3种不同种子处理方法对水稻发芽及幼苗素质的影响

室内采用滤纸法,研究种子包衣后浸种、浸种后种子包衣和催芽后种子包衣3种不同的处理方式对稻花香、天优华占和保丰3个水稻品种发芽率及幼苗素质的影响.结果显示：在所测试的浓度范围内,分别采用3种不同的处理方式,每个水稻品种的发芽率均随着噻虫嗪·苯醚甲环唑23％悬浮种衣剂用量的增加而增加.且随着悬浮种衣剂用量的增加水稻病苗率降低;同一用量条件下,3个水稻品种发芽率由高到低依次为：催芽后种子包衣＞种子包衣后浸种＞浸种后种子包衣.病斑率由小到大依次为：催芽后种子包衣＞种子包衣后浸种＞浸种后种子包衣.这表明噻虫嗪·苯醚甲环唑23％悬浮种衣剂可以明显抑制水稻种子携带的病原菌;随着种衣剂用量的增加水稻幼苗的根数、主根长和株高增加.对天优华占、稻花香和保丰3个水稻品种幼苗素质影响由大到小依次为：催芽后种子包衣＞种子包衣后浸种＞浸种后种子包衣.这表明：水稻种子处理方法对水稻幼苗素质有一定的影响.     

聚乙烯醇共混改性膜作为农药种衣剂成膜剂的性能研究

以水溶性聚合物聚乙烯醇(PVA)和水不溶性聚合物乙酸乙烯-乙烯共聚物(VAE)乳液为原料,采用溶液共混法制备了PVA-VAE共混膜,为农药成膜剂的制备开辟了新途径。红外光谱、透射电镜、激光粒度仪测试结果显示,PVA溶液中的胶束被打开,体系的比表面积急剧增大,两相间的界面消失,说明共混体系分子间具有良好的相容性;透水性与耐水性测定结果表明,PVA-VAE的质量比为80∶ 20、70∶ 30、60∶ 40时其共混膜的性能适用于农药种衣剂的成膜剂;种子发芽试验显示,与单独使用PVA膜相比,引入适当比例VAE后的共混膜用于种子包衣,其耐水性显著提高,渗水率适宜,对种子发芽无明显影响。     

种衣剂17号包衣对小麦条锈菌影响的组织病理学研究

种衣剂１７号内含三唑醇等杀菌剂和其它化学成分,小麦种子用种衣剂包衣,出苗后一叶期接咱小麦条锈菌毒性小种,采用荧光染色技术和整叶透明技术,研究了种衣剂１７号对条锈菌在寄主内发育的影响。观察结果表明,该种衣剂对对叶表的夏孢子萌发和芽管入侵无明显影响,但可使菌丝扩展和菌丝分枝严重受抑,吸器母细胞和吸器形成的数目减少,每一侵染点的吸器一般不超过２个,并且对吸器具有致畸作用。在多数侵染点内可观察到寄主细胞坏     

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.     

甘肃河西制种区不同成熟期玉米杂交种贮藏期种子活力变化

选择先玉335、郑单958和吉祥1号三个杂交种制种田,于授粉后32 d每隔5 d采收果穗直到授粉后72 d,测定种子电导率、标准发芽率和冷浸发芽率,次年测定田间出苗率以及上述指标,对比分析不同收获期种子在贮藏过程中的变化及其贮藏特性。研究结果表明,随着收获期的推迟,玉米杂交种种子贮藏后标准发芽率和冷浸发芽率降幅减小,电导率的增幅也减小,并且收获后期种子的贮藏性高于前期收获的种子。在授粉后32~47 d、47~62 d、62~72 d采收种子的标准发芽率平均降低6.90%、4.99%、4.48%,前期发芽率的降低速率为中后期的3.75倍;冷浸发芽率依次降低9.70%、13.33%、10.78%,降低幅度明显高于标准发芽率,说明低温冷害后的贮藏性降低。对于不同基因型的玉米杂交种种子,其贮藏后标准发芽率、冷浸发芽率降低程度也不同,先玉335分别降低2%和6.8%,吉祥1号分别降低3.5%和6.9%,郑单958降低3.7%和15%,电导率却依次增大,分别为0.46μs·cm~(-1)·g~(-1)(先玉335)、0.56μs·cm~(-1)·g~(-1)(吉祥1号)、0.49μs·cm~(-1)·g~(-1)(郑单958),说明贮藏10个月后郑单958种子活力衰退幅度最大,贮藏性最差,其次为吉祥1号,先玉335最小,而在活力衰退最小范围内先玉335的适宜收获期为授粉后47~57 d,吉祥1号为授粉后52~57 d,郑单958为授粉后57~62 d,为获得高活力种子提供理论依据。     

