水霉属菌(Saprolegnia)分离培养技术研究   总被引：1，自引：0，他引：1  

文冰  郑耘 《植物病理学报》1996,26(3):277-281

 对水霉(Saprolegnia)的分离培养技术进行了探索,筛选出大麻籽、油菜籽、红花籽、苍蝇、蚜虫、小麦粒、玉米片、茶叶、葵花仁9种材料作为诱发水霉菌的诱饵。其中油菜籽能防止腐霉菌(Pythium)污染,是初步纯化菌种、排除杂菌的适宜饵料。同时发现控制温度能使水霉在最短时间内分别产生无性或有性繁殖。在水培条件下,25℃左右适合菌丝及无性器官的发育,有性器官却不能产生,而只有在15~17℃条件下才能使水霉很快进入有性生殖阶段;在加入200mg/L链霉素的CMA培养基上促发有性阶段则需要在25℃左右的温度下进行,方能缩短培养时间。  相似文献   

Infection pressure of potato virus YN     

H. A. Vanhoof 《European journal of plant pathology / European Foundation for Plant Pathology》1979,85(1):31-37

Potato virus Y^N (PVY^N) infection was determined by the tobacco test in Swifterbant (Eastern Flevoland). In plots with beet, wheat and seed potatoes the infection exhibited an identical course. No differences were found either between PVY^N infection in the border and that in the middle of a field planted with ware potatoes, although infection pressure was clearly higher here than in the plot with seed potatoes. A barrier crop of 10 rows of wheat did not decrease the infection pressure of the virus.From August onwards, the spread of PVY^N in Lienden (Betuwe) was followed. Here virus transmission was found continuously, even until mid-November.Potato volunteers outside as well as in potato fields are serious infection sources. In 1976 and in 1977 virus spread was detected before the flight ofMyzus persicae, as determined with yellow Moericke traps. Infection pressure can be measured more efficiently by the tobacco test than by aphid trapping. The effect of rogueing at the time of virus spread should be reconsidered.If infection pressures in different areas or successive years are to be compared, the tobacco test should be standardized. A proposal to this effect is made.Samenvatting In Swifterbant (Oostelijk Flevoland) werd de infectie met het aardappel-Y^N-virus (PVY^N) bepaald met behulp van de tabakstoests. In percelen met bieten, tarwe en pootaardappelen bleek de infectie hetzelfde verloop te hebben. Tussen het infectieverloop van PVY^N in de rand en in het midden van een veld consumptieaardappelen werd eveneens geen verschil gevonden. Wel was de infectiedruk hier duidelijk hoger dan in het pootgoedperceel. Een barrier crop van 10 rijen tarwe verminderde de infectiedruk niet.De volgende conclusies kunnen worden getrokken. Aardappelopslag buiten en in aardappelvelden vormt een zeer belangrijke infectiebron. Zowel in 1976 als in 1977 vond de virusverspreiding plaats vóór de vlucht vanMyzus persicae begon, zoals deze werd bepaald met behulp van de gele Moericke vangbakken. Het effect van opzuiveren ten tijde van de virusverspreiding dient aan een nader onderzoek te worden onderworpen. De infectiedruk kan met de tabakstoets op meer directe wijze worden vastgesteld dan met bladluisvangsten mogelijk is.Wil men overgaan tot het vergelijken van de infectiedruk in verschillende gebieden of in verschillende jaren, dan dient de tabakstoets te worden gestandaardiseerd. Een voorstel hiertoe wordt gedaan.  相似文献   

不同饲养密度对鳝苗的生长性能研究     

包淋斌 《江西水产科技》2014,(4):7-9

本试验以水蚯蚓作为饵料,研究了60日龄鳝苗不同密度下的增重、存活率及饵料转化率。试验分3个密度组,其对应的密度分别为2000尾/m2、3000尾/m2、4000尾/m2,每个密度组设4个平行;试验时间为30d。结果表明:在本试验条件下,3个密度组鳝苗的增重率、存活率随着密度的增大呈下降趋势,而其饵料系数随着密度增大而增大;其中在4000尾/m2的密度下,鳝苗的增重率最低,仅为1.12±0.13;饵料系数最高,为5.71±1.37。  相似文献   

Effects of water‐misting sprays with forced ventilation on post mortem glycolysis,AMP‐activated protein kinase and meat quality of broilers after transport during summer          下载免费PDF全文

