Uptake, translocation, metabolism and selectivity of glyphosate in Canada thistle and leafy spurge

The uptake, translocation and metabolism of glyphosate [N-(phosphonomethyl) glycine] by Canada thistle (Cirsium arvense (L.) Scop.) (susceptible) and leafy spurge (Euphorbia esula (L.)) (resistant) were examined in an attempt to elucidate the nature of the differential sensitivity. The pattern of uptake and translocation was similar in both species. Glyphosate moved readily in the apoplast and the symplast. High humidity and/or surfactant greatly increased the amount of ¹⁴C-glyphosate absorbed and translocated over that in low humidity and/or without surfactant. No ¹⁴Cmetabolites were detected in either species 1 week after treatment with ¹⁴C-glyphosate. More of a glyphosate spray solution containing a fluorescent dye was received and retained on Canada thistle by virtue of its growth habit than on leafy spurge. More glyphosate should therefore be available for uptake by Canada thistle and this may account for the differential sensitivity of these two species.     

Effects of herbicides or mowing on musk thistle seed production*

Mowing musk thistle (Carduus nutans L.) within 2 days of the first terminal heads in a plant population showing anthesis eliminated the production of germinable seed from all mowed stalks. Mowing later than 4 days after anthesis led to significant amounts of germinable seed being produced. Regrowth, which produced viable seed, usually occurred from plants mowed before first terminal heads began anthesis. A single mowing usually did not give satisfactory control due to wide differences in the maturity of plants in a natural population. When the terminal heads had reached late bud or more mature stages, 2,4-D ester [isoocyt] ester of (2,4-dichlorophenoxy) acetic acid] at M kg/ha or 2–2 kg/ha did not provide satisfactory control. In general, the most effective herbicide treatments tested at all three stages of maturity were dicamba (3,6-dichloro-o-anisic acid) at 056 kg/ha plus 2,4-D amine (dimethyl amine salt) at M kg/ha, 2,4-D ester at 4–4 kg/ha, or dicamba at 0–56 kg/ha. Inconsistent control of musk thistle results from variability within naturally occurring populations. Uneven development of stands as well as variation among plants are suggested as possible causes.     

Glyphosate effects on Canada thistle (Cirsium arvense) roots, root buds, and shoots

Glyphosate ? ? Mention of irademark or proprietary product does not constitute a gtiarantee or warranty oC the product by the U.S. Department of Agriculture and does nut imply its approval to the exclusion of other products thai may also be suitable.
was sprayed at 0009–1·12 kg a.i. ha^?1 on the foliage of large potted glasshouse-grown Canada thistle [Cirsium arvense (L.) Scop.], which had extensive, well-developed roots. Increasing the glyphosate rate progressively reduced the total number of visible adventitious root buds plus emerged secondary shoots per plant proportionately more than root biomass, 10 days after treatment. Cortical tissue of thickened propagative roots became soft, water-soaked, darkened, and some regions decomposed, exposing strands of vascular tissue. Lateral roots completely decomposed. When thickened roots were segmented to stimulate secondary shoot emergence from root buds 10 days after foliar treatment, Fewer secondary shoots emerged than expected from the number of visible adventitious root buds present on both control and herbicide-treated plants. Increasing the rate of glyphosate also reduced the regrowth potential of root buds proportionately more than root biomass. Regrowth potential was measured as the number of emerged secondary shoots 35 days after segmenting unearthed roots from plants that had been sprayed 10 days earlier. When foliar-applied at 0·28 kg ha^?1, glyphosate decreased the regrowth potential of root buds to zero in 2 and 3 days, as measured by secondary shoot dry weight and number, respectively, even though root fresh weight was unchanged 3 days after foliar treatment. These dose-response and time-course experiments demonstrate that glyphosate did not reduce root biomass as much as it decreased root bud numbers and secondary shoot regrowth potential from root buds.     