控制大豆孢囊线虫生物种农剂的研制及沈阳田间小区防效的初步试验

以“辽豆15”为材料,采用田间小区试验,探讨了自行研制的生物种衣剂对大豆孢囊线虫数量的影响。试验结果表明：2007年在沈阳汪家的试验中,处理4（复配菌株F1024,B482,A4+微量元素组合3+助剂）对大豆根外孢囊的抑制率达65.66%,与对照有显著差异。2008年对处理4进行了精细的试验设计,并在2个不同地点布置试验,结果处理5（复配菌株F1024,B482,A4+元素组合+助剂）在汪家和康平2个试验点的根外孢囊数量及根内线虫数量都与对照差异达到显著水平,2个试验点的根外孢囊抑制率分别为 62.13%和46.45%,根内线虫抑制率分别为62.50%和81.78%。     

Burial depth and cultivation influence emergence and persistence of Phalaris paradoxa seed in an Australian sub-tropical environment

Emergence and persistence characteristics of Phalaris paradoxa seeds in no- and minimum-till situations and at different burial depths were studied in a sub-tropical environment. Three experiments were carried out using naturally shed seeds. In the first experiment, seedlings emerged from May through to September each year, although the majority of seedlings emerged in July. In the second experiment with greater seed density, cultivation in March of each year stimulated seedling emergence, altered the periodicity of emergence and accelerated the decline of seeds in the seedbank compared with plots that received no cultivation. The majority of seedlings in the cultivated plots emerged in May whereas the majority of seedlings in the undisturbed plots emerged in July. Emergence accounted for only 4–19% of the seedbank in both experiments over 2 years. Seed persistence was short in both field experiments, with less than 1% remaining 2 years after seed shed. In the third experiment, burial depth and soil disturbance significantly influenced seedling emergence and persistence of seed. Seedlings emerged most from seed mixed in the top 10 cm when subjected to annual soil disturbance, and from seed buried at 2.5 and 5.0 cm depths in undisturbed soil. Emergence was least from seed on the soil surface, and buried at 10 and 15 cm depths in undisturbed soil. Seeds persisted longest when shed onto the soil surface and persisted least when the soil was tilled. These results suggest that strategic cultivation may be a useful management tool, as it will alter the periodicity of emergence allowing use of more effective control options and will deplete the soil seedbank more rapidly.     

Changes in germinability, dormancy and viability of Amaranthus retroflexus as affected by depth and duration of burial

Changes in dormancy and viability of Amaranthus retroflexus seeds were examined after placement in pots that were buried in the field. Seeds were placed in woven nylon envelopes on the soil surface or buried at depths of 2.5, 5 or 10 cm. After 1, 3, 6, 9 and 12 months seeds were exhumed and their germinability was tested to assess changes in dormancy and viability. Depletion of seed stocks placed on the soil surface was partly because of in situ germination that did not exceed 21% and did not vary significantly over the 12-month study period. Less germination of buried seeds occurred in situ , and seeds that did not germinate appeared to acquire dormancy. Exhumed seeds germinated readily; germinability was linearly related to the depth of burial, with those retrieved from the surface germinating least. Cyclical changes in germinability occurred during the 12-month burial period, but this influence was identical for seeds buried at all depths. Germinability was greatest after periods with the lowest mean monthly temperatures and least during the hottest periods. The stimulation of remaining ungerminated seeds exhumed at each period, by the addition of ethephon to the germination medium, provided further evidence of a seasonal acquisition of dormancy, and it was concluded that other unknown factors besides cyclical changes in seasonal temperature were responsible. Irrespective of placement, all seeds lost viability at an exponential rate over time. However, the decline was most rapid for those placed on the surface, whereas the loss in viability became less with increased depth of burial. Possible explanations for this adaptation of enhanced survival when buried are discussed.     

