用空心莲子草评价草甘膦水剂的室内生测方法

为了评价由新型助剂制成的草甘膦水剂的生物活性,研究建立了用空心莲子草评价草甘膦水剂的室内生测方法.以空心莲子草为生测靶标,采朋喷雾法,培养介质为土壤,以地上部分鲜重抑制率为评价指标来筛选适合旱地使用的草甘膦水剂;以空心莲子草为生测靶标,采用喷雾法,培养介质为清水,以总鲜重抑制率为评价指标来筛选适合湿地或水域使用的草甘膦水剂.     

莲子草属药用植物的研究进展

从化学成分、药理作用及临床应用三个方面综述了莲子草属植物的研究进展,着重总结了空心莲子草在临床上的抗病毒作用,为莲子草属植物和空心莲子草的进一步开发应用提供了参考.空心莲子草的开发利用是目前抗病毒药物研究的方向之一.     

空心莲子草资源化利用研究

空心莲子草的研究不仅仅局限在农业方面,在中医药领域也有广泛的应用。本文从空心莲子草的研究现状和医药领域的应用两个方面讨论空心莲子草资源化利用研究。     

水培条件下四种水生植物对富营养化水体氮磷去除效果研究

选取凤眼莲、空心莲子草、碎米莎草、丁香蓼4种水生植物进行水培试验。在两种供磷条件下,通过营养液培养,研究了4种水生植物对氮、磷的吸收能力。结果表明,植物对氮、磷的吸收量受植物生物量的影响。不论供磷水平高低,凤眼莲和空心莲子草的生物量较大,对氮、磷的吸收量相对较高;碎米莎草和丁香蓼的生物量较小,对氮、磷的吸收量相对较小。相比较而言,凤眼莲和空心莲子草较适合用于去除污水中的氮、磷元素。     

人工湿地对城市生活污水的净化研究

利用本地土壤为基质,分别构建美人蕉、菖蒲、麦冬、鱼腥草和空心莲子草人工湿地,研究其对城市生活污水的净化效率,并探讨了处理流量对城市生活污水中各污染物净化效率的影响.结果表明,各种人工湿地对城市生活污水的TP、TN和NH4 -N的去除效果都很好;美人蕉、菖蒲、麦冬人工湿地对COD和浊度的去除效果较好;空心莲子草人工湿地对COD的去除效率稍差一些,鱼腥草人工湿地对浊度的去除稍差一些.     

K_2CO_3活化空心莲子草制备活性炭及表征

以入侵生物空心莲子草为原料,以K_2CO_3为活化剂,经一步共混活化法制备活性炭。研究了K_2CO_3与空心莲子草质量比、活化温度及活化时间对活性炭得率及吸附性能的影响。利用扫描电子显微镜(SEM)对不同温度下得到的活性炭进行了表面形貌观察。实验结果表明,K_2CO_3活化空心莲子草的最佳活化条件为:质量比为1.5,活化温度及时间分别为800℃,3.0h,此时活性炭得率为13.79%,其碘吸附值及亚甲基蓝吸附值分别为1477mg·g~(-1)和384mg·g~(-1)。当氮气流量在20~100ml·min-1范围内变化时,K_2CO_3的回收率相差不大,且其回收率均能达到80%以上。SEM结果表明活化温度对活性炭孔结构具有明显影响。     

土壤微生物种群与酶活性对草铵膦和草甘膦胁迫响应的差异

[目的]通过研究草铵膦和草甘膦对土壤微生物种群及酶活性的影响,为评价2种除草剂对土壤生态环境效应的差异提供参考。[方法]采用室内培养法研究土壤细菌、真菌、放线菌种群数量及土壤脲酶、酸性磷酸酶和酸性转化酶活性对50～500 mg/kg 5种不同质量分数草铵膦和草甘膦的胁迫响应。[结果]草铵膦和草甘膦对土壤细菌和放线菌种群的生长表现为低剂量促进高浓度抑制;对土壤真菌种群的生长表现为抑制作用;对土壤脲酶和酸性磷酸酶活性也表现为抑制作用,且随药剂剂量提高逐渐增强;对土壤酸性转化酶活性草铵膦表现为低剂量促进高剂量抑制,草甘膦表现为随药剂剂量提高促进作用逐渐增强。[结论]土壤可培养细菌、真菌、放线菌,脲酶、酸性磷酸酶、酸性转化酶对2种除草剂胁迫的响应均表现为草铵膦敏感于草甘膦。     

