稗属植物的分类与系统学研究概况

稗属杂草是一类严重的恶性杂草,广泛分布于全球,对多种农作物造成了严重危害。由于稗属植物在形态上变异强烈,这为稗属的分类及防除带来了一定困难。本文综述了稗属植物形态学、细胞学、分子标记等方面的研究概况,旨在为该类植物的综合管理提供依据。     

多年生杂草问荆生物学特性的研究进展

本文总结了多年生杂草问荆的名称，分布与习性，生长发育及其繁殖特性等，并且对于如何进一步研究问荆的生物学特性提出了几点建议。     

稻田稗属杂草田间种群对五氟磺草胺的抗性监测

五氟磺草胺是一种乙酰乳酸合成酶抑制剂类除草剂.为探明稻田稗草对五氟磺草胺的抗性现状,采用整株生物测定法测定了采自中国7省70地稻区的稗草田间种群对五氟磺草胺的抗性.结果表明:所监测的稗草种群对五氟磺草胺均产生了不同程度的抗性,其中高水平抗性种群达50.0％,中水平抗性种群达47.1％,低水平抗性种群为2.9％,无敏感种...     

稻田稗草生物学特性及其综合防除

稗草为世界性恶性杂草,能够危害大部分农作物如水稻、大豆、棉花、玉米、小麦、蔬菜、果树和牧草。我国稗草有9种5变种,广泛分布于各省耕田和路边。由于种子休眠、不同环境条件下的萌发以及在与水稻竞争中强的生长势,稗草是稻田中分布最广、危害最重的杂草。本文从稻田稗草的休眠与萌发方面详细综述了其生物学特性,并探讨了稻田稗草综合防治方法,展望了今后稗草防治的新动向。     

贵州南部地区苎麻地杂草发生规律及主要杂草生物学特性观察

贵州南部地区苎麻地杂草发生规律及主要杂草生物学特性观察罗天琼，莫本田，卢敏（贵州麻类科学研究所独山５５８２００）苎麻是一种重要的经济作物，其纤维是纺织工业的主要原料。世界上很多国家都有大面积种植，我国湖南、湖北、江西、广西、四川、贵州等省区也都有种植...     

稗草致病菌--尖角突脐孢菌的生物学特性

从稗草病株上分离到一尖角突脐孢菌.对该菌生物学特性的研究表明,其菌丝生长的适宜温度为25～32℃,最适温度为30℃,最适pH为4～6, 对光照无要求; 碳、氮、磷和硫等元素是该菌菌丝体生长的必需元素,钾和镁对菌丝体的生长有极大的促进作用,加入少量的铁和锌对菌丝生长有利,铜元素抑制该菌的生长; 缺碳和氮素明显影响菌落的生长.该菌生长最合适的速效碳源是葡萄糖,缓效碳源是玉米粉,最适无机氮源是硝酸铵,最适有机氮源是酵母粉; 分生孢子萌发的适合温度范围为20～30℃; 分生孢子快速萌发的酸碱条件为初始pH4～7,最佳初始pH值为5; 光照不利于分生孢子快速萌发.     

二氯喹啉酸抗性生物型(QR)稗草和敏感性生物型(QS)稗草生物学特性比较研究

在非竞争性条件下在田间对二氯喹啉酸敏感性生物型（QS）稗草和抗性生物型（QR）稗草的生物学特性进行了系统比较研究，结果表明敏感性生物型稗草在植株高度、根及地上部分生长量、株穗粒度及种子千粒重方面要优于抗性生物型稗草；两者移植后单株分蘖能力没有什么大的差异；抗性生物型稗草剑叶长而窄，敏感性生物型稗草剑叶短而宽；抗性生物型较敏感性生物型稗草生活史短，抗性生物型稗草在移植28d时抽穗率为12.26%，而敏感性生物型稗草在移植46d时抽穗率为15.37%。     

