共查询到20条相似文献，搜索用时 78 毫秒
1.
为明确牡丹皮(Cortex Moutan Radicis)的除草活性并初步探索其活性成分分离条件,采用平皿法、土壤喷雾法及茎叶喷雾法测定了牡丹皮不同极性溶剂萃取物对反枝苋Amaranthus retroflexus和稗Echinochloa crus-galli的除草活性。平皿法测定结果显示,在1 mg/mL浓度下,牡丹皮正丁醇萃取物的除草活性最强,对反枝苋幼根和幼茎的抑制率分别为67.88%和65.71%,对稗草幼根和幼茎的抑制率分别为68.72%和71.32%;毒力测定结果表明,牡丹皮正丁醇萃取物对反枝苋幼根和幼茎的IC50分别为12.28 mg/L和19.67 mg/L,对稗草幼根和幼茎的IC50分别为43.35 mg/L和72.79 mg/L。土壤喷雾法和茎叶喷雾法测定结果显示,在5 mg/mL浓度下,牡丹皮正丁醇萃取物对反枝苋和稗草的鲜重抑制率最高,其中土壤喷雾法对反枝苋和稗草的鲜重抑制率分别为81.43%和83.18%;茎叶喷雾法对两种杂草的鲜重抑制率分别为80.83%和83.65%。由此可见,牡丹皮的除草活性成分主要集中在正丁醇... 相似文献
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为明确唑嘧磺草胺、丙炔氟草胺与乙草胺混用的联合作用特性及其对大豆田杂草的防除效果,采用温室盆栽法和田间药效试验,分别评价了混配组方的联合作用类型及对大豆田杂草的防除效果。温室盆栽试验结果表明:唑嘧磺草胺、丙炔氟草胺与乙草胺混用对稗草、马唐和苘麻的联合作用类型为相加作用,对反枝苋为相加或增效作用;当唑嘧磺草胺、丙炔氟草胺和乙草胺以质量比2 : 3 : 45混用时,对反枝苋的增效作用最强。田间药效试验结果显示:唑嘧磺草胺、丙炔氟草胺和乙草胺以质量比2 : 3 : 45混用,当用量为有效成分800和1 000 g/hm2时,可有效控制大豆田中杂草的为害,且对大豆安全。 相似文献
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《中国植保导刊》2020,(7)
为明确多靶标除草剂协同使用对水直播稻田内抗性稗草的防除效果及对水稻的安全性,在长江中下游地区5省5地开展水直播稻田化学除草试验,采用封杀结合的二次化学除草技术,即播后苗前统一采用300 g/L丙草胺乳油土壤封闭处理,再在稗草3～4叶期喷施不同茎叶处理除草剂。发现使用40%氰氟草酯油悬浮剂、10%噁唑·氰氟乳油进行茎叶处理防除稗草的效果最好,药后35 d株防效均在98%以上;其次是23%五氟·氰氟草油悬浮剂、15%嗪吡·五氟油悬浮剂、100 g/L氰氟草酯乳油+360 g/L异噁草松乳油、3%氯氟吡啶酯油悬浮剂+300 g/L丙草胺乳油,药后35 d株防效均在85%以上;25 g/L五氟磺草胺油悬浮剂、50%二氯喹啉酸可湿性粉剂防除效果较差,药后35 d在浙江金华、湖北黄梅、湖南汉寿试验点的株防效均低于85%。将不同作用机制除草剂混配使用,可有效降低除草剂选择压,提高对抗性稗草的防效。 相似文献
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为明确以天然产物阿魏酸为母体进行化学结构改造得到的化合物4-羟基-3-甲氧基肉桂酸乙酯的生物活性及其除草机制,利用茎叶喷雾法和小杯法测定其对马唐和反枝苋的生物活性,基于生理生化指标及功能基因表达量对其除草作用机制进行研究。结果表明:4-羟基-3-甲氧基肉桂酸乙酯对马唐茎叶鲜重抑制中浓度IC50为46.27 mg/L;对反枝苋胚根和芽的IC50分别为129.94 mg/L和147.33 mg/L,且在500 mg/L浓度处理时可抑制反枝苋种子萌发;对拟南芥根长的IC50为43.82 mg/L,在160 mg/L浓度处理时拟南芥几乎停止生长、叶片发黄、根毛堆积。该化合物以1 000 mg/L浓度处理马唐叶片2、3、8 h后,电导率较对照组分别增加了22.70%、18.46%和25.62%;1 000 mg/L浓度处理下叶绿素a/b为2.43,较对照的3.62显著下降;处理后叶表微观结构观察发现化合物浓度越大,植物叶片表皮毛倒伏和褶皱越严重;拟南芥AT4G04820基因表达量显著下降,在处理45 min时下降最显著,与对照组相差42.52倍,微管蛋白含量下降,造成微管解离,从而抑制植物生长。表明4-羟基-3-甲氧基肉桂酸乙酯具有较强的除草活性,可能通过破坏细胞结构、抑制光合作用及阻止根生长等途径使杂草生长受到抑制甚至死亡。 相似文献
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硝草酮在玉米田的除草效果及安全性研究 总被引：2，自引：0，他引：2
2005年在北京市小汤山进行了田间试验,对硝草酮做茎叶处理的除草效果及对玉米的安全性进行了研究。结果表明:供试试验田反枝苋、苍耳、苘麻、苦蘵、龙葵、稗草、马唐对硝草酮敏感。铁苋菜、马齿苋对该药中度敏感。牛筋草、狗尾草、葎草、野西瓜苗、扁蓄、打碗花、刺儿菜、半夏对该药不敏感。该药对阔叶杂草防效好于对禾本科杂草的效果。供试剂量范围内,随施药量增加对敏感杂草防效提高。杂草3～4叶期施用10%硝草酮水悬浮剂70g/667m2的处理对稗草和马唐鲜重防效接近90%,对反枝苋、苍耳、苘麻鲜重防效在90%以上;100g/667m2及140g/667m2的处理对稗草和马唐鲜重防效为90%～95%,对反枝苋、苍耳、苘麻鲜重防效在95%～100%。杂草叶龄越小,硝草酮对其防效越高。禾本科杂草3～4叶期前用药防效理想,阔叶杂草反枝苋、苘麻等10叶期施药也能达到较好防效。10%硝草酮水悬浮剂施药剂量应为70～100g/667m2商品量。硝草酮100～140g/667m2的处理个别玉米植株叶片表现白化,叶片白化的植株占全小区植株数的3%～20%,但随作物生长药害症状消失。硝草酮水悬浮剂40～70g/667m2在玉米3～8叶期用药,对玉米中单44产量无影响。该剂量在玉米3～4叶期用药,对8个供试玉米品种生长及产量无影响。 相似文献
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禾耐斯与农达混用防除免耕玉米田杂草的效果 总被引：1，自引：0，他引：1
用90％禾耐斯乳油50～75ml／亩＋41％农达水剂100～150ml／亩可有效地防除免耕玉米田内的马唐、狗尾草、旱稗、牛筋草、藜、铁苋菜和反枝苋等多种杂草,兼备了禾耐斯与农达的除草特点,对大草具有茎叶处理效果,同时还具有封闭除草作用,二者混用也具有一定程度的增效作用。 相似文献
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硝磺草酮的除草活性及对玉米的安全性 总被引：2，自引：0，他引：2
通过温室盆栽试验,研究茎叶喷施硝磺草酮对反枝苋、稗草和千金子的活性及对玉米的安全性。结果表明硝磺草酮对玉米和反枝苋、千金子、稗草的选择性指数分别为6．73、5．95、5．34。说明硝磺草酮对玉米和杂草的选择性很强,可安全地使用茎叶处理法防除玉米田杂草。 相似文献