K2CO3活化空心莲子草制备活性炭及表征

以入侵生物空心莲子草为原料,以K₂CO₃为活化剂,经一步共混活化法制备活性炭。研究了K₂CO₃与空心莲子草质量比、活化温度及活化时间对活性炭得率及吸附性能的影响。利用扫描电子显微镜（SEM）对不同温度下得到的活性炭进行了表面形貌观察。实验结果表明,K₂CO₃活化空心莲子草的最佳活化条件为：质量比为1.5,活化温度及时间分别为800℃,3.0 h,此时活性炭得率为13.79%,其碘吸附值及亚甲基蓝吸附值分别为1477 mg·g^-1和384 mg·g^-1。当氮气流量在20～100 ml·min^-1范围内变化时,K₂CO₃的回收率相差不大,且其回收率均能达到80%以上。SEM结果表明活化温度对活性炭孔结构具有明显影响。     

百草枯与氟草烟混剂防除空心莲子草增效作用的生理生化研究

以12.40%、13.96%百·氟EC为供试药剂,以20%百草枯AS及20.6%氟草烟EC为对照药剂,从植物生理生化角度研究了百草枯与氟草烟混用防除空心莲子草的增效作用。结果表明,12.40%百·氟EC处理对空心莲子草净光合速率、叶绿素以及丙二醛含量等较其他处理差异明显,表现出较强的增效作用。     

莲子草假隔链格孢毒素的基本性质与组分分析

莲子草假隔链格孢在改良Fries培养基中能够产生使空心莲子草致病的毒素,培养滤液经DM-130大孔树脂吸附-甲醇洗脱-蒸干-乙酸乙酯浸提,获得毒素粗提物。经HPLC分析,毒素粗提物由5个组分组成,其中最大的吸收峰是保留时间为9.520 min的组分。基本性质研究结果表明,毒素为非蛋白类、相对分子质量在10000以下的小分子物质,在121°C和pH 1~11的条件下能够稳定存在。     

Sorption of Al (III) from aqueous solution by fresh macrophyte alligator weed: Equilibrium and kinetics

The removal of Al (III) ions from aqueous solution by locally abundantly low-cost fresh macrophyte, alligator weed, was examined in batch system. Effect of initial solution pH on Al (III) adsorption was investigated and the Al (III) species present in aqueous solution were identified. The main functional groups of the alligator weed were characterized by Fourier transform infrared spectrometer (FT-IR). The equilibrium data fitted to Freundlich and Langmuir isotherms satisfactorily. The pseudo-second-order equation fitted the kinetic data very well. The intraparticle diffusion played an important role in the Al (III) sorption process. Al (III) ions were favorably adsorbed by alligator weed and the values of K_f and 1/n (Freundlich constant) at 25 °C and pH 3.5 were found as 1.9963 (mg/g)/(mg/L)^1/n and 0.7875, respectively, which are comparable to those of granular activated carbon (2.20 (mg/g)/(mg/L)^1/n and 0.8695, respectively).     

喜旱莲子草基活性炭制备及其对苯酚吸附性能的研究

利用喜旱莲子草制备活性炭,选择了活化剂、活化剂浓度、碳化时间、碳化温度等作为实验的四个因素,每个因素选取三个水平,采用正交实验法,得出了最佳制备条件:以2 mol/L的H3PO4作为活化剂,碳化温度400℃,碳化时间1 h。比较了不同时间、不同活性炭用量、不同温度下,喜旱莲子草基活性炭对苯酚的吸附效果。此外,动态吸附实验表明:提高活性炭用量(即增加填料高度),降低进水苯酚浓度以及减小进水流量均能相应延长喜旱莲子草基活性炭去除苯酚到达穿透点的时间,从而增加最大吸附容量。     

