嘧霉胺悬浮剂的润湿性能及其靶标表面性质研究

采用光学视频接触角测量仪对加入不同润湿分散剂(7227-A、SOPROPHOR FD和SC-4)的40%嘧霉胺悬浮剂的表面张力及其分量进行了测定,同时研究了作用靶标黄瓜和番茄叶片的表面自由能,以及药液在其上的润湿展布性能。结果显示:不同配方的嘧霉胺悬浮剂其表面张力在39~51 mN/m之间,且均以色散分量为主,其中加入SC-4的药剂表面张力最低(39~48 mN/m);黄瓜和番茄叶片的表面自由能均较小,在22 mJ/m2左右,不利于药液润湿,且以极性分量占主导;各配方药液的水稀释液在番茄叶面上的接触角在51~86°之间,在黄瓜叶面上的接触角在30~62°之间,药液在黄瓜叶面上更易附着,其中加入7227-A的药剂在黄瓜叶片上润湿性能最好,加入SOPROPHOR FD的药剂在番茄叶片上润湿性能最好;田间防治效果与药液的润湿性能呈正相关。表明嘧霉胺悬浮剂对靶标的润湿性能不仅与药液的表面张力有关,也与其分量有关,同时受到靶标表面性质的影响,通过研究药液对靶标润湿性能可分析评价其药效。     

助剂对10%苯醚甲环唑水分散粒剂在荔枝叶片表面润湿性能的影响

采用接触角测量仪测定了10%苯醚甲环唑水分散粒剂 (difenoconazole WG) 不同倍数稀释液在荔枝叶片上的静态接触角和0～60 s动态接触角,用于计算荔枝叶片的临界表面张力和表面自由能,进而分析药液在荔枝叶片表面的润湿性能;采用全自动张力仪测定了在10%苯醚甲环唑WG不同稀释液中分别添加体积分数为0.4%的silwet stik和0.2%的as 100 2种助剂后溶液的表面张力,研究了助剂添加前后表面张力的变化。结果表明:荔枝叶片近轴面的表面自由能为23.74 mJ/m2,远轴面的表面自由能为11.89 mJ/m2,均以色散力分量 (非极性分量) 为主导。在10%苯醚甲环唑WG 500倍稀释液中加入体积分数为0.4%的silwet stik溶液,其表面张力为21.90 mN/m,低于荔枝叶片的临界表面张力 (22.64 mN/m),且在0～10 s内接触角下降最快。研究结果表明:荔枝叶片的近轴面比远轴面更易被药液润湿;在荔枝园喷施10%苯醚甲环唑WG时,若在稀释倍数500倍的药液中添加0.4%的silwet stik助剂,则可使药液在叶片上能更快更好的润湿铺展。     

2.5%高效氟氯氰菊酯水乳剂在苹果叶片表面的润湿性能

采用光学视频接触角测量仪测定了苹果叶片的表面自由能,以及2.5%高效氟氯氰菊酯水乳剂(beta-cyfluthrin EW)稀释液的表面张力及静态接触角、0~60 s动态接触角。结果表明:苹果叶片近轴面的表面自由能为52.76 m J/m2,以极性分量为主导;而远轴面的表面自由能为21.79 m J/m2,且以色散力分量(非极性分量)为主导。高效氟氯氰菊酯水乳剂2 000倍稀释液的表面张力为52.45 m N/m,与25 g/L高效氟氯氰菊酯乳油3 000倍稀释液的相近,远低于去离子水的表面张力74.65 m N/m;其静态接触角与25 g/L高效氟氯氰菊酯乳油3 000倍稀释液的无显著差异,且在0~60 s内接触角下降趋势最快。研究表明:苹果叶片的近轴面比远轴面更易被药液润湿;在苹果园喷施2.5%高效氟氯氰菊酯水乳剂时,药液的稀释倍数不宜太高,以2 000倍为最佳。     