Nannan Jiang  Tong Xing  Minyi Han  Shaolin Deng  Xinglian Xu 《Animal Science Journal》2016,87(5):718-728

Effects of water‐misting sprays with forced ventilation on post mortem glycolysis, adenosine monophosphate‐activated protein kinase (AMPK) and meat quality of broilers after transport during summer were investigated in the present paper. A total of 105 mixed‐sex Arbor Acres broilers were divided into three treatment groups: (i) 45 min transport without rest (T); (ii) 45 min transport with 1 h rest (TR); and (iii) 45 min transport with 15 min water‐misting sprays with forced ventilation and 45 min rest (TWFR). Each treatment consisted of five replicates with seven birds each. The results indicated that the water‐misting sprays with forced ventilation could mitigate the stress caused by transport under high temperature conditions during summer, which reduced the energy depletion in post mortem Pectoralis major (PM) muscle. This resulted in a higher energy status compared to the T group, which would decrease the expression of phosphorylation of AMPK (p‐AMPK). Furthermore, decreased the expression of p‐AMPK then slowed down the rate of glycolysis in post mortem PM muscle during the early post mortem period, which in turn lessened the negative effects caused by transport on meat quality. In conclusion, water‐misting sprays with forced ventilation may be a better method to control the incidence of the pale, soft and exudative meat in broilers.  相似文献   

Effect of Preharvest Sprays of Calcium on Cracking and ‘Schattenmorelle’ Sour Cherry Fruit Quality Harvested Mechanically     

Paweł Wójcik  Paweł Wawrzyńczak 《Journal of plant nutrition》2014,37(9):1487-1497

The aim of the study was to examine effect of preharvest sprays of calcium (Ca) in the form of Ca-chloride (CaCl₂), Ca-nitrate [Ca(NO₃)₂], or a mixture of Ca-formate, Ca-acetate, CaCl₂, and Ca(NO₃)₂ on cracking and quality of ‘Schattenmorelle’ sour cherry fruit harvested mechanically. The experiment was conducted in 2008–2009 at a commercial orchard in central Poland. Mature trees grew on a coarse-textured soil poor in organic matter, at a spacing of 4.0 × 1.5 m. The spray treatments of Ca were performed at 7-day intervals, starting 28 days before harvest, at the rates of 5.0–5.6 kg Ca ha^?1 per season. The trees sprayed with water were treated as the control. Fruit were harvested mechanically when peduncle-fruit detachment force dropped below 3 N. The results showed that preharvest Ca sprays caused no leaf damage. This measure did not affect yield, mean fruit weight, soluble solids concentration and titratable acidity of fruit, and weight loss of fruit during 24 h after harvest. Fruit sprayed with Ca had improved status of this nutrient, and were less liable to juicy leakage from the stem scar, rain-induced cracking, and preharvest decay caused by Glomerella cingulata. The above effects of Ca sprays did not depend on the tested material. It was concluded that preharvest sprays of Ca as CaCl₂ and/or Ca(NO₃)₂ should be recommended in ‘Schattenmorelle’ sour cherry orchards to reduce fruit losses resulting from rain-induced cracking, leakage of juice, and the incidence of cherry bitter rot.  相似文献   

孕穗期叶面喷素对小麦穗粒数和粒重的影响     

田艳云  张国钊  郑春风  段建钊  秦一凡  朱云集  赵丽  杨家蘅 《麦类作物学报》2016,36(7):919-924

为探讨孕穗期叶面喷素对小麦穗粒数和粒重的调控效应,于2014-2015年在河南农业大学科教示范园区进行试验,以半冬性品种豫麦49-198为供试材料,在小麦拔节后25d(4月6号),以清水为对照,叶面分别喷施硼砂(B)、6苄基腺嘌呤(6-BA)、6-BA+B、奇善宝(QSB)、双增1号(CPD),对不同喷素条件下小花败育速率和籽粒灌浆进程及其成熟后小麦穗部性状进行观察和分析。结果表明,与对照相比,不同喷素处理均能降低小花的败育速率,显著增加小麦不同部位的小穗粒数和粒重。对小麦各部位小穗粒数的促进效果,以CPD处理对小麦下、中部小穗粒数提高幅度最大,分别较对照增加了1.95个和4.85个;对不同部位小穗粒重的促进效果,也以CPD处理效果最佳,使小麦下、中和上部小穗粒重分别较对照提高了11.97%、5.87%和9.32%。  相似文献   