AES在草铵膦水剂中的应用研究

将阴离子表面活性剂脂肪醇聚氧乙烯醚硫酸钠(AES)添加到草铵膦水溶液中,考察了配制得到的草铵膦制剂的低温和热贮稳定性,并对其表面张力、渗透力和药效等性能进行测定。实验发现,当配方组成为草铵膦母药20%、AES 20%时,制剂的低温和热贮稳定性符合水剂的质量技术指标,表面张力大大降低,渗透力大大提高,且对牛筋草和空心莲子草有较高的生物活性。     

Effect of weed management in coffee plantation on soil chemical properties

Coffee plantation in south Sumatra, Indonesia, is developed on the slopes in hilly areas, where soil erosion is a severe problem. Introduction of weed as cover plant has been found to be effective in the reduction of soil erosion. Here the effect of weed management, weeding and coverage with Paspalum conjugatum Berg. or natural weeds, on soil chemical properties was investigated. After 4 years, contents of total C, total N, available P, and exchangeable (ex.) Mg in the 0–10 cm and 10–20 cm depth layers were significantly greater in the Paspalum conjugatum and natural weed plots than in the weeding plot. In the 0–10 cm layer, ex. K and ex. Ca were also greater in the weed-introduced plots than in the weeding plot. Decrease in soil pH (H₂O) and the increase in ex. Al under coffee plantation were reduced by the coverage with weeds. Thus soil coverage with weeds in coffee plantation on slopes was effective in the maintenance of soil fertility.     

水稻直播田化学除草药剂试验初报

为进一步推广新型化学除草剂,进行了当前常规或新出的9种除草剂防除直播田各类杂草的3个阶段性试验。水稻浸种催芽播种后4d进行土壤封闭处理防除各类杂草效果突出,3个处理防除各类杂草的效果均很好;3～4叶低草龄期,广灭灵与韩乐盛混用对单子叶草、阔叶草和莎草均有较高的防效;5～6叶高草龄期,韩秋好防除千金子、稗草和莎草效果明显。     

Exploitation of allelopathy for weed control in annual and perennial cropping systems

A variety of crops, cultivars, and accessions have been evaluated over the past six years for superior capability to suppress weed growth. The most successful of these approaches has been to grow cover crops of rye (Secale cereale), wheat (Triticum aestivum), sorghum (Sorghum bicolor), or barley (Hordeum vulgare) to a height of 40–50 cm, desiccate the crops by contact herbicides or freezing, and allow their residues to remain on the soil surface. Often, up to 95% control of important agroecosystem weed species was obtained for a 30- to 60-day period following desiccation of the cover crop. The plant residues on the soil surface exhibit numerous physical and chemical attributes that contribute to weed suppression. Physical aspects include shading and reduced soil temperatures which were similarly achieved using poplar (Populus) excelsior as a control mulch. Chemical aspects apparently include direct release of toxins, as well as production of phytotoxic microbial products. Numerous chemicals appear to work in concert or in an additive or synergistic manner to reduce weed germination and growth.     

免耕玉米田化学除草新混剂使用技术

通过对免耕玉米田不同除草剂使用方法和用量的研究表明,田间若以禾本科杂草为主可用单剂防治,若禾本科杂草和阔叶杂草混生以使用混剂为好,且采用土壤处理法防效最佳。49.2%烟·乙·莠WP茎叶处理最佳用量为1476～2214ga.i./hm2;63%烟·莠WP最佳用量为756～945ga.i./hm2;施药时期为玉米4～6叶期,杂草2～4叶期。49.2%烟·乙·莠WP土壤处理最佳用量为738～1107ga.i./hm2;48%乙·莠SC用量为1440ga.i./hm2。     

Rye residues contribute weed suppression in no-tillage cropping systems

The use of allelopathic cover crops in reduced tillage cropping systems may provide an ecologically sound and environmentally safe management strategy for weed control. Growers often plant winter rye (Secale cereale L.) for increased soil organic matter and soil protection. Spring-planted living rye reduced weed biomass by 93% over plots without rye. Residues of fall-planted/spring-killed rye reduced total weed biomass over bare-ground controls. Rye residues also reduced total weed biomass by 63% when poplar excelsior was used as a control for the mulch effect, suggesting that allelopathy, in addition to the physical effects of the mulch, did contribute to weed control in these systems. In greenhouse studies, rye root leachates reduced tomato dry weight by 25–30%, which is additional evidence that rye is allelopathic to other plant species.Journal Article No. 10712 of the Michigan Agricultural Experiment Station. Supported by United States Department of Agriculture Competition Grant No. 78-59-2261-0-1-060-1.     

