共查询到20条相似文献，搜索用时 15 毫秒
1.
为明确转基因抗草甘膦抗虫棉田草甘膦的使用适期,于棉花子叶期、3~4片真叶期和花铃期喷施不同浓度的草甘膦,比较药害发生情况、棉花产量和纤维品质。棉花子叶期、3~4片真叶期和花铃期喷施1 640~9 840 g/hm2(有效成分,下同)草甘膦后,施药初期棉花均表现出一定的药害症状,药后4~8 d药害株率和药害指数达最大值,药后12 d药害症状逐渐减轻或消失。棉花子叶期和3~4片真叶期喷施草甘膦,对棉花产量无显著影响,但棉花花铃期喷施2 460~9 840 g/hm2草甘膦后,棉花产量显著降低,降幅达35.0%~63.3%。3个时期喷施草甘膦均不影响棉花的纤维品质。研究表明,转基因抗草甘膦抗虫棉田草甘膦的使用适期为棉花苗期。 相似文献
2.
3.
在温室条件下,研究了草甘膦对北京、河北等地田旋花种群生长及其莽草酸含量变化的影响。结果表明,不同地区田旋花种群对草甘膦具有普遍的耐受能力,其中河北元氏的田旋花种群对草甘膦的耐受能力最强,GR50值为4 014.92 g a.i./hm2;北京海淀田旋花种群对草甘膦相对敏感,GR50值为957.65 g a.i./hm2。经922.5 ga.i./hm2草甘膦处理后,耐药性最高的河北元氏田旋花种群体内莽草酸含量累积缓慢,处理后14 d所受伤害能自行恢复并保持正常生长;敏感的北京海淀田旋花种群体内莽草酸迅速积累,在处理后7 d莽草酸含量达到最高值,植株生长受到一定程度的抑制。田旋花体内莽草酸含量与其耐药性高低呈负相关,因此可以通过检测田旋花经草甘膦处理后体内莽草酸的含量来明确不同地区田旋花对草甘膦耐受水平的高低。 相似文献
4.
研究了空心莲子草Alternanthera philoxeroides在土壤中含高浓度锰(简称高锰)胁迫下的生长特性及对草甘膦的耐性。空心莲子草在锰添加量为8～128 mg/kg的土壤中培养20 d后,分枝数比对照(4.43个/株)增加了22.57％～48.31%, 主茎长度比对照(23.85 cm)增长了16.60％～19.87%,地下根茎数比对照(1.54个/株)增加29.87％～47.40%,全株干重比对照(0.23 g)增加22.45%～27.00%;植株叶面积在锰添加量为32～128 mg/kg范围内也显著高于对照(增加10.53%～11.10%)。用草甘膦(有效成分按草甘膦酸计) 68、102和136 g/hm2分别进行茎叶处理后21 d,锰添加量为128 mg/kg的处理,鲜重抑制率分别比不添加锰处理组下降27.39％、24.57％和30.06％。结果表明,土壤高锰条件下空心莲子草的生长和繁殖能力增强,这可能是土壤酸化背景下空心莲子草蔓延加剧的重要原因。土壤高锰条件下生长的空心莲子草对草甘膦的耐性显著增强,使得该杂草的防控形势更为严峻。 相似文献
5.
麦冬、土麦冬和阔叶土麦冬都对草甘膦具有较高的天然耐药性,其耐药性的主要机制是由于EPSPS基因结构差异、基因多拷贝以及高表达量,但是,靶标机制并不能完全解释阔叶土麦冬的耐药性最高,麦冬的耐药性最低,土麦冬居于中间。为了进一步揭示其耐药性的非靶标机制,采用光镜和扫描电镜观察了麦冬、土麦冬和阔叶土麦冬的叶表皮显微结构,发现麦冬、土麦冬和阔叶土麦冬的气孔主要分布于叶片下表皮,气孔密度分别为37.6、36.15和23.92个/mm~2。但是,土麦冬和阔叶土麦冬的气孔在叶片上表皮也有分布,并且阔叶土麦冬上表皮的气孔明显多于土麦冬。麦冬草气孔带和非气孔带细胞在细胞长度、面积和长宽比等方面均存在差异。麦冬气孔周围的表皮细胞平周壁具明显瘤状突起,导致气孔下陷;土麦冬气孔周围的表皮细胞平周壁呈波浪状突起,使气孔略下陷;阔叶土麦冬气孔周围的表皮细胞平周壁基本无突起,气孔下陷不显。这些结构特征差异可能与麦冬草对草甘膦的耐药性差异有一定的相关性。 相似文献
6.
