Response of wheat (Tritium aestivum) to low rates of glyphosate and glufosinate

Field studies were conducted in 2007 and 2008 at Hamilton Farms near Lonoke, Arkansas, USA to evaluate the potential impact of sub-lethal doses of glyphosate and glufosinate on winter wheat (Tritium aestivum). Three wheat cultivars were seeded, and glyphosate and glufosinate were applied at 1/10 and 1/20 times the labeled dose at the 3- to 4-leaf, panicle initiation, and boot stages. Both herbicides caused significant injury to wheat; however, wheat response to both herbicides was different. Glufosinate injury occurred rapidly and consisted of mainly leaf necrosis. Glyphosate injury to wheat was minimal and manifested in the form of leaf yellowing. Glyphosate caused shortened flag leaf when applied at PI and reduced canopy height when applied at boot. Injury was minimal to wheat across all treatments, with the highest level of injury being 34% following glufosinate applied at boot. Conversely, wheat was most sensitive to glyphosate at the 3- to 4-leaf stage. Flag leaf length was reduced the greatest by glyphosate at PI, whereas glufosinate reduced flag leaf length minimally. Even though glyphosate injury was lower than that of glufosinate, yield was reduced more by glyphosate. Wheat seed weight and germination were not affected by either herbicide. Wheat appears to be slightly more sensitive to glyphosate with respect to yield; however, it is slightly more sensitive to glufosinate with respect to foliar injury.     

菊花‘北甘菊’和‘神马’对除草剂草丁膦的敏感性研究

[目的]探究不同菊花品种对除草剂草丁膦的敏感性。[方法]以野生菊花‘北甘菊’和秋季切花菊‘神马’为材料,研究了菊花对除草剂草丁膦的敏感性表现。[结果]不同品种不同营养生长期的植株对草丁膦的敏感性不同,‘神马’植株平均叶片数为13叶片期时对草丁膦的敏感浓度为40 mg/L,‘甘菊’植株平均叶片数为8叶期时对草丁膦的敏感浓度为50 mg/L。[结论]为草丁膦抗性的转基因菊花的筛选提供了理论依据。     

转Bar基因紫花苜蓿杂交组合的筛选与评价

为探究抗除草剂转基因紫花苜蓿（Medicago sativa）的高效杂交种选育技术。本试验以‘公农1号’作为父母本配置了1个对照组合,以转Bar基因的抗草铵膦除草剂转基因紫花苜蓿作为父本,以雄性不育系MS-GN-1A作为母本,配置了11个杂交组合。对后代植株的抗性进行Bar试纸条、PCR检测,对产量和品质性状进行评价和筛选,结果表明,试验中有7个杂交组合的后代表现优异。此试验以紫花苜蓿雄性不育系作为母本配置杂交种,使抗除草剂转基因紫花苜蓿的目标性状高效且稳定遗传,同时在此试验基础上筛选出了优良杂交后代,为良种繁育提供了一定的理论基础。     

水稻密码子优化基因Mat#增强草铵膦抗性

来自细菌Nocardia sp.AB2253的蛋氨酸砜N-乙酰基转移酶基因(methionine sulfone Nacetyltransferase gene,Mat)编码产物具有N-乙酰基转移酶活性,能解除灭生性除草剂草铵膦的毒性,但在植物中表达效率较低.本研究用水稻(Oryza sativa)偏爱密码子优化的Mat#基因转化籼稻品系9K(Oryza sativa ssp.indica),经过PCR和Southern杂交验证,证明该基因已经整合至水稻基因组中.除草剂抗性检测结果显示,该转化体的芽期草铵膦耐受浓度至少为600 mg/L、秧苗期草铵膦耐受浓度至少为1 000 mg/L,对草铵膦的抗性水平不低于转双丙氨酰膦抗性基因(bialaphos resistance gene,Bar)水稻9KA2.酶活性测定结果显示,该转化体叶片中的N-乙酰基转移酶活性约为非转基因对照中的6.6倍.说明优化后的Mat#基因增强了草铵膦抗性,可作为转化筛选标记和抗除草剂目的基因应用于转基因作物育种.     

不同施氮水平下GS抑制剂对小麦灌浆期碳氮代谢的影响

为了解小麦叶片和籽粒内碳代谢和氮代谢之间的关联性,采用盆栽试验,研究了谷氨酰胺合成酶(GS)抑制剂(Glufosinate)对不同施氮水平下两个小麦基因型灌浆期氮、碳同化特性的影响及其相互关系.结果表明,叶片GS被抑制后,高蛋白类型品种豫麦47籽粒内氮含量显著升高、叶片内可溶性糖含量上升;而低蛋白类型豫麦50则表现出相反的趋势.穗GS被抑制后,高蛋白类型品种豫麦47叶片和籽粒内氮含量均显著下降、叶片和籽粒内的可溶性糖含量也显著下降;而低蛋白类型豫麦50则表现叶片和籽粒内氮含量均显著下降,但可溶性糖含量显著上升.说明高蛋白品种豫麦47籽粒和叶片内氮、碳同化相对独立,而低蛋白品种豫麦50籽粒和叶片内氮、碳同化过程关联紧密.这一结果还说明高蛋白品种籽粒花后氮同化可以直接利用从根部或茎秆而来的氮素,而低蛋白品种则必须经过叶片.因此,在小麦生产上,不同类型品种必须采取不同的氮肥运筹方案,对于低蛋白类型品种,氮肥可适当前移,而对于高蛋白类型品种,则宜采用前促后补的策略.     