新型种衣剂防治小麦禾谷孢囊线虫病研究

在田间条件下研究了甘农种衣剂Ⅰ号、甘农种衣剂Ⅱ号、甘农种衣剂Ⅲ号、阿维菌素种衣剂AV1、阿维菌素种衣剂AV2和5.7%甲维盐等6个种衣剂对小麦孢囊线虫病的防治效果。播种前对麦种进行8个不同种衣剂包衣处理,比较小麦收获后土壤中孢囊数量的变化以及小麦增产情况。结果表明,不同种衣剂处理对土壤中孢囊线虫的繁殖均有一定抑制作用,其中甘农种衣剂Ⅲ号(1∶35)、甘农种衣剂Ⅰ号(1∶50)和甘农种衣剂Ⅱ号(1∶35)孢囊减退率分别为56%、53%和47%。不同种衣剂处理的小麦产量增加,甘农种衣剂Ⅲ号(1∶35)、甘农种衣剂Ⅰ号（1∶50）、甘农种衣剂Ⅱ号（1∶35）和甘农种衣剂Ⅰ号（1∶35）增产率分别为37.6%、19.4%、17.9%和17.7%。本项目中自主研发的甘农种衣剂Ⅲ号防治效果最显著,不仅对小麦孢囊线虫病具有较好的防效,而且具有安全、低毒、省工、经济的特点,可在农业生产实践中进行推广应用。     

Witconol NP-100 与Morwet D-425在悬浮种衣剂中的应用

以Morwet D-425和Witconol NP-100代替20%福·克和30%多·福·克 悬浮种衣剂配方中的乳化剂,结果表明:Morwet D-425和Witconol NP-100在20%福·克 种衣剂中质量分数分别为3.0%和1.0%、在30%多·福·克种衣剂中质量分数分别为4.0%和1.0%时,出料1 d后制剂粘度分别为390和510 mPa·s;经过30 d室温或14 d、(54±2)℃贮藏后,制剂的颗粒聚结数低于10%,并且无不可逆沉淀形成;热贮析水体积分别为5%和9%,较原配方种衣剂降低了20%以上,室温贮藏析水体积不足1%。用激光粒度分析仪分别检测添加Morwet D-425、Witconol NP-100或原配方乳化剂的种衣剂经过0.5、1.0、1.5、2.0 h研磨后的粒度分布,新配方种衣剂经过1.5 h研磨平均粒径分别达到1.85和1.91 μm,而原配方种衣剂经2.0 h研磨平均粒径仍大于2 μm。     

三唑酮种子包衣对冬小麦种子萌发和幼芽抗逆因子的影响

为评价三唑酮种子包衣对冬小麦种子萌发的安全性,以苯醚甲环唑为对照药剂,研究了不同包衣剂量三唑酮对周麦22和铭贤169小麦种子发芽及周麦22抗逆相关生化因子的影响。结果表明:周麦22和铭贤169小麦种子发芽指数、种子活力指数和发芽率均与三唑酮包衣剂量呈负相关,且符合指数方程Y=A+B×e(-x/k),但铭贤169种子发芽指数、种子活力指数和发芽率对三唑酮剂量变化更敏感;三唑酮种子包衣能引起小麦幼芽体内赤霉素(gibberellins,GAs)含量降低和脱落酸(abscisic acid,ABA)含量升高,且GAs含量下降程度和ABA水平升高程度均随三唑酮包衣剂量的增加而增加,从理论上解释了三唑酮可对小麦种子萌发产生抑制作用且抑制作用与包衣剂量相关的原因。但通过对幼芽相关抗逆因子的研究表明,三唑酮包衣有利于新长成幼芽中叶绿素含量、根系呼吸速率、可溶性蛋白质含量和α-淀粉酶活性的增加以及细胞膜通透性降低,说明三唑酮包衣在一定程度上有助于新长出幼芽抗逆性的增加。相比之下,苯醚甲环唑对小麦种子萌发的抑制作用比三唑酮小,且更有利于幼芽抗逆性增加。     

三唑酮种衣剂在小麦种表的超微分布及抗脱落淋失研究

 应用扫描电镜观察到三唑酮种衣剂(Tri SCF)以具网眼结构的膜状物包被于小麦种子表面,膜状物厚度约4~7.5μm,种表包被率达95%;对照处理三唑酮可湿性粉剂(TriWP)拌种在小麦种表呈点状或片状零散分布,种表被药剂覆盖率低于80%。振荡试验中TriSCF包衣药剂脱落率为2%,显著低于TriWP干拌种(43%)或湿拌种(25%)。放射性同位素示踪检测表明,TriSCF包衣处理的小麦种子在17%含水量砂床上发芽1~7d内,保持种子内的¹⁴C-二唑酮放射性强度显著高于TriWP拌种处理,而然失到砂床上的¹⁴C-三唑酮放射性强度低开Tri WP拌种处理。     

Relative contribution of genotype, seed size and environment to secondary seed dormancy potential in Canadian spring oilseed rape (Brassica napus)