Weirich JW Shaw DR Coble KH Owen MD Dixon PM Weller SC Young BG Wilson RG Jordan DL 《Pest management science》2011,67(7):785-789
BACKGROUND: The introduction of glyphosate‐resistant (GR) crops in the late 1990s made weed control in maize, cotton and soybean simple. With the rapid adoption of GR crops, many growers began to rely solely on glyphosate for weed control. This eventually led to the evolution of GR weeds. Growers are often reluctant to adopt a weed resistance best management practice (BMP) because of the added cost of additional herbicides to weed control programs which would reduce short‐term revenue. This study was designed to evaluate when a grower that is risk neutral (profit maximizing) or risk averse should adopt a weed resistance BMP. RESULTS: Whether a grower is risk neutral or risk averse, the optimal decision would be to adopt a weed resistance BMP when the expected loss in revenue is greater than 30% and the probability of resistance evolution is 0.1 or greater. However, if the probability of developing resistance increases to 0.3, then the best decision would be to adopt a weed resistance BMP when the expected loss is 10% or greater. CONCLUSION: Given the scenarios analyzed, risk‐neutral or risk‐averse growers should implement a weed resistance BMP with confidence that they have made the right decision economically and avoided the risk of lost revenue from resistance. If the grower wants to continue to see the same level of return, adoption of BMP is required. Copyright © 2011 Society of Chemical Industry 相似文献
7.
Shaw DR Owen MD Dixon PM Weller SC Young BG Wilson RG Jordan DL 《Pest management science》2011,67(7):741-746
Glyphosate-resistant (GR) crop technology has dramatically impacted agriculture. The adoption of GR systems in canola, maize, cotton, soybean and sugar beets has been widespread in the United States. However, weed scientists are concerned that growers' current herbicide programs and weed management tactics will affect their sustainability and effectiveness. Without proper management, the potential for weed populations to express a high degree of resistance to glyphosate will adversely impact the utility of glyphosate. In 2005, weed scientists from six universities initiated a long-term research study to assess the sustainability of GR technology. This paper introduces five other articles in this series. Over 150 fields of at least 10 ha were selected to participate in a long-term field-scale study, and each field was split in half. On one-half the grower continued using the current weed management program; on the other half the grower used academic-recommended herbicide resistance best management practices. Field data were collected in 2006-2008 to determine the impact of the two weed management programs on weed populations, diversity, seedbank, crop yields and economic returns. This long-term study will provide invaluable data for determining the sustainability and profitability of diversified weed management programs designed to lower the risk of evolving weed resistance to glyphosate. 相似文献
8.
Weirich JW Shaw DR Owen MD Dixon PM Weller SC Young BG Wilson RG Jordan DL 《Pest management science》2011,67(7):781-784
BACKGROUND: Glyphosate‐resistant (GR) crops have changed the way growers manage weeds and implement control strategies. Since the introduction of GR crops, growers in many instances have relied on glyphosate almost exclusively to control a broad spectrum of weeds. This overreliance on glyphosate has resulted in the evolution of glyphosate resistance in some weed species. Growers and scientists are concerned about the sustainability of GR crops and glyphosate. When a grower is making decisions about weed control strategies, economic costs and benefits of the program are primary criteria for selection and implementation. Studies across six states were initiated in 2006 to compare the economics of using a weed resistance best management practice (BMP) system with a grower's standard production system. RESULTS: Resistance BMP systems recommended by university scientists were more costly but provided similar yields and economic returns. Rotation of GR crops resulted in a higher net return (maize and soybean) compared with continuous GR crop (cotton or soybean) or rotating a GR crop with a non‐GR crop (maize). CONCLUSION: Growers can implement weed resistance BMP systems with the confidence that their net returns will be equivalent in the short run, and, in the long term, resistance BMP systems will prevent or delay the evolution of GR weeds in their fields, resulting in substantial savings. Copyright © 2011 Society of Chemical Industry 相似文献
9.
10.