抗除草剂转基因玉米快速有效鉴定方法的建立

以含草铵膦乙酰转移酶基因(phosphinothricin acetyl transferase gene,bar)为筛选标记的抗除草剂转基因玉米为研究材料,通过叶片喷雾法和叶片离体平板培养法试验,建立快速有效鉴定转基因玉米的方法,并探索可有效区分转化和非转化植株的筛选剂剂量。研究结果表明:这两种方法都能快速、有效、方便地鉴定抗除草剂转基因玉米;2000mg/L草铵膦叶片喷雾和培养基中含有5mg/L草铵膦叶片离体培养可快速有效区分是否转入bar基因。通过Bar试纸条分子检测法验证了该鉴定方法的准确性。该鉴定方法的建立为快速有效的筛选大量转基因材料节约大量时间和经费。本研究建立的鉴定方法在转基因材料鉴定和转基因安全评估中具有重要意义。     

大豆对草丁膦敏感性研究

分析了大豆品种东农50对不同浓度草丁膦(Glufosinate)的敏感性表现。结果表明:施用50 mg.L-1草丁膦后3 d东农50开始表现枯黄、萎蔫,随着浓度增大毒害作用增强,扩散整个叶片;子叶、茎、真叶不同位置的草丁膦处理显示新叶、子叶对草丁膦最敏感,茎的敏感性最低;全株喷施75 mg.L-1草丁膦时可直接观察到草丁膦对叶片的毒害作用,二次喷施效果显著,易于观察。     

花生胚小叶的离体再生及筛选压力选择

以花生胚小叶为外植体,优化离体再生条件,通过对再生苗进行筛选,为外源基因的遗传转化提供实验依据。研究表明,不同基因型胚小叶的再生能力差异显著,在供试基因型中中花8号不定芽诱导率和成苗率最高,且外植体状态最好。中花8号胚小叶再生的最佳诱导培养基为MSB + 6-BA（4.5mg/L）+NAA（1mg/L）+AgNO3（2mg/L）,最佳诱导培养时间为21d。对中花8号再生苗进行筛选浓度实验,草丁膦（PPT）为20mg/L时,可筛选出抗性苗;300mg/L的卡那霉素（Km）可用于较小幼苗筛选,而对较大幼苗则需将Km的浓度提高至400mg/L以上。     

大豆子叶节遗传转化体系优化及抗逆基因AtNHX5的转化研究

以河北省优良大豆品种冀豆15、五星2号和NF-58的子叶节为受体材料,利用农杆菌介导法进行遗传转化,探讨了影响农杆菌侵染后子叶节不定芽诱导的因素。结果表明:以萌发6 d、4℃处理24 h的子叶节为外植体,农杆菌侵染后经超声波处理30 s、共培养基中添加20 mg·L-1硝酸银,能够提高子叶节丛生芽诱导率,转化植株经草铵膦筛选以及PCR检测,T0代转化率达0.97%。利用该体系对大豆品种五星2号进行At NHX5基因的遗传转化,获得3株T0代RT-PCR检测阳性植株,且2-1号T1代阳性植株检测具有一定耐盐性,初步证明获得了转At NHX5基因的大豆新材料。     

Glutamine synthetase activity and ammonium accumulation is influenced by time of glufosinate application

Time of glufosinate application impacts weed control. Although leaf angle of velvetleaf significantly contributes to the time of day (TOD) effect, it is not the sole reason for reduced efficacy. Absorption and translocation of glufosinate, glutamine synthetase (GS) activity, and ammonium accumulation were investigated as possible physiological components of the TOD effect. Absorption and translocation were not associated with a decrease in glufosinate efficacy. GS activity, ammonium accumulation, and plant biomass were influenced by the time of glufosinate application. Velvetleaf GS activity quickly diminished during the light period and remained high during the dark period following glufosinate treatment. GS activity was higher in plants treated at 10:00 pm than in those treated at 2:00 pm 12 HAT. With little GS inhibition during the dark period, ammonium accumulation occurred only during the light period. At 72 HAT, ammonium concentration was nearly 1.5-fold greater in plants treated at 2:00 pm versus those treated at 10:00 pm with 160 g/ha glufosinate. Plant biomass of plants treated with 160 g/ha glufosinate at 10:00 pm was greater than those treated at 2:00 pm at 72 HAT. Increasing the application rate from 160 to 320 g/ha removed these differences in GS activity, ammonium accumulation, and plant biomass. These results demonstrate that GS activity and ammonium accumulation are physiological processes involved in the TOD effect.