Root Distribution and Potential Interactions Between Allelopathic Rice,Sprangletop (<Emphasis Type="Italic">Leptochloa</Emphasis> spp.), and Barnyardgrass (<Emphasis Type="Italic">Echinochloa crus-galli</Emphasis>) based on <Superscript>13</Superscript>C Isotope Discrimination Analysis

Weed-suppressive rice cultivars hold promise for improved and more economical weed management in rice. Interactions between roots of rice and weeds are thought to be modulated by the weed-suppressive activity of some rice cultivars, but these phenomena are difficult to measure and not well understood. Thus, above-ground productivity, weed suppression, and root distribution of 11 rice cultivars and two weed species were evaluated in a drill-seeded, flood-irrigated system at Stuttgart, Arkansas, USA in a two-year study. The allelopathic cultivars, PI 312777 and Taichung Native 1 (TN-1), three other weed-suppressive cultivars, three indica-derived breeding selections, and three non-suppressive commercial cultivars were evaluated in field plots infested with barnyardgrass (Echinochloa crus-galli (L.) Beauv.) or bearded sprangletop (sprangletop, Leptochloa fusca (L.) Kunth var. fascicularis (Lam.) N. Snow). The allelopathic cultivars produced more tillers and suppressed both weed species to a greater extent than did the breeding selections or the non-suppressive cultivars. ¹³C isotope discrimination analysis of mixed root samples to a depth of 15 cm revealed that the allelopathic cultivars typically produced a greater fraction of their total root mass in the surface 0–5 cm of soil depth compared to the breeding selections or the non-suppressive cultivars, which tended to distribute their roots more evenly throughout the soil profile. These trends in root mass distribution were apparent at both early (pre-flood) and late-season stages in weed-free and weed-infested plots. Cultivar productivity and root distribution generally responded similarly to competition with the two weed species, but barnyardgrass reduced rice yield and root mass more than did sprangletop. These findings demonstrate for the first time that roots of the allelopathic cultivars PI 312777 and TN-1 explore the upper soil profile more thoroughly than do non-suppressive cultivars under weed-infested and weed-free conditions in flood-irrigated U.S. rice production systems. They raise the interesting prospect that root proliferation near the soil surface might enhance the weed-suppressive activity of allelochemical exudates released from roots. Plant architectural design for weed suppressive activity should take these traits into consideration along with other proven agronomic traits such as high tillering and yield.     

32种除草剂对银胶菊的生物活性

[目的]银胶菊是一种原产于中美洲的重要外来入侵杂草,在我国很多省市均有分布,为更好的在分布地有效控制该入侵杂草,防止其扩散蔓延,系统测定了常用除草剂防除银胶菊的效果.[方法]采用温室盆栽法,分别采用播后苗前土壤喷雾处理和4～6叶期茎叶喷雾处理,测定了16种土壤处理剂和23种茎叶处理剂对银胶菊的生物活性.[结果]土壤处理剂对银胶菊生物活性很好的有硝磺草酮、异(噁)草松、磺草酮、砜嘧磺隆,IC90值分别为13.73、41.27、83.85、35.71 g a.i./hm2,均低于其田间推荐剂量;莠去津的防效也较好.茎叶处理剂对银胶菊生物活性很好的有磺草酮、硝磺草酮、莠去津、嗪草酮,IC90值分别为16.69、18.66、881.55、354.60 g a.i./hm2,亦低于其田间推荐剂量;另外对银胶菊防效较好的还有苯磺隆、草甘膦、异丙隆,其IC90值分别为38.23、923.76、1898.12 g a.i./hm2,为其田间推荐剂量的1～2倍.[结论]筛选出5种土壤处理剂和7种茎叶处理剂对银胶菊防除效果均较好,可以作为备选药剂进行田间试验,以保证不同地块选用各自适宜的除草剂品种和药剂种类间交替轮换用药.