转基因抗草甘膦玉米CL38-1的草甘膦耐受性及杂草化风险评价

以我国自主研制的转EPSPS基因抗除草剂玉米CL38-1为试验材料,通过抗除草剂喷施和生存竞争能力评价,研究其对目标除草剂草甘膦的耐受性以及在农田和荒地环境下杂草化的可能性。结果表明,在喷施41%草甘膦异丙胺盐水剂1 230 g/hm~2(推荐剂量)和2 460 g/hm~2(推荐剂量的2倍量)1、2、4周后,对玉米的株高及生长无不良影响,受害率为0。在农田环境下,转基因玉米CL38-1与非转基因对照郑58在生育期、株高、覆盖度、产量等方面无明显差异,在栽培地环境中可正常生长;在荒地条件下,较之杂草没有竞争优势,无杂草化风险。     

抗草甘膦转基因大豆（Glycine mac (L.) Merri）杂草性评价的试验实例

 【目的】评价美国孟山都公司生产的抗草甘膦转基因大豆40-3-2作为加工原料引入中国可能带来的演化为杂草的生态风险,验证转基因大豆杂草化环境安全评价条款的可操作性。【方法】在农田生态环境下比较了抗性大豆、受体品种和当地常规品种的生存竞争能力、繁育能力、自生苗、种子落粒性和延续能力。【结果】在适宜季节种植的转基因大豆的生存竞争能力和繁育能力明显低于当地常规品种,表现在复叶数少、植株较矮、结实率低;受体品种的生存竞争能力和常规品种相似,但繁育能力低于常规品种。在非适宜季节三者的生存竞争能力相似,而受体品种和抗性大豆的结实能力都比常规品种略强。3个品种的落粒性都不强,形成自生苗的可能性也都很小。所有供试大豆种子的延续能力都很弱。【结论】以上研究结果表明美国孟山都公司生产的抗草甘膦转基因大豆40-3-2在中国南京地区环境条件下演化为杂草的可能性较小,其作为加工原料进口后演化为杂草的生态风险小。试验证实了转基因大豆环境安全评价标准的杂草性条款具有可操作性。     

抗旱转基因小麦(Triticum aestivum L.) 的杂草性评价

【目的】全球转基因作物商业化迅猛发展,包括杂草化在内的一系列生态风险评估和研究尤为重要。文章中系统评价抗旱转基因小麦MGX-L大面积推广种植可能带来的演化为杂草的生态风险,为转基因抗旱小麦的环境安全评价标准制定提供科学依据。【方法】通过比较荒地和栽培地上抗旱转基因小麦、受体小麦和当地常规品种的农艺性状,评价转基因小麦的生存竞争能力;并比较荒地上生存的转基因小麦与受体的繁殖系数,评价转基因小麦群体在野外的生存能力。比较转基因小麦和受体品种的自生苗比率、种子落粒性、及深埋和浅埋地下种子萌发情况,评价转基因小麦的自然延续能力。比较转基因小麦和受体品种的花粉活力、花粉大小和花粉育性,评价转基因小麦的自然繁育能力。综合分析以上各项评价结果,评价抗旱转基因小麦演变为杂草的可能性。【结果】转基因小麦在栽培地上种植,其株高、总穗数和穗粒数与受体品种相比,没有显著差异,而转基因小麦的产量、千粒重显著高于受体品种。但和其他非转基因当地主栽小麦品种相比,或没有显著差异,或低于其他非转基因小麦品种,因此,转基因小麦与其非转基因小麦对照相似,在栽培地种植没有更强的生存竞争能力。在荒地环境下,转基因小麦生存竞争能力和受体品种没有显著差异。在荒地上种植且成熟的转基因小麦,单位面积内收获的总籽粒数少于上一年种下的种子粒数,其繁殖系数低于1。转基因小麦群体不可能在野外环境中自然维持下去。转基因小麦种子的落粒性和产生自生苗比率与受体品种相比没有显著差异。深埋20 cm以下土层的转基因小麦和受体品种的种子全部腐烂;浅埋3 cm土层的转基因小麦和受体品种的种子或者腐烂或者出苗,没有发现未萌发且保存完好能够保持活力继续发芽的种子,二者的种子腐烂或出苗的比率没有显著差异,说明转基因小麦和受体品种种子的延续能力低且无显著差异。【结论】转基因抗旱小麦MGX-L与其受体对照品种济麦22及其他非转基因当地主栽品种相似,耐旱性状的引入不会增加小麦的杂草化潜势。     

Selection pressure effects on the proportion and movement of resistance alleles introgressed from wheat in Aegilops cylindrica

