Pathogenicity of Hymenoscyphus fraxineus towards leaves of three European ash species: Fraxinus excelsior,F. angustifolia and F. ornus

This study aimed to demonstrate the association of the ash dieback pathogen Hymenoscyphus fraxineus with leaf symptoms on Fraxinus excelsior and to test its pathogenicity towards leaves of three European ash species, F. excelsior, F. angustifolia and F. ornus, in wound inoculation experiments. On F. excelsior, H. fraxineus was isolated from 94% of leaf rachises with necrotic lesions and from 74% of necrotic leaflet midribs. Following wound inoculation of leaf rachises, in two separate experiments performed in 2010 and 2011, the ash dieback pathogen caused symptoms (necrotic rachis lesions, leaf wilting and premature leaf shedding) on all three ash species, while control leaves remained symptomless. Hymenoscyphus fraxineus was consistently reisolated from fungus‐inoculated rachises. All 10 isolates tested were pathogenic to the three ash species and varied in virulence. Koch's postulates for H. fraxineus as causal agent of leaf symptoms on F. excelsior were fulfilled in this study. Complemented with the isolation of the fungus from naturally infected, symptomatic leaf rachises of F. angustifolia and F. ornus in previous investigations, H. fraxineus was confirmed to be a leaf pathogen of these ash species as well. The leaf inoculation experiments showed that F. excelsior was highly susceptible to H. fraxineus, F. angustifolia was equally or slightly less susceptible, whereas F. ornus was the least affected species; however, F. ornus should also be regarded as a host tree for the ash dieback pathogen. This susceptibility ranking corresponds well with field observations and previous stem inoculation experiments.     

TaULP5 contributes to the compatible interaction of adult plant resistance wheat seedlings-stripe rust pathogen

Adult plant resistance indicates that plant is susceptible to pathogen at seedling stage, but resistant at adult stage. Understanding the mechanism of the interactions between APR wheat plants and Puccinia striiformis f. sp. tritici (Pst) is important for the creation of strategies to improve cultivar disease resistance. In this study, a full-length cDNA was isolated from APR wheat cultivar Xingzi 9104 (XZ), and was designated as ubiquitin-like protein 5 (TaULP5). TaULP5 was likely to be located in the cytoplasm, with a percentage of 75.9% Arabidopsis protoplasts number. The expression of TaULP5 was largely induced in the compatible interaction of wheat seedlings to Pst, while no obvious change was found in the incompatible interaction of wheat adult plants to Pst. Moreover, when TaULP5 was knocked down, the wheat resistance at seedling stage to Pst was improved. In addition, knockdown of TaULP5 increased the expression levels of some biotic stress-related genes, such as PR1 and PR2. It is the first time to confirm that ubiquitin-like protein could contribute to the compatible interaction of XZ to Pst, and the results will lay a foundation for understanding the mechanisms of different interactions between APR wheat plants and Pst at post-translational level.     

香芋全粉喷雾干燥工艺参数研究

以香芋为原料,在单因素试验的基础上,通过正交试验优化香芋全粉喷雾干燥工艺参数,并对包埋剂进行了探讨。结果表明,添加0.01%的黄原胶作为包埋剂可提高出粉率,加速干燥,防止粘壁;香芋全粉喷雾干燥最佳工艺参数为:进料速率51 m L/min,进风温度190℃,料液浓度22%,雾化器转速21 000 r/min,该条件下喷雾干燥效果较好,制得的香芋全粉呈淡紫色,质地光滑,香芋固有气味浓郁,出粉率为15.74%,水分活度0.421,色泽L*值18.41,a*值2.65,b*值3.48,流动性13.9 cm,堆积密度0.46 g/m L。本研究获得的香芋全粉可作为食品配料应用在各类加工食品中。     