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以2,5-二氯苯胺、6-氯水杨醛和4,6-二甲氧基-2-甲砜基嘧啶为原料,设计并合成了2-嘧啶氧基-N-芳基苄胺类化合物N-(2,5-二氯苯基)-6-氯-2-(4,6-二甲氧基-2-嘧啶氧基)苄胺,其化学结构经核磁共振氢谱和质谱分析确证。室内生物测定结果显示,该化合物对单子叶杂草稗草、马唐、狗尾草以及双子叶杂草反枝苋、芥菜具有较好的芽后除草活性,在有效剂量75 g/hm2下其抑制率达到80% ~100%;对棉花安全,在有效剂量225 g/hm2下未产生明显药害,在棉花和棉田杂草反枝苋之间的选择性系数为24.93。初步表明该化合物在棉田具有一定开发应用价值。 相似文献
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The community assembly rules and species coexistence have always been interested by ecologists.The community phylogenetic structure is the consequence of the interaction process between the organisms and the abiotic environmentand has been used to explain the relative impactof abiotic and biotic factors on species co-existence. In recent years, grassland degradation and biodiversity loss have become increasingly severe on the Mongolian Plateau,while the drivers for these changes are not clearly explored, especially whether climate change is a main factor is debated in academia. In this study, we examined the phylogenetic structure of grassland communities along five transects of climate aridity on the Mongolian Plateau, and analyzed their relations with environmental factors, with the aims to understand theformation mechanismof the grasslandcommunities and the role of climatic factors.We surveyed grassland communities at 81 sites along the five transects,and calculated theirnet relatedness index (NRI)attwo different quadratscales (smallscale of 1 m2 and largescale of 5 m2) to characterize thecommunity phylogenetic structure andanalyzeitsrelationship withthe key 11 environmental factors. We also calculatedthe generalized UniFrac distance (GUniFrac)among the grassland communities to quantify the influence of spatial distance and environmental distance on the phylogenetic β diversity. The results indicated that plant community survey using the largescalequadrat contained sufficient species to represent community compositions. The community phylogenetic structure of grasslandswas significantly overdispersed at both the small and largescales, and the degree of overdispersion was greater at the large scalethan at the smallscale, suggesting that competitive exclusion instead of habitat filtering played a major role in determination of community composition. Altitude was the main factor affecting the community phylogenetic structure, whereas climatic factors, such as precipitation and temperature, had limited influence. Theprincipal component analysis of the 11 environmental factorsrevealed that 94.04% of their variation was accounted by the first four principal components.Moreover only 14.29% and 23.26% of the variation in community phylogenetic structurewere explained by the first four principal componentsat the small and largescales, respectively. Phylogenetic β diversity was slightly significantly correlated with both spatial distance and environmental distance, however,environmental distancehada less explanatory powerthan spatial distance, indicating a limited environmental effect on the community phylogenetic structure of grasslands on the Mongolian Plateau. In view of the limited effect of climatic factors on the community phylogenetic structure of grasslands, climate change may have a smaller impact on grassland degradation than previously thought. 相似文献