作物叶片表面自由能及喷雾助剂对农药药液在5种作物叶片上润湿性能的影响

为了解不同作物叶片表面润湿性能,科学选用助剂提高化学防治水平,采用光学视频接触角测量仪分别测定了小麦、玉米、辣椒、大豆和苹果5种作物叶片的表面自由能及其分量,进一步测定了2%甲氨基阿维菌素苯甲酸盐微乳剂和20%阿维 ? 杀虫单微乳剂两种药液液滴在添加Silwet 408和GY-Spry两种喷雾助剂后其在5种作物叶片上的接触角。结果表明:5种作物叶片正反面表面自由能差异较大,表面自由能最大和最小的分别为辣椒叶片 (54.12、45.08 mJ/m2) 和小麦叶片 (3.76、6.42 mJ/m2);同种作物叶片正反面表面自由能均有差异,其中辣椒叶片正反面和大豆叶片正面自由能以极性分量占主导,表现出亲水性,小麦、玉米、苹果叶片正反面及大豆叶片反面自由能以色散分量占主导,表现出疏水性。在2%甲氨基阿维菌素苯甲酸盐微乳剂5000倍液和20%阿维 ? 杀虫单微乳剂750倍液中分别添加两种助剂后,药液液滴在5种作物叶片上的接触角均有不同程度降低,其中添加Silwet 408后两种药液接触角分别降低82.63%~100%和85.07%~100%,添加GY-Spry后分别降低0~57.54%和10.96%~59.13%,说明添加Silwet 408比GY-Spry使接触角降低得更为显著;加入助剂的两钟药剂在5种作物叶面上接触角下降趋势一致,0~30 s内接触角下降程度明显高于30~60 s。本研究表明,喷雾助剂Silwet 408 和GY-Spry能提高2%甲氨基阿维菌素苯甲酸盐微乳剂和20%阿维 ? 杀虫单微乳剂对5种靶标的润湿性,效果上Silwet 408 好于GY-Spry。     

虫生真菌玫烟色棒束孢PF904表面活性剂的筛选

为筛选适用于玫烟色棒束孢Isaria fumosorosea PF904菌株的表面活性剂,采用OWRK法和表面张力法测定了甘蓝、苹果、茄子和黄瓜叶片的表面自由能以及添加4种表面活性剂后玫烟色棒束孢孢子悬浮液的表面张力和临界胶束浓度(CMC),并采用量角法和重量差值法测定了4种不同植物叶片上的接触角和最大稳定持留量,同时对筛选获得的表面活性剂进行了安全性评价。结果表明:PEG-12聚二甲基硅氧烷(OFX-0193)、ɑ-烯基磺酸钠(AOS)和二异丁基萘磺酸钠(Nekal)3种表面活性剂在125~500 mg/L下均可提高玫烟色棒束孢孢子悬浮液在4种供试植物叶片上的润湿性能;其中250 mg/L的Nekal在甘蓝和苹果叶片上的最大持留量(11.90和13.28 mg/cm^2)和接触角(29.5°和27.5°)均显著优于OFX-0193和AOS,润湿效果最好;在茄子叶片上,添加125 mg/L的OFX-0193时持留量最大(9.45 mg/cm^2);而添加普鲁兰多糖(Pullulan)达到临界胶束浓度时的溶液表面张力大于甘蓝、苹果和茄子叶片的表面自由能,润湿性能最差。孢子萌发抑制率的测定结果表明:添加Nekal和OFX-0193对玫烟色棒束孢PF904的孢子萌发无抑制作用,而AOS则对其表现为抑制作用。因此,在玫烟色棒束孢PF904中添加OFX-0193和Nekal 2种表面活性剂可用于防治苹果、甘蓝类害虫,添加OFX-0193还可用于防治茄类害虫。     