杂草图谱

~~杂草图谱     

阔稗威防除稻田杂草研究初报

通过对６种不同除草剂药效筛选试验结果表明，阔稗威防除稻田杂草效果最好，既能防除禾本科和莎草科杂草，又能兼除阔叶杂草。大田小型示范，除草效果达８９．５～１００％，增产１５．１０～３０．４７％。     

Physiochemical factors affecting the salt tolerance of Echinochloa crus-galli Beauv. var. formosensis Ohwi

The effects of NaCl-induced stress on physiochemical factors such as inorganic cations, proline, malondialdehyde (MDA) and polyamines were investigated in the gramineous weed, Echinochloa crus-galli Beauv. var. formosensis Ohwi ( E. crus-galli ) and rice ( Oryza sativa L. cv. Nipponbare). Growth inhibition at the 2nd leaf stage under salt stress was more severe in rice than in E. crus-galli . Water content in the 2nd leaves was also more severely decreased in rice, indicating that E. crus-galli was more salt-tolerant. After NaCl treatment, Na⁺ accumulated in the 2nd leaves of both plant species but not in their roots. Proline accumulation in the 2nd leaves was significantly higher in salt stressed E. crus-galli than in rice, suggesting the significance of proline production in the salt tolerance of this weed. Content of MDA of the rice increased more greatly with NaCl treatment than that in E. crus-galli . NaCl treatment affected polyamine metabolism of both plant species, but the response of each plant to salt stress was somewhat different, especially in the leaves. Leaf putrescine and spermidine contents were high in non-stressed plants in salt-sensitive rice, although rather lower in E. crus-galli in response to NaCl concentrations. These results indicate that an increase in proline and changes in polyamines relates to the salt tolerance of E. crus-galli .     

Joint action of Cochliobolus lunatus and atrazine on Echinochloa crus-galli (L.) Beauv.

The potential of the endemic fungus Cochliobolus lunatus as a biological control agent against Echinochloa crus-galli was investigated. Under appropriate conditions the fungus produced leaf necrosis on E. crus-galli resulting in death of young seedlings. However, plants with more than two leaves mostly recovered after some time. Bean, barley, maize, oat, rye, tomato and wheat were highly resistant to the fungus. In experiments in a climate room or in a glasshouse E. crus-galli with more than two leaves could effectively be controlled by C. lunatus in combination with a sub-lethal dosage of atrazine as low as 2.5 mg m^?2 due to a positive interaction between fungus and herbicide.     

Timing of molinate applications for the control of Echinochloa crus-galli (L.) Beauv. in rice

