Herbicides, weeds and endangered species: management of bitou bush (Chrysanthemoides monilifera ssp. rotundata) with glyphosate and impacts on the endangered shrub, Pimelea spicata

Environmental weed invasion threatens the biodiversity of native species. Unfortunately, managing these weeds may also affect biodiversity adversely. A recent example occurred when glyphosate, a herbicide used to control the highly invasive weed, bitou bush (Chrysanthemoides monilifera ssp. rotundata), accidentally drifted over a small population of an endangered shrub, Pimelea spicata. Following concerns that the affected population would not recover and, thereby, cause the local extinction of P. spicata, we conducted a series of glasshouse and field experiments to explore the impacts of glyphosate on this endangered species. Seedlings and young plants of P. spicata, in which the tap root was undeveloped, were killed by a single application of glyphosate. Older plants with a well developed tap root also died back initially, but about 50% of individuals re-sprouted. This re-growth was associated with a significant decrease in tap root diameter, implying that further disturbance, including repeated treatment with glyphosate, would kill plants by impairing their potential for recovery. Unlike some sclerophyllous native shrubs, the tolerance of P. spicata to glyphosate was limited, even when its growth was slowed artificially by limiting water availability. Winter applications of glyphosate to manage infestations of bitou bush will impact adversely on populations of P. spicata and may also affect the other rare and endangered species whose survival is threatened by this species, even though some natives are unaffected by the herbicide. Protecting native biodiversity from bitou bush will involve sustainable weed management that minimises impacts on non-target native species.     

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。     

Glyphosate degradation as a soil health indicator for heavy metal polluted soils

Glyphosate is a commonly used herbicide in grassland soils and microorganisms control its degradation. We introduce the concept of using the degradation rate as an indicator for ecosystem health. Testing this concept, we used soils with a long history of heavy metal pollution (Cu, Pb, and Zn). We hypothesized lower degradation rates in metal-polluted compared to less polluted soils. The degradation rates were measured by repeated measurements of the parent compound in spiked soil-water slurries incubated at 20 °C over 21 days. Average rates showed no differences comparing among soils. We observed a positive correlation between glyphosate degradation rates and soil metal pollution. Therefore, we concluded that the expected impact of the metals on the bacteria responsible for the herbicide degradation was not established. We discuss the potential influence on biological degradation rates of soil pH and adsorption and implications using the concept of the soil health indicator.     

In vivo 31P and 1H HR-MAS NMR spectroscopy analysis of the unstarved Aporrectodea caliginosa (Lumbricidae)

This study demonstrates that ³¹P and ¹H high resolution-magic angle spinning (HR-MAS) nuclear magnetic resonance (NMR), a recently developed NMR technique, can be applied to the in vivo analysis of metabolites from an unstarved earthworm. The endogeic earthworm Aporrectodea caliginosa was cut into lengths and then the different body parts (anterior, middle, posterior) with the gut content were analyzed. With the HR-MAS NMR, metabolites show well-resolved signals, whereas, with conventional NMR, spectra are highly dependent on the gut content. ³¹P HR-MAS NMR has been used to evaluate the effect of an acute exposure of the earthworm to glyphosate. Our observations support a low toxicity of the herbicide and suggest that glyphosate could be trapped in the cutaneous mucus. Earthworms could therefore play a role in horizontal dispersion and stabilization of glyphosate in the drilosphere. Phosphorylated metabolites, such as phospholombricine and lombricine, were clearly identified and their amount measured during experiments. The ¹H HR-MAS NMR method offers the opportunity to measure, on the same sample and simultaneously, both the hydrosoluble metabolites and lipids. The data on lipid location and relative succinate concentration shed light on the physiological and metabolic functions of the different body parts of the earthworm.     

