 non-A-type genes. The consensus sequences of the heme-binding regions of A-type and non-A-type CYP proteins are ‘PFGXGRRXCPG’ and ‘FXXGPRXCXG’, respectively. Illumina transcriptome sequence results showed that there were 53 differentially expressed CYP genes on the basis of high variation in expression between HBS and HBR, nicosulfuron-treated and untreated samples. These genes may contribute to nicosulfuron tolerance in maize. A hierarchical clustering analysis obtained four main clusters named C1 to C4 in which 4, 15, 21, and 13 CYP genes were found in each respective cluster. The expression patterns of some CYP genes were confirmed by RT-q PCR analysis. The research will improve our understanding of the function of maize cytochrome P450 in herbicide metabolism.
基金Supported in part by the National Natural Science Foundation of China under Grant No.19677102,and the Natural Science Foundation of Hebei Province.
文摘A general cascade package is used to handle the J/φ and φ' production and absorption for different Et bins in S-U and Pb-Pb collisions.We study the combined effect of nuclear absorption and final state interaction with co-movers on the J/φ and φ' suppression.The experimental data of J/φ production can be fitted for different Er-bins in S-U collisions and for lower Eτ-bins in Pb-Pb collisions.However,φ' data for high Eτ-bins in both S-U and Pb-Pb collisions can not be explained.
文摘以表面张力、扩展直径、干燥时间和最大持液量为评价指标,测定植株油类喷雾助剂GY-Tmax、矿物油类助剂GY-T12及有机硅类助剂GY-S903喷雾助剂不同添加量对40 g/L烟嘧磺隆可分散油悬浮剂药液物理性状的影响。结果表明,3种助剂均能显著降低其药液的表面张力,增加其扩展直径,GY-S903对其影响最大。3种助剂对药液的干燥时间和最大持液量的影响存在显著差异。添加0.25%～0.75%的GY-Tmax,在保证对玉米田杂草防治效果相当的情况下,烟嘧磺隆用量可减少50%;添加0.03%～0.07%的GY-S903及0.3%～0.6%的GY-T12可使烟嘧磺隆用量减少40%。在整个生育期内,未发现40 g/L烟嘧磺隆可分散油悬浮剂30 g ai/hm^2添加喷雾助剂各处理对玉米的明显受害症状,烟嘧磺隆添加GY-Tmax较30 g ai/hm^2烟嘧磺隆增产6.6%～7.6%,增产作用最强。GY-S903对烟嘧磺隆的增产作用与GY-T12相当,较30 g ai/hm^2烟嘧磺隆处理分别增产4.3%～7.0%及3.9%～7.4%。