In winter wheat in the USA, Aegilops cylindrica is one of the most troublesome weeds, while the pathogen Oculimacula spp. causes foot rot disease. Imazamox‐resistant (IR) and foot rot‐resistant (FR) wheat cultivars represent effective tools to control the weed and prevent disease infection. However, resistance allele (RA) movement between wheat and A. cylindrica facilitates the introgression process under herbicide and disease selection pressure. Field experiments using IR and FR A. cylindrica plants intermixed with susceptible plants were conducted to measure the proportion of the RAs in the progeny and RA movement with and without herbicide and disease selection. Yield components of A. cylindrica plants were determined across treatments. The herbicide RA proportion in the progeny was greater when plants were treated with the herbicide imazamox in both years. Disease RA proportion was greater with disease occurrence only in one year. Herbicide RA movement from resistant to susceptible plants was greater with herbicide than without it only in one year. Plants carrying the RAs had greater total spikelet weight and 1000‐spikelet weight compared with susceptible plants with or without selection. However, susceptible plants produced more spikelets than the resistant ones in the absence of selection. If plants within an A. cylindrica population acquire the herbicide RA, its proportion will increase each generation under selection. These findings contribute to the understanding of crop allele introgression into related species and the evolution of increased weediness, with weed management implications.     

抗草铵膦转基因水稻明恢86B杂草化潜力评价

 为评估抗草铵膦转基因水稻明恢86B大规模推广后演化为杂草的生态风险,在农田生态环境下比较了明恢86B、明恢86和杂交稻组合汕优63的生存竞争能力、繁育能力、落粒性、种子生存能力以及对常规除草剂氟吡磺隆的耐药性。结果表明,无论在适宜季节还是非适宜季节,明恢86B和明恢86的生存竞争能力和繁殖力都低于杂交稻组合汕优63,尤其在非适宜期时,汕优63的生存竞争力、繁殖力明显强于明恢86B和明恢86。主要表现在植株较高、分蘖较多以及高产。明恢86B的生存竞争力和繁殖力都略低于明恢86。3个材料的落粒性都不强,且尚未见自生苗产生。在浅埋和深埋处理下,明恢86B种子的生存能力弱于汕优63和明恢86。3个材料对除草剂氟吡磺隆的耐药性无明显差异。表明抗草铵膦转基因水稻86B在中国南京地区环境条件下演化为杂草的可能性较小。     

抗除草剂转基因大豆的生态安全评价进展

中国是大豆(Glycine max)的起源中心,大豆是中国的重要作物。转基因大豆向环境释放后可能带来的生态风险问题越来越受到人们的重视。中国自然状态下分布着丰富的野大豆(G.soja)遗传资源,转基因抗除草剂大豆能够在自然条件下与野大豆发生基因交流。转基因抗除草剂大豆释放后,由于大量单一使用草甘膦,田间杂草已经进化出了抗药性。大量使用的除草剂以及转基因大豆根际分泌物会对土壤微生物、非靶标生物产生影响,并影响到植物的固氮能力。本文在综述研究进展的基础上,提出了转基因大豆生物安全研究与管理的建议,为我国将来转基因大豆的产业化提供参考。     

Effect of Weediness on the Water Content of the Soil: A Field Study

Abstract

Maize is a vigorous and tall‐growing plant. Still, as a widely spaced crop, maize is highly susceptible to competition from weeds during its early growth period, with losses greater than 30% commonly reported. To characterize the nature of maize–weed competition, nutrient and water contents of maize and weed plants and the soil were determined in a field study. The experiment was carried out at Baracska, Hungary, in 2003, in a 9.2‐ha project area. Sampling areas (2×2 m in size, 21 altogether) were assigned, identified with global positioning system (GPS) coordinates, and left without weed control. After the emergence of maize, the frequency and density of weeds at the sampling sites were regularly determined, and samples of crop and weed plants and soil (from the depths of 0–20, 20–40, 40–60, 60–80, and 80–100 cm) were taken for analysis of water and nutrient contents. Three weed species were dominant: jimsonweed (Datura stramonium L.), broomcorn millet (Panicum miliaceum L.), and wild hemp (Cannabis sativa L.). A linear negative relationship was observed between the weediness and the water content in the top 20‐cm layer of the soil at the sampling areas.     

抗草甘膦转基因大豆的抗性及栽培地生存竞争能力研究

研究以实验室自主培育的抗草甘膦转基因大豆SHZD32-01为材料,以非转基因受体中豆32和适合当地栽培的皖豆31为对照,通过田间喷施不同剂量草甘膦,比较转基因大豆和受体大豆成活率及株高的差异;此外,在常规栽培条件下,比较不同时期的转基因大豆SHZD32-01、受体大豆和皖豆31的株高、复叶数、相对覆盖度的差异及成熟期(R8)后繁育系数和落粒率的差异,研究转基因大豆在常规栽培条件下的生存竞争能力。结果表明,SHZD32-01在喷施1.230~4.920kg/hm2草甘膦条件下生长不受抑制;栽培地条件下,不同时期的3个大豆品种的上述调查指标均无显著差异。因此,SHZD32-01对草甘膦抗性较好,无栽培地生存竞争优势,不具有杂草化的潜力。