Genetically-modified herbicide-resistant (GMHR) crops a two-edged sword? An Americas perspective on development and effect on weed management

GMHR crops have been cultivated in the Americas for nearly 20 years. Prior to release, regulators asked the question, “will herbicide selection pressure for evolution of HR weeds increase significantly as a result of GMHR crop cultivation?” In hindsight, they could not have imagined the rapid, widespread adoption of glyphosate-resistant (GR) crops and subsequent chain of events: surge in glyphosate usage at the expense of other herbicides, sharp drop in investment in herbicide discovery, unrelenting rise of GR and multiple-HR weed populations, and increasing herbicide use in GMHR cropping systems. In this brief review, we outline grower adoption of GMHR soybean, maize, cotton, and oilseed rape (canola) in the Americas, and their impact on herbicide-use practices for weed management. Cultivars with stacked-HR traits (e.g., glyphosate + glufosinate + dicamba or 2,4-D) will provide a short-term respite from HR weeds, but will perpetuate the chemical treadmill and selection of multiple-HR weeds. The only sustainable solution is for government or end-users of commodities to set herbicide-use reduction targets in our major field crops similar to European Union member states, and include financial incentives or penalties in agricultural programs to support this policy. Concomitantly, industry incentives must expand to improve grower adoption of best management practices for HR weeds. New or emerging technologies will provide additional tools for reactive HR weed management in the future, but their time of arrival is uncertain.     

转抗虫抗草甘膦除草剂基因(Cry1Ac+EPSPS)棉的检测技术与生存竞争能力研究——基于草甘膦压力和对靶标害虫不防治环境下

此研究为国家转抗虫抗草甘膦除草剂基因(Cry1Ac+EPSPS)棉环境安全评价技术建立而设。在草甘膦压力和对靶标害虫不防治环境下的检测技术,以杂交抗虫棉赣棉杂1号和非转基因棉赣棉11号为2个对照,来检测评价转抗虫抗草甘膦除草剂基因(Cry1Ac+EPSPS)棉的生存竞争能力。结果:转Cry1Ac+EPSPS棉与两个对照相比不显示抗虫优势;株高增长无竞争力;覆盖度有不显著的弱竞争力;单株成铃、单铃籽棉重、单铃皮棉重、衣分率、脱落率、籽棉产量、皮棉产量与赣棉杂1号比呈现显著或极显著的负竞争优势,与赣棉11号比无竞争优势;果枝层数前期与两对照相比有极显著的负竞争优势,后期与赣棉杂1号比无竞争优势,与赣棉11号比有显著的负竞争优势。结论:转Cry1Ac+EPSPS棉推广种植可行性较差。本项检测技术和评价方法有较好的适用性。     

四种常见农药对日本三角涡虫的急性毒性研究

为研究农药对低等水生动物的影响,研究了草甘膦、乙草胺、敌百虫、敌杀死4种农药对涡虫的急性毒性。结果显示草甘膦、乙草胺、敌百虫、敌杀死对涡虫的24hLC50分别是：41．78、12．22、1．45、1．42mg／L;48h的LC50分别是35．42、8．41、1．34、1．37mg／L;72h的LC50分别是29．83、7．46、1．29、1．32mg／L96h的LC50分别是27．97、6．98、1．23、1．27mg／L。4种农药对涡虫的安全浓度分别是草甘膦（7．64mg／L）、乙草胺（1．19mg／L）、敌百虫（0．34mg／L）、敌杀死（0．38mg／L）,对涡虫的急性毒性是敌百虫〉敌杀死〉乙草胺〉草甘膦。实验结果表明涡虫用于监测草甘膦、乙草胺、敌百虫、敌杀死对低等水生动物的影响具一定可行性。     

转基因抗草甘膦油菜籽中草甘膦氧化还原酶基因的检测方法研究

应用PCR技术，分析草某膦氧化还原酶基因（GOX）和修饰草甘膦氧化还原酶基因的核苷酸序列及表达蛋白质的氨基酸序列，建立了检测转基因抗草甘膦油菜籽中草甘膦氧化还原酶基因的技术和方法。     

苗圃常用除草剂草甘膦对胶东卫矛生理生化影响的研究

主要研究草甘膦对胶东卫矛生长发育的影响。实验通过对88.8%草甘膦水溶性粒剂在三种浓度处理下对胶东卫矛叶片内叶绿素含量、POD活性、SOD活性、质膜相对透性的测定,再结合生长量指标进行分析。结果表明:草甘膦即使浓度在1.5 g/L时,仍会对胶东卫矛苗木的生长量产生极强的抑制作用。所以在胶东卫矛苗圃地除草时,应避免接触到苗木的茎叶。