Owen MD Young BG Shaw DR Wilson RG Jordan DL Dixon PM Weller SC 《Pest management science》2011,67(7):747-757
A six-state, 5 year field project was initiated in 2006 to study weed management methods that foster the sustainability of genetically engineered (GE) glyphosate-resistant (GR) crop systems. The benchmark study field-scale experiments were initiated following a survey, conducted in the winter of 2005-2006, of farmer opinions on weed management practices and their views on GR weeds and management tactics. The main survey findings supported the premise that growers were generally less aware of the significance of evolved herbicide resistance and did not have a high recognition of the strong selection pressure from herbicides on the evolution of herbicide-resistant (HR) weeds. The results of the benchmark study survey indicated that there are educational challenges to implement sustainable GR-based crop systems and helped guide the development of the field-scale benchmark study. Paramount is the need to develop consistent and clearly articulated science-based management recommendations that enable farmers to reduce the potential for HR weeds. This paper provides background perspectives about the use of GR crops, the impact of these crops and an overview of different opinions about the use of GR crops on agriculture and society, as well as defining how the benchmark study will address these issues. 相似文献
11.
The response of Cuscuta campestris Yuncker, a non‐specific above‐ground holoparasite, to amino acid biosynthesis inhibitor (AABI) herbicides, was compared with other resistant and sensitive plants in dose–response assays carried out in Petri dishes. Cuscuta campestris was found to be much more resistant to all AABI herbicides tested. The I50 value of C. campestris growth inhibition by glyphosate was eightfold higher than that of transgenic, glyphosate‐resistant cotton (RR‐cotton). The I50 value for C. campestris shoot growth inhibition by sulfometuron was above 500 μM, whereas that of sorghum roots was only 0.004 μM. Cuscuta campestris exposed to glyphosate gradually accumulated shikimate, confirming herbicide penetration into the parasite and interaction with an active form of the target enzyme of the herbicide, 5‐enolpyruvylshikimate‐3‐phosphate synthase. More than half of the C. campestris plants associated with transgenic, glyphosate‐resistant sugarbeet (RR‐sugarbeet) treated with glyphosate or with transgenic, sulfometuron‐resistant tomato (SuR‐tomato) treated with sulfometuron recovered and resumed regular growth 20–30 days after treatment. New healthy stems developed, followed by normal flowering and seed setting. The results of the current study demonstrate the unique capacity of C. campestris to tolerate high rates of AABI. The mechanism of this phenomenon is yet to be elucidated. 相似文献
12.
Givens WA Shaw DR Newman ME Weller SC Young BG Wilson RG Owen MD Jordan DL 《Pest management science》2011,67(7):758-770
BACKGROUND: A survey was conducted with nearly 1200 growers in US states (Illinois, Indiana, Iowa, Mississippi, Nebraska and North Carolina) in 2005 with the objective in part of determining the awareness of the potential for development of glyphosate resistance, the experience with glyphosate‐resistant (GR) weeds and the sources of information that growers had utilized for information on glyphosate resistance. Growers were asked a series of questions to determine the level of glyphosate resistance awareness and to list the sources of information used to learn about glyphosate resistance issues. RESULTS: The majority of the growers (88%) were aware of a weed's potential to evolve resistance to herbicide, while 44% were aware of state‐specific documented cases of GR weeds, and 15% reported having had personal experience with GR weeds. Among sources of information concerning glyphosate resistance issues, farm publications, dealers/retailers and university/extension were the most frequent responses (41, 17 and 14% respectively). Based on a 1‐10 effectiveness scale, growers ranked tillage the least effective practice (5.5) and using the correct label rates of herbicides at the proper timing for the size and type of weeds present the most effective practice (8.6) with respect to how effectively the practices mitigated the evolution of GR weeds. CONCLUSION: Results from this survey can be used by researchers, extension specialists and crop advisors further to bridge the information gap between growers and themselves and better to disseminate information concerning glyphosate resistance and glyphosate resistance management practices through more targeted information and information delivery methods. Copyright © 2011 Society of Chemical Industry 相似文献
13.
Transgenic glyphosate-resistant (GR) soybean [Glycine max (L.) Merr.] has enabled highly effective and economical weed control. The concomitant increased application of glyphosate could lead to shifts in the soil microbial community. The objective of these experiments was to evaluate the effects of glyphosate on soil microbial community structure, function and activity. Field assessments on soil microbial communities were conducted on a silt loam soil near Stoneville, MS, USA. Surface soil was collected at time of planting, before initial glyphosate application and 14 days after two post-emergence glyphosate applications. Microbial community fatty acid methyl esters (FAMEs) were analyzed from these soil samples and soybean rhizospheres. Principal component analysis of the total FAME profile revealed no differentiation between field treatments, although the relative abundance of several individual fatty acids differed significantly. There was no significant herbicide effect in bulk soil or rhizosphere soils. Collectively, these findings indicate that glyphosate caused no meaningful whole microbial community shifts in this time period, even when applied at greater than label rates. Laboratory experiments, including up to threefold label rates of glyphosate, resulted in up to a 19% reduction in soil hydrolytic activity and small, brief (<7 days) changes in the soil microbial community. After incubation for 42 days, 32-37% of the applied glyphosate was mineralized when applied at threefold field rates, with about 9% forming bound residues. These results indicate that glyphosate has only small and transient effects on the soil microbial community, even when applied at greater than field rates. 相似文献
14.