喷雾助剂对氟啶虫胺腈在富士苹果叶片表面润湿和持留的影响

为明确喷雾助剂在苹果园化学防治中的作用，采用表面张力、接触角和最大稳定持留量等分析了GY-T12、NF-100和迈润等3种喷雾助剂在达到临界胶束浓度 (CMC) 时对22%氟啶虫胺腈悬浮剂药液的表面张力及其在苹果叶片表面润湿性能和持留量的影响。结果显示:当添加的3种喷雾助剂达到其CMC时，氟啶虫胺腈药液表面张力降低至27.64~35.64 mN/m；根据水滴在苹果叶片表面的接触角小于或大于90°判定苹果叶片近轴面为亲水性表面、远轴面为疏水性表面，添加助剂使药液在近轴面和远轴面30 s的静态接触角分别降低23.2°~41.3°和68.0°~93.5°，同时使亲水性近轴面黏附功降低5.36~12.56 mJ/m2，而黏附张力增大9.27~11.26 mN/m，在疏水性远轴面黏附功与黏附张力分别增大27.45~36.66 mJ/m2和47.55~53.28 mN/m，对改善远轴面的黏附润湿性更显著；药液表面张力和最大稳定持留量存在抛物线状函数关系，当表面张力为40.89 mN/m时，持留量达最大值12.53 mg/cm2；3种助剂中，NF-100和GY- T12可显著增加药液持留量，且GY-T12对靶标害虫苹果黄蚜有显著增效作用。本研究结果表明，在苹果园应用时应依据预期目标选择适当的喷雾助剂，并通过调节药液表面张力使其处于适宜范围以增加药液持留量、提高对靶标害虫的毒力。     

4种园林植物幼苗对干旱胁迫的生长和生理响应

以水曲柳、蒙桑、桃叶卫矛和黄檗幼苗为试验材料,采用盆栽称重控水法,研究不同干旱胁迫强度对4种植物的形态生长、抗氧化酶活性和渗透调节物质含量的影响,并通过隶属函数法对其抗旱性进行综合评价。结果表明:干旱胁迫显著抑制了水曲柳和黄檗的形态生长,且MDA含量迅速增加,但对蒙桑和桃叶卫矛的形态生长、MDA含量影响较小。受干旱胁迫的影响,蒙桑和桃叶卫矛的脯氨酸、可溶性糖和可溶性蛋白含量与对照相比均显著升高,水曲柳的可溶性蛋白含量、黄檗的脯氨酸和可溶性糖含量均出现不同程度降低;SOD、POD和CAT活性变化趋势不一致。运用隶属函数法对4种园林植物的抗旱能力进行综合评定,抗旱性依次为蒙桑>桃叶卫矛>水曲柳>黄檗。     

梨网蝽的发生特点及防治

梨网蝽Stoephanitis nashi Esaki et Takeya属半翅目．网蝽科,又名梨军配虫、花扁虫,花编椿。除为害梨外,还可以为害桃、李、杏、花红等果树。成虫和若虫群栖于寄主植物的叶背吸取汁液．被害叶表面呈现苍白色斑点．背面遍布斑斑点点的褐色液体排泄物．使叶背呈锈黄色或黑褐色．受害严重时．叶面一片苍白,引起叶片早期脱落,严重影响树势。     

桃潜叶蛾的危害及防治

桃潜叶蛾是近几年危害核果类果树叶片的主要害虫之一 ,严重时能造成果园绝产。主要危害桃、杏、李、樱桃等核果类果树 ,同时又危害苹果、梨等果树叶片。一、危害症状以幼虫在叶组织内潜食危害 ,串成弯曲潜道 ,并将粪便充塞其中 ,叶表皮不破裂 ,由叶面可透视虫道。叶受害严重时枯死脱落 ,严重时造成果园绝产。二、虫源及发生规律桃潜叶蛾属鳞翅目 ,潜叶蛾科 ,又称桃叶潜蛾。它１年发生６～７代 ,以蛹在被害叶上结一白色丝茧越冬。来年桃展叶后 ,羽化成虫一夜间在叶表皮内产卵 ,幼虫孵化后危害 ,老熟后在叶内吐丝结白色薄茧化蛹 ,５月上中旬发…     

