除草剂草甘膦的性质及环境行为综述

草甘膦是一种广谱、非选择性芽后除草剂,它被越来越广泛地应用于农业。本文总结了草甘膦的一些基本性质及其在环境中的行为和降解机理,概述了国内外的研究现状,及影响其在土壤环境去向的一些因素,如土壤性质、磷酸盐、重金属和DOC的存在等,为进一步研究提供一些建设性的参考。     

蚯蚓粪对柑橘幼苗抗草甘膦胁迫的影响

草甘膦在柑橘园除草中得到大量使用,对农作物生长、果实品质、产量和质量造成影响。如何降低草甘膦对柑橘树的生物可利用性,从而降低其对农作物造成的药害、提高果实品质和食品安全将至关重要。本文在前期研究的基础上通过施用蚯蚓粪,表征蚯蚓粪作用下土壤中残留草甘膦对柑橘幼苗的生物有效性和生物毒性效应。结果显示,蚯蚓粪能够显著增强其生物有效性（BCF值显著增大）;显著降低草甘膦在土壤中的残留量到草甘膦单独处理组的55.15%,从而减少草甘膦在柑橘幼苗植株中的积累。同时,蚯蚓粪的施用能促进植物的茁壮生长,使抗氧化酶活力较对照组显著提高,从而具有更强的抗逆能力。在这两方面的共同作用下,蚯蚓粪显著减轻了土壤中残留草甘膦对柑橘幼苗的胁迫,使其株高、根长和相应的干重较草甘膦单独施用时增长了26.23%-140.11%,甚至成为对照组的1.03倍和1.13倍。此研究对兼顾化肥有机替代的草甘膦污染土壤的修复和高效利用具有重要意义。     

Glyphosate resistance of molecularly identified Conyza albida and Conyza bonariensis populations

In the initial screening, 18 out of 32 Conyza albida and 7 out of 28 Conyza bonariensis populations, sampled from main perennial crop regions of central and southern Greece, were found to be resistant to glyphosate. The level of resistance determined in dose–response experiments with representative populations of the two species was found to range from 7.7 to 37.3 for C. albida and from 3.4 to 7.8 for C. bonariensis. The comparison of the resistant and susceptible C. albida and C. bonariensis EPSPS gene sequences indicated that possess single nucleotide changes compared to Conyza canadensis EPSPS gene, but none of these changes is located at the position 106 that has been reported to confer resistance to glyphosate. Finally, the cpDNA sequence comparison analysis used for the most resistant population of each species and the respective susceptible counterparts was found to be a reliable tool for discrimination of conventionally classified C. albida and C. bonariensis plants that are morphologically similar. This is the first report for molecular identification of Conyza species.     

草甘膦对毛竹笋用林土壤理化性质的影响分析

在毛竹笋用林中长期使用草甘膦且又不进行施肥等抚育措施,会对土壤的结构产生影响,造成容重增加,总孔隙度降低,不利于竹鞭的正常生长,通过增施有机肥可有效降低草甘膦对土壤结构的影响.试验结果表明,长期使用草甘膦对土壤有机质有一定影响,但对全氮、全磷、水解氮、速效磷、速效钾、pH值、交换性氢和交换性铝均未有显著差异.     

除草剂对不同种植年限柑橘园土壤氮转化过程及温室气体排放的影响

为探讨除草剂施用对柑橘园土壤氮转化及温室气体排放的影响,在实验室培养条件下,研究了0年(林地)、种植10年和30年的柑橘园土壤中分别添加除草剂草甘膦和丁草胺后,尿素态氮含量、硝化和反硝化作用以及温室气体排放的变化。研究结果表明,橘园土壤中尿素第1 d的水解率、氮肥硝化率、反硝化作用损失总量以及N_2O和CO_2排放量显著高于林地土壤(P0.05)。与10年橘园土壤相比,30年橘园土壤显著增加了尿素的水解速率、氮肥硝化率和CO_2排放量(P0.05),但二者的反硝化损失量没有显著差异。施用草甘膦和丁草胺都显著促进了林地土壤的尿素水解(P0.05),第1 d尿素态氮含量分别降低11.20%和12.43%;但对3种土壤氮肥的硝化率均没有明显影响。施用丁草胺显著降低了林地土壤的CO_2排放量(P0.05),对两种橘园土壤的CO_2排放没有明显影响,但明显增加了两种橘园土壤的N_2O排放总量(P0.05),分别比不施除草剂增加56.27%和85.41%;施用草甘膦对3种土壤的N_2O和CO_2排放均没有明显影响。可见,草甘膦和丁草胺的施用不会对柑橘园土壤的氮转化过程产生影响,但丁草胺显著增加了柑橘园土壤的N_2O排放。     