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YuanRun ZHENG LianHe JIANG Yong GAO Xi CHEN GePing LUO XianWei FENG YunJiang YU Ping AN Yi YU Hideyuki SHIMIZU 《干旱区科学》2013,5(3):331-339
Clarifying the persistence time of seedlings of dominant species under continual drought will help us understand responses of ecosystems to global climate change and improve revegetation efforts.Drought tolerance of four dominant psammophytic shrub species occurring in different environments was studied in the semi-arid areas of Inner Mongolian grasslands.Seedlings of Hedysarum laeve,Caragana korshinskii,Artemisia sphaerocephala and Artemisia ordosica were grown under four air temperature regimes(night/day:12.5/22.5℃,15/25℃,17.5/27.5℃ and 20/30℃)within climate(air temperature and humidity)controlled,naturally lit glasshouses with a night/day relative humidity of 70%/50%.Pots were watered to field capacity for each temperature treatment.Soil water condition was monitored by weighting each pot every day using an electronic balance.Date of seedling death for each treatment was recorded and the dead plants were harvested.Plant dry weights were determined after oven drying at 80℃ for 3 days.Two Artemisia species had higher growth rates than H.laeve and C.korshinskii,and the growth of all four species increased with increasing temperatures.The two Artemisia species had the highest leaf biomass increment,followed by C.korshinskii,and then H.laeve.Shoot biomass increment was higher for A.ordosica and C.korshinskii,intermediate for A.sphaerocephala and lowest for H.laeve.C.korshinskii had the highest root biomass increment.The final soil water content at death for all four species varied from 1% to 2%.C.korshinskii,A.sphaerocephala,H.laeve and A.ordosica survived for 25-43,24-41,26-41,and 24-37 days without watering,respectively.C.korshinskii,A.sphaerocephala,H.Laeve,and A.ordosica seedlings survived longer at the lowest temperatures(12.5/22.5℃)than at the highest temperatures(20/30℃)by 18,17,15 and 13 days,respectively.Increased climatic temperatures induce the death of seedlings in years with long intervals between rainfall events.The adaptation of seedlings to droughts should be emphasized in revegetation efforts in the Ordos Plateau,Inner Mongolia. 相似文献
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本文选苹果重要病害轮纹病作为研究对象，通过皿内抑菌试验、抑制孢子萌发试验、离体枝条及田间药效试验，研究中草药源杀菌剂“轮纹一扫光”对苹果枝干轮纹病的防治作用，以便为果农提供有效防治该病害的药剂。结果表明，在室内试验中，“轮纹一扫光”对菌丝生长、分生孢子器的产生、孢子的萌发有100%的抑制作用；在离体枝条的试验中，“轮纹一扫光”的保护效果为68.06%，治疗效果较好为87.26%；田间防治试验中，刮除病斑后“轮纹一扫光”的防治效果达到100%。该研究结果为苹果轮纹病的生物防治提供了新思路，对苹果病害的防治具有重要意义。 相似文献
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Masamitsu Tsukamoto Tadashi Nakamura Hirohiko Kimura Hitoshi Nakayama 《Journal of Pesticide Science》2021,46(2):125