<Emphasis Type="Italic">Spongospora subterranea</Emphasis> soil contamination and its relationship to severity of powdery scab on potatoes     

Takato Nakayama  Mitsuo Horita  Tadayuki Shimanuki 《Journal of General Plant Pathology》2007,73(4):229-234

We investigated soil contamination by Spongospora subterranea f. sp. subterranea (Sss) and disease severity of powdery scab in 29 potato fields in Hokkaido, Japan, using a hydroponic culture method with tomato seedlings as bait plants. The quantity of Sss infection on the roots of bait plants was evaluated using the polymerase chain reaction (PCR) and expressed in terms of the infection potential in the soil. The infection potential was positively correlated with the disease severity of harvested tubers, whereas the spore ball density determined using PCR had an indistinct relationship with disease severity. The infection potential can be useful in evaluating soil contamination and in applying countermeasures against powdery scab.  相似文献   

利用诱饵树防治桑天牛的研究   总被引：6，自引：1，他引：6  

张贤开  雷永春 《林业科学》1992,28(5):466-470

湖南省洞庭湖区的欧美杨、黑杨林,从苗期至成林都不同程度地受到桑天牛(Apriona germari)为害,轻则生长受抑,重则死亡,为此,我们根据桑天牛成虫具有补充营养的特性,于1985—1988年在广州军区南湾湖农场,开展了以诱饵树招引诱杀桑天牛成虫的大面积试验工作。一、研究方法及结果 (一)成虫补充营养与产卵量及寿命的关系(见表1)。  相似文献   

无公害灭鼠剂克鼠星在陕西退耕还林中的应用效果     

王明春  韩崇选  宗德禄  张宏利  杨清娥 《安徽农业科学》2007,35(36):11891-11893

[目的]探讨无公害灭鼠剂克鼠星对退耕还林地鼠害的防治效果。[方法]于2000～2004年在陕西省吴旗、甘泉、千阳、麟游、永寿和淳化6县,采用无公害灭鼠剂克鼠星对退耕还林地鼠害进行防治推广试验。[结果]在鼠害严重的造林地,造林前用克鼠星防治1次,造林后再用克鼠星防治1次,平均造林成活率达到97.1%,造林后2年平均保存率达到95.3%,分别比对照提高18.4%和28.5%。果树由于立地条件较好,鼠害防治彻底,2年保存率达到97.3%。应用灭鼠剂克鼠星1号进行鼢鼠防治,春季和秋季的防治效果均在89.4%以上,对达乌尔鼠兔的防治率均在84.7%以上。[结论]灭鼠剂克鼠星的研制与应用,杀灭了害鼠,同时保护了天敌,在农林牧业鼠害的防治方面,具有广阔的应用前景。  相似文献   

喷焊余温淬火改善深松铲尖铁基涂层耐磨性   总被引：4，自引：4，他引：0  

赵建国  李建昌  王安  马璐萍  郝建军  张晋国  马跃进 《农业工程学报》2018,34(3):65-71

针对深松铲尖耐磨性能差、失效频繁等问题,采用火焰喷焊技术在45钢基体上制备了铁基合金涂层,并利用喷焊后试件余温对其进行了淬火处理。利用扫描电镜、能谱仪、X射线仪分析了涂层显微组织、元素构成及物相组成,利用显微硬度计、磨损试验机测试了涂层显微硬度及磨损性能。结果表明,涂层与基体呈良好冶金结合,淬火涂层主要由碳化物Cr_(23)C_6、Cr_7C_3,硼化物Fe_2B,复合相(Cr,Fe)_7C_3以及固溶体γ-Fe(Cr,Ni,C,Si)等组成。与未淬火涂层相比,组织得到细化,涂层显微硬度平均为800 HV左右,较未淬火涂层提高了约100 HV。淬火涂层试件(45钢基体)和未淬火涂层试件(45钢基体)平均磨损质量分别为0.30和0.35 g;田间试验的涂层淬火深松铲尖(65Mn基体)磨损质量为32 g,无涂层65Mn铲尖为70 g,涂层深松铲尖具有较好的耐磨性,该研究可为延长深松铲尖使用寿命提供参考。  相似文献