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。     

草甘膦母液的沉淀处理研究

[目的]探究有效去除草甘膦母液中亚磷酸根的方法。[方法]采用化学沉淀法研究了沉淀剂种类、pH、投加量、静置时间等因素对草甘膦母液中亚磷酸根去除率的影响。[结果]加入AlCl3.6H2O,当pH为9、投加量0.24 mol/L、快搅30 s、强度300 r/min、慢搅2.5min、强度100 r/min、静置时间为30 min时对草甘膦母液中亚磷酸根的去除效果达到60%以上。[结论]为膜技术在草甘膦母液资源化处理中的工业化推广与应用提供了理论依据。     

Glyphosate management strategies,weed diversity and soybean yield in Argentina

From their introduction in 1996, glyphosate resistant (GR) soybean cultivars have been rapidly adopted by farmers in Argentina and in other countries in the world. The high rate of adoption of this technology seems to be based on the simplicity of use provided by a single herbicide (glyphosate), its high efficacy to control many weeds and, the low costs of the technology relative to that used in conventional crops. During 2001–2002, 2002–2003 and 2003–2004 soybean growing seasons, field surveys and field experiments were performed with the aim of studying the effect of different glyphosate management strategies on the diversity of soybean weed communities, weed control, individual survival, fecundity and crop yield. In addition, the emergence pattern of three important weeds, Digitaria sanguinalis, Cyperus rotundus and Anoda cristata, was also studied. Both field surveys and field experiments were carried out on no-till soybean crops sown immediately after wheat or barley harvest (double cropped system). Experiments were set up in commercial soybean crops and consisted of different times of a single glyphosate application, two glyphosate applications and also the application of glyphosate plus a residual herbicide imazethapyr. A. cristata, D. sanguinalis, Stellaria media, Chenopodium album and Cyperus sp. were the most prevalent weeds recorded at pre-harvest of the soybean crops, showing regional constancy higher than 80% in both years. In three out of four field experiments, crop yield was not increased when glyphosate was applied twice compared with a single application of the herbicide. In addition there was a lower negative effect on weed species richness when glyphosate was applied once during the crop cycle than with two applications of glyphosate or glyphosate plus imazethapyr. D. sanguinalis escaped the glyphosate early treatment because of the long weed emergence period, while A. cristata and C. rotundus survived treatments due to their high individual tolerance. The results suggest that it is possible to manage glyphosate application to get high crop yield with a low impact on weed diversity, depending on the weed species and their abundance.     

草甘膦与百草枯及其混剂对三叶草生理生化的影响

为研究草甘膦与百草枯复配剂防除三叶草中表现出的拮抗作用的机理,本试验用95%草甘膦、30.5%百草枯及其混剂为供试药剂对三叶草进行处理,采用分光光度法测定了药剂对三叶草的根系活力、叶片电导率、氧自由基产生速率、茎叶莽草酸含量等生理生化指标的影响。结果表明,草甘膦与百草枯混剂(4∶1,有效成分质量比)对三叶草的根系活力、叶片电导率、氧自由基产生速率、茎叶莽草酸含量的影响表现出明显的拮抗作用,其中对氧自由基产生速率的影响拮抗作用最强,其实际抑制率与理论抑制率的百分比M为-169.58。因此,在农业生产中切忌将草甘膦与百草枯混用防除田间杂草。     

草甘膦对土壤微生物的影响

以东北地区黑土为材料,探讨草甘膦对土壤呼吸、土壤可培养菌种群数量、大豆固氮根瘤菌和大豆根腐镰刀菌数量的影响。研究结果表明,随着草甘膦浓度的加大,土壤呼吸的抑制作用增强,土壤中草甘膦含量为1 mg&;#8226;kg-1、10 mg&;#8226;kg-1、100 mg&;#8226;kg-1时,危害系数分别为1.20、0.322、0.0760,远小于无危害标准系数20,确定草甘膦对土壤微生物低毒或无实际危害。不同浓度的草甘膦对土壤真菌、放线菌种群数量具有一定影响。土壤可培养菌种群数量随草甘膦浓度的升高抑制作用逐渐增强,随着草甘膦加入时间的延长,真菌、细菌、放线菌的种群数量有所恢复,其中放线菌与真菌同细菌相比对草甘膦敏感,土壤细菌对草甘膦具有较强的耐受或降解能力。草甘膦对大豆根瘤菌和大豆根腐镰刀菌有一定影响,对大豆根瘤菌的抑制作用与草甘膦浓度呈正比;低浓度草甘膦对镰刀菌产生激活作用,高浓度草甘膦对镰刀菌具有抑制作用;伴随草甘膦加入时间的延长,其对大豆根瘤菌和大豆根腐镰刀菌的抑制作用逐渐减弱。     

Maximizing oilseed rape's yield by glyphosate under Mediterranean conditions

Adverse hot and dry environmental conditions prevailing during the period of oilseed rape ripening can be blamed for considerable yield losses during the crop's mechanized harvesting in the Mediterranean area. In this paper, the effect of chemical dessication of oilseed rape with glyphosate applied 35 days after anthesis for reducing seed yield loss was studied. The experiment was conducted in four fields at two locations in central Greece and for two growth periods following a completely randomized plot design with 8 treatments in three replications. Treatments include all possible combinations of two crop varieties and four levels of glyphosate (as dessicant) application. A significant positive effect of dessicant application level on crop yield for both studied varieties was found. The application dose of 200 g a.i. of glyphosate per hectare had the best results. The highest dry weight was found among the plants sprayed with 200 g. a.i. of glyphosate per hectare. The highest seed yield and oil yield were found among the plants sprayed with 200 g a.i. per hectare, which makes clear the positive effect of this spraying minimizing pod shattering and yield losses. The greatest 1000-seed weight was found among the plants sprayed with 200 g a.i. ha⁻¹, due to the greater size of seeds that remained on the plants until harvesting.     