33％草甘膦·精喹禾灵·乙羧氟草醚可分散油悬浮剂对非耕地杂草防除效果研究

[目的]明确33％草甘膦·精喹禾灵·乙羧氟草醚可分散油悬浮剂对非耕地杂草的最佳使用剂量.[方法]采用田间药效试验研究33％草甘膦·精喹禾灵·乙羧氟草醚可分散油悬浮剂对非耕地杂草的防除效果.[结果]33％草甘膦·精喹禾灵·乙羧氟草醚可分散油悬浮剂200.0～400.0 g/hm2对非耕地杂草有明显的防除效果,茎叶喷雾处理15 d后对试验地杂草的株防效达87.53％ ～92.92％,35 d后平均鲜重防效达88.37％～93.89％.[结论]在单子叶杂草大部分6～8叶、阔叶杂草10～ 12叶时采用该制剂进行茎叶喷雾,用量为有效成分990.0～1 980.0 g/hm2(制剂量3 000.0～6 000.0 g/hm2).     

农杆菌介导的抗草甘膦基因(sxglr-11)的玉米遗传转化

利用根瘤农杆菌(Agrobacterium tumefaciens)介导法将抗草甘膦基因(sxglr-11)导入优良玉米再生系HiII,共转化幼胚1 673个,分化出再生苗67株,其中,28株移栽成活,经PCR检测13株为阳性植株,阳性率为46.4%。采用草甘膦浓度梯度筛选,确定了未转基因的对照植株的致死浓度范围为1%～2%。利用2%的草甘膦对T0转基因植株6～8叶龄苗的叶片进行涂抹,结果表明,阳性植株均具有草甘膦抗性。T1植株经2%草甘膦抗性筛选,转基因植株表现出3∶1的孟德尔分离方式。     

Glyphosate affects chlorophyll, nodulation and nutrient accumulation of “second generation” glyphosate-resistant soybean (Glycine max L.)

The recently developed “second generation” of Roundup Ready® soybean (RR2) cultivars commercially available for farmers in 2008 were promoted as higher yielding relative to the “first generation” RR cultivars (RR1). Previous studies showed that glyphosate reduced such yield components as photosynthesis, water absorption, nutrient uptake and symbiotic N₂ fixation in RR soybean cultivars; however, no data are available regarding the glyphosate effects on these physiological factors in RR2 soybean. Thus, the objective of this research was to evaluate the nutrient accumulation and nodulation of both generations of RR soybeans at different rates of glyphosate applied at various growth stages. In general, increased glyphosate rates and late applications decreased the nutrient accumulation, nodulation, and shoot and root biomass in both RR1 and RR2. All macro- and micronutrients, with exception of N and K, accumulated more in RR1 than RR2. Although this result may be an individual cultivar characteristic, it suggests that the RR2 cultivar was also inefficient in nutrient uptake and translocation or was unable to rapidly recover from potential chelating effects of glyphosate. These studies suggest that applying glyphosate at early growth stages using the lowest glyphosate rate might have less damage on growth and productivity of RR soybeans.     

警惕!进口大宗粮谷中频繁截获超级杂草

本文介绍了超级杂草的特点、危害性、发生原因和过程,并探讨了检疫系统及相关部门为降低其传入我国风险应采取的检疫措施.     

Glyphosate accumulation,translocation, and biological effects in Coffea arabica after single and multiple exposures

In perennial crops like coffee, glyphosate drift exposure can occur multiple times during its commercial life span. Due to limited glyphosate degradation in higher plants, a potential accumulation of glyphosate could lead to increased biological effects with increased exposure frequency. In this study, we investigated glyphosate translocation over time, and its concentration and biological effects after single and multiple simulated spray-drift exposures. Additionally, shikimic acid/glyphosate ratios were used as biomarkers for glyphosate binding to its target enzyme.Four weeks after the exposure, glyphosate was continuously translocated. Shikimic acid levels were linear correlated with glyphosate levels. After two months, however, glyphosate appeared to have reduced activity. In the greenhouse, multiple applications resulted in higher internal glyphosate concentrations. The time of application, however, was more important regarding biological effects than the number of applications both in the greenhouse and in the field. In the field, berry yield, the most important biological response variable, was reduced 26% by the first out of four sequential applications of glyphosate at 64 g a.e. ha⁻¹ each. The three subsequent applications did not reduce yield any further.