根外追肥对银杏光合作用的影响

为解决银杏育苗中土壤养分供应不足导致光合作用差,幼苗生长较弱的问题,试验拟采取根外追肥方式供给银杏养分,提高其光合效率促进生长。以3年生银杏幼苗为试材,设置T1(CK)、T2(0.50%尿素和0.50%过磷酸钙)、T3(0.50%尿素和0.50%磷酸二氢钾)、T4(0.50%尿素、0.50%磷酸二氢钾、0.10%微量元素)4个处理,田间小区试验设计,3次重复。结果表明：银杏不同月份净光合效率不同,追肥种类不同对净光合速率的影响不同,整个试验期间T4处理净光合速率均显著高于对照;根外追肥可以提高银杏叶片的蒸腾速率,T3、T4与对照相比差异显著,T3、T4之间无显著差异;除7月份之外,其余月份T4处理气孔导度始终处于最高值,与对照相比差异显著,其次为T3处理,T2处理对提高银杏气孔导度效果不显著;胞间CO2浓度除7月份之外T4处理均处于最低值,与对照相比差异显著;根外追肥可以影响银杏叶片水分利用效率。综合分析认为,T4处理对提高银杏叶片光合效率效果最佳。     

食用菌原位高值化利用林间低值材效果初探

以湖南省林业科学院院内林荫道杜英修剪枝材、试验林场板栗林间伐、修剪产生的低值材为原料,利用香菇、木耳、灵芝等腐生性食药用菌菌种之不同菌型就地接种上述常规作业剩余物,测定各菌种在三种基质上的生长和产菇情况,结果表明:1用于原位接种林荫道杜英修剪枝、板栗林修剪枝及林间非目的树种泡桐的菌种可选毛木耳、香菇、野生平菇、糙皮侧耳等食用菌品种。2不同菌种不同菌型应用效果有差异。香菇宜选用子弹头菌型,其萌动时间、菌丝布满段木时间和子实体平均发生时间最短,分别为17.2天、45.6天和80.4天,第一批生物学转化率最高,为37.49%。毛木耳、野生平菇可用牙签菌型,子实体平均发生时间分别为85.8天、53.1天,第一批生物学转化率分别为39.58%、32.40%。以树皮封口的方式,牙签菌型的污染率最低。3利用食用菌原位接种板栗枝可达到板栗修枝的目的,节约人工,提高效益。     

高地隙自走式植保机械喷杆系统结构优化与研究

我国植保机械相对国外较落后,存在农药利用率低、劳动强度大及农民中毒现象频发等问题。为此,对高地隙自走式植保机械喷杆系统结构做了简要叙述,并对喷杆展开机构进行了自由度分析计算及运动学理论分析;同时,运用ADAMS仿真软件对喷杆展开机构进行了运动学仿真分析,提出了将液压缸替换为电推杆的优化方案,并对优化后的方案进行了运动学仿真分析。结果表明:优化后的展开性能明显提高,这一改进为自走式植保机械的进一步发展提供了依据。     

高效松材线虫病预防注射药剂配制与林间药效研究

为有效防治松材线虫病,采用阿维菌素和甲维盐为主药,吐温等为表面活性剂,复配混合药剂;同时,模制长喙50 m L容积药瓶,组合成适合向松树注输药物的专用注射针剂,在松材线虫病发生林地开展树干注入药剂抗松材线虫病试验。林间抗松材线虫病试验,采用2种方法进行,即树干注入药剂后作人工接种病原松材线虫和自然感染病原松材线虫;同时,用日本专用松材线虫病预防注射剂作对比试验。结果表明,日本药物(A类药)对人工接种病原松材线虫具有75%的预防效果;自配的阿维菌素(C21类药)和甲维盐(C22类药)对人工接种获得50%和100%的预防效果,使自然感染松材线虫病的松树死亡率平降至2.70%;而对照试验的人工接种病线虫的松树死亡率为100%,自然感染松树死亡率为22.36%。结果表明:试验开发的松树注射剂阿维菌素C21和甲维盐C22,能有效预防松树个体的松材线虫病发生与危害。     