Translocation of apple proliferation phytoplasma via natural root grafts – a case study

Apple proliferation (AP), a phytoplasma-induced disease of apple trees, was proven to be transmitted through infected grafting material and sap-sucking insects. To date there are little firm data on disease propagation in the field via natural root grafts. This question was thus addressed in the present case study by investigating trees of a 24-year old commercial apple orchard (‘Red Chief’ on MM 111), where the existence of root connections was discovered accidentally. After having displayed specific AP symptoms, nine trees were cut down and the stubs were infiltrated or brushed with glyphosate. Herbicide injury, however, remained not only restricted to the treated stubs, but also spread to approximately 50 neighbouring trees. Surprisingly, none of the pollinators (‘Granny Smith’ on M 9) growing interjacently and alternating between herbicide-damaged main crop trees was affected. Respective to the position of the nine AP-infected and glyphosate-treated cut stumps, four sections in the orchard were defined, from which a total of 122 trees was sampled and analysed using qualitative real-time PCR for detection of AP phytoplasma. The pathogen was found in 71.4% of ‘Red Chief’ trees with severe herbicide damage and 18.8% of trees with partial herbicide damage. None of the 31 investigated pollinators was AP-infected. Our data indicate that root connections seem to play a role for the spread of AP phytoplasma at least in older orchards and between trees on vigorous rootstocks.     

Determination of differences in crop injury from aerial application of glyphosate using vegetation indices

Crop injury caused by off-target drift of herbicide can seriously reduce growth and yield and is of great concern to farmers and aerial applicators. Farmers can benefit from identifying an indirect method for assessing the level of crop injury. This study evaluates the combined use of statistical methods and vegetation indices (VIs) derived from multispectral images to assess the level of crop injury. An experiment was conducted in 2009 to determine glyphosate injury differences among the cotton, corn, and soybean crops. The crops were planted in eight rows spaced 102 cm apart and 80 m long with four replications. Seven VIs were calculated from multispectral images collected at 7 and 21 days after the glyphosate application (DAA). At each image collection date, visual injury estimates were assessed and data were collected for plant height, chlorophyll content, and shoot dry weight. From the seven VIs evaluated as surrogate for glyphosate injury identification using a canonical correlation analysis (CCA), the Chlorophyll Vegetation Index (CVI) showed the highest correlation with field-measured plant injury data. CVI image values were subtracted from the CVI average values of the non-injured area to generate CVI residual images (CVI_res). Frequency distribution histograms of CVI_res image values were calculated to assess the level of injury between crops. These data suggested that injury increased from 7DAA to 21DAA with corn exhibiting higher severity of injury than cotton or soybean, while only moderate injury was observed for cotton. The techniques evaluated in this study are promising for estimating the level of glyphosate herbicide drift, which can be used to make appropriate management decisions considering crop proximity.     

耐草甘膦菜豆耐性分子学机理研究

用耐性菜豆根尖为材料，以λgt10为载体获得了4.8×105个重组噬菌体的cDNA文库。以植物EPSP合成酶基因保守序列合成二段探针，经噬菌体原位杂交筛选出了阳性克隆，并进行了酶切鉴定。测定 cDNA 序列长度为2024个核苷酸，其中编码长1569个核苷酸，共编码523个氨基酸和一个终止密码子，与已发表的其它植物成熟EPSP合成酶氨基酸序列相比具有很高的同源性（≥84.8%），但进入叶绿体运输肽的氨基酸同源性低。以耐性菜豆EPSP合成酶的cDNA序列为模板，用RT-PCR方法扩增感性菜豆EPSP合成酶cDNA片段，并克隆于pUC18质粒上，经测定序列并比较发现:感性菜豆EPSP合成酶cDNA核苷酸序列1737位碱基为G，而耐性的为C，从而表达出的513位氨基酸残基感性的为E，耐性的为Q，表明两种菜豆EPSP合成酶cDNA核苷酸序列一位点的差异是它们对草甘膦耐性不同的原因。     

Glyphosate efficacy is contributed by its tissue concentration and sensitivity in velvetleaf (Abutilon theophrasti)

Glyphosate efficacy was examined in young velvetleaf plants from the standpoint of its tissue distribution and sensitivity. In whole plant assays, manual application of a sub-lethal dose to the first leaf resulted only in meristem injury while other tissues remained visually healthy. Our studies showed that this differential tissue response was caused by a combination of differential distribution as well as sensitivity to glyphosate. Using [¹⁴C]glyphosate, we measured tissue injury and glyphosate residue, and calculated tissue threshold for 50% growth inhibition. Our studies showed that roots and meristem have high glyphosate distribution (45 and 34% of translocated, respectively) and low inhibition thresholds (0.23 and 0.21 ppm, respectively) resulting in tissues that were easily killed by glyphosate. In contrast, the base stem contained a much higher inhibition threshold (8.4 ppm) with only intermediate distribution (10%) resulting in a tissue that was most difficult to kill. We observed a linear relationship between glyphosate dose and tissue concentration; furthermore, tissue distribution pattern was independent of dose or surfactants class. At a sub-lethal dose, sensitive tissues that received a large distribution of glyphosate were preferentially killed. As the dose was increased, more glyphosate was available for distribution, and all tissues received a proportionately greater amount of glyphosate. Plant death occurred when the applied dose was sufficient to attain the lethal threshold in all tissues.