Soybean metabolism of chlorimuron ethyl: Physiological basis for soybean selectivity

Chlorimuron ethyl (2-([(4-chloro-6-methoxypyrimidine-2-yl)amino carbonyl]amino sulfonyl)benzoic acid, ethyl ester) is a highly active sulfonylurea herbicide for preemergence and postemergence use in soybeans. Excised soybean (Glycine max. cv. ‘Williams’) seedlings rapidly metabolized [¹⁴C]chlorimuron ethyl with a half-life of 1–3 hr. Common cocklebur (Xanthium pensylvancium Wallr.) and redroot pigweed (Amaranthus retroflexus L.), which are sensitive to chlorimuron ethyl, metabolized this herbicide much more slowly (half-life >30 hr). The major metabolite of chlorimuron ethyl in soybean seedlings is its homoglutathione conjugate, formed by displacement of the pyrimidinyl chlorine with the cysteine sulfhydryl group of homoglutathione. A minor metabolite is chlorimuron, the deesterified derivative of chlorimuron ethyl. Each of these metabolites is inactive against plant acetolactate synthase, the herbicidal target site of chlorimuron ethyl. Thus, soybean tolerance to chlorimuron ethyl results from its rapid metabolism in soybean seedlings to herbicidally inactive products.     

Overview of pest warning systems in Canada*

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加拿大进境大豆上检出菜豆荚斑驳病毒

本研究采用DAS ELISA、IC RT PCR及序列测定方法,对加拿大进境大豆种子进行菜豆荚斑驳病毒（Bean pod mottle virus, BPMV）和大豆花叶病毒（Soybean mosaic virus,SMV）检测,结果表明,BPMV的DAS ELISA和IC RT PCR检测结果均为阳性,且PCR扩增产物序列与已报道的BPMV基因序列相似性达97%以上,而SMV的DAS ELISA和IC RT PCR检测结果都为阴性。综合血清学、分子生物学检测结果,确认该批大豆携带有菜豆荚斑驳病毒。     

Interaction between purple nutsedge,maize and soybean

The study was designed to determine the mode of interaction between maize ( Zea mays L.) and soybean ( Glycine max Merr.) in association with purple nutsedge. This was investigated under glasshouse conditions using the replacement (substitutive) series design. Maize and soybean competed with purple nutsedge for growth resources, and purple nutsedge significantly retarded the growth and development of maize and soybean. Maize was more susceptible to purple nutsedge interference compared with soybean.     

灭草松对花生的安全性及除草生物活性测定

灭草松防除花生田阔叶杂草反枝苋、马齿苋及莎草科杂草碎米莎草等具有很好的效果,施药后40 d株防效为80.54%～92.72%,鲜重防效为72.68%～90.00%。对花生安全性好,施药后花生未见叶片黄化、畸形及苗株矮化等药害症状。施药后40 d,花生株高及株重与人工除草无显著性差异。说明灭草松对花生安全,对产量无影响,除草、增产效果显著。     

The effect of shade on the growth of variegated thistle (Silybum marianum L.) and cotton thistle (Onopordum sp.)*

The effects of shading on growth of the annual, variegated thistle (Silybum marianum L.) and the biennial, cotton thistle (Onopordum sp.*) were studied in an unheated glasshouse during winter. The response to relative level of irradiance (r.l.i.) of both thistles was similar, seedling growth being systematically reduced with increased shading. Relative growth rates of seedlings of both thistles were virtually identical at all levels of irradiance up to 0.68 r.l.i. Light compensation points for growth were close to 0.024 r.l.i., equivalent to c. 2 W m^?2 photosynthelically active radiation under the winter conditions. Increased shading progressively delayed time of initiation of leaves and decreased their total number at harvest. Apart from reduction in plant size, increased shading had only minor effects on gross seedling morphology until irradiance was reduced to less than 0.20 r.l.i. Although the thistle seedlings are quite shade tolerant, it is suggested that heavy shading by persistent pasture species in cool seasons could contribute to the control of thistle infestations in subhumid tableland environments of southeastern Australia.     

灭·喹·氟磺胺微乳剂对大豆田主要杂草的防效测定

为了解灭·喹·氟磺胺微乳剂对大豆田杂草的除草效果及安全性进行试验。结果表明:灭·喹·氟磺胺42%微乳剂能有效防除大豆田的稗草、藜、苋、苍耳、刺菜,总防效为87.5%以上;在试验剂量范围内对大豆安全。     

The selectivity of methabenzthiazuron between barley, perennial ryegrass and Poa trivialis

In field experiments methabenzthiazuron at 1.1 kg ai/ha applied pre-emergence gave good control of Poa trivialis L. in perennial ryegrass S23 which was undersown in spring barley (Zephyr); no significant damage to barley or perennial ryegrass resulted from 2.2 kg ai/ha. However this dose applied when barley had three to four leaves decreased the subsequent barley yield. In pot experiments in the glasshouse methabenzthiazuron was active mainly due to uptake through the soil. Much greater damage to barley and perennial ryegrass resulted when herbicide-treated soil was placed below seed level than above the seed. The difference was less marked with P. trivialis. The latter started to develop secondary roots near the soil surface earlier than either perennial ryegrass or spring barley.     