Sarah H Lancaster Emily B Hollister Scott A Senseman Terry J Gentry 《Pest management science》2010,66(1):59-64
Background: Repeated applications may have a greater impact on the soil microbial community than a single application of glyphosate. Experiments were conducted to study the effect of one, two, three, four or five applications of glyphosate on soil microbial community composition and glyphosate mineralization and distribution of 14C residues in soil. RESULTS: Fatty acid methyl esters (FAMEs) common to gram‐negative bacteria were present in higher concentrations following five applications relative to one, two, three or four applications both 7 and 14 days after application (DAA). Additionally, sequencing of 16S rRNA bacterial genes indicated that the abundance of the gram‐negative Burkholderia spp. was increased following the application of glyphosate. The cumulative percentage 14C mineralized 14 DAA was reduced when glyphosate was applied 4 or 5 times relative to the amount of 14C mineralized following one, two or three applications. Incorporation of 14C residues into soil microbial biomass was greater following five glyphosate applications than following the first application 3 and 7 DAA. CONCLUSION: These studies suggest that the changes in the dissipation or distribution of glyphosate following repeated applications of glyphosate may be related to shifts in the soil microbial community composition. Copyright © 2009 Society of Chemical Industry 相似文献
15.
This study was conducted to determine the effects of three organosilicone-based and six conventional organic adjuvants on the absorption and translocation of 14 C-glyphosate in guineagrass and redroot pigweed. The organosilicone adjuvants produced rapid absorption of the 14 C-glyphosate into the redroot pigweed leaves, reaching maximum absorption within 0.5–1.0 h after application. The conventional adjuvants produced slower absorption of the 14 C-glyphosate, as the maximum absorption was not achieved until at least 24 h after application in redroot pigweed, remaining similar until 72 h. In guineagrass, the maximum absorption of the glyphosate was earlier than 24 h with the organosilicone-based adjuvants, compared with longer times for the conventional adjuvants. The organosilicone-based adjuvants also increased the glyphosate translocation in redroot pigweed, but not in guineagrass. Organosilicone adjuvants have the potential to provide greater rainfastness to glyphosate on redroot pigweed and, to a lesser extent, on guineagrass. 相似文献
16.
阿拉善干旱荒漠区灌木多样性的特点 总被引：1，自引：0，他引：1
阿拉善干旱荒漠区是我国典型的荒漠生态系统,它不仅是我国北方重要的生态屏障,也是我国六大生物多样性中心之一。在这一区域由于特殊的自然生态背景使之成为灌木种类的\"天然王国\"。拥有23科57属137种灌木、半灌木。灌木是荒漠植被的主要组分,它在维持荒漠生态系统生物多样性、生态服务功能及其稳定性方面具有重要作用。20世纪下半叶,随着人口快速增长导致的高强度人类活动,已深刻地改变了荒漠生态系统的结构及水分和能量循环过程,导致了灌木植物严重受损退化。为了保育灌木资源,提高人们对灌木在草地恢复中重要作用的认识,文中分析了灌木多样性分布的特点,论述了灌木在干旱荒漠区的特殊作用。结果显示:阿拉善高原丰富的灌木多样性具有广泛的代表性,是我国温带草原灌木多样性分布的中心和我国灌木资源多样性保育的关键地区之一。 相似文献
17.