不同品种(系)烟草普通花叶病(TMV)的抗病性鉴定

【目的】筛选地方性优质抗烟草普通花叶病(TMV)烟草种质,为湘中北烤烟抗TMV育种提供优良的种质资源。【方法】采用苗期温室病圃人工接种诱发方法结合大田病圃鉴定,以Coker176为抗病对照、革新3号为中抗对照、G140为感病对照,对9625、金星6007、小黄金0019、401-2、小黄金1025、NGLAUCA、延烟2号等18个烤烟品种(系)进行TMV抗病性鉴定。【结果】在供试品种(系)中,筛选出抗病品种(系)2个,分别为T61和9625,占供试品种(系)总数的11.1%;中抗品种5个,分别为金星6007、03-4-3、胎里黄1061、VESTA33和云烟98,占27.8%;感病品种(系)11个,分别为小黄金0019、401-2、311、小黄金1025、NGLAUCA、延烟2号、大白筋0522、沪金3号、大叶永烟、长脖黄和NC95,占61.1%。【结论】筛选出T61和9625两个抗TMV烤烟品种,可作为湘中北地区抗TMV育种的重要种质资源;同时可在湘中北地区进行T61和9625的示范性推广种植。     

Suppressing Mediterranean fruit fly (Diptera: Tephritidae) with an attract-and-kill device in pome and stone fruit orchards in Western Australia

Attract-and-kill is a possible alternative to the conventional control of Mediterranean fruit fly (medfly), Ceratitis capitata Wiedemann (Diptera: Tephritidae) with bait or cover sprays of organophosphate insecticides. In this study, we determined if an attract-and-kill device (MagMED^®) could be applied alone at the recommended rate (80 devices/ha), or needed to be combined with other conventional control tactics to suppress medfly in deciduous fruit orchards (apple, nectarine, peach, pear, plum). We also determined if attract-and-kill had any detrimental effects on naturally occurring beneficial insects. Based on an acceptable level of crop loss of 2–5% (the level of crop loss growers can tolerate), attract-and-kill suppressed medfly and reduced crop loss below the acceptable level in orchards with additional controls. Attract-and-kill was most effective when combined with either bait spraying, cover spraying or both. Combining attract-and-kill with cover sprays of fenthion resulted in a drop in crop loss of apples from 2.5% to 0.5%. By combining attract-and-kill with weekly bait sprays and two cover spray applications, crop loss fell from 13.7% to 4.3% in peaches, from 6.3% to 5% in nectarines and from 6.3% to 3.7% in pears. Twice weekly bait spraying was the most effective technique at suppressing medfly, providing acceptable control when applied alone, which further improved by combining with attract-and-kill. By combining attract-and-kill with twice weekly bait spraying crop loss fell from 2% to 1% in nectarines and from 4% to 2% in apples. In laboratory trials, attract-and-kill devices killed 100% of brown lacewings (Micromus tasmaniae Walker) and 94% of transverse ladybeetles (Coccinella transversalis Fabricius) 24 h after contact. However, orchard samples suggest that it may not pose any significant negative impact on naturally occurring beneficials such as Neuroptera, Hymenoptera, Coleoptera, Thysanoptera and Syrphidae in the field.     

客土喷播措施中保水剂对紫穗槐光合、蒸腾特性的影响

用Li-6400便携式光合仪,于2008年7月测定不同保水剂用量下紫穗槐的光合速率与蒸腾速率,研究光合速率和蒸腾速率日变化特征及保水剂因子对其产生的影响。结果表明：8种基质条件下的紫穗槐Pn和Tr日变化趋势基本相同,均呈双峰型曲线。Pn双峰值均出现在10：00和16：00,最低值出现在6：00和18：00;Tr第1峰值比Pn峰值推迟,在11：00出现,而Tr第2峰值出现在14：00。不同保水剂含量使紫穗槐的Pn和Tr明显分布在3个水平上,保水剂过少或过多均对植物的Pn和Tr产生负作用,保水剂含量0.15%、0.20%,0.30%是对紫穗槐生长最有利的3个梯度。