灰叶胡杨异形叶的类型及其时空特征

为了探讨灰叶胡杨个体发育过程中异形叶发生和垂直空间分布随径级的变化规律及其相互间的关系,在塔里木盆地西北缘调查同一立地条件下,各径级灰叶胡杨异形叶的类型及空间分布规律。结果显示:1阔椭圆形叶、圆形叶和阔卵形叶有规律地出现在不同的径级阶段,其中阔椭圆形叶出现在2~20径级阶段,圆形叶和阔卵形叶分别从4、6径级开始出现,它们在树冠上的出现均始于树冠的顶部,异形叶的出现与个体发育阶段相关;2 3种异形叶出现频率及垂直空间分布区占冠高的比例,随径级变化而发生动态的消长变化,其中,阔椭圆形叶出现频率及垂直空间分布区占冠高的比例,随径级增加逐渐减小,圆形叶出现频率及垂直空间分布区占冠高的比例,随径级增加先增大后减小,阔卵形叶出现频率及垂直空间分布区占冠高的比例,随径级增加则逐渐增大;3阔椭圆形叶在树冠垂直空间的出现频率及垂直空间分布占冠高的比例,均与胸径、树高呈极显著负相关,圆形叶仅出现频率与胸径、树高呈极显著正相关,阔卵形叶出现频率及垂直空间分布区占冠高的比例,均与胸径、树高呈极显著正相关。说明各类异形叶出现频率及时空变化与胡杨个体发育阶段密切相关,灰叶胡杨的异形叶性是由个体发育阶段决定的,灰叶胡杨在不同发育阶段出现的异形叶是其生长适应策略。     

绿盲蝽为害对不同空间位置桃叶生理指标的影响

为明确绿盲蝽为害不同时期桃树的应激反应发生发展过程,采用生化测定方法分析了桃树上、中、下部不同受害程度叶片内的可溶性糖、蛋白质、游离氨基酸含量以及防御性酶活性的变化。结果表明,绿盲蝽为害后,随着时间的延长,受轻度为害的桃树叶片内可溶性糖含量由28.61 mg/g减少至19.21 mg/g,蛋白质含量由1.29 mg/g先增加至2.01 mg/g,后减少至1.66 mg/g,游离氨基酸含量由0.49 mg/g增加至0.72 mg/g;而受重度为害的叶片内可溶性糖和蛋白质的含量均先减少后增加,游离氨基酸含量则先增加后减少。防御性酶活性随绿盲蝽为害程度的加重也发生了不同程度的变化,随着时间的延长,受轻度为害的叶片内超氧化物歧化酶活性降低,过氧化物酶和过氧化氢酶活性有所升高;而受重度为害的叶片内超氧化物歧化酶活性先降低后升高,过氧化物酶活性升高,过氧化氢酶活性降低。说明不同位置桃树叶片对绿盲蝽的为害胁迫产生了应激反应,通过调整其体内各种防御性物质的含量,对绿盲蝽为害产生诱导抗性,且与为害程度有一定的相关性。     

Wettability of soybean (Glycine max L.) leaves by foliar sprays with respect to developmental changes

BACKGROUND: Leaf wettability considerably defines the degree of retention of water and agrochemical sprays on crop and non‐target plant surfaces. Plant surface structure varies with development therefore the goal was to characterise the wettability of soybean leaf surfaces as a function of growth stage (GS). RESULTS: Adaxial surfaces of leaves developed at GS 16 (BBCH) were 10 times more wettable with water than leaves at the lower canopy (GS 13). By measuring contact angles of a liquid having an intermediate surface tension on different leaf patches, an illustrative wetting profile was elucidated, showing to what degree wetting varies (from > 120° to < 20°) depending on leaf patch and GS. While the critical surface tension of leaf surfaces at different GSs did not correlate with the observed changes, the slope of the Zisman plot accurately represented the increase in wettability of leaves at the upper canopy and lateral shoots (GSs 17 to 19, 21 and 24). The discrimination given by the slopes was even better than that by water contact angles. SEM observations revealed that the low wettability observed at early GSs is mainly due to a dense layer of epicuticular wax crystals. The Zisman plot slope does not represent the changes in leaf roughness (i.e. epicuticular wax deposition), but provides an insight into chemical and compositional surface characteristics at the droplet–leaf interface. CONCLUSIONS: The results with different wettability measurement methods demonstrated that wetting is a feature that characterises each developmental stage of soybean leaves. Positional wettability differences among leaves at the same plant and within the same leaf are relevant for performance, selectivity and plant compatibility of agrochemicals. Implications are discussed. Copyright © 2011 Society of Chemical Industry     