淡紫拟青霉发酵滤液对大豆胞囊线虫趋化性的影响

 实验室条件下,研究了大豆胞囊线虫幼虫对大豆根和根浸出液的趋化性以及淡紫拟青霉代谢产物对其趋化性的影响。结果表明,大豆胞囊线虫二龄幼虫(J₂)对大豆根存在着一定的趋化性,而淡紫拟青霉发酵滤液对J₂存在明显的驱避性。在根浸出液、真菌滤液及其混合液剂处理下,大豆胞囊线虫J₂在WA平板上靠近处理液的0~1cm区间中分布率存在极显著差异(P <0.0 1),而加样时间(液剂与线虫同时放置或提前2 4h处理)对其分布率没有显著影响。大豆幼根蘸取滤液后对线虫J₂在该区间的分布与不经处理的幼根差异显著(P <0.0 5),证明淡紫拟青霉发酵滤液可以明显地降低线虫与大豆根的亲和力,并强烈抑制线虫对大豆根的侵染。     

南美斑潜蝇对番茄的选择性与叶毛数和营养物质含量的关系

采用自由选择法测定了南美斑潜蝇对不同番茄品种的选择性。结果表明,南美斑潜蝇对21个供试番茄品种间的选择性存在显著差异,其对红枣小番茄的选择性最强,与对原番茄二号、中杂9号、圣星果、丰园红番茄、奥粉一号、大黄156、佳粉十五号等7个品种的选择性存在显著差异(p<0.05),而与其余13个品种的选择性差异不显著(p>0.05)。番茄不同品种间的叶毛数、可溶性糖含量及蛋白质含量存在显著差异。相关分析表明,南美斑潜蝇对番茄品种的选择性与叶毛数存在极显著的负相关关系(r=-0.675 2,p<0.001);与叶片的可溶性糖含量呈极显著正相关关系(r=0.554 7,p<0.01);而与叶片的蛋白质含量相关不显著。     

Plant links between eastern Asia and eastern Australia*

Plant links between eastern Asia and eastern Australia, regions showing considerable climatic differences, are discussed under five headings, namely, garden plants or ornamentals; naturalized plants; plants used in traditional Chinese medicine or Oriental Materia Medica; plants not yet well enough studied whose distribution suggests they may have originated in regions of the western Pacific; and comparisons between barnyardgrasses (Echinochloa spp.) in the two regions. A table is presented showing simple climatic data; mean monthly maximum and minimum temperatures and mean monthly and annual precipitation, along with latitude and altitude for 25 places extending from Monbetsu (about 44 N) in Hokkaido, Japan, through the subtropics and tropics to Hobart (approximately 43 S) in Tasmania, Australia.     

植物光合作用测定法确定灭草松和特丁津混用的最低致死剂量

在荷兰瓦赫宁根国际植物研究所温室内,用植物光合作用测定法研究了光合作用抑制型除草剂灭草松和特丁津桶混防除6种常见阔叶杂草的最低致死剂量。结果表明,药剂对杂草的生长有明显的抑制作用,在施药2 d后可观察到明显的灭草松的防效,在施药8 d后可观察到明显的特丁津的防效。随着施药剂量的增加,杂草叶片的植物光合作用测定(PPM)值和杂草地上部分鲜重显著下降。供试的6种杂草对该混剂的敏感性存在显著差异:红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感,ED90值分别为47.65、71.67和29.17 g/hm2;春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感,ED90值分别为96.91、114.20 g/hm2;而番茄不敏感。比较施药后2、4和6 d时杂草叶片的PPM值与施药后16 d时杂草地上部分鲜重防效的相关性可以发现,施药后4 d杂草叶片的PPM值与鲜重防效的相关性最好,相应的R2为0.924 7。表明PPM值可以较好地预测防效,在本试验条件下,施药后4 d的PPM值的预测效果最好。     