Herein, we provide a brief overview of the synthesis and applications of trifluoromethylpyridine (TFMP) and its derivatives in the agrochemical and pharmaceutical industries. Currently, the major use of TFMP derivatives is in the protection of crops from pests. Fluazifop-butyl was the first TFMP derivative introduced to the agrochemical market, and since then, more than 20 new TFMP-containing agrochemicals have acquired ISO common names. Several TFMP derivatives are also used in the pharmaceutical and veterinary industries; five pharmaceutical and two veterinary products containing the TFMP moiety have been granted market approval, and many candidates are currently undergoing clinical trials. The biological activities of TFMP derivatives are thought to be due to the combination of the unique physicochemical properties of the fluorine atom and the unique characteristics of the pyridine moiety. It is expected that many novel applications of TFMP will be discovered in the future. 相似文献
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Reliable estimation of the mass-flux profiles of aeolian sediment is essential for predicting sediment transport rates accurately and designing measures to cope with wind-erosion. Vertical mass-flux profiles from seventeen wind-erosion events were re-evaluated using five typical models based on observed data obtained from a smooth bare field at the southern fringe of the Taklimakan Desert, China. The results showed that the exponential-function model and the logarithmic-function model exhibited the poorest fit between observed and predicted mass-flux profiles. The power-function model and the modified power-function model improved the fit to field data to an equivalent extent, while the five-parameter combined-function model with a scale constant(σ) of 0.00001 m(different from the σ value proposed by Fryear, which represented the height above which 50% of the total mass flux occurred) was verified as the best for describing the vertical aeolian sediment mass-flux profiles using goodness of fit(R2) and the Akaike Information Criterion(AIC) values to evaluate model performance. According to relationships among model parameters, the modified power model played a prominent explanatory role in describing the vertical profiles of the observed data, whereas the exponential model played a coordinating role. In addition, it was found that the vertical profiles could not be extrapolated using the five selected models or easily estimated using an efficient model without field observations by a near-surface sampler at 0 to 0.05 m. 相似文献