结合药液表面张力与苹果树冠层参数预测喷雾药液用量的方法及应用

为了保证果树精准施药，减少药剂流失，通过4种常用表面活性剂调节药液的表面张力，借助界面张力仪、微重力天平和植物冠层扫描仪等测定手段建立了药液表面张力与苹果叶片最大稳定持液量 (R_m) 之间的关系，并结合果树常用冠层参数，提出了一种预估果树施药液量的方法。结果表明:生长前期苹果叶片近轴面的R_m值明显高于生长后期；在同一生长期，苹果叶片远轴面的R_m值均高于近轴面，且R_m值随叶倾角的增大而减小；生长前期苹果叶片远轴面的R_m值受药液表面张力的影响大于近轴面，但随着叶倾角的增大，叶片近、远轴面的R_m受药液表面张力的影响减小。当药液中表面活性剂的浓度未达到其临界胶束浓度 (cmc) 时，药液的表面张力与苹果叶片的R_m值成正相关关系，由此可建立一元线性回归方程，结合果树平均叶片倾角、叶面积指数和冠层地面投影面积等植物冠层参数，可以估算果树的最大施药液用量。采用4种常用的农药制剂验证了所建方法的实用性。该研究结果可以为苹果园喷雾施药时预估药液用量、减少药剂流失提供理论依据。     

一种农药药液润湿性测试卡的制备及其性能分析

本论文介绍一种农药药液润湿性测试卡的制作,即将指示剂涂布在特定图案的纸卡上,再覆盖一层石蜡.使用时,把液滴加到测试卡上,液滴铺展所到之处发生显色反应,根据显色面积读数,以此判断溶液的润湿性.选用不同浓度有机硅表面活性剂Silwet 408水溶液,对其表面张力,在测试卡上的铺展系数和接触角,在黄瓜、番茄、油菜等6种植物叶片表面的接触角分别进行了测定,初步分析了该测试卡的润湿性能.结果表明,该种测试卡具有与其他自然植物叶片相似的性质.浓度0.003％的Silwet 408水溶液铺展系数为3.3,对应表面张力26.79 mN/m,在小麦表面的接触角66.5°,可见测试卡能反映药液的铺展系数、表面张力、接触角等多种因素,为田间喷雾助剂的选用提供了快速直观的判别工具.     

不同类型界面液滴蒸发特性与农药利用效果研究进展

农药液滴在靶标植物叶片表面的蒸发是农药对靶沉积后的重要过程,也是影响农药利用率和对有害生物防控效果的关键。液滴蒸发过程存在多种模式:接触半径恒定的CCR（Constant contact radius）模式、接触角恒定的CCA（Constant contact angle）模式以及混合模式（Mixed mode）等,不同蒸发模式下液滴的形态变化及蒸发时间均有一定差异。文章综述了液滴在光滑固体界面、人工修饰后具有不同微观结构的粗糙界面以及不同植物界面上的蒸发动力学研究进展。现有研究表明:在光滑固体界面上,液滴蒸发速率随蒸发时间呈线性变化趋势;在不同微观结构修饰后的粗糙界面上,液滴蒸发速率和蒸发模式受固体表面特性的影响;在不同植物界面上,叶片表面的微观结构与组分特性是影响农药液滴在叶片上沉积、持留、铺展及药液渗透过程的重要因素,富含蜡质层以及微纳米结构的叶片,一般不易被农药液滴润湿,液滴铺展面积小,蒸发相对较慢。通过加深对靶标植物叶片表面农药液滴蒸发行为的认知,可以根据有害生物为害特性与有效防控剂量需求,合理调控农药液滴在靶标植物叶面的蒸发时间,同时可为指导农药制剂中表面活性剂的合理应用及提高农药有效利用率提供理论依据。     