The efficacy of the commercial glyphosate [( N -phosphonomethyl) glycine] formulations Roundup Ultra, Touchdown and Engame were compared for the control of prickly sida ( Sida spinosa L.), morningglory ( Ipomeae hederacea var. integriuscula Gray), sicklepod ( Senna obtusifolia L.) and purple nutsedge ( Cyperus rotundus L.). Engame is a new formulation of glyphosate that contains glyphosate acid and 1-aminomethanamide dihydrogen tetraoxosulfate (AMADS), a proprietary mixture of sulfuric acid and urea, other than glyphosate salt and surfactants. Injury by Engame differed from Roundup Ultra and Touchdown in that necrotic lesions formed on leaves several hours after treatment. Leaves of very susceptible species, such as prickly sida, were rapidly, although incompletely, desiccated and then became chlorotic and died in a manner typical of other glyphosate formulations. Engame was 2–3 times more active to growth inhibition than either the Roundup Ultra or Touchdown formulations, based on GR50 comparisons expressed on an acid equivalent basis. The GR50 estimates did not change over the 3 week evaluation period for prickly sida and purple nutsedge, and after 2 weeks after treatment for morningglory. The GR50 estimates for sicklepod decreased over the 3 week evaluation period indicating a slower response to glyphosate. The application of AMADS alone caused minute necrotic lesions on sicklepod and purple nutsedge, and lesions up to 3 mm in diameter on prickly sida and morningglory. Further injury from AMADS was not noted and plants resumed growth without apparent delay. At glyphosate rates above 1120 g ha−1 , greater than 80% control was achieved at 7 days after treatment. These results demonstrate that glyphosate efficacy can be further enhanced by formulations that apparently improve uptake and translocation. 相似文献
18.
It has long been known that calcium ion antagonizes glyphosate, but it was not clear whether the stoichiometry of their interaction is 1:1 or 1:2. Two independent methods were used to determine which stoichiometry was the most probable. First, dose–response curves of barley ( Hordeum vulgare L.) plants treated with glyphosate were determined in the presence of 0, 1.25, 2.5, 5 and 10 mM CaCl2 . The doses of 'free' glyphosate (=not inactivated by calcium ion) were computed using the assumptions of 1:1 and 1:2 stoechiometries. The response curves were redrawn as a function of 'free' glyphosate. Analysis showed that the 1:2 hypothesis could be rejected, whereas the 1:1 hypothesis was highly probable. Second, kinetics of glyphosate penetration into barley leaves were determined in the presence of 0, 2.5 and 10 mM CaCl2 . The concentrations of 'free' glyphosate were computed as above. The kinetics of glyphosate penetration at these concentrations were established and were compared to the kinetics of glyphosate penetration in the presence of CaCl2 . Again, the 1:2 hypothesis was rejected, whereas the 1:1 hypothesis was more probable. These results strongly suggest that the stoichiometry of the Ca2+ :glyphosate association is 1:1 in deposit residuals on the leaf surface. 相似文献
19.
Xia Ge D André d'Avignon Joseph JH Ackerman R Douglas Sammons 《Pest management science》2010,66(4):345-348
BACKGROUND: Glyphosate‐resistant (GR) weed species are now found with increasing frequency and threaten the critically important GR weed management system. RESULTS: The reported 31P NMR experiments on glyphosate‐sensitive (S) and glyphosate‐resistant (R) horseweed, Conyza canadensis (L.) Cronq., show significantly more accumulation of glyphosate within the R biotype vacuole. CONCLUSIONS: Selective sequestration of glyphosate into the vacuole confers the observed horseweed resistance to glyphosate. This observation represents the first clear evidence for the glyphosate resistance mechanism in C. canadensis. Copyright © 2010 Society of Chemical Industry 相似文献
20.
本文对草甘膦喷施土壤后对作物的安全性进行了初步研究。采用室内盆栽的方法,测定了不同剂量的35%草甘膦水剂在壤土和砂土条件下对小麦Triticum aestivum L.、玉米Zea mays L.、大豆Glycine max(L.) Merr.、甘蓝Brassica oleracea var.capitata L.、小白菜Brassica pekinensis L.、番茄Lycopersicon esculentum L.和茄子Solanum melongena L.等7种作物的叶色、叶长、叶宽、植株鲜重和光合作用等生长、生理指标的影响。研究结果表明：在标签剂量(1 575 g/hm~2)下施用于壤土时,草甘膦对茄子的叶长和叶宽影响显著,对其他6种作物的各测定指标未产生显著影响;在砂土条件使用时,除对小麦和茄子的叶色、番茄的叶宽、小白菜和番茄的鲜重方面有显著影响外,对玉米、大豆和甘蓝都安全。在2倍标签剂量(3 150 g/hm~2)下,在壤土和砂土条件下使用时,除对茄子在叶色、叶长、叶宽和鲜重4个指标都有显著影响外,对番茄的光合效率也有显著影响,同时对其他作物的其他指标也有不同的影响,... 相似文献