Secondary seed dormancy has been linked to seedbank persistence of volunteer oilseed rape (Brassica napus) in western Canada. It has been suggested that there is a genetic component to secondary seed dormancy expression in oilseed rape, but little is known of its importance in relation to non‐genetic factors. In a series of experiments we investigated the relative importance of genotype, seed size, time of windrowing and pre‐ and post‐harvest environment on the expression of secondary seed dormancy. We found that genotype contributed between 44 and 82% to the total variation in secondary seed dormancy. A broad range in secondary seed dormancy expression was observed among 16 genotypes examined. Nevertheless, three‐quarters of the genotypes investigated exhibited relatively high potential for the expression of secondary seed dormancy (back‐transformed mean 71% dormant seeds). Seed size contributed 21% to the total variation, while the influence of seed maturity (harvest regime) on secondary seed dormancy expression was negligible. Despite diverging environmental conditions during the four growing seasons spanning these experiments, the influence of pre‐harvest environment on seed dormancy expression was relatively small and ranged from 0.1% to 4.5%. Secondary seed dormancy potential decreased over time during seed storage. This decrease was greatest when seeds were stored at ambient temperatures and least when seeds were stored at ?70°C.     

50%噻虫嗪悬浮种衣剂的研制及其对棉花蚜虫的防治效果

为研制高含量的噻虫嗪悬浮种衣剂,提高其对棉花蚜虫的防治效果,分别采用流点法及因素轮选法等对润湿剂、分散剂、成膜剂和增稠剂等助剂进行筛选及优化,最终采用湿法砂磨超微粉碎法研制了50%噻虫嗪悬浮种衣剂,对其性能指标进行了测试,并测定了其对棉花种子发芽势和发芽率的影响以及对棉花蚜虫的田间防治效果。结果表明:以质量分数为50%的噻虫嗪为有效成分、3%的FD及1%的BC-10为润湿剂、2.5%的SP-2836及2.5%的SK-24为分散剂、1%的硅酸铝镁及0.05%的黄原胶为增稠剂和2.5%的BF308为成膜剂而研制的50%噻虫嗪悬浮种衣剂性状良好,悬浮率高,热贮稳定性好,对棉花种子的发芽势及发芽率的影响较清水对照差异显著。田间试验结果显示,在有效剂量为187.5 g/hm2时50%噻虫嗪悬浮种衣剂对棉花4、5叶期蚜虫的防效分别达83.94%和53.94%,适合田间应用。     

4种药剂拌种对白背飞虱的防治效果

白背飞虱是水稻上的重要害虫,而且是近年来发生严重的南方水稻黑条矮缩病毒的唯一传播介体。为有效降低白背飞虱自身的危害及其传播的南方水稻黑条矮缩病的发生,在云南德宏开展了4种拌种剂防治白背飞虱的田间药效试验。在25%吡蚜酮WP、60%吡虫啉FSC、35%丁硫克百威DS及70%噻虫嗪WS中,35%丁硫克百威DS在拌种后31d对白背飞虱种群的防效仍高达93.6%,其他3种拌种剂的防效分别为75.0%、55.0%及49.3%。因此35%丁硫克百威DS是适合于当地防治白背飞虱的水稻拌种剂。     

种衣剂对玉米田双斑长跗萤叶甲的防效评价

为评价种衣剂防治玉米田双斑长跗萤叶甲的可行性,通过选用内吸性强、持效期长的种衣剂,设置常规剂量对玉米种子进行包衣处理,采取田间罩网小区试验,明确种衣剂对双斑长跗萤叶甲的防效及对玉米出苗、生长的安全性。结果表明,30%噻虫嗪FS、10%氟虫腈FSC、38%噻虫胺FSC、40%噻虫嗪·溴氰虫酰胺FS、30%噻虫嗪·氟虫腈FSC、30%噻虫胺·氟虫腈FSC、20%噻虫胺·氟啶虫酰胺FSC等7种种衣剂对玉米出苗、生长均安全;38%噻虫胺FSC有效成分用量7.6 g/kg种子处理对双斑长跗萤叶甲的防治效果为70.6%～78.5%,防效最好,显著高于除30%噻虫胺·氟虫腈FSC 7.5 g/kg处理外的其他种衣剂处理(P<0.05),并且可使双斑长跗萤叶甲成虫羽化出土始现期、出土高峰期推迟5～10 d,可以使成虫高峰期避开玉米吐丝期。玉米田双斑长跗萤叶甲防控前移推荐使用38%噻虫胺FSC,有效成分剂量为7.6 g/kg种子。