Initial Infection and Colonization of Leaves and Stems of Cling Peach by Tranzschelia discolor

ABSTRACT Initial infection processes and the subsequent colonization of leaves and young stems of peach by Tranzschelia discolor were studied. On leaves where multiple disease cycles of peach rust occur during the growing season, urediniospores germinated after 4 h of wetness. Germ tubes became septate and formed appressoria only over leaf stomata beginning 18 h after inoculation. No appressoria, however, formed over stomata of positive replicas of leaf surfaces indicating nonthigmotropic responses of germ tubes. On young, primary-growth stems (ca. 8 weeks old), stomata were mostly closed, less frequent than on leaves, and recessed from the surface of the cuticle of the epidermis. Although appressoria formation was not observed on inoculated stems, germ tube growth of urediniospores was directional toward stomata. Penetration of stem tissue is apparently a less common event that was reflected by a lower occurrence of stem lesions compared with that of leaf lesions in our potted plant inoculation studies and previous field observations. Still, stem lesions are important as sources of primary inoculum each spring and were reproduced in this study for the first time. Fungal colonization of leaves and stems was subepidermal-intercellular and haustoria were commonly found within mesophyll or cortical cells, respectively. No fungal colonization was observed in cambial stem tissue. Vascular tissue was also not colonized and delimited lesions in leaves and stems. Morphological host responses were not observed in infections on either leaves or young stems. In older stems (>32 weeks old), however, the infection was delimited by a wound periderm after uredinial formation. Furthermore, with continued secondary growth, stems recovered and fungal lesions became part of the bark tissue of woody branches. Thus, the fungus must infect primary-growth branches each year to establish stem lesions.     

Peach red marbling and peach sooty ringspot, two new virus-like degenerative diseases of Prunus

More than 600 Prunus samples were examined by using a nonradioactive digoxigenin-labelled RNA probe specific for hop stunt viroid (HSVd). Prunus salicina and Prunus armeniaca appeared to be better hosts than Prunus persica . The weak viroid concentration in flowers and young leaves of peach trees growing in the field did not permit its detection in such samples. The diagnosis was more reliable (about 85%) with bark and leaves aged 4 months and more, from regrowths of GF 305 peach seedlings inoculated and kept in the greenhouse. Detection of HSVd in leaves and bark of apricot and Japanese plum plants aged 3 months or more also proved reliable (about 80% and 90%, respectively). HSVd could be transmitted in apricot, peach and plum nucleic acid preparations to GF 305 peach seedlings by repeated stem slashing, and to cherries ( Prunus avium and Prunus serrulata ) by approach grafting with an infected P. salicina source. The viroid was eliminated from 18% of the clones obtained after thermotherapy.
In the course of this study, 25 selected Prunus accessions suspected to be infected by unusual diseases were analysed by hybridization with a HSVd-specific probe and by indexing on GF 305 peach seedlings in the greenhouse. Fifteen of these accessions were found to be infected by HSVd, 19 induced reddish marbling, and four induced small blackish spots on the leaves aged about 4 months. Repeated assays showed that these foliar symptoms were not caused by the viroid. Peach red marbling (PRMa) has not been associated with any known virus and seems to be caused by an infectious agent not yet described. That could also be the case with the agent of peach sooty ringspot (PSRS). PRMa and PSRS symptoms were reproduced by grafting and indexing, and their causal agents eliminated by thermotherapy in a significant fraction of the treated plants. They behave like viral agents and can infect the different Prunus species studied.