几丁质酶活性与大豆抗疫霉根腐病的关系

测定了大豆不同抗性品种接种大豆疫霉菌后的几丁质酶活性的变化情况。结果表明：未接种的不同大豆品种中的几丁质酶活性无明显区别。大豆疫霉菌侵染后不同抗性的大豆品种的几丁质酶的含量和活性均有不同程度的提高。抗病品种酶活性上升的速度比感病品种快,酶的高活性维持的时间较长。抗病品种在接种后24 h酶活性达到峰值,中感和感病品种在接种后48 h达到峰值。说明大豆疫霉菌可诱导几丁质酶产生,大豆品种的抗病性与几丁质酶的活性呈正相关关系。酶学特性的研究结果表明,酶反应的最适温度为45 ℃,最适pH为5。该酶在45 ℃以下,pH在4~6时酶活性稳定,超过60 ℃,pH超过7时酶活性丧失较快。Mn2+、Zn2+、Ba2+、Fe3+、Ca2+对酶活性有激活作用,Al3+、Ag+、Fe2+、K+、Mg2+、Cu2+、Hg2+对酶活性有抑制作用。     

13％2甲4氯水剂及与48％灭草松水剂混用防除耳叶水苋菜试验

通过不同剂量13％2甲4氯水剂及与48％灭草松水剂混用等处理来防除水稻田的耳叶水苋菜,进行药效对比试验。结果表明：在水稻分蘖盛期,3000、3750mL／hm^213％2甲4氯水剂对耳叶水苋菜有较好的防效,药后15d的防效分别达88．55％、91．04％,且安全性较好。     

大豆孢囊线虫大豆和烟草群体寄生性比较分析

通过盆栽试验,测定大豆孢囊线虫(Heterodera glycines,soybean cyst nematode,SCN)大豆群体(SCNS)和烟草群体(SCN_T)对5个大豆品种(SCN生理小种鉴别寄主)和9个烟草栽培品种的寄生性。结果发现,SCNS在5个大豆品种上的平均繁殖系数(Rf=P_f/P_i)为0.60(0.14~1.90),在感病对照品种‘Lee’上平均Rf高达1.90;SCN_T在5个大豆品种上的平均Rf为0.18(0.06~0.44),在感病对照品种‘Lee’上Rf为0.44。SCNS对9个烟草品种几乎无寄生性,平均Rf为0.06(0.00~0.10);SCN_T则能寄生9个烟草品种,平均Rf为1.26(0.45~1.95)。接种35d后,在不同大豆品种根内SCNS和SCN_T的幼虫数量均极少,侵染率基本相同;在不同烟草品种根内SCNS的幼虫数量均为0,而SCN_T的幼虫数量平均为26.5(14.6~57.0)。研究表明,供试SCNS属于14号生理小种,但供试SCN_T与之寄生性差异大,属于新的SCN致病类型。     

Chemical structure and fungicide selectivity

Adoxophyes orana could be mass-reared on a wheat germ medium with agar as a gelating agent or with agar replaced by lucerne meal. On these media, production reached 131 and 111 moths per rearing container, respectively. Good sanitary measures and well chosen rearing conditions were important. The rearing system was analysed and modelled by a computer programme written in Fortran IV, which allowed calculation of the optimum rearing method. The minimum cost per moth was calculated atf0.015–0.03, depending on wages and size of culture. The calculations were based on preliminary estimates and need to be refined.     

Effect of herbicides alachlor,metolachlor and oryzalin on soybean (Glycine max) leaf nitrate reductase activity*

Experiments were conducted in the field, greenhouse, and with leaf disks in test tubes to determine whether the herbicides alachlor, metolachlor, and oryzalin, commonly used for weed control in soybeans [Glycine max (L) Mer.] affect in vivo nitrate reductase activity. Plants in the field, growing in soil treated at the recommended rates were sampled at 30 and 60 days after planting. Plants grown in the greenhouse in pots non-treated and treated at the recommended area rates and at 1/2 and 3/2 times these rates were sampled at 20 and 40 days for chemical assay. In addition plants were grown in the greenhouse and sampled at 30 days for chemical assay after direct addition of the herbicide dilutions to the reagent solutions. No differences, statistically significant according to Duncan's test at the 5% level were revealed between controls and any treatment.