Application of molinate to young rice (Oryza sativa L.) immediately before the ihird flushing irrigalion, when seedlings of E. crus-galli were in the 2 2½-leaf stage, resulted m bctier weed control and greater increases in crop growth and yield than earlier application prior to ihe second flushing, or than later application prior to permanent flooding, Molinale applied prior to a flushing was lost from the soil rapidly. 79–85% loss within 13 days. Chemical remaining after this time disappeared more slowly and little further loss occurred until permaneni flooding 24 days afier application. Despite the rapid dissipation of molinate. application of 3 kg/ha before a flushing irrigation controlled newly-emerging E. crus-galli until permaneni Hood ing I S days after spraying. Epoque des traiiemenia au molinaie pour la lutte contre Echinochloa crus galli (L.) Beauv. en rizière L'applicaiion du molinate sur du riz [Oryza saliva L.) jeune. immédiatement apres la troisiéme irrigation par submersion, lorsque les plantules d’E crus galliétaient au stade 2 feuilles/2 feuilles 1/2adonné un meilleur résultat et des augmentations de croissance et de rendement du riz plus grandes qu'une appli cation plus précoce. avant la seconde irrigation, on qu'une application plus tardive avant la submersion permanente. Le molinate appliqué avant une irrigation a disparu rapidementdu sol: 79 à 85% de perte en 13 jours, Le produit persistant après cette date a disparu pius leniement et il n'y a euque peude pertes ultérieures jusquà la submersion permanenie. 24 jours apres le traitement. En dépit de la rapide dégradation du molinate. un traitement à 3 kg/ha avant une irrigation par submersion a été efficace contre les E. crus galli nouvellement levés. jusquà la submersion permanentc. 15 jours après le traitement. Der günstigste Zeitpunkt für Anwendung von Molinat zur Bekämpfung von Echinochloa crus-galli (L.) Beauv. in Reis Die Anwendung von Molinate injungem Reis (Oryza sativa L.) unmittelbar vor der dritten Rieselbewä.sserung. wenn die Pflanzen von E. crus-galli im 2 bis 2 1/2-Blatlsiadium waren. bewirkte eine bessere Unkrautbekämpfung. ein bcsseres Wachstum der Kultur und einen höheren Ertrag alseine Be handlung zu einem früheren Zeitpunkt vor der zweiien Rieselbewässerung. Oder eine spätere Anwendung vor der permanenten Überstauung. Wurde Molmat vor emer Rieselbewässerung appliziert. traten innerhalb von 13 Tagen Herbizidveriuste von 79–85% im Boden ein Der Rest des Herbizids verschwand langsamer. und bis zum Zeitpunkt der permanenten Über-stauung—24 Tage nach der Applikation—ging nur wenig Her-bizid verloren. Troiz des schnellen Veriusts des Herbizids wurden durch die Anwendung von 3 kg/ha Molinat vor einer Rieselbewässerung frisch aufgelaufene E.crus-galli-Pflanzen bis zum Zeitpunki der permanenten Überstauung bckämpft. Der Zeilraum zwischen Spritzung und Überstauung betrug in den Versuchen 1 5 Tage.     

银胶菊花对苘麻和稗的化感作用

通过室内培养皿法,研究了银胶菊花水浸提液及其乙酸乙酯相、正丁醇相、剩余水相不同极性组分对苘麻和稗种子萌发及幼苗生长的影响。定性测定结果表明,在50 g/L浓度处理下,水浸提液完全抑制苘麻和稗种子萌发,对苘麻和稗根长、芽长、鲜重抑制率分别为82.6%、89.1%、84.3%和91.7%、55.8%、39.1%;正丁醇相抑制苘麻种子萌发和幼苗生长最强,乙酸乙酯相抑制稗种子萌发和幼苗生长最强。定量测定结果表明,在1 g/L浓度处理下,乙酸乙酯相生物活性最高,苘麻和稗种子萌发率分别为13.3%和33.3%,对苘麻和稗根长、芽长、鲜重的抑制率分别为63.1%、80.0%、58.3%和51.3%、26.7%、23.3%。     

江苏省昆山市直播稻田千金子、稗草等回升的原因与防除措施

20世纪90年代以来，直播水稻技术在我市迅速普及，种植面积逐年增加，至今已占水稻种植面积的60％以上。在开始种植直播稻的几年里，草害是制约其发展的重要原因，随着化除技术的不断进步，90年代中期，直播稻田除草技术已基本成熟，因而种植面积发展迅速。然而，近年来直播水稻生产中出现了化学除草效果下降，杂草危害有抬头的趋势，必须引起足够重视。     

Differential ability of alcohol fermentation between the seeds of flooding-tolerant and flooding-susceptible varieties of Echinochloa crus-galli (L.) Beauv.