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Extracted from the dried root bark of Dictamnus dasycarpus Turcz., Family Rutaceae, fraxinellone exhibited multiple bioactivities, e.g. feeding-deterrent, growth-control and toxic activities against insects. We investigated the effect of fraxinellone on fifth instar larvae of eastern armyworm, Mythimna separata Walker. Through traditional stomach-poison method, fraxinellone showed the delayed and strong stomach-poison activity. Light and electron microscope observations revealed, treatment with 20 mg/mL fraxinellone, increasing damages of the larvae midgut epithelium along with time. Fraxinellone destroyed the peritrophic membrane of the midgut of larvae of M. separata. The organelles of treated larvae of M. separata changed obviously, e.g. the rough endoplasmic reticulum dilated, some of mitochondrial cristaes disappeared and got vacuolated, the wall of globet cell invaginated, the inner organelle disordered, the chromatin became concentrated, and the quantities of secondary lysosome increased. Meanwhile, fraxinellone could let microvilli rupture or incline, even partially fall off. 相似文献
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Abdulla S SAPAROV 《干旱区科学》2013,5(2):166-171
This paper presented the results from the study of irrigation erosion of irrigated lands in southern Kazakhstan. The main purpose of the work is the conservation of the fertility of irrigated soils, and then the soils of the upper, middle and lower sections of the slopes at the experimental site were studied. Based on field investigations, authors studied the water resistance of aggregates of gray-brown soils and light gray soils before and after irrigation and qualitative indicators of changes in physical and chemical properties of structured soils in irrigation were determined by conventional methods of soil research. The results indicated that the changes in the physical properties of soils by using polymeric compounds created a fundamentally new opportunity to control water erosion of soils. 相似文献
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Cyclohexanediones (e.g., sethoxydim) are known to be inhibitors of plastid acetyl-CoA carboxylase (ACCase) of monocotyledonous plants and provoke plant death. When rape leaves were treated with 10−3 M sethoxydim, growth rate, chlorophyll and lipid contents were reduced, but plant resisted to herbicide. [1–14C] Acetate labelling showed that lipid synthesis was affected by sethoxydim, probably through inhibition of chloroplast homomeric ACCase activity, and the fatty acid synthase activity (FAS) was reduced because of malonyl-CoA deficiency. In contrast, sethoxydim treatment provoked an increase in phenylalanine ammonia lyase (PAL) activity with an accumulation of cinnamic acid, naringenin and anthocyanins. The accumulation of anthocyanins seems to reduce the damaging effect of the herbicide stress. Thus, in plant cell, the flux of carbon seems to be oriented towards protective mechanisms, and the two ACCases could have an important role in this orientation. 相似文献
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绿僵菌Metarhizium spp.是虫生真菌的主要类群之一,是当前世界上研究和应用最广的虫生真菌之一。由于绿僵菌能在自然土壤环境下长期存活,对地下害虫的控制具有明显优势。本研究从蛴螬僵虫上分离出一株寄生真菌,结合形态学和EF-1α基因5'端序列分析结果鉴定为黄绿绿僵菌Metarhizium flavoviride var. pemphigi。菌株培养的试验表明,乳糖有利于该菌株的菌丝生长,葡萄糖有利于该菌株产孢,KNO3为该菌株最适宜的氮源,在乳糖和KNO3为碳氮源时,C/N比为34:1有利于菌丝生长及产孢,添入微量元素Mn能促进产孢。在灭菌土中含5×106孢子/g时该菌株的对筛胸梳爪叩甲幼虫的校正累积死亡率为57.14%,幼虫逃逸率为4.76%。 相似文献