Seed germination and respiratory metabolism under aerobic and anaerobic conditions were studied in the flooding-tolerant and flooding-susceptible varieties of Echinochloa crus-galli with an identical genome and common ancestry . In the flooding-tolerant E. crus-galli var. formosensis , the seeds imbibed under nitrogen could germinate and exhibited an I/N quotient > 0.6. They accelerated glycolysis and concomitantly produced large and equimolar quantities of carbon dioxide and ethanol, suggesting that the seeds of this variety showed operation of the Pasteur effect and respired through alcohol fermentation under anaerobic conditions. The seeds excreted most of the toxic fermentation product. In contrast, the seeds of the flooding-susceptible E. crus-galli var. praticola were capable of germinating only under aerobic conditions through the conventional aerobic respiration and were unable to anaerobically respire to germinate through alcohol fermentation regardless of the presence of both sufficient alcohol dehydrogenase activity and a high redox charge of the pyridine nucleotides.     

Effects of surfactants on primisulfuron activity in barnyardgrass (Echinochloa crus-galli [L.] Beauv.) and green foxtail (Setaria viridis [L.] Beauv.)

Laboratory and greenhouse studies were conducted to measure the contact angle of primisulfuron droplets with and without surfactants on the leaf surfaces of barnyardgrass and green foxtail, to determine the primisulfuron activity on these weed species, and to examine the spray deposit of primisulfuron with and without surfactants on the leaf surface of green foxtail using scanning electron microscopy. A non-ionic surfactant (NIS) and an organosilicone wetting agent (OWA) were used. The contact angles of 1 μL droplets were measured on the leaf surface using a goniometer. The activity of primisulfuron on barnyardgrass and green foxtail was assessed at 3 weeks after treatment based on visual injury and the fresh weight. The contact angles of the droplets of primisulfuron on the adaxial surface of the barnyardgrass and green foxtail leaves were 152° and 127°, respectively, when applied without surfactant. The addition of either surfactant markedly reduced the contact angle for both weed species, which was lowest when the OWA was added to primisulfuron. The percentage injury of barnyardgrass was very low, even at the higher rate of primisulfuron, regardless of the surfactant. Primisulfuron at 40 g ha⁻¹ controlled 43% of green foxtail without surfactant, which increased to 65% with the NIS and 83% with the OWA. Primisulfuron with a surfactant markedly reduced the fresh weight of green foxtail compared with primisulfuron applied alone, regardless of the primisulfuron rate and surfactant type. The scanning electron micrographs showed a uniform deposit of spray droplets, with close contact of the droplets to the leaf epicuticular surface in green foxtail in the presence of a surfactant compared with no surfactant. The enhanced primisulfuron activity on green foxtail with surfactants was related to the reduced contact angle and uniform deposition of the primisulfuron spray droplets on the leaf surface.     

Weed biology serves practical weed management

Weed science is an applied science that serves practical weed management. Traditionally, effective weed management has been dependent upon farmers gaining knowledge of the characteristics of the weeds they were managing. The advent of herbicides has not made this knowledge-based approach redundant and problems, including herbicide resistant weeds, have made weed biology studies necessary even in the herbicide era. Weed populations continue to evolve and weed problems persist, sustaining a requirement for effective management strategies. In this paper, we exhibit several approaches to linking weed biology studies to practical weed management. These approaches demonstrate both the value of and synergy between an in-depth knowledge of weed biology and weed management practices to provide practical solutions in the field.     

Characterization of aryl acylamidase activity from propanil-resistant barnyardgrass (Echinochloa crus-galli [L.] Beauv.)

The enzyme, aryl acylamidase, was characterized in propanil-susceptible and propanil-resistant barnyardgrass with respect to kinetic parameters, the effects of inhibitors, and the levels of activity in dark- and light-grown tissues. The enzyme reaction in the resistant tissue preparation proceeded linearly with time over a 5 h time course, while activity in the susceptible tissue preparation was 2- to 4-fold lower and the activity tended to decrease after 2 h. The apparent K_m values were 62.1 mmol L⁻¹ and 3.1 mmol L⁻¹ for the enzyme activity in the susceptible and resistant tissue preparations, respectively. Two herbicides (anilofos and piperophos), previously shown to synergize propanil injury against the resistant biotype, were found to be potent inhibitors of the in vitro